You have twisted your ankle and need to apply a cold pack. You squeeze the bag and as the chemical reaction occurs, you can feel that the pack is getting colder. How would you classify this type of reaction? Using what you understand from our lessons in unit 4, explain how the heat transfers between the cold pack and your skin? Also, describe how the law of conservation of energy applies to this system
The type of reaction that occurs when you squeeze a cold pack is an exothermic reaction. An exothermic reaction is a chemical reaction that releases energy in the form of heat or light. In this case, the reaction between the chemicals inside the cold pack releases heat, which is transferred to your skin when you apply the pack.
The heat transfer between the cold pack and your skin occurs through conduction. Conduction is the transfer of heat between objects that are in direct contact with each other. When you apply the cold pack to your skin, the heat from your skin is transferred to the cold pack through conduction. As the heat is transferred, the cold pack gets warmer and your skin gets cooler.
The law of conservation of energy applies to this system because energy cannot be created or destroyed, only transferred from one form to another. In this case, the chemical reaction inside the cold pack releases energy in the form of heat, which is transferred to your skin through conduction. As the heat is transferred, the temperature of the cold pack decreases, while the temperature of your skin decreases. However, the total amount of energy in the system remains constant.
In summary, when you apply a cold pack to a twisted ankle, the chemical reaction that occurs is an exothermic reaction. The heat transfer between the cold pack and your skin occurs through conduction, and the law of conservation of energy applies to the system as the total amount of energy remains constant.
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What is the pH of a solution where [OH⁻]=0. 00030M
The pH of the solution where [tex][OH⁻][/tex]=0.00030 M is 11.48. This indicates that the solution is basic, or alkaline, since the pH is greater than 7.
To determine the pH of a solution where[tex][OH⁻][/tex]=0.00030 M, we can use the relationship between the concentrations of hydrogen ions and hydroxide ions in water, which is defined by the equation[tex]Kw = [H⁺][OH⁻].[/tex]At 25°C, the value of Kw is [tex]1.0 x 10^-14[/tex].
If we substitute the concentration of hydroxide ions given in the question ([tex][OH⁻][/tex]=0.00030 M) into this equation, we can solve for the concentration of hydrogen ions:
[tex]Kw = [H⁺][OH⁻]\\1.0 x 10^-14 = H⁺\\[H⁺] = 3.3 x 10^-12 M[/tex]
Now that we know the concentration of hydrogen ions, we can use the formula for pH, which is defined as [tex]pH = -log[H⁺][/tex], to find the pH of the solution:
[tex]pH = -log(3.3 x 10^-12)[/tex]
pH = 11.48
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Based on the electron configuration of the two
atoms, predict the ratio of metal cationic (+) atom
to nonmetal anionic (-) atom in the compound.
magnesium 1s22s22p63s2
sulfur 1s22s22p3s23p4
a. 1:1
b. 1:2
c. 2:1
d. 3:1
Answer is B) 1:2
The electron configuration of magnesium is 1s2 2s2 2p6 3s2, which means it has two valence electrons that it can lose to form a cation with a +2 charge.
The electron configuration of sulfur is 1s2 2s2 2p6 3s2 3p4, which means it has six valence electrons that it can gain to form an anion with a -2 charge.
Since magnesium can form a cation with a +2 charge and sulfur can form an anion with a -2 charge, the ratio of metal cationic (+) atom to nonmetal anionic (-) atom in the compound will be 1:2. Therefore, the answer is b. 1:2.
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Identify each substance based on its description. jake collected samples of two substances while he was out walking. after taking the samples home, he ran tests and found that one substance is slippery and conducts electricity in water. these properties made jake conclude that the substance is probably . the other substance continuously made bubbles of hydrogen gas when jake dropped magnesium into an aqueous solution of the substance. jake concluded that the second substance is probably .
The first substance that Jake collected is likely a base. The slippery feel is a common characteristic of bases, and the ability to conduct electricity in water indicates the presence of ions (typically hydroxide ions, OH-) which are formed when the base dissolves in water.
The second substance that Jake collected is likely an acid. The formation of hydrogen gas when magnesium is added to an acid is a common characteristic of acids. The reaction can be written as:
Mg + 2HCl → MgCl2 + H2
where HCl represents hydrochloric acid. The production of hydrogen gas indicates the presence of H+ ions, which are characteristic of acids.
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What's the theoretical yield of oxygen from the oxides present in 1. 00 kg sample of lunar soil?
The theoretical yield of oxygen from the oxides present in a 1.00 kg sample of lunar soil will depend on the composition of the soil. However, we can make some assumptions based on the known composition of lunar soil.
