The phrase "survival of the fittest," popularised in Charles Darwin's fifth edition of On the Origin of Species (published in 1869), argued that animals most adapted to their environment have the best chances of surviving.
What does "survival of the fittest" mean in terms of species?The environment and its conditions are continually changing, and the fittest individuals must generate even more fit offspring in order to ensure their survival. Here is when evolution comes into play.
Are organisms who are physically fitter more likely to survive and pass on their genes?An evolutionary mechanism is natural selection. Environment-adapted organisms have a higher chance of surviving and dispersing the genes that contributed to their success.
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If hydrochloric acid reacts with 13.7g of sodium sulfate, how many grams of sulfuric acid are produced?
Answer:
The balanced chemical equation for the reaction between hydrochloric acid (HCl) and sodium sulfate (Na2SO4) is:
2 HCl + Na2SO4 → 2 NaCl + H2SO4
This equation shows that two moles of hydrochloric acid react with one mole of sodium sulfate to produce one mole of sulfuric acid. Therefore, we need to first calculate the number of moles of sodium sulfate that react with the given mass of hydrochloric acid, and then use the mole ratio to find the number of moles (and mass) of sulfuric acid produced.
Calculate the number of moles of sodium sulfate:
molar mass of Na2SO4 = 2(23.0 g/mol) + 1(32.1 g/mol) + 4(16.0 g/mol) = 142.1 g/mol
moles of Na2SO4 = mass/molar mass = 13.7 g/142.1 g/mol = 0.0965 mol
Use the mole ratio to find the number of moles of sulfuric acid produced:
From the balanced equation, we see that 2 moles of HCl react with 1 mole of Na2SO4 to produce 1 mole of H2SO4.
So, the number of moles of H2SO4 produced = (0.0965 mol Na2SO4) x (1 mol H2SO4 / 1 mol Na2SO4) = 0.0965 mol H2SO4
Calculate the mass of sulfuric acid produced:
molar mass of H2SO4 = 1(2.0 g/mol) + 1(32.1 g/mol) + 4(16.0 g/mol) = 98.1 g/mol
mass of H2SO4 = moles x molar mass = 0.0965 mol x 98.1 g/mol = 9.50 g
Therefore, 9.50 grams of sulfuric acid are produced when hydrochloric acid reacts with 13.7 grams of sodium sulfate.
which of the following is an appropriate use for reflux? to remove the solvent from a reaction mixture to carry out a reaction that needs heating to prepare a sample for filtration
A. to remove the solvent from a reaction mixture
What is a Flux?Flux is a term used to describe the flow of energy, particles, or material in a given area. It is typically used to describe the rate of flow of a certain substance, such as the rate of electrons flowing through a circuit.
Flux is also used to describe the concentration of a certain substance in a given area. For example, the amount of a particular chemical in an environment can be described as a flux. Flux is also used to describe the rate of change in a given system, such as the rate of temperature change in a room over time.
Finally, flux can refer to the rate at which energy is exchanged between two objects, such as the rate of heat exchange between two objects.
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One mole of which substance contains a total of 6. 02 X 10²³ atoms
One mole any of which substance contains a total of 6.023 X 10²³ atoms by atoms/molecule.
6.02 X 10²³ units of any given substance make up one mole of that material. The fact that one mole of a material has a mass in grammes that is exactly equal to the substance's formula weight is also significant. As a result, one mole of an element contains 6.02 X 10²³ of the element's atoms and has a mass in grammes equal to the element's atomic weight.
Make sure to be clear about what you're referring to while discussing the diatomic gases, sulphur, and phosphorus, which do not exist as single atoms.
1 mole of substance contains 6.023 X 10²³ molecules.
Volume of solution = 100 mL = 0.1 L
Molarity of solution = 0.02 M
Molarity = number of moles of solute/ Volume of solution (in L)
no. of moles of solute = molarity × volume
=0.02 mol L−1×0.1 L
= 0.002 mol.
Thus, 12.044 x 10²⁰ molecules of H2SO4 are present in 100mL of 0.02 M H2SO4 solution.
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Complete question;
One mole of any substance contains 6.022 × 1023 atoms/molecules. Number of molecules of H2SO4 present in 100 mL of 0.02M H2SO4 solution is.
