Answer: A cold compress used by athletes is an endothermic reaction.
Explanation:
A pack of cold compress used by athletes contains water that holds another bag or tube inside it which is filled with ammonium nitrate fertilizer.
So, on hitting the cold compress the tube breaks down due to which fertilizer gets mixed with water. This mixture absorbs the heat when placed on the area of body having pain, strain or bump.
As a result, we tend to feel cold at the affected area of our body.
Thus, we can conclude that a cold compress used by athletes is an endothermic reaction.
What would the Kc value be from this reaction: H2 + I2 = 2HI.
(Because of the coefficient "2" in front of HI, you will have to square the concentration
of HI to find Kc. Kc = ?
Answer: The value of [tex]K_{c}[/tex] for the given reaction is [tex]K_{c} = \frac{[HI]^{2}}{[H_{2}][I_{2}]}[/tex] .
Explanation:
The ratio of concentration of products and reactants raised to the power of their concentration is called equilibrium constant.
It is denoted by the symbol [tex]'K_{c}'[/tex].
For example, [tex]H_{2} + I_{2} \rightarrow 2HI[/tex]
The expression for [tex]K_{c}[/tex] of this reaction is as follows.
[tex]K_{c} = \frac{[HI]^{2}}{[H_{2}][I_{2}]}[/tex]
So, by putting the respective concentrations of the species involved in the reaction it is possible to determine the value of [tex]K_{c}[/tex] for the given reaction.
Thus, we can conclude that the value of [tex]K_{c}[/tex] for the given reaction is [tex]K_{c} = \frac{[HI]^{2}}{[H_{2}][I_{2}]}[/tex] .
Every system in the body is made from atoms, molecules, cells, tissues, and organs. These building blocks all work together to allow you to grow, obtain energy, move, stay healthy, and reproduce. Each system provides a different function to support life. Which of the following is a control system in the body?
Circulatory
Reproductive
Nervous
Muscular
Answer:
THE RIGHT ONE IS THE NERVOUS SYSTEM
Explanation:
THE EXPLANATION IS THAT : The nervous system is the part of an animal's body that coordinates its behavior and transmits signals between different body areas. In vertebrates it consists of two main parts, called the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS contains the brain and spinal cord.
A graduated cylinder contains 50.0 ml of water. A 23.5 g piece of unknown metal is carefully dropped into the cylinder. When
the metal is completely covered with water, the water rises to the 53.4 ml mark. What is the density of the unknown piece of
metal in g/ml?
To find the density of the unknown piece of metal, we can use the formula:
Density = mass / volume.
How to find the density ?The volume of the metal can be calculated by deducting the starting water volume (50.0 ml) from the final water volume (53.4 ml) after the metal is introduced. We know the mass of the unknown metal is 23.5 g.Volume of metal = 53.4 ml - 50.0 ml = 3.4 ml.Now we can substitute the values into the density formula: Density = 23.5 g / 3.4 ml = 6.9 g/ml.Therefore, the density of the unknown piece of metal is 6.9 g/ml.To know more about density , check out :
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How many short columns are on the periodic table?
Answer:
They are 4 short column on the periodic table
Starting with 2.50 mol of N2 gas (assumed to be ideal) in a cylinder at 1.00 atm and 20.0C, a chemist first heats the gas at constant volume, adding 1.36 * 104 J of heat, then continues heating and allows the gas to expand at constant pressure to twice its original volume. Calculate (a) the final temperature of the gas; (b) the amount of work done by the gas; (c) the amount of heat added to the gas while it was expanding; (d) the change in internal energy of the gas for the whole process.