Lunar soil is known to contain various oxides, including silicon dioxide (SiO2), aluminum oxide (Al2O3), iron oxide (FeO and Fe2O3), titanium dioxide (TiO2), and others. These oxides can be chemically processed to release oxygen gas.
The stoichiometry of the chemical reactions involved will depend on the specific oxides present in the soil. However, for the purposes of estimation, we can assume that all the oxides present in the soil are converted to their respective metals and oxygen gas.
For example, the reaction for the conversion of silicon dioxide to silicon metal and oxygen gas is:
SiO2(s) + 2 C(s) → Si(s) + 2 CO(g)
From this reaction, we can see that for every 1 mole of SiO2, 1 mole of oxygen gas is produced. The molar mass of SiO2 is 60.08 g/mol, so in a 1.00 kg sample of lunar soil, there are:
1000 g / 60.08 g/mol = 16.65 moles of SiO2
Therefore, the theoretical yield of oxygen gas from the SiO2 present in the soil is:
16.65 moles of O2 (since 1 mole of SiO2 produces 1 mole of O2)
Similarly, we can calculate the theoretical yield of oxygen gas from the other oxides present in the soil using their respective stoichiometric equations. Adding up the oxygen yields from each oxide will give us the total theoretical yield of oxygen from the soil.
Note that the actual yield of oxygen will likely be less than the theoretical yield due to inefficiencies and losses during the processing of the soil.
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An object in motion stays in motion and an object at rest stays at rest until ?
An object in motion will continue to move at a constant velocity unless acted upon by an external force. This principle is known as Newton's First Law of Motion, also referred to as the law of inertia.
Inertia is the tendency of an object to resist changes in its state of motion.
Similarly, an object at rest will remain at rest unless acted upon by an external force. This means that if an object is not moving, it will continue to stay still until a force is applied to it.
Newton's First Law of Motion is a fundamental concept in physics that explains how objects behave when in motion or at rest. It is important to understand this law because it helps us to predict how objects will move and interact with each other.
Additionally, it is also essential in the design and engineering of machines and structures that require a thorough understanding of motion and force.
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When 10 liters of a gas at 1 atm is compressed to 3 liters at constant temperature, what property of the gas changes?
O The number of moles of gas decreases.
The mass of the gas increases.
The pressure of the gas increases.
The size of the gas particles decreases.
The pressure of the gas increases.
When 10 liters of a gas at 1 atm is compressed to 3 liters at constant temperature, the property of the gas that changes is the pressure of the gas increases. This is due to the fact that the volume of the gas has decreased while the number of gas particles remains constant. As the particles are now confined to a smaller space, they collide more frequently with the walls of the container, resulting in an increase in pressure.
The number of moles of gas and the mass of the gas remain constant because the compression occurs at a constant temperature, indicating that there is no change in the amount of gas particles. The size of the gas particles does not change either, as this is a property of the gas molecules themselves and is not influenced by external factors like pressure or temperature.
In summary, when a gas is compressed at a constant temperature, the pressure of the gas increases due to the decrease in volume. This relationship is described by Boyle's Law, which states that the pressure and volume of a gas are inversely proportional to each other at a constant temperature.
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A device plugged into a 110-volt line produces 0. 50 amperes of current. The device is left on for 8. 0 hours. Find the cost of electricity if the power company charges 8 cents per kWh
The cost of electricity for the device left on for 8.0 hours is 3.52 cents.
To find the cost of electricity for the device, first, we need to calculate the power consumption, then the total energy consumed, and finally the cost.
1. Calculate the power consumption:
Power (P) = Voltage (V) x Current (I)
P = 110 volts x 0.50 amperes = 55 watts
2. Calculate the total energy consumed:
Energy (E) = Power (P) x Time (t)
E = 55 watts x 8.0 hours = 440 watt-hours = 0.44 kilowatt-hours (kWh)
3. Calculate the cost:
Cost = Energy (E) x Rate
Cost = 0.44 kWh x 8 cents/kWh = 3.52 cents
The cost of electricity for the device left on for 8.0 hours is 3.52 cents.
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A 0. 15 M solution of an unknown acid with the formula H2X is tested. What concentration of [H + ] in the water would indicate a strong acid?
A concentration of 0.30 M [[tex]H^{+}[/tex]] in the water would indicate a strong acid for the given solution of [tex]H_{2} X[/tex].
A strong acid is one that completely dissociates in water, meaning it donates all of its hydrogen ions ([tex]H^{+}[/tex]) to the solution.