Which of the following does "cup A" represent in the experimental set-up?
independent variable - it is changed for each group to test for results
dependent variable - it is what is measured
control - it is kept the same (no experimental treatment) to keep the results reliable
none of the above
Cup A represents the independent variable in the experimental set-up. An independent variable is a variable that is changed for each group in an experiment to see what effect it has on the results.
In this case, Cup A is the independent variable because it is the one that is being changed or manipulated in the experiment. For example, in this set-up, cup A might contain different amounts of a certain nutrient to see how it affects the growth of the plants. The dependent variable is what is measured, such as the growth rate of the plants. The control is kept the same (no experimental treatment) to keep the results reliable and to act as a comparison to the experimental results. This control is used to make sure that any changes in the dependent variable are due to the independent variable and not some other factor.
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for the reaction, determine how many moles of chlorine cl2 would be needed to react with 3 moles of phosphorus p4 to entirely use up all the phosphorus
For the given reaction, the moles of chlorine required to react with 3 moles of phosphorus to completely use up all the phosphorus.
The balanced chemical equation for the reaction is:
P4 + 6Cl2 → 4PCl3
Now, the stoichiometric ratio between P4 and Cl2 can be seen from the balanced equation as 1 mole of P4 reacts with 6 moles of Cl2.
So,
3 moles of P4 will require= 6 moles of Cl2 × (3 moles of P4 / 1 mole of P4)= 18 moles of Cl2
Therefore, 18 moles of Cl2 would be required to react with 3 moles of P4 to entirely use up all the phosphorus.
Note:
The balanced chemical equation is used to calculate the moles of reactants and products involved in a chemical reaction.
The mole ratio between the reactants and products can be determined from the balanced chemical equation.
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the density of normal water (the hydrogens do not have neurons) at 20c is 0.9982 g/ml. calculate the density you would expect for heavy water by assuming the deuterium is the same size as normal hydrogen when it is part of the water
The density of heavy water at 20°C is 0.112 g/ml.
The density of normal water at 20°C is 0.9982 g/ml. To calculate the density of heavy water, we need to consider the difference in mass between normal hydrogen (H) and deuterium (D).
Since deuterium has one proton and one neutron, its mass is about twice that of hydrogen.
Assuming the size of deuterium is the same as normal hydrogen when it is part of water, the molar mass of heavy water would be 2 x 1.0079 g/mol (the molar mass of H2O), or 2.0158 g/mol.
Since the density of a substance is equal to the mass of the substance per unit volume, the density of heavy water at 20°C would be equal to 2.0158 g/mol/18 g/mol, which is equal to 0.112 g/ml.
This is approximately 11.2% greater than the density of normal water at 20°C.
Water consists of two hydrogen atoms bonded to one oxygen atom. In the case of normal water, both hydrogen atoms are normal hydrogen (H), while in heavy water, one of the hydrogen atoms is replaced by deuterium (D).
As deuterium is about twice as massive as hydrogen, its presence increases the mass of the molecule, resulting in a higher density.
The density of heavy water at 20°C is approximately 11.2% greater than the density of normal water, due to the presence of deuterium, which has twice the mass of hydrogen.
By assuming the size of deuterium is the same as normal hydrogen, the expected density of heavy water at 20°C by multiplying the molar mass of water (1.0079 g/mol) by two, giving us a density of 0.112 g/ml.
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for the reaction 2KlO3 —> + 3O2 how many moles of potassium iodate are required to produce 250g of oxygen
To determine the number of moles of KIO3 required to produce 250g of O2, we need to use stoichiometry and the molar mass of O2. the molar mass of O2 The molar mass of O2 is 32 g/mol 16 g/mol for each oxygen atom.
What is an atom ?An atom is the basic unit of matter, consisting of a nucleus of protons and neutrons, with electrons in orbit around the nucleus. Atoms are incredibly small, with a diameter of about 0.1 to 0.5 nanometers. The identity of an element is determined by the number of protons in the nucleus of its atoms.
