Question

1.) The specific heat of a certain type of metal is 0.128 J/(g⋅∘C). What is the final temperature if 305J of heat is added to 41.7 g of this metal, initially at 20.0 ∘C?

2.) When 1723 J of heat energy is added to 42.3 g of hexane, C6H14, the temperature increases by 18.0 ∘C.

Calculate the molar heat capacity of C6H14

3.) Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb 7.50 MJ of energy in the form of heat if the temperature of the sodium is not to increase by more than 10.0 °C? Use CP=30.8 J/(K⋅mol) for Na(l) at 500 K.

4.) If you combine 400.0 mL of water at 25.00 ∘C and 100.0 mL of water at 95.00 ∘C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water.

5.) A hot lump of 35.235.2 g of iron at an initial temperature of 71.6 °C is placed in 50.0 mL H2O initially at 25.0 °C and allowed to reach thermal equilibrium. What is the final temperature of the iron and water, given that the specific heat of iron is 0.449 J/(g⋅°C)? Assume no heat is lost to surroundings.

6.) A researcher studying the nutritional value of a new candy places a 4.70 g sample of the candy inside a bomb calorimeter and combusts it in excess oxygen. The observed temperature increase is 2.09 ∘C. If the heat capacity of the calorimeter is 41.20 kJ⋅K−1, how many nutritional Calories are there per gram of the candy?

7.)The balanced combustion reaction for C6H6 is 2C6H6(l)+15O2(g)⟶12CO2(g)+6H2O(l)+6542 kJ If 5.800 g C6H6 is burned and the heat produced from the burning is added to 5691 g of water at 21 ∘ C, what is the final temperature of the water?

8.) If the heat of combustion for a specific compound is −1270.0 kJ/mol and its molar mass is 27.81 g/mol, how many grams of this compound must you burn to release 346.20 kJ of heat?

9.) Given that

H2(g)+F2(g)⟶2HF(g)ΔH∘rxn=−546.6 kJ

2H2(g)+O2(g)⟶2H2O(l)ΔH∘rxn=−571.6 kJ

calculate the value of ΔH∘rxnΔHrxn∘ for

2F2(g)+2H2O(l)⟶4HF(g)+O2(g)

10.) Using the standard enthalpies of formation, what is the standard enthalpy of reaction?

CO(g)+H2O(g)⟶CO2(g)+H2(g)

11.) For a particular isomer of C8H18, the combustion reaction produces 5093.7 kJof heat per mole of C8H18(g) consumed, under standard conditions.

C8H18(g)+252O2(g)⟶8CO2(g)+9H2O(g)ΔH∘rxn=−5093.7 kJ/mol

What is the standard enthalpy of formation of this isomer of C8H18(g)?

12.) What is the heat of combustion of ethane, C2H6, in kilojoules per mole of ethane? Enthalpies of formation can be found in the table of thermodynamic properties.

Answer 1

Answer (1)