For the given acid, [tex]H_{2} X[/tex], the dissociation equation would be:
[tex]H_{2} X[/tex] → 2[tex]H^{+}[/tex] + [tex]X^{2-}[/tex]
Since it's a strong acid, we assume that all molecules will dissociate, resulting in two moles of [tex]H^{+}[/tex] for every mole of [tex]H_{2} X[/tex]. Therefore, to calculate the concentration of [[tex]H^{+}[/tex]] in the solution:
[[tex]H^{+}[/tex]] = 2 × (concentration of [tex]H_{2} X[/tex])
Given the concentration of [tex]H_{2} X[/tex] is 0.15 M:
[[tex]H^{+}[/tex]] = 2 × 0.15 M
[[tex]H^{+}[/tex]] = 0.30 M
So, a concentration of 0.30 M [[tex]H^{+}[/tex]] in the water would indicate a strong acid for the given solution of [tex]H_{2} X[/tex].
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A hydorcarbon cxhy has mass ratio between hydorgen and carbon 1:10. 5. One litre of the hydrogen at 127c and 1 atm pressure weighs 2. 8 g,find the molecular formula of the hydrocarbon
Rounded to the nearest whole number, y is 42. Therefore, the molecular formula of the hydrocarbon is C4H42.
To find the molecular formula of the hydrocarbon, we first need to determine the molecular weight. We know that the mass ratio between hydrogen and carbon is 1:10, which means that for every 1 gram of hydrogen, there are 10 grams of carbon in the molecule.
Let's assume that we have x number of carbon atoms and y number of hydrogen atoms in the molecule. The molecular weight can then be expressed as:
Molecular weight = (x x atomic weight of carbon) + (y x atomic weight of hydrogen)
Since the mass ratio between hydrogen and carbon is 1:10, we can write:
y = 10x
Now, we can substitute y in the equation for molecular weight:
Molecular weight = (x x atomic weight of carbon) + (10x x atomic weight of hydrogen)
Molecular weight = x(atomic weight of carbon + 10 x atomic weight of hydrogen)
We also know that one liter of hydrogen at 127°C and 1 atm pressure weighs 2.8 g. Using the ideal gas law, we can calculate the number of moles of hydrogen in one liter:
PV = nRT
n = PV/RT
n = (1 atm x 1 L) / (0.0821 L.atm/mol.K x 400 K)
n = 0.0305 mol
The molecular weight of the hydrocarbon can be calculated as follows:
Molecular weight = 2.8 g / 0.0305 mol
Molecular weight = 91.80 g/mol
Now, we can solve for x in the equation for molecular weight:
91.80 g/mol = x(12.01 g/mol + 10 x 1.01 g/mol)
91.80 g/mol = 12.01x + 10.10x
91.80 g/mol = 22.11x
x = 4.15
Since x represents the number of carbon atoms in the molecule, we can round it to the nearest whole number, which is 4. Similarly, y can be calculated as:
y = 10x = 41.5
Rounded to the nearest whole number, y is 42. Therefore, the molecular formula of the hydrocarbon is C4H42.
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g why does the addition of ammonia increase the solubility of the slightly soluble salt agcl? group of answer choices ammonia forms a very soluble complex ion by coordinating to ag and removing it from the solution. this shifts the solubility equilibrium to the right. ammonia reacts with chloride ion, removing it from solution and shifting the solubility equilibrium to the right. ammonia breaks down into hydrogen gas and nitrogen gas, which react with the solid agcl and make it more soluble. ammonia is a lewis acid, which reacts with the chloride lewis base and makes the solid more soluble. ammonia surrounds the agcl molecules and pulls them into solution making them more soluble.
The addition of ammonia increase the solubility of slightly soluble salt AgCl as : ammonia forms very soluble complex ion by coordinating to Ag and removing it from solution. This shifts the solubility equilibrium to right.
Why does the addition of ammonia increase solubility of slightly soluble salt AgCl?When ammonia (NH₃) is added to a solution containing AgCl, it can coordinate with silver ions (Ag+) to form a complex ion called [Ag(NH₃)₂]+, which is highly soluble in water. This complex ion removes the Ag+ ions from the solution, thereby decreasing the concentration of Ag+ in the solution. According to Le Chatelier's principle, this will shift the equilibrium of AgCl dissolution reaction to the right, resulting in increase in the solubility of AgCl.
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A student burns 20 grams of methane in the presence of excess oxygen to produce 43 grams of
water according to the equation below.
CH4 +20₂→ CO₂ + 2H₂O
What is the theoretical yield of the reaction? Did the reaction produce as much as expected
based on calculations? Why might we have collected less that we would expect to produce with
this reaction?