Answer:
a) [tex]T_b=590.775k[/tex]
b) [tex]W_t=1.08*10^4J[/tex]
d) [tex]Q=3.778*10^4J[/tex]
d) [tex]\triangle V=4.058*10^4J[/tex]
Explanation:
From the question we are told that:
Moles of N2 [tex]n=2.50[/tex]
Atmospheric pressure [tex]P=100atm[/tex]
Temperature [tex]t=20 \textdegree C[/tex]
[tex]t = 20+273[/tex]
[tex]t = 293k[/tex]
Initial heat [tex]Q=1.36 * 10^4 J[/tex]
a)
Generally the equation for change in temperature is mathematically given by
[tex]\triangle T=\frac{Q}{N*C_v}[/tex]
Where
[tex]C_v=Heat\ Capacity \approx 20.76 J/mol/K[/tex]
[tex]T_b-T_a=\frac{1.36 * 10^4 J}{2.5*20.76 }[/tex]
[tex]T_b-293k=297.775[/tex]
[tex]T_b=590.775k[/tex]
b)
Generally the equation for ideal gas is mathematically given by
[tex]PV=nRT[/tex]
For v double
[tex]T_c=2*590.775k[/tex]
[tex]T_c=1181.55k[/tex]
Therefore
[tex]PV=Wbc[/tex]
[tex]Wbc=(2.20)(8.314)(1181_590.778)[/tex]
[tex]Wbc=10805.7J[/tex]
Total Work-done [tex]W_t[/tex]
[tex]W_t=Wab+Wbc[/tex]
[tex]W_t=0+1.08*10^4[/tex]
[tex]W_t=1.08*10^4J[/tex]
c)
Generally the equation for amount of heat added is mathematically given by
[tex]Q=nC_p\triangle T[/tex]
[tex]Q=2.20*2907*(1181.55-590.775)\\[/tex]
[tex]Q=3.778*10^4J[/tex]
d)
Generally the equation for change in internal energy of the gas is mathematically given by
[tex]\triangle V=nC_v \triangle T[/tex]
[tex]\triangle V=2.20*20.76*(1181.55-293)k[/tex]
[tex]\triangle V=4.058*10^4J[/tex]
The table shows the thickness, top density, and bottom
density of the different layers of the Earth.
Which statement is supported by the information in the
table?
Thickness
(km)
Density
(g/cm)
Top Bottom
Types of Rock
Found
As depth increases, the density of the layers increases.
As depth increases, the density of the layers decreases.
As depth increases, the thickness of the layers
increases.
As depth increases, the thickness of the layers
decreases.
Crust
30
2.2
2.9
Silicic rocks
720
3.4
4.4
Upper
mantle
Peridotite
2,171
4.4
Lower
mantle
5.6
Magnesium and
silicon oxides
Outer
2,259
9.9
12.2
Iron+oxygen
core
1,221
12.8
13.1
Inner
core
Iron+oxygen
Se
[tex]\huge{\textbf{\textsf{{\color{pink}{An}}{\red{sw}}{\orange{er}} {\color{yellow}{:}}}}}[/tex]
As depth increases, the density of the layers decreases.
Thanks.Hope it helps.The statement, that describes the thickness, top density, and bottom density of the different layers of the Earth is "as depth increases, the density of the layers decreases."
What is density layers of Earth?The density of the Earth's inner layers determines their order. The densest layer is the solid metal inner core, the mantle is of intermediate density, and the lithosphere, particularly the continental lithosphere, is the least dense layer.
Pressure rises as you go deeper. Mass/volume = density. As a result, as the volume drops, so does the density. Because of pressure, the strata beneath us become extremely dense. As a result, as the depth of the earth increases, so does the density.
Hence the correct answer is as depth increases, the density of the layers decreases.
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Please help ASAP!!
Explain why a pond at 18 °C has more thermal energy than a cup of boiling water at
100 °C.
Answer:
The pond has more energy because I is so much larger that the Cup of boiling water. Since that mass of the pond is so much larger, It is generating more energy than a boiling cup of water.
what is van't hoff factor?
state the formulas to calculate " i " during association or dissociation.
tysm! :)
The relationship between the calculated concentration of a material and the actual concentration of particles is known as the Van't Hoff factor.
