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4 years ago

What area of study in chemistry is concerned with the heat transfers that occur during chemical reactions?

Chemistry

2 answers:

Finger [1]4 years ago

8 0

Thermochemistry is an area of study that's concerned with heat transfer during chemical reactions.

monitta4 years ago

6 0

Answer:

Thermochemistry

Explanation:

Thermochemistry is the area of study in chemistry that is concerned with the heat transfers that occur during chemical reactions.

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A gas has a pressure of 7.01 atm at 227°C. What will its temperature be if the pressure is increased to 12.1 atm and volume is h

kirill [66]

Answer:

The temperature of the gas will be 590.05 C.

Explanation:

Gay-Lussac's law can be expressed mathematically as follows:

$\frac{P}{T} =k$

Where P= Pressure, T = temperature, K = Constant

This law indicates that the ratio between pressure and temperature is constant.

This law indicates that, as long as the volume of the container containing the gas is constant, as the temperature increases, the gas molecules move faster. Then the number of shocks against the walls increases, that is, the pressure increases. That is, the gas pressure is directly proportional to its temperature.

In short, when there is a constant volume, as the temperature increases, the gas pressure increases. And when the temperature decreases, gas pressure decreases.

It is desired to study two different states, an initial state and an final state. You have a gas that is at a pressure P1 and at a temperature T1 at the beginning of the experiment. When the temperature varies to a new T2 value, then the pressure will change to P2, and the following will be true:

$\frac{P1}{T1} =\frac{P2}{T2}$

In this case:

P1= 7.01 atm
T1= 227 C= 500 K (being 0 C= 273 K)
P2= 12.1 atm
T2= ?

Replacing:

$\frac{7.01 atm}{500 K} =\frac{12.1 atm}{T2}$

Solving:

$T2=12.1 atm*\frac{500 K}{7.01 atm}$

T2= 863.05 K= 590.05 C

The temperature of the gas will be 590.05 C.

6 0

3 years ago

7. How many liters of NH3, at STP will react with 10.6 g O2 to form NO2 and water? 4NH3(g) + 7O2(g) → 4NO2(g) + 6H2O(g) *

Alexus [3.1K]

7) Answer is: c. 4.24 L.

Balanced chemical reaction: 4NH₃(g) + 7O₂(g) → 4NO₂(g) + 6H₂O(g).

m(O₂) = 10.6 g; mass of oxygen.

n(O₂) = m(O₂) ÷ M(O₂).

n(O₂) = 10.6 g ÷ 32 g/mol.

n(O₂) = 0.33 mol; amount of oxygen.

Vm = 22.4 L/mol; molar volume at STP (Standard Temperature and Pressure).

At STP one mole of gas occupies 22.4 liters of volume.

V(O₂) = n(O₂) · Vm.

V(O₂) = 0.33 mol · 22.4 L/mol.

V(O₂) = 7.42 L; volume of oxygen.

From balanced chemical reaction: n(O₂) : n(NH₃) = 7 : 4.

n(NH₃) = 4 · 0.33 mol ÷ 7.

n(NH₃) = 0.188 mol; amount of ammonia.

V(NH₃) = 0.188 mol · 22.4 L/mol.

V(NH₃) = 4.24 L.

8) Answer is: a. 3.7 g.

Balanced chemical reaction: P₄(g) + 6H₂(g) → 4PH₃(g).

m(P₄) = 3.4 g; mass of phosphorous.

n(P₄) = m(P₄) ÷ M(P₄).

n(P₄) = 3.4 g ÷ 123.9 g/mol.

n(P₄) = 0.0274 mol; limiting reactant.

n(H₂) = 4 g ÷ 2 g/mol.

n(H₂) = 2 mol; amount of hydrogen.

From balanced chemical reaction: n(P₄) : n(PH₃) = 1 : 4.

n(PH₃) = 4 · 0.0274 mol.

n(PH₃) = 0.1096 mol.

m(PH₃) = 0.1096 mol · 34 g/mol.

m(PH₃) = 3.726 g.

9) Answer is: d. Percent yield is the ratio of theoretical yield to actual yield expressed as a percent.

Percent yield = actual yield / theoretical yield.

Theoretical yield is the maximum amount of product that can be produced from limiting reactant and actual yield is a product that is obtained by experimentation.

For example:

the percent yield = 250 g ÷ 294.24 g · 100%.

the percent yield = 84.5 %.

3 0

3 years ago

Help(Must be done by 2/22/2018)

alekssr [168]

These are 6 questions and 6 answers.