What is a nucleus ?The nucleus is a dense, positively charged central core of an atom that contains protons and neutrons. It is surrounded by negatively charged electrons that orbit around the nucleus in shells or energy levels. The number of protons in the nucleus determines the atomic number and chemical properties of an element. The nucleus also holds most of the mass of an atom. In summary, the nucleus is the central region of an atom where most of its mass is concentrated, and it is made up of protons and neutrons.
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how the temperature and vapor pressure are related knowing the enthalpy of vaporization at the boiling temperature
8.
a) Will all of the salt dissolve?
b) What mass of NaNO3 will dissolve at this temperature?
Grams of solute
Oh oh
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
KI
b. 10g of Ce₂(SO4)3 at 10°C.
c. 125g of KNO3 at 60°C.
NH37
d. 65g of NH4Cl at 80°C.
e. 12g of NH3 at 90°C.
NaNO3
KCIO3
KNO3
NHẠC
Ce2(SO4)3
0
0 10 20 30 40 50 60 70 80 90 100
Temperature (°C)
KCI
Naci
Determine if each of the following is unsaturated (U), saturated (S), or
supersaturated (S.S).
a. 55g of NH3 at 20°C.
f. 80g of NaNO3 at 10°C..
g. 145g of NaNO3 at 80°C.
h. 35g of NaCl at 100°C..
Whether a substance dissolves in a particular solvent depends on several factors, including the solubility of the substance in the solvent, the temperature of the solvent, and the amount of substance and solvent involved.
What is solubility?Solubility refers to the ability of a substance to dissolve in a solvent, which is typically a liquid, gas, or solid.
The solubility of salts tends to increase with temperature, so it is likely that more Ce₂(SO₄)₃ will dissolve at higher temperatures and not at 10°C.At 60°C, it is likely that all 125g of KNO₃ will dissolve in the solvent.At 80°C, it is likely that all 65g of NH₄Cl will dissolve in the solvent.55g of NH3 is less than what can dissolve in 1 liter of water at this temperature. Thus, the solution is unsaturated (U).At 10°C, the solubility of NaNO₃ in water is about 80 g/100 mL. Since the amount of NaNO₃ is equal to or less than the maximum amount that can dissolve in 100 mL of water, the solution is saturated (S).At 80°C, the solubility of NaNO₃ in water is about 200 g/100 mL. Since the amount of NaNO₃ is greater than the maximum amount that can dissolve in 100 mL of water, the solution is supersaturated (S.S).At 100°C, the solubility of NaCl in water is about 40 g/100 mL. Since the amount of NaCl is less than the maximum amount that can dissolve in 100 mL of water, the solution is unsaturated (U).To find out more about solubility, visit:
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What change takes place in a substance as the molecular motion of that substance increases? Responses A. The substance changes from a liquid to a gas. A. The substance changes from a liquid to a gas. B. The substance changes from a gas to a liquid. B. The substance changes from a gas to a liquid. C. The substance changes from a liquid to a solid. C. The substance changes from a liquid to a solid. D. The substance changes from a gas to a solid.
The distance between atoms widens as their vibrations get more rapid. The substance's state of matter is determined by the movement and spacing of its particles. The thing grows or enhanced molecular mobility.
What causes molecules inside a substance to move differently?Because kinetic energy of a liquid's molecules rises as the temperature does. As a result, the molecules have more flexibility to travel across larger volumes as the forces that attraction between them are eventually overcome.
What is required to promote molecular motion?According to the gas kinetic theory, as a gas's temperature rises, the typical kinetic energy of its molecules rises, leading to more motion. This real gases equation PV=NkT predicts that the increased velocity will increase the gas's outer pressure.
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In the lab, you modeled the effect of Earth's surface on properties of the atmosphere.
Which general principle of science is shown by the lab?
1. Every system has only two parts, such as Earth's surface and its atmosphere.
2. Each part of a system works independently of the other parts.
3. Changes to one part of a system can affect other parts of the system.
4. A model can describe only one part of a system.
Answer:
The general principle of science shown by the lab is: "Changes to one part of a system can affect other parts of the system."
