A 1.90-mol sample of hydrogen gas is heated at constant pressure from 306 K to 410 K. (a) Calculate the energy transferred to the gas by heat. 5.747 kJ Correct: Your answer is correct. (b) Calculate the increase in its internal energy. 4.105 kJ Correct: Your answer is correct. (c) Calculate the work done on the gas. -1.642 kJ Correct: Your answer is correct.

a. Q = 5.711 kJ

b. ΔE = 4.051 kJ

c. W = -1.660 kJ

Explanation:

1a. The amount of energy transferred to a gas when heated at constant pressure is given as Q = nCpΔT

where n = number of moles of gas;

Cp = molar specific heat of the gas at constant pressure,

ΔT = temperature change

From the given data; n = 1.90 moles , Cp of hydrogen gas (from tables) = 28.9 J/mol/K, ΔT = 104 K

Substituting the given values:

Q = 1.90 * 28.9 * 104

Q = 5710.64 J

Q = 5.711 kJ

b. The change in internal energy of a confined gas that undergoes a temperature change due to any process is given by the formula: ΔE = nCvΔT

where  n = number of moles of gas;

Cv = molar specific heat of the gas at constant volume,

ΔT = temperature change

From the given data; n = 1.90 moles , Cv of hydrogen gas (from tables) = 20.4 J/mol/K, ΔT = 104 K

substituting the values

ΔE = 1.90 * 20.5 * 104

ΔE = 4050.8 J

ΔE = 4.051 kJ

c. From the first law of thermodynamics, ΔE = Q + W

where W is work done on the system.

from our calculations, ΔE = 4.051 kJ, Q = 5.711 kJ

W = ΔE - Q

W = (4.051 - 5.711) kJ

W = -1.660 kJ

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.