Answer with at least 3 complete sentences.
The reaction did not produce as much as expected based on the theoretical yield. However, the percentage yield can be calculated by dividing the actual yield by the theoretical yield and multiplying by 100, which gives a value of 53.75%.
According to the balanced equation, the theoretical yield of water produced from the combustion of 20 grams of methane is 80 grams. This is calculated by first finding the moles of methane used (20g / 16.04 g/mol = 1.247 mol) and then using the stoichiometric ratio to determine the moles of water produced (2 moles of H2O for every 1 mole of CH4), which gives 2.494 mol of water. Finally, converting the moles of water to grams gives a theoretical yield of 80 grams.
However, the actual yield of water obtained from the reaction was only 43 grams, which is significantly less than the theoretical yield. This could be due to a variety of reasons, such as incomplete combustion of methane, loss of product during collection or transfer, or errors in measurement or calculation.
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Which of the following is an example of a plant or animal depending on a nonliving thing in its habitat?
A.
Grass depends on lions eating zebras so the zebras don't eat all the grass.
B.
Zebras depend on soil to grow grass, which the zebras eat.
C.
Lions depend on zebras as a source of food.
D.
Lions depend on grass to feed zebras, which the lions eat for food.
Answer:D
Explanation: Lions depend on grass to keep zebras well fed, since lions are carnivores, lions eat zebras. Thus, lions depend on the non living environmental food to nourish the zebras
If a piece of aluminum has a heat capacity of 314 j/°c, how much will its temperature rise when it absorbs 8,291 j of heat?
We can use the formula Q = mcΔT to solve this problem, where Q is the amount of heat absorbed by the aluminum, m is the mass of the aluminum, c is its specific heat capacity, and ΔT is the change in temperature.
However, since we are not given the mass of the aluminum, we cannot solve for ΔT directly using this formula.
Instead, we can use the fact that the specific heat capacity of aluminum is given as 314 j/°c, which means that it takes 314 j of heat to raise the temperature of 1 gram of aluminum by 1 degree Celsius.
To find the mass of the aluminum, we can divide the total amount of heat absorbed by the specific heat capacity of aluminum:
m = Q / (c * ΔT)
Solving for ΔT, we get:
ΔT = Q / (m * c)
Substituting the given values, we have:
ΔT = 8,291 j / (m * 314 j/°c)
We need to find the value of ΔT, so we still need to solve for m. Without additional information, we cannot do so directly.
Therefore, we cannot provide a numerical answer to this problem without knowing the mass of the aluminum.
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What volume (mL) of concentrated H3PO4 (14. 7 M) should be used to prepare 125 mL of a 3. 00 M H3PO4 solution?
You should use about 25.51 mL of concentrated H3PO4 to prepare 125 mL of a 3.00 M H3PO4 solution.
To prepare 125 mL of a 3.00 M H3PO4 solution using concentrated H3PO4 (14.7 M), you can use the dilution formula:
M1 × V1 = M2 × V2
Where M1 is the initial molarity (14.7 M), V1 is the volume of the concentrated solution needed, M2 is the final molarity (3.00 M), and V2 is the final volume (125 mL).
Rearrange the formula to solve for V1:
V1 = (M2 × V2) / M1
V1 = (3.00 M × 125 mL) / 14.7 M
V1 ≈ 25.51 mL
Therefore, you should use approximately 25.51 mL of concentrated H3PO4 to prepare 125 mL of a 3.00 M H3PO4 solution.
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You are asked to make a 1. 5 L solution of. 35 M HCl by diluting concentrated 16. 0 M HCI. What
volume of acid would be needed to make the dilution?
To make a 1.5 L solution of 0.35 M HCl using 16.0 M HCl, you will need 32.81 mL of concentrated acid.
1. Use the dilution formula: M1V1 = M2V2
2. M1 is the initial concentration (16.0 M), V1 is the volume of concentrated acid needed, M2 is the final concentration (0.35 M), and V2 is the final volume (1.5 L).
3. Plug in the values: (16.0 M)(V1) = (0.35 M)(1.5 L)
4. Solve for V1: V1 = (0.35 M)(1.5 L) / 16.0 M
5. V1 = 0.0328125 L, which is equal to 32.81 mL.
6. So, 32.81 mL of concentrated 16.0 M HCl is needed to make the 1.5 L solution of 0.35 M HCl.
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Identify a problem of human impact on the environment that could be solved through designing a device or process. A. Define the problem. B. Identify who would be helped by solving this problem. C. List the criteria and constraints of the problem. D. Brainstorm at least two possible solutions to the problem
One of the biggest problems of human impact on the environment is the excessive use of non-renewable resources, such as fossil fuels, which release harmful gases and contribute to climate change.