I is the difference between a typical or theoretical colligative quality and an observable one.
What does the connection van t Hoff factor mean?The van 't Hoff factor is the difference between the concentration of a material determined by its mass and the concentration of particles actually formed when the substance is dissolved. The van 't Hoff factor is virtually 1 for the majority of non-electrolytes dissolved in water.
What does Van t Hoff factor mean in terms of connection and dissociation?For dissociation, association, and the non-electrolyte solute, the Van't Hoff factor value is more than one, less than one, and equal to one respectively.
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No links!! Round two decimal places please
Answer:
255.46 grams NO3
Explanation:
The molar mass of NO3 is 62.0049 g/mol.
To get grams from moles, multiply the moles by the molar mass.
4.12*62.0049 = 255.4602 = 255.46 grams NO3
Suppose two materials: (1) titanium and (2) a new synthetic polymer are tested by hanging a mass from a test sample made from each material. Both samples have an initial length of and a cross-section area of . The synthetic polymer is know to behave similarly to the Kelvin-Voigt model, and has parameters and . Use MATLAB to plot the deformation in each specimen for the first ten seconds of the test. Neglect the mass of each test specimen, and assume that the hanging mass is instantly applied to each material at time .
Answer:
ffffffffffffff
Explanation:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
Identify the Precipitation Reaction Below:
A) CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)
B) H2SO4(aq) + 2 LiOH(aq) → 2 H2O(l) + Li2SO4(aq)
C) Mg(s) + Cu(NO3)2(aq) → Mg(NO3)2(aq) + Cu(s)
D) HCl(aq) + (NH4)2S(aq) → H2S(g) + 2 NH4Cl(aq)
E) NaCl(aq) + AgNO3(aq) → AgCl(s) + NaNO3(aq)
Answer:
(E)
Explanation:
When aqueous solutions are added together, one of the products is s solid.
the enthaply of formation of water is -285.8kj/mol. what can be inferred from this statement
Answer: It takes 285.8 kJ of energy to form one mole of water
Explanation:
The enthalpy of formation of a substance is the change in enthalpy that occurs when a substance is formed from its elements in their standard states. The enthalpy of the formation of water is -285.8 kJ/mol, which means that it takes 285.8 kJ of energy to form one mole of water from its elements (hydrogen and oxygen) under standard conditions. This value is negative, which means that the formation of water releases energy. This is why water is often referred to as an "exothermic" substance because it releases energy when it is formed. The negative value of the enthalpy of formation for water can be explained by the fact that the bonds formed between hydrogen and oxygen atoms in water are stronger than the bonds between hydrogen and oxygen atoms in the individual elements. This means that it takes less energy to break the bonds in the elements than it releases when the bonds in water are formed, resulting in a net release of energy.
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Answer:
This means that 285.8 kJ/mol is evolved when one mole of water is formed.
What is the enthalpy of formation?
The term enthalpy of formation has to do with the energy that is released or absorbed when a molecule of water if formed from its constituents.
The fact that the enthalpy of formation of water is -285.8 kJ/mol implies that 285.8 kJ/mol is evolved when one mole of water is formed.
Explanation:
9)
Which solution will have the highest concentration of solute particles?
A) 0.50 M NaCl
B) 1,00 M CaCl2
C) 2.00 M sodium ions
D) 2.50 M C6H1206
Answer: The answer is B) 1.00 M CaCl2
Explanation: I just did it on usatestprep and it said it was correct .
As long as proper
safety precautions have been taken, why can explosives be transported long distances without exploding?
Compressing a spring increases its
a.kinetic energy
b.potential energy
c.electrical energy
d.chemical energy
Answer:
B. potential energy
Explanation:
Potential energy ( Mechanical in this case ) is energy stored by force. so If you are compressing a spring you are increasing more potential to it by force.