Explanation:
This principle is also known as the principle of interdependence, which states that parts of a system are interconnected and can influence one another. In this case, the lab modeled how changes to Earth's surface, such as deforestation or urbanization, can affect the properties of the atmosphere, such as temperature and composition.
ms. salis explains to her class that sodium (na) and chlorine (cl) atoms bond to make table salt (nacl). which is the best description of table salt?
Two elements, sodium (Na) and chlorine (Cl) come together, they form a compound called sodium chloride (NaCl), which is also known as table salt.
Table salt is that it is a chemical ionic compound made up of sodium and chlorine atoms that are bonded together.
Table salt is one of the most common chemical compounds found on earth. It is a white, crystalline substance that is highly soluble in water. It is used in many ways, including cooking, preserving food, and as a seasoning.
Table salt has a number of properties that make it useful in various applications. It is highly reactive with other chemicals, which makes it a good cleaning agent.
It is also highly conductive, which makes it useful in electrochemical applications. Additionally, it is non-toxic, which makes it safe to use in food applications.
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What salt would be produced by the reaction of H2SO4 with LiHCO3? a) Li2S b) LiSO4
c) Li2SO4 d) Li2CO3
The salt that would be produced by the reaction of H2SO4 with LiHCO3 is option C-Li2SO4.
Lithium sulfate (Li2SO4) is an inorganic compound with the formula Li2SO4. It is a white crystalline material that is soluble in water. The salt would be produced as a result of the following reaction: H2SO4 + LiHCO3 → Li2SO4 + H2O + CO2.
Lithium carbonate (Li2CO3) would not be produced in this reaction because LiHCO3 reacts with H2SO4 to form Li2SO4. Li2S cannot be produced because it requires Li2S2, which is not one of the reactants or products. LiSO4 is not produced because H2SO4 reacts with LiHCO3 to form Li2SO4 instead. Thus, option (c) Li2SO4 is the correct answer.
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A scientist is preparing a beaker of boiling water to use in order to rapidly heat some frozen samples. If this scientist wishes to increase the heat of the boiling water as much as possible, what could she do?
If the scientist wishes to increase the heat of the boiling water as much as possible, she can increase the heat source's temperature or increase the amount of heat being supplied to the water.
This can be done by increasing the flame on the stove, increasing the power of the heating element, or adding more heat from an external source. However, it is important to note that the boiling point of water is 100°C at standard atmospheric pressure, so the water will not get any hotter than that unless the pressure is increased. Also, caution should be taken when working with boiling water to prevent burns or accidents.
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when 25.0 ml of 0.500 m agno3 solution is mixed with 40.0 ml of 0.250 m na2so4, solid ag2so4 precipitates out. what mass of ag2so4 is formed? (the molar mass of ag2so4 is 311.8 g/mol.)
The mass of [tex]Ag_2SO_4[/tex] precipitates out is 3.8975 g
We need to use the stoichiometry of the chemical reaction between [tex]AgNO_3[/tex] and [tex]Na_2SO_4[/tex] to determine how much [tex]Ag_2SO_4[/tex] will be formed. The balanced chemical equation for the reaction is:
[tex]AgNO_3 + Na_2SO_4[/tex] → [tex]Ag_2SO_4 + 2NaNO_3[/tex]
From the equation, we can see that one mole of [tex]AgNO_3[/tex] reacts with one mole of [tex]Na_2SO_4[/tex] to form one mole of [tex]Ag_2SO_4[/tex]. Therefore, the first step is to calculate how many moles of [tex]AgNO_3[/tex]and Na_2SO_4 are present in the solution.Moles of [tex]AgNO_3[/tex] = volume (in L) × molarity
= 0.025 L × 0.500 mol/L
= 0.0125 mol
Moles of [tex]Na_2SO_4[/tex] = volume (in L) × molarity
= 0.040 L × 0.250 mol/L
= 0.010 mol
Since the reaction is 1:1 between [tex]AgNO_3[/tex] and [tex]Na_2SO_4, AgNO_3[/tex]is the limiting reactant, and all of the [tex]AgNO_3[/tex] will react to form [tex]Ag_2SO_4[/tex].The number of moles of [tex]Ag_2SO_4[/tex] formed is equal to the number of moles of [tex]AgNO_3[/tex]:
Moles of Silver nitrate ([tex]Ag_2SO_4[/tex]) = 0.0125 mol
Calculate the mass of [tex]Ag_2SO_4[/tex]:
Mass of [tex]Ag_2SO_4[/tex]= moles of [tex]Ag_2SO_4[/tex] × molar mass
Mass of [tex]Ag_2SO_4[/tex] = 0.0125 mol × 311.8 g/mol
Mass of [tex]Ag_2SO_4[/tex] = 3.8975 g
Therefore, the mass of [tex]Ag_2SO_4[/tex] formed is 3.8975 g.