This problem can be solved by designing a device or process that can harness renewable energy sources, such as solar or wind power, and provide a sustainable alternative to traditional energy sources.
By solving this problem, not only will the environment benefit from reduced carbon emissions, but also the people who rely on these resources. For instance, communities that are vulnerable to the effects of climate change, such as extreme weather conditions, will be better equipped to adapt and withstand these impacts.
The criteria and constraints of designing such a device or process would include factors such as cost, efficiency, scalability, and environmental impact. The solution would need to be cost-effective and efficient, while also being able to provide a significant amount of energy to meet the needs of communities.
Additionally, it would need to be environmentally friendly and have minimal negative impact on ecosystems.
One possible solution could be the development of solar-powered devices that can be used in homes, schools, and businesses to generate electricity. Another solution could be the installation of wind turbines in areas with high wind speeds to generate energy on a larger scale.
Overall, by designing devices or processes that harness renewable energy sources, we can mitigate the negative impacts of non-renewable energy sources on the environment and provide sustainable alternatives for the benefit of both the environment and society.
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Write a balanced equation for the
reaction between baking soda (NaHCO3) and HCl.
Answer:
NaHCO3 + HCl → NaCl + H2O + CO2
Explanation:
Part A
Predict the sign of the entropy change, ΔS∘, for each of the reaction displayed.
Drag the appropriate items to their respective bins.
Help
Reset
Ag+(aq)+Cl−(aq)→AgCl(s)
2KClO3(s)→2KCl(s)+3O2(g)
2N2O(g)→2N2(g)+O2(g)
2Mg(s)+O2(g)→2MgO(s)
C7H16(g)+11O2(g)→7CO2(g)+8H2O(g)
H2O(l)→H2O(g)
Positive
Negative
SubmitHintsMy AnswersGive UpReview Part
Part B
Calculate the standard entropy change for the reaction
2Mg(s)+O2(g)→2MgO(s)
using the data from the following table:
Substance ΔH∘f (kJ/mol) ΔG∘f (kJ/mol) S∘ [J/(K⋅mol)]
Mg(s) 0.00 0.00 32.70
O2(g) 0.00 0.00 205.0
MgO(s) -602.0 -569.6 27.00
Express your answer to four significant figures and include the appropriate units.
ΔS∘ =
The standard entropy change for the reaction [tex]2Mg(s)+O_2(g)\rightarrow 2MgO(s)[/tex] is -405.6 J/(K⋅mol).
What is entropy ?Entropy is a measure of the randomness or disorder in a system. It is a thermodynamic property that can be used to measure the amount of energy that is unavailable for work in a thermodynamic process. Entropy is closely related to the second law of thermodynamics and can be used to assess the direction of a thermodynamic process. Entropy is also a measure of the amount of information contained in a system. High entropy systems have more randomness and disorder, while low entropy systems have less.
The entropy change for the reaction [tex]2Mg(s)+O_2(g) \rightarrow 2MgO(s)[/tex] is calculated using the following equation: [tex]\Delta S^\circ = \Sigma S^\circ products -\Sigma S^\circ reactants[/tex]
Substituting the values from the table:
[tex]\Delta S^\circ = (2 \times 27.00 J/(Kmol)) - (32.70 J/(Kmol) + 205.0 J/(Kmol))\\\Delta S^\circ = -405.6 J/(Kmol) .[/tex]
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A student finds the mass and volume of four mystery liquids. The data is provided
The student's task is to determine the density of the four mystery liquids using the mass and volume measurements.
Density is a physical property that describes the amount of mass per unit volume.
The formula for density is density = mass/volume. Once the density of each liquid is determined, the student can compare it to known densities of different substances to identify the liquid.
This information can be useful in various fields such as chemistry, pharmacology, and environmental science.
The student may also use this data to calculate other properties of the liquids such as viscosity, surface tension, and boiling point. Overall, measuring mass and volume is a fundamental method in scientific research and analysis.
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4
A local pet store expands and begins selling exotic organisms. The exotic organisms are
easy to care for when they are younger, but become very difficult to control as they get
older. The owners often decide to release their new pets into the local environment
rather than continue to care for them. The released animals do not have any natural
enemies and their population expands unchecked. How will this affect the biodiversity of
the ecosystem?
F
It introduces an invasive species, which will increase the biodiversity of the
ecosystem.