The half-life of carbon-14 is 5715 years. How long would it take for 100 grams to decay to
12.5 grams
We are given:
half-life of carbon = 5715 years
Initial mass = 100 grams
Final mass = 12.5 grams
Finding the time taken:
Number of half-lives:
We know that in the relation:
[tex]\frac{Final\_mass}{Initial\_mass} = \frac{1}{2^{n}}[/tex], n is the number of half-lives taken
replacing the given values:
12.5 / 100 = 1/2ⁿ
1/8 = 1/2ⁿ
2ⁿ = 8
2ⁿ = 2³
n = 3
Hence, it took 3 half-lives to reduce the mass to 12.5 grams
Number of years:
Time taken = 3 half-lives
we know that one half-life is 5715 years, replacing that value:
Time taken = 3*(5715) years
Time taken = 17145 years
Therefore, after 17145 years, a 100 gram sample of carbon will decay and only 12.5 grams will remain
HELP!!! Please
A Probability Swim in Lake S Orbital
1. How did you determine where the lake was most likely to be?
2. Why was it important to take ten obse
swimmers were located?
3. Explain why the statement "electrons are always located close to the nucleus of an atom" is not really accurate,
5 lollipops = 6 gumballs
8 gumballs = 6 lemonheads
14 lemonheads = 11
Explanation:
5 lollipops = 6 gumballs
8 gumballs = 6 lemonheads
14 lemonheads = 11 lollipops
It is in chain rule form.
Answer:
야만적 인 사랑은 누군가가 천사처럼 보이지만 야만적 인 사랑은 당신의 마음을 부러 뜨리게했다너무 귀엽다
Explanation:
난 천사야 네가 무슨 뜻인지 말해줘나는 모든 것을 가지고 나는 그것을 다시 포기하지 않을 것이다
How much energy (in J) is lost when a sample of iron with a mass of 28.3 g cools from 66.0 degrees celsius to 24.0 degrees celsius.
Answer:
-533.68J
Explanation:
Using the formula as follows:
Q = m × c × ∆T
Where;
Q = amount of heat required (Joules)
m = mass of substance (g)
c = specific heat of substance (J/g°C)
∆T = change in temperature (°C)
According to the information provided in this question;
Q = ?
m = 28.3 g
c of iron = 0.449 J/g°C
∆T = 24°C - 66°C = -42°C
Using the formula, Q = m × c × ∆T
Q = 28.3 × 0.449 × (-42)
Q = -533.68
Q = -533.68J
This means that 533.68J is lost to the environment when iron of 28.3g cools from 66°C to 24°C.
5. (a-c) In the balanced equation below, how many grams of solid iron can be formed if 50.0g Fe2O3 reacts with 10.0g of CO?
Fe2O3(s) + 3CO(g) → 2Fe(s) +3CO2
a. What mass of the excess reactant remains after the reaction occurred?
b. If you conducted an experiment and 11.5 grams of Fe(s) was formed what would be the percent yield?
c. If the percent yield for the process to obtain 75 kg of CO2 was 80.7%, how many kg of CO is needed?
From the balanced equation of the reaction, the mole ratio of the reactants is 1:3.
Mole of 50.0 g [tex]Fe_2O_3[/tex] = 50/160 = 0.3125 mol
Mole of 10.0 g CO = 10/28 = 0.3571 mol
Stoichiometric equivalent of [tex]Fe_2O_3[/tex] = 0.3571/3 = 0.1190 mol
In other words, [tex]Fe_2O_3[/tex] is in excess.