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a mixture containing nitrogen and hydrogen weighs 3.54 g and occupies a volume of 7.48 l at 305 k and 1.03 atm. calculate the mass percent of n2. assume ideal-gas behavior and report answer as a percent. (3 sf) [1.24]
Answer: Mass percent N2 = 79.55% (to 3 significant figures).
To calculate the mass percent of N2 in the mixture, first calculate the molar mass of the mixture, which is:
Molar mass = (3.54g * 1 mol/28.0134 g) + (7.48 l * 1.03 atm * 0.08206 l * atm / (305 K * 0.7302 mol/g))
Molar mass = 3.542 g/mol
Then, calculate the mass percent of N2 in the mixture:
Mass percent N2 = (28.0134 g * 1 mol/3.542 g) * 100%
Mass percent N2 = 79.55% (to 3 significant figures).
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Using the formula M1V1 = M2V2, how many millimeters of 6.0M sodium hydroxide are required to prepare 2.0L of a 1.0M sodium hydroxide solution?
Question Options:
200 mL
1200 mL
300 mL
330 mL
Answer: 330 i just took the test
Explanation:
330 mL of 6.0M sodium hydroxide are required to prepare 2.0L of a 1.0M sodium hydroxide solution. This is done by Molarity method.
What is Molarity?A substance's concentration in a liquid is referred to as its molarity, or molar concentration. The substance being dissolved is referred to as a solute, while the liquid is referred to as a solvent. The number of moles per liter is the precise definition of molarity.
Solids, other liquids, or even gases can all dissolve into a liquid and become a solute. Finding molarity is straightforward if you are aware of the solute's molecular weight and the amount of solvent it is dissolved in.
Using the formula M₁×V₁ = M₂×V₂
M₁ = 6.0 M
M₂ = 1.0 M
V₂ = 2.0 L
substituting the values ,
V₁ = 330 mL
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a saturate solution of lead (ii) chloride (pbcl2) has a ksp value of 17.10-5. if 0.90 moles of chloride ions (cl-) is added to the solution, what will be the concentration of lead ions be in solution?
Therefore, the concentration of Pb2+ ions in the solution is 0.0098 M. The chemical equation describing how lead (II) chloride dissolves in water Pb2+ (aq) + 2Cl- PbCl2 (s) (aq) For this reaction.
Ksp = [Pb2 +] [Cl -] 2 We are provided that the Ksp value of PbCl2 is 1.7 × 10^-5. Also, we are informed that 0.90 moles of Cl- ions have been added to the mixture. We may assume that the concentration of Pb2+ ions is insignificant compared to the concentration of Cl- ions since the stoichiometry of the reaction is 1:2 for Pb2+:Cl-. Let x be the concentration of Pb2+ ions in the solution. Then, the concentration of Cl- ions is 2x (because the stoichiometry is 1:2 for Pb2+:Cl-). The total concentration of Cl- ions in the solution is therefore:
[Cl-]total = 2x + 0.90
Since the solubility product expression for[tex]PbCl2 is Ksp = [Pb2+][Cl-]^2, \\[/tex]we can write:
[tex]Ksp = x(2x + 0.90)^2Solving for x, we get:x = 0.0098 M[/tex]
Therefore, the concentration of Pb2+ ions in the solution is 0.0098 M.
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Answer:
Explanation:
The statement mentioned in the question is not a question. However, I can provide some information related to the given statement.Nickel(II) chloride refers to the chemical compound with the formula NiCl2. It is also known as Nickelous chloride. When nickel(II) chloride is dissolved in water, it forms a saturated solution of concentration 1 M (1 mole/Liter). A saturated solution refers to the solution in which no more solute can be dissolved in it at a given temperature and pressure.To summarize, the given statement means that if you dissolve nickel(II) chloride in water, you will obtain a saturated solution of concentration 1 M (1 mole/Liter).