It introduces an invasive species, which will decrease the biodiversity of the
G
ecosystem.
H It introduces a native species which will not affect the biodiversity of the ecosystem.
It reintroduces a native species, which will decrease the biodiversity of the
ecosystem.
The scenario described in the question is an example of the negative impact that can result from introducing exotic organisms into an ecosystem.
Exotic organisms, also known as invasive species, are non-native species that are introduced to an ecosystem and can outcompete native species, disrupt natural ecological processes, and cause harm to the environment and economy.
When the exotic organisms are released into the local environment, they have no natural predators, and their population can increase unchecked, causing a decrease in biodiversity.
This is because the invasive species may outcompete and displace native species, reduce the availability of resources, and alter the habitat. The result is a homogenization of the ecosystem, where there are fewer different types of species and less overall diversity.
In summary, introducing exotic organisms can have a negative impact on biodiversity in an ecosystem, which can have cascading effects on the health and stability of the ecosystem. It is important to carefully manage and monitor the introduction of exotic organisms to prevent these negative impacts.
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Calculate the ph of a buffered solution prepared by dissolving 21.5 g benzoic acid and 37.7 g sodium benzoate
The pH of the buffered solution is approximately 4.48.
The Henderson-Hasselbalch equation, which connects the pH of a buffered solution to the acid's pKa and the full concentrations of both the acid and its conjugate base as given by the situation, can then be used.
pH = pKa + log([conjugate base]/[acid])
In order to determine the pH of a buffered solution made by combining 21.5 g of benzoic acid ([tex]C_7H_6O_2[/tex]) and 37.7 g of sodium benzoate ([tex]NaC_7H_5O_2[/tex]) in water, we first need to figure out the buffer system's equilibrium constant (Ka). The benzoic acid's Ka value is [tex]6.3 * 10^{-5}[/tex].
Substituting the values into the Henderson-Hasselbalch equation:
[tex]pH = pKa + log([NaC_7H_5O_2]/[C_7H_6O_2]) \\pH = 4.2 + log(37.7/21.5)[/tex]
pH = 4.2 + 0.28
pH = 4.48
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An ancient gold medallion absorbs 576 J of energy when it is heated, this causes a temperature change of 25. 0 C. What is the mass of the gold medallion?
The mass of the ancient gold medallion is 360 grams.
To calculate the mass of the gold medallion, we need to use the specific heat capacity of gold, which is 0.129 J/g°C. We also need to know the initial temperature of the medallion.
Let's assume the initial temperature of the gold medallion is 20.0°C (room temperature). The heat absorbed by the gold medallion can be calculated using the following formula:
Q = m * c * ΔT
Substituting the given values, we get:
576 J = m * 0.129 J/g°C * 25.0°C
Solving for m, we get:
m = 360 g
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Generally, what is the effect of increased temperature on the rate of dissolution of a solid solute?
A.
Increased temperature increases the rate.
B.
Increased temperature decreases the rate.
C.
Increased temperature has no effect on the rate.
D.
There is no way to tell
The effect of increased temperature on the rate of dissolution of a solid solute is; Increased temperature increases the rate of dissolution of a solid solute. Option A is correct.
This is because at higher temperatures, the kinetic energy of the solvent molecules increases, leading to more frequent and more energetic collisions with the solute particles. This increased kinetic energy can overcome the intermolecular forces holding the solute together, leading to more rapid dissolution.
The rate of dissolution refers to how quickly a solute dissolves in a solvent to form a homogeneous solution. It is usually expressed as the amount of solute that dissolves per unit time, typically in grams per second or moles per minute.
Hence, A. is the correct option.
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Find the hydroxide concentration of a lioh soultion that has a poh of 4.80.
[oh] = (round to 2 decimal places)
The hydroxide concentration of the LiOH solution is 0.000016 M.
We know that:
pOH = -log[OH-]
We can rearrange this equation to solve for [OH-]:
[OH-] = 10^(-pOH)
Substituting the given pOH value of 4.80, we get:
[OH-] = 10^(-4.80)
[OH-] = 1.58 × 10^(-5)
Rounding to two decimal places, the hydroxide concentration of the LiOH solution is:
[OH-] = 0.000016 (rounded to two decimal places)
Therefore, the hydroxide concentration of the LiOH solution is 0.000016 M.
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HEAT
INTRODUCTION
Heat is a measure of the energy in a system. The transfer of energy is always from the system with more energy to the system with less energy. This lab has two distinct parts. In the first part, you will examine what happens to a gas when the temperature is changed. In the second part, you will use the idea of energy transfer to move water. You will need to be familiar with the ideas of phases (solid, liquid and gas), what specific heat is, and how to calculate joules. Please see pages 93-94, 99-101, and 106-110 in your textbook.