Excess mole = 0.3125 - 0.1190 = 0.1935 mol
Mass of 0.1935 mol [tex]Fe_2O_3[/tex] = 0.1935 x 160 = 30.96 grams
Mole ratio of CO to Fe = 3:2
Equivalent mole of Fe that would be formed = 0.3571 x 2/3
= 0.2381 mol
Mass of 0.238 mol Fe = 0.238 x 56 = 13.328 grams
Percent yield of Fe = 11.5/13.328 x 100 = 86.28%
Mole of 75 gk CO2 = 75000/44 = 1704.55 mol
Mole ratio of CO2 and Co = 1:1
Equivalent mole of CO = 1704.55 mol
Mass of 1704.55 mol CO = 1704.55 x 28 = 47.73 kg
80.7% = 47.73 kg
100% = 100 x 47.73/80.7
= 59.14 kg
In other words, 59.14 kg of CO would be needed.
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A sample of AgCl is treated with 5mL of 2M Na2CO3 solution to produce Ag2CO3. The remaining solution contained 0.003gm of Cl per litre. Calculate solubility product of AgCl.(Ksp of Ag2CO3=8.2×10^-12)
Answer: The solubility product of AgCl is [tex]10.73 \times 10^{-9}[/tex].
Explanation:
The reaction equation is as follows.
[tex]Ag_{2}CO_{3} \rightleftharpoons 2Ag^{+} + CO^{2-}_{3}[/tex]
Let us assume the concentration of [tex]2Ag^{+}[/tex] is 2S and concentration of [tex]CO^{2-}_{3}[/tex] is S. Hence, the expression for [tex]K_{sp}[/tex] of this reaction is as follows.
[tex]K_{sp} = [Ag^{+}]^{2}[CO^{2-}_{3}]\\8.2 \times 10^{-12} = (2S)^{2}(S)\\8.2 \times 10^{-2} = 4S^{3}\\S = 1.27 \times 10^{-4}[/tex]
This means that [tex][Ag^{+}][/tex] is [tex]1.27 \times 10^{-4}[/tex]. Now, the concentration of [tex]Cl^{-}[/tex] is calculated as follows.
[tex][Cl^{-}] = \frac{mass}{molar mass}\\= \frac{0.003 g}{35.5 g/mol}\\= 8.45 \times 10^{-5} M[/tex]
Hence, [tex]K_{sp}[/tex] for AgCl is calculated as follows.
[tex]K_{sp} = [Ag^{+}] \times [Cl^{-}]\\= 1.27 \times 10^{-4} \times 8.45 \times 10^{-5}\\= 10.73 \times 10^{-9}[/tex]
Thus, we can conclude that solubility product of AgCl is [tex]10.73 \times 10^{-9}[/tex].
Explain the phenomenon of diffussion.
Answer:
the movement of particles from a higher consentration to a lower consentration through a mechanical support.
Explanation:
If a photon dropping from the n = 7 to the n = 1 level hit the surface of Au, what would be the wavelength of the ejected electron in nanometers?
Answer:
here's the answer.hope it helps
Which statement is true about a reversible reaction? (5 points)
The forward and reverse reactions stop.
The product is a salt and the reactant is an acid.
The products react to re-form the original reactants.
The forward reaction continues but reverse reaction stops.
Answer:
C: The products react to re-form the original reactants.
Explanation:
A reversible reaction is one where the conversion of reactants to products as well as the conversion of products to reactants happen at the same time.
What this means is that the products of the reaction could react to reform the initial reactants.
Thus, option C is the correct answer.
Answer:
C
Explanation:
The products react to re-form the original reactants.
5. 16.3 g of NaCl is dissolved in water to make 1.75 L of solution. What is the molarity of this solution? A 0.159 M B 0.278 M C 9.31 M D 33.4 M
Answer: The molarity of this solution is 0.159 M.
Explanation:
Given: Mass of solute = 16.3 g
Volume = 1.75 L
Number of moles is defined as the mass of substance divided by its molar mass.
Hence, moles of NaCl (molar mass = 58.44 g/mol) ar calculated as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{16.3 g}{58.44 g/mol}\\= 0.278 mol[/tex]
Molarity is the number of moles of a substance present in a liter of solution.
So, molarity of the given solution is calculated as follows.