What happens to the charges in current electricity?
Answer:
This is just a quick tip.
Explanation:
An electric current is the movement of particles, starting at the moment when an external voltage is applied at one of the ends of the conductor. That, in turn, generates an electric field on the negatively charged electrons that are attracted to the positive terminal of the external voltage.
brainly plutonium-239 has a half life of 24000 yearas and is considered safe only ewhens it radiactively has dropped to 1% of the original level approximately how long the pu-239 be stored securely to be considered safe
Plutonium-239 is a radioactive isotope that has a half-life of 24000 years. When it has decayed to 1% of its original level, it is considered safe.
PLUTONIUM -
As plutonium isotopes decay, they undergo chemical changes. They might change into new elements like uranium or neptunium or into new isotopes of plutonium.
These "daughter products" frequently contain radioactive elements themselves. The atomic number 94 metal element plutonium is radioactive.
Scientists looking for a way to break atoms for use in nuclear weapons made the discovery in 1940. When uranium atoms absorb neutrons in a nuclear reactor, plutonium is produced.
The vast majority of plutonium in the world is produced artificially.
To be considered safe, it must be stored securely for approximately 240,000 years.
How long must the pu-239 be stored securely to be considered safe?
The decay of Plutonium-239 to 1% of its initial level, which is considered safe, requires approximately ten half-lives.
As a result, plutonium-239 must be kept securely for ten times its half-life, or approximately 240,000 years, to be considered safe.
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1. Write a hypothesis based on observations and scientific principles. (Hint: This means you write a prediction about how you think natural selection will lead to changes in the specific traits in populations of moths in the simulation. Don't forget to write it in the if-then statement format
A sample of ideal gas occupies 208ml at 36. 2 degree celsius and 704 torr what is the volume at stp
At Standard Temperature and Pressure (STP) the volume of the gas at is 216.1 ml.
A sample of ideal gas occupies 208ml at 36.2 degree Celsius and 704 torr what is the volume at stp
For a sample of ideal gas, the relationship between volume, pressure, and temperature is given by the Ideal Gas Law:
PV = nRT
Where P is the pressure of the gas, V is the volume of the gas, n is the number of moles of the gas, R is the universal gas constant, and T is the temperature of the gas.
At STP (Standard Temperature and Pressure), the pressure of the gas is 1 atm and the temperature of the gas is 0°C (273 K). Therefore:
P1 = 704 torr
V1 = 208 mL
T1 = 36.2°C = 309.35 K
P2 = 1 atm
V2 = ?
T2 = 0°C = 273 K
To find V2, we can use the following equation:
V2 = V1(P2/P1)(T1/T2)
Plugging in the given values:
V2 = 208 mL (1 atm/704 torr) (309.35 K/273 K)
V2 = 208 mL (0.939) (1.132)
V2 = 216.1 mL
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if a zero order reaction has a half-life of 350 s when the initial reactant concentration is 1.50 m, how long until 0.1% of the reactant remains?
It will take 3401 seconds for 0.1% of the reactant to remain.
The half-life of a zero-order reaction is the time taken for the concentration of the reactant to decrease by half. This can be calculated using the equation:
t1/2 = 0.693/k
Where k is the rate constant of the reaction. The amount of time it takes for 0.1% of the reactant to remain, we can use the following equation:
t = (-log(0.001))/k
The rate constant of the reaction can be calculated as:
k = 0.693/t1/2 = 0.693/350 = 0.001988
t = (-log(0.001))/k = (-log(0.001))/0.001988 = 3401 seconds
Therefore, it will take 3401 seconds for 0.1% of the reactant to remain.
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starting with a 1.00 l of a buffer that is 0.700 m hf and 0.553 m naf, calculate the ph after the addition of 0.100 mol naoh. ka (hf) 7.1 x 10-4
The pH after the addition of 0.100 mol NaOH to 1.00 L of a buffer that is 0.700 M HF and 0.553 M NaF. The pH is 7.031.