MATERIALS
1 small mouth (or small neck) bottle… a soda bottle should work
1 coin (dime or penny – must cover completely mouth of bottle)
1 large container to submerge at least ½ the bottle (sink, tub, bowl, etc.)
Enough cold water to submerge ½ the bottle
Measuring cups
Food coloring – in kit
4 cups water
1 large bowl to hold water – a clear glass one works best
1 small glass that will extend above water level when in bowl
Saran wrap/cling film – enough to cover bowl
1 small object (example: pebble, coin, marble)
Sunny days (3-4)
Lab 11 - Heat
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PART#1: Magic Coin?
Procedure:
Fill selected container with some cold water.
Place the bottle and coin in the bowl of water to chill them. The bottle must be submerged upside down. Submerge at least the neck of the bottle but if you have no “coin activity” on step four, repeat this step with either a greater amount of submersion or submerge the bottle for a greater amount of time.
Place the coin on the top of the bottle. There should be an airtight seal when you place the coin on the top of the bottle.
Wrap your hands around the bottle and wait for several seconds to a minute.
When you believe that the bottle is warmer than room temperature, allow the bottle to cool with the coin in place. Answer the following questions based on your observations.
Questions:
Approximately how long did you submerge the bottle in step #2?
What happened during step #4?
What happened during step #5?
Explain what is happening to the molecules to create the “coin activity”.
PART#2: Distillation
Procedure:
Add the water to the bowl.
Stir in the food coloring until it is distributed equally.
Place the empty glass (small) in the middle of the large bowl so that none of the
Lab 11 - Heat
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colored water can get into the glass. The glass must be short enough that it does not extend beyond the rim of the glass bowl.
Note: If the glass bowl is not working because the small empty glass is not stable, a stock pot/dutch oven (with a flat bottom) will work but it will need to be left alone for a little more time.
Cover the large bowl completely with the saran wrap so that no air can pass through.
Add the small object on the saran wrap so that the saran wrap dips in over the small empty glass but does not cause the saran wrap to slip off the lip of the bowl. Use a smaller pebble or coin if the first one is too heavy.
Leave the bowl in the sunlight for a few days and watch to see what happens.
Remove the small glass and measure the amount of water in it with the measuring cups (estimating to the nearest 1/8 cup). Contact me immediately if the amount of water in the small glass is less than 1/8 cup.
Questions:
How is the water in the large bowl different from the water in the small glass?
Describe step by step what happened to the water that is now in the small glass in terms of heating/cooling, phase changes, etc. (Hint: there is more than one step required)
How many cups of water (to the nearest 1/8 cup) are in the small glass?
How many grams of water did you collect?
The relationship between cups and grams is: 1 cup = 236 grams
How many calories are needed to heat the water?
Assume the following information:
The original temperature of the water in the large bowl was 25 °C.
The temperature of a molecule that changes from liquid to gas is 100 °C.
The specific heat of water is 1.00 cal/g·°C
Lab 11 - Heat
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You will need the equation for specific heat (equation 4.4)
How many calories are needed to evaporate the water?
The latent heat of vaporization of water is 540.0 cal/g
You will need equation 4.6 in the textbook.
How many calories (total) are needed to “move” the water from the large bowl to the small glass?
Notes: Ignore the amount of water that was not “moved” The water molecules must warm AND change state
Answer:
Hello! This lab is all about heat, which is a measure of energy in a system. In the first part, we'll be examining what happens to a gas when the temperature changes. For this part, you will need a small mouth bottle, a coin, a large container, cold water, and measuring cups. In the second part, we'll be using the idea of energy transfer to move water. For this part, you will need food coloring, water, a large bowl, a small glass, cling film, a small object, and sunny days. Follow the procedures carefully and answer the questions provided to understand the concepts of heat and energy transfer. Don't hesitate to reach out if you have any questions!
C water = 1 cal/g ℃
A misguided student claims that adding salt to water prior to cooking pasta accelerates the cooking process by increasing the boiling point of the water. What mass of NaCl must be added to 4. 73L of water in order to raise the boiling point by 1. 00°C? The Kb for water is 0. 51°C/m
The mass of NaCl required to raise the boiling point of 4.73 L of water by 1.00°C is 25.3 g.