[tex]Molarity = \frac{no. of moles}{Volume (in L)}\\= \frac{0.278 mol}{1.75}\\= 0.159 M[/tex]
Thus, we can conclude that the molarity of this solution is 0.159 M.
The amount of water (density 1.00 g mL-1) in grams that must be added to 26.2 g of
MgCl2 in the preparation of a 1.5 % by mass solution is:
Answer:
1720.8g water are necessaries
Explanation:
Mass percent is defined as the mass of solute (In this case, MgCl2) in 100g of solution (Mass MgCl2 + Mass water). To solve this question we must find the mass of solution that we need to produce th 1.5% by mass solution. Thus, we can find the mass of water that we need as follows:
Mass solution:
26.2g MgCl2 * (100g Solution / 1.5g MgCl2) = 1747g solution
Mass water:
1747g solution - 26.2g MgCl2 = 1720.8g water are necessaries
PROBLEM 1.22 Give the hybridization state of each carbon in the following
compounds:
(a) Carbon dioxide (0 = C = O)
(d) Propene (C*H_{3}*CH = C*H_{2})
(b) Formaldehyde (H_{2}*C = O)
(e) Acetone [(CH 3 ) 2 C = OI
(c) Ketene (H_{2}*C = C = O)
(f) Acrylonitrile ( C*H_{2} =CHC equiv N)
SAMPLE SOLUTION
(a) Carbon in C*O_{2} is directly bonded to two other atoms. It
is sp-hybridized.
To solve this we must be knowing each and every concept related to hybridisation. Therefore, the hybridisation of the given molecule can be given as below.
What is hybridisation?Only during bond formation does hybridization occur, not in an individual gaseous atom. If the bonding of a molecule is known, the geometry of the molecule may be predicted.
compound hybridisation
Carbon dioxide (0 = C = O) sp
Propene (CH[tex]_3[/tex]CH = CH[tex]_2[/tex]) sp³, sp²,sp²
Formaldehyde (H[tex]_2[/tex]C = O) sp²
Acetone [(CH[tex]_3[/tex] )[tex]_2[/tex] C = O sp³, sp², sp³
Ketene (H[tex]_2[/tex]C = C = O) sp², sp
Therefore, the hybridisation of the given molecule can be given as above.
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Under the right conditions aluminum will react with chlorine to produce aluminum chloride.
2 Al + 3 Cl2 - 2 AICI3
How many grams of aluminum are needed to react completely with 11.727 liters of chlorine?
CORRECT ANSWER IS 9.42, but what are the steps to get that answer ?
Answer:
9.42 g
Explanation:
Step 1: Write the balanced equation
2 Al + 3 Cl₂ ⇒ 2 AICI₃
Step 2: Calculate the moles corresponding to 11.727 L of Cl₂
Since the conditions are not specified, we will assume Cl₂ is at standard temperature and pressure. At STP, 1 mole of Cl₂ occupies 22.4 L.
11.727 L × 1 mol/22.4 L = 0.524 mol
Step 3: Calculate the moles of Al needed to react with 0.524 moles of Cl₂
The molar ratio of Al to Cl₂ is 2:3. The moles of Al needed are 2/3 × 0.524 mol = 0.349 mol
Step 4: Calculate the mass corresponding to 0.349 moles of Al
The molar mass of Al is 26.98 g/mol.
0.349 mol × 26.98 g/mol = 9.42 g
If 14.7 g of NO2 are reacted, what mass of H2O is reacted with it?
Answer:
no se englesh
ajajajaja
How many moles of NaCl would you have in 100 mL of this solution?
Answer:
You didnt give me a molarity so ill show you how to solve it with an equation
Explanation:
Molarity represent by M
M= mols/ Volume (in liters)
so mols = (whatever the molarity was) x (.100L because it is =100ml)
Mols= M x (.100)
plug in the molarity you have for x and you are done