A 7.50 g marshmallow is placed in a calorimeter and burned in excess oxygen. The temperature increases by 4.69°C. The calorimeter has a heat capacity of 22.3 kJ/°C. What is the approximate food value of marshmallows in Cal/g? (1 Cal = 4.184 kJ) 3.33 Cal/g d. 13.9 Cal/g a. b. 105 Cal/g e. 1.60 Cal/g c. 25.0 Cal/g

Hypothetical elements A2 and B2 react according to the following equation, forming the compound AB. A2(aq)+B2(aq)2AB(aq);H=+271kJ/mol If solutions A2(aq) and B2(aq), starting at the same temperature, are mixed in a coffee-cup calorimeter, the reaction that occurs is a exothermic, and the temperature of the resulting solution rises. b endothermic, and the temperature of the resulting solution rises. c endothermic, and the temperature of the resulting solution falls. d exothermic, and the temperature of the resulting solution falls. e exothermic or endothermic, depending on the original and final temperatures.

A 21.3-mL sample of 0.977 M NaOH is mixed with 29.5 mL of 0.918 M HCl in a coffee-cup calorimeter (see Section 6.6 of your text for a description of a coffee-cup calorimeter). The enthalpy of the reaction, written with the lowest whole-number coefficients, is 55.8 kJ. Both solutions are at 19.6C prior to mixing and reacting. What is the final temperature of the reaction mixture? When solving this problem, assume that no heat is lost from the calorimeter to the surroundings, the density of all solutions is 1.00 g/mL, the specific heat of all solutions is the same as that of water, and volumes are additive.

A 29.1-mL sample of 1.05 M KOH is mixed with 20.9 mL of 1.07 M HBr in a coffee-cup calorimeter (see Section 6.6 of your text for a description of a coffee-cup calorimeter). The enthalpy of the reaction, written with the lowest whole-number coefficients, is 55.8 kJ. Both solutions are at 21.8C prior to mixing and reacting. What is the final temperature of the reaction mixture? When solving this problem, assume that no heat is lost from the calorimeter to the surroundings, the density of all solutions is 1.00 g/mL, and volumes are additive.

You wish to heat water to make coffee. How much heat (in joules) must be used to raise the temperature of 0.180 kg of tap water (enough for one cup of coffee) from 30C to 96C (near the ideal brewing temperature)? Assume the specific heat is that of pure water, 4.18 J/(gC).

How much heat is absorbed by a 44.7-g piece of leadwhen its temperature increases by 65.4°C?

Chlorine dioxide, ClO2, is a reddish yellow gas used in bleaching paper pulp. The average speed of a ClO2 molecule at 25C is 306 m/s. What is the kinetic energy (in joules) of a ClO2 molecule moving at this speed?

Natural gas companies in the United States use the therm as a unit of energy. One therm is 1105 BTU. (a) How many joules are in one therm? (1J=9.48104BTU) (b) When propane gas, C3H8, is burned in oxygen, CO2 and steam are produced. How many therms of energy are given off by 1.00 mol of propane gas?

When a 0.740-g sample of trinitrotoluene (TNT), C7H5N2O6, is burned in a bomb calorimeter, the temperature increases from 23.4 C to 26.9 C. The heat capacity of the calorimeter is 534 J/C, and it contains 675 mL of water. How much heat was produced by the combustion of the TNT sample?

The temperature of the cooling water as it leaves the hot engine of an automobile is 240 F. After it passes through the radiator it has a temperature of 175 F. Calculate the amount of heat transferred from the engine to the surroundings by one gallon of water with a specific heat of 4.184 J/g oC.