Question 1:

Answer: 33.7 atm

Explanation:

1) Data:

p=?
m = 1360.0 g N2O
V = 25.0 liter
T = 59.0°C

2) Formulas:

Ideal gas law: p V = n R T
n = mass in grams / molar mass

3) Solution

n = mass of N2O in grams / molar mass of N2O

molar mass of N2O = 2 * 14 g/mol + 16 g/mol = 44 g/mol

n = 1360.0 g / 44 g/mol = 30.9 mol

T = 59.0 + 273.15 K = 332.15 K

R = 0.0821 atm*liter / K*mol

=> p = nRT / V = 30.9 mol * 0.0821 [atm*liter / K * mol] * 332.15K / 25.0 liter = 33.7 atm

Answer: 33.7 atm

Question 2:

Answer: 204.5 liter

Explanaton:

1) Data:

m = 11.7 g of He
V = ?
p = 0.262 atm
T = - 50.0 °C

2) Formulas:

pV = nRT

n = mass in grams / atomic mass

3) Solution:

atomic mass of He = 4.00 g/mol

n = 11.7 g / 4.00 g/mol = 2.925 mol

T = - 50.0 + 273.15 K = 223.15 K

pV = nRT => V = nRT / p

V = 2.925 mol * 0.0821 [* liter / K*mol] *223.15K / 0.262 atm = 204.5 liter

Answer: 204.5 liter

Question 3.

Answer: 97.8 mol

Explanation:

1) Data:

Ethane
T = 15.0 °C
p = 100.0 kPa
V = 245.0 ml
n = ?

2) Formula

pV = nRT

3) Solution

pV = nRT => n = RT / pV

T = 15.0 + 273.15K = 288.15K

R = 8.314 liter * kPa / (mol*K)

n = 8.314 liter * kPa / (mol*K) * 288.15K / [100.0 kPa * 0.245 liter] = 97.8 mol

Answer: 97.8 mol

Question 4:

Answer: 113.67 K = - 159.48 °C

Explanation:

1) Data:

V = 629 ml of O2
p = 0.500 atm
n = 0.0337 moles
T = ?

2) Formula:

pV = nRT

3) Solution:

pV = nRT => T = pV / (nR)

T = 0.500 atm * 0.629 liter / (0.0337 mol * 0.0821 atm*liter/K*mol ) = 113.67 K

°C = T - 273.15 = - 159.48 °C

Question 5.

Answer: 5.61 g

Explanation:

1) Data:

V = 3.75 liter of NO
T = 19.0 °C
p = 1.10 atm
m = ?

2) Formulas

pV = nRT

mass = number of moles * molar mass

3) Solution:

pV = nRT => n = pV / (RT)

T = 19.0 + 273.15 K = 292.15 K

n = 1.10 atm * 3.75 liter / [ (0.0821 atm*liter / K*mol) * 292.15 K ] = 0.17 mol

molar mass of NO = 17.0 g/mol + 16.0 g/mol = 33.0 g/mol

mass = 0.17 mol * 33.0 g/mol = 5.61 g

Question 6:

Answer: 22.4 liter

Explanation:

1) Data:

STP
n = 1.00 mol
V = ?

Solution:

1) It is a notable result that 1 mol of gas at STP occupies a volume of 22.4 liter, so that is the answer.

2) You can calculate that from the formula pV = nRT

3) STP stands for stantard pressure and temperature. That is p = 1 atm and T = 0°C = 273.15 K

4) Clear V from the formula:

V = nRT / p = 1.00 mol * 0.0821 atm*liter / (K*mol) * 273.15 K / 1.00 atm = 22.4 liter

7 0

3 years ago

What happens immediatesly after you dissolve acid in water? Positively charged hydrogen atoms are released. Positively charged h

jeka94

Answer:

The correct answer is A.

Explanation:

The acids with hydrogen atoms in them are the ones that dissolve best in water and when they do, they get diluted, raising their pH level by releasing hydrogen ions (H+) into the solutions.

So when acids get dissolved in water, positively charged hydrogen atoms are released.

The answer is A.

I hope this helps.

4 0

4 years ago

NEED HELP ON 17,18,19,20,21,22,23. ONLY IF YOU ARE POSITIVE ABOUT THE ANSWER!!!!

Alex777 [14]

Answer:

17. D. Chemical change

18. C. Cell wall

19. D. To transfer matter and energy within and between organisms.

20. A. Transporting materials

21. C. Carbon dioxide

22. A. Cellular respiration

23. C. Produce food and give off oxygen

Explanation:

I have been able to supply the correct answers. The cell wall functions as a structure that provides structural support and protection to the cell. It is tough, flexible and at times rigid. In a chemical change, new materials with new properties are manufactured. So, the process of photosynthesis is a chemical change.

The endoplasmic reticulum actually transports material. It transports materials like protein and lipids made within the cell and sends it to where they are needed.

Carbon dioxide is the the gas that animals give off and plants use it during photosynthesis. Cellular respiration involves the activities that result to the breaking down of food in order to release energy.

8 0

3 years ago