To calculate the pH after the addition of 0.100 mol NaOH to 1.00 L of a buffer that is 0.700 M HF and 0.553 M NaF, we can use the Henderson-Hasselbalch equation.
The Henderson-Hasselbalch equation is: pH = pKa + log ([A-]/[HA])
Where [A-] is the concentration of the anion (in this case, NaF) and [HA] is the concentration of the acid (in this case, HF).
pKa for HF is 7.1 x 10-4
Before we add the 0.100 mol NaOH, the pH of the buffer is:
pH = 7.1 x 10-4 + log ([0.553 M NaF]/[0.700 M HF])
= 7.1 x 10-4 + log(0.787)
= 7.1 x 10-4 + -0.103
= 6.997
Now, let's calculate the concentration of NaOH after we add 0.100 mol of it to the buffer. We know that 1 mole of NaOH will produce 1 mole of OH- ions, so the concentration of OH- ions is 0.100 M.
Since the buffer already contains HF and NaF, the total concentration of anions is 0.653 M.
We can now calculate the new pH using the Henderson-Hasselbalch equation:
pH = 7.1 x 10-4 + log([0.653 M anions]/[0.700 M HF])
= 7.1 x 10-4 + log(0.933)
= 7.1 x 10-4 + -0.069
= 7.031
Therefore, the pH of the buffer after the addition of 0.100 mol NaOH is 7.031.
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naphthalene, the active ingredient in one variety of mothballs, is an organic compound that contains carbon and hydrogen only. complete combustion of a 20.10 mg sample of naphthalene in oxygen yielded 69.00 mg of co2 and 11.30 mg of h20. determine the molecular formula of naphthalene
The molecular formula of naphthalene is C6H6 if it involves the complete combustion of a 20.10 mg sample of naphthalene in oxygen yielded 69.00 mg of co2 and 11.30 mg of h20.
We have the complete combustion of a 20.10 mg sample of naphthalene in oxygen yielded 69.00 mg of co2 and 11.30 mg of h20.
Mass of C in CO2 is,
= 12/44 x 69.00
= 18.82mg
Mass of H in H2O is,
= 2/18 x 11.30
= 1.256mg
We have to find Mole ratios.
C= 18.82/12= 1.568
H= 1.256/1= 1.256
Now we have to divide by the smaller mole ratio.
C= 1.568/1.256= 1.2=1
H= 1.256/1.256= 1
So the empirical formula is CH.
The empirical formula of a compound is defined as the formula which gives us the lowest whole number ratio of that particular compound.
A molecular formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule.
Empirical formula weight=12+1=13
We can get the mass of the empirical formula can be computed by dividing the molar mass of the compound by it.
Molecular weight=78
n= Molecular weight / Empirical formula weight
= 78/ 13
=6
Molecular formula=(CH) n =(CH) 6 =C6H6
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Sometimes liquid ammonia, NH3, is used as a solvent rather than water. Which expression defines the ammonia autoionization counterpart of Kw?
a.[H3O+][OH-]
b.[NH3][NH4+]
c.[NH2-][NH4+]
d.[H3O+][NH2-]
e.[NH4+][OH-}
The ammonia autoionization counterpart of Kw is defined by the expression c. [tex][NH_2^-][NH_4^+].[/tex]
The autoionization of liquid ammonia, [tex]NH_3[/tex], involves the transfer of a proton from one ammonia molecule to another, producing the ammonium ion ([tex]NH_4^+[/tex]) and the amide ion ([tex]NH_2^-[/tex]):
[tex]NH_3 + NH_3[/tex]⇌ [tex]NH_2^- + NH_4^+[/tex]
This is because ammonia ([tex]NH_3[/tex]) can act as both a base and an acid in a solvent, and autoionizes into [tex]NH_2^-[/tex] (amide ion) and [tex]NH_4^+[/tex] (ammonium ion)
The equilibrium constant expression for this reaction is:
[tex]K = [NH_4^+][NH_2^-]/[NH_3]^2[/tex]
Therefore, the ammonia autoionization counterpart of Kw would be:
[tex]Kw = [NH_4^+][NH_2^-][/tex]
Therefore, the correct answer is (c) [tex][NH_2^-][NH_4^+].[/tex].
