# Worksheet: Using Calorimetry Measurements

In this worksheet, we will practice using the specific heat of a material to calculate the mass, temperature change, or amount of heat exchanged.

**Q1: **

When 2.0 g of fructose, , a sugar commonly found in fruits, is burned in oxygen in a bomb calorimeter, the temperature of the calorimeter increases by .

If the heat capacity of the calorimeter and its contents is , calculate the heat released by this combustion, , to 2 significant figures.

From the value of , calculate the molar enthalpy of combustion for fructose to 2 significant figures.

**Q2: **

The addition of 3.15 g of to a solution of 1.52 g of in 100 g of water in a calorimeter caused the temperature to fall by . Assuming the specific heat of the solution and products is , what is the approximate amount of heat absorbed by the reaction? Give your answer in kilojoules to two significant figures.

The reaction can be represented by the following equation.

**Q7: **

A 600 mL bottle of water at room temperature and a 2 L bottle of water at the same temperature were placed in a refrigerator. After 30 minutes, the 600 mL bottle of water had cooled to the temperature of the refrigerator. An hour later, the 2 L of water had cooled to the same temperature.

Which sample of water lost the most heat?

- AThe 2 L bottle of water lost more heat because a greater mass of water was cooled.
- BThe bottles lost the same amount of heat because they started at the same temperature and finished at the same temperature.
- CThe 600 mL bottle of water lost more heat because it cooled more quickly.
- DIt is not possible to determine which bottle lost the most heat because we do not know the initial temperature and the final temperature of the water.

**Q9: **

The enthalpy change when calcium chloride dissolves in water is kJ/mol. The heat capacity of the solution is approximately equal to that of water . If 90 g of dissolves in 5.0 L of water at , what is the temperature of the resulting solution?

**Q10: **

The melting enthalpy of ice is 6.01 kJ/mol. At , combustion of 10.0 g of butane releases sufficient heat to melt 1.20 kg of ice and increase the temperature of the resulting water ( = 4.184 J/gโ K) to . What is the enthalpy of combustion of butane?

- A kJ/mol
- B kJ/mol
- C kJ/mol
- D kJ/mol
- E kJ/mol

**Q11: **

Aqueous iron(II) chloride and hydrogen peroxide react in excess dilute
hydrochloric acid according to the equation:
The enthalpy change for this reaction is
kJ/mol. At
, solutions
containing 1.901 g of and 0.260 g of in 1 M aqueous are mixed in an
insulated container. The final solution has a volume of 100 cm^{3}, a density of 1.000 g/cm^{3},
and a specific heat of 4.184 J/gโ
K. Calculate, to 1 decimal place, the temperature of the
solution at the end of the reaction.

**Q12: **

Natural gas is mostly methane. Burning natural gas in air is a highly efficient way of generating heat.

Methane combusts completely in air according to the following equation: The combustion of 10.0 mmol of methane and excess oxygen heats a small amount of water in a bomb calorimeter by . The water has a mass of 100 g and specific heat of . Assuming the water absorbs all heat generated by the reaction, calculate the molar enthalpy of combustion of methane.

**Q13: **

Aqueous sodium periodate reacts with aqueous hydroiodic acid according to the equation:

The enthalpy change for this reaction is kJ/mol
and the enthalpy of solution for
is kJ/mol.
At ,
1.85 g of is
dissolved in 150 cm^{3} of 0.100 M aqueous
in an
insulated container. It is assumed that the solution
has a density of 1.00 g/cm^{3} and specific heat of
4.184 J/gโ
K and that the mass of solute is negligible.
By identifying the limiting reagent and determining the
total heat absorbed or released by the solution, calculate
the temperature of the solution at the end of the reaction to 1 decimal place.

**Q18: **

Ethanol can be used as a fuel, either as an additive to gasoline or in pure form. Complete combustion of 50.0 mL of ethanol releases 906 kJ of heat under standard conditions. Given that the density of ethanol is 0.789 g/mL, what is the standard molar enthalpy of combustion of ethanol?

**Q19: **

Aqueous sodium hydroxide and hydrochloric acid react according to the equation:
At , 4.00 g of in 100 cm^{3} of water is added to 100 cm^{3} of 1.50 M aqueous . The temperature of the resulting solution is .

What is the enthalpy change for this reaction? Assume, for all solutions, that the heat capacity is 4.184 J/gโ
K and the density is 1.00 g/cm^{3}.

**Q20: **

Aqueous sodium hydroxide reacts with aqueous
phosphoric acid according to the equation:
The enthalpy change for this reaction is
kJ/mol. When 1.52 g of solid is dissolved in 300 cm^{3} of 0.100 M aqueous ,
the temperature of the solution changes from to . The solution has a
density of 1.00 g/cm^{3} and specific heat of 4.184 J/gโ
K and absorbs all heat generated by
the reaction. What is the enthalpy of solution for , to 2 significant figures?

**Q21: **

An insulated cup contains 100 mL of water at . When this water is warmed, its density and specific heat remain approximately constant. Which of the following, if poured into the cup, would increase the temperature of its contents by the largest amount?

- A5 mL of water at
- B20 mL of water at
- C10 mL of water at
- D80 mL of water at
- E40 mL of water at

**Q22: **

An insulating bucket contains 3.00 kg of sand mixed with 900 g of water . The mixture cools uniformly by overnight. To 2 significant figures, how much heat has been released by the mixture?

**Q23: **

A 250 g potato at is added to 1.50 L of oil at . The oil has a density of 0.875 g/mL and a specific heat capacity of 1.67 J/gโ K. The final temperature of the oil and the potato is . To two significant figures, what is the specific heat capacity of the potato?

**Q24: **

A solid zinc catalyst suspended in a toluene solution makes up 10% of the total mass. A reactor supplies 50.0 MJ of energy to the suspension, increasing its temperature by . To 2 significant figures, what is the total mass of the suspension?

**Q25: **

A 30.0 g block of aluminum is heated from to and placed into 100 g of water. The specific heat of aluminum is and that of water is . Calculate, to the nearest , the temperature of the water and aluminum at equilibrium.