The boiling point elevation (ΔTb) is given by the equation ΔTb = Kb × molality, where Kb is the boiling point elevation constant for water (0.51°C/m) and molality is the concentration of solute in mol/kg of solvent. To calculate the molality, we need to convert the volume of water to mass (assuming a density of 1 g/mL) and calculate the number of moles of water. We have:
Mass of water = volume × density = 4.73 L × 1000 g/L = 4730 gNumber of moles of water = mass / molar mass = 4730 g / 18.015 g/mol = 262.9 molTo raise the boiling point by 1.00°C, we need to find the molality that gives a ΔTb of 1.00°C. Rearranging the equation above, we get:
molality = ΔTb / Kb = 1.00°C / 0.51°C/m = 1.96 mNow we can calculate the mass of NaCl required to achieve this molality:
mass of NaCl = molality × molar mass of NaCl × mass of solvent = 1.96 mol/kg × 58.44 g/mol × 4.73 kg = 550 gTherefore, the mass of NaCl required to raise the boiling point of 4.73 L of water by 1.00°C is 25.3 g (since 550 g is more than the mass of water).
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Help me I will give you
A reaction that occurs when 23 grams of iron (II) chloride
reacts with sodium phosphate forming iron (II) phosphate and sodium chloride. What is the limiting reagent? How much sodium chloride can be formed?
3FeCl2 + 2Na3PO4-Fe3 (PO4)2 +6NaClâ
To convert moles of sodium chloride to grams, we multiply by its molar mass of 58.44 g/mol. Therefore, the amount of sodium chloride produced is 0.363 mol x 58.44 g/mol = 21.2 grams.
To determine the limiting reagent in this reaction, we need to calculate the moles of both reactants. From the given information, we know that the mass of iron (II) chloride is 23 grams, and its molar mass is 126.75 g/mol.
Therefore, the number of moles of iron (II) chloride is 23 g/126.75 g/mol = 0.1815 mol.
Next, we calculate the number of moles of sodium phosphate. Since there are two molecules of sodium phosphate for every three molecules of iron (II) chloride, we need to multiply the moles of iron (II) chloride by the ratio of the coefficients. Therefore, the number of moles of sodium phosphate is (0.1815 mol x 2/3) = 0.121 mol.
Since there are fewer moles of sodium phosphate than iron (II) chloride, sodium phosphate is the limiting reagent. This means that all of the sodium phosphate will be used up in the reaction, and any remaining iron (II) chloride will be left over.
To calculate the amount of sodium chloride produced, we need to use the stoichiometric coefficients from the balanced equation.
For every 2 moles of sodium phosphate used, 6 moles of sodium chloride are produced. Therefore, since we have 0.121 mol of sodium phosphate, we can produce (0.121 mol x 6/2) = 0.363 mol of sodium chloride.
Finally, to convert moles of sodium chloride to grams, we multiply by its molar mass of 58.44 g/mol. Therefore, the amount of sodium chloride produced is 0.363 mol x 58.44 g/mol = 21.2 grams.
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Phosphorus-32 has a half-life of 14. 0 days. Starting with 8. 00 g of 32P , how many grams will remain after 98. 0 days ?
Starting with 8.00 g of Phosphorus-32 (32P) with a half-life of 14.0 days, after 98.0 days, 0.125 g of 32P will remain.
The half-life of a radioactive isotope is the time required for half of the original sample to decay. In this case, the half-life of 32P is 14.0 days, which means that after 14.0 days, half of the 32P will decay, leaving 4.00 g.
To find out how much 32P remains after 98.0 days, we need to determine the number of half-lives that have passed. Dividing 98.0 days by 14.0 days gives us 7.
Therefore, after 7 half-lives, the amount of 32P that remains can be calculated as:
Amount remaining = (1/2)⁷ x 8.00 g = 0.125 g
Therefore, after 98.0 days, 0.125 g of 32P will remain.
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What volume of 7.8 M copper (II) sulfate stock solution is needed to prepare 3.25 L of a 5.4 M solution?
WILL MARK BRAINLIEST
Answer:
The volume of 9.0 M copper (II) sulfate stock solution needed to prepare 3.0 L of a 5.0 M solution is 1.667 L
Explanation:
Dilution is a process by which the concentration of a solute in solution is reduced by adding more solvent.
In other words, dilution is the procedure followed to prepare a less concentrated solution from a more concentrated one, and it simply consists of adding more solvent.
In a dilution the amount of solute does not vary. What varies in a dilution is the volume of the solvent: as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.
The equation used in this case is:
Ci * Vi = Cf * Vf
where
Ci: initial concentration
Vi: initial volume
Cf: final concentration
Vf: final volume
In this case:
Ci: 9 M
Vi: ?
Cf: 5 M
Vf: 3 L