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How many moles are in 1.2 x 10^24 formula units of Li₂SO4? (round your answer to the nearest tenths place)
In 1.2 x [tex]10^{24}[/tex] formula units of [tex]Li_{2} (SO)_{4}[/tex], there are roughly 1.993 moles of
[tex]Li_{2} (SO)_{4}[/tex].
How many moles of [tex]Li_{2} (SO)_{4}[/tex] are contained in 1.2 x [tex]10^{24}[/tex] formula units?Using Avogadro's number, or 6.022 x [tex]10^{23}[/tex] molecules/mol, we can calculate the number of moles of Li2SO4 in 1.2 x [tex]10^{24}[/tex]formula units.
First, we need to figure out how many moles of [tex]Li_{2} (SO)_{4}[/tex] are needed to equal 1.2 x [tex]10^{24}[/tex] formula units:
Formula units equal 6.022 x [tex]10^{23}[/tex] per mole of [tex]Li_{2}(SO)_{4}[/tex].
As a result, there are: 1.2 x [tex]10^{24}[/tex] moles of [tex]Li_{2}(SO)_{4}[/tex] in the formula units.
1.993 moles are equal to 1.2 x [tex]10^{24}[/tex] formula units / 6.022 x [tex]10^{23}[/tex] formula units/mol.
Hence, 1.2 × [tex]10^{24}[/tex] formula units of [tex]Li_{2} (SO)_{4}[/tex] contain about 1.993 moles.
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A rigid container with a volume of 35.0 mL is filled with enough gas to have a
pressure of 2.62 atm and then sealed so no more gas could enter and none could
leave. The original temperature is 298.52 K and the final temperature is 357.30
K. What is the pressure in the container at the higher temperature.
The pressure in the container at the higher temperature would be 3.37 atm.
Ideal gas equationTo solve this problem, we can use the ideal gas law:
PV = nRT
where P is the pressure, V is the volume, n is the number of moles of gas, R is the universal gas constant, and T is the temperature in Kelvin.
Since the container is sealed and the number of moles of gas cannot change, we can set the initial and final pressures and volumes equal to each other, and solve for the final pressure:
P1V1/T1 = P2V2/T2
Where P1, V1, and T1 are the initial pressure, volume, and temperature, respectively, and P2 and T2 are the final pressure and temperature, respectively.
Substituting the given values, we get:
2.62 atm × 35.0 mL / 298.52 K = P2 × 35.0 mL / 357.30 K
Simplifying, we get:
P2 = (2.62 atm × 35.0 mL / 298.52 K) × (357.30 K / 35.0 mL)
P2 = 3.37 atm
Therefore, the pressure in the container at the higher temperature is approximately 3.37 atm.
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help me please and thank you
The explanation that best describes what beta particles are blocked by is: This type of radiation is blocked by aluminum or metal foil.
What are beta particles?Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive decay. Beta particles have a lower penetrating power than gamma rays and can be stopped by thin layers of materials such as aluminum or metal foil.
However, if the beta particle is more energetic, it may require a thicker material such as plastic, wood or thick clothing to block it. Lead or concrete can also be effective in stopping beta particles, but they are not as effective as they are in blocking gamma rays.
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we know that most solids are more soluble in warm water than in cold water. does thesolubility of nh4cl fit this pattern? explain
Yes, the solubility of NH4Cl fits the pattern that most solids are more soluble in warm water than in cold water.
On increasing the temperature of the solvent, the solubility of the solute increases. The solubility of NH4Cl, which is an example of a solid, follows this trend. In other words, ammonium chloride (NH4Cl) dissolves more readily in warm water than in cold water.
When water is heated, the kinetic energy of the water molecules increases, causing them to move more rapidly. As a result, more space is created in the water, allowing it to dissolve more solute.
NH4Cl is a soluble salt that dissolves in water with a pH value of less than 7. It is readily soluble in water, with a solubility of 372 g/L at 20 degrees Celsius. As a result, increasing the temperature will increase the solubility of NH4Cl.
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