Solving various thermodynamics questions
Chemistry assignment help: Solving various thermodynamics questions
1 – The air in an inflated balloon (defined as the system) is warmed over a toaster and absorbs 130J of heat. As it expands, it does 76kJ of work. What is the change in internal energy for the system?
2 – A piston has an external pressure of 8.00 atm. How much work has been done in joules if the cylinder goes from a volume of 0.140 liters to 0.450 liters.
3 – A volume of 105mL of H2O is initially at room temperature (22.0∘C). A chilled steel rod at 2.00∘C is placed in the water. If the final temperature of the system is 21.3∘C, what is the mass of the steel bar?
Use the following values:
specific heat of water = 4.18 J/(g∘C)
specific heat of steel = 0.452 J/(g∘C)
4 – The specific heat of water is 4.18 J/(g∘C). Calculate the molar heat capacity of water.
5 – It takes 47.0J to raise the temperature of an 11.3g piece of unknown metal from 13.0∘C to 24.1∘C. What is the specific heat for the metal?
6 – The molar heat capacity of silver is 25.35 J/mol∘C . How much energy would it take to raise the temperature of 11.3g of silver by 19.0∘C?
7 – What is the specific heat of silver?
8 – If this expansion occurs against an external pressure of 1.0 atm, how much work (in J ) is done during the expansion?
9 – A gas is compressed from an initial volume of 5.40L to a final volume of 1.20L by an external pressure of 1.00 atm . During the compression the gas releases 128J of heat.
What is the change in internal energy of the gas?
10 – A mole of X reacts at a constant pressure of 43.0 atm via the reaction
X(g)+4Y(g)→2Z(g), ΔH ∘ =−75.0 kJ
Before the reaction, the volume of the gaseous mixture was 5.00 L . After the reaction, the volume was 2.00 L . Calculate the value of the total energy change, ΔE , in kilojoules.
11 – The change in internal energy for the combustion of 1.0 mol of octane at a pressure of 1.0 atm is 5084.2kJ .If the change in enthalpy is 5074.4kJ how much work is done during the combustion?
12 – What mass of natural gas (CH 4 ) must you burn to emit 267kJ of heat?
CH 4 (g)+2O 2 (g)→CO 2 (g)+2H 2 O(g) ΔH ∘ rxn =−802.3kJ
13 – Determine the mass of CO 2 produced by burning enough carbon (in the form of charcoal) to produce 530kJ of heat.
C(s)+O 2 (g)→CO 2 (g)ΔH ∘ rxn =−393.5kJ
14 – In the following experiment, a coffee-cup calorimeter containing 100 mL of H 2 O is used. The initial temperature of the calorimeter is 23.0 ∘ C If 5.70g of CaCl 2 is added to the calorimeter, what will be the final temperature of the solution in the calorimeter? The heat of solution ΔH soln of CaCl 2 is −82.8 kJ/mol.
