8. Thermochemistry

Which equation is commonly used to calculate the change in thermal energy (q) of a substance during a temperature change?

How many BTUs are required to convert 1 pound of ice at 20°F to steam at 220°F?

Which energy changes are associated with a liquid boiling?

How much energy is released when 42.5 g of water freezes at 0°C? (The enthalpy of fusion for water is 334 J/g.)

What happens when hot water is added to cold water in an insulated container?

A 15.0-g sample of ice at -15.0 °C is heated until it becomes liquid water at 45.0 °C. How much energy (in joules) is required for this process? (Given: specific heat of ice = 2.09 J/g·°C, specific heat of water = 4.18 J/g·°C, heat of fusion of ice = 334 J/g)

When 20.0 g of water at 25 °C is mixed with 30.0 g of water at 80 °C in an insulated container, what is the final temperature of the mixture? (Assume no heat loss to the surroundings and that the specific heat capacity of water is 4.18 J/g·°C.)

Which of the following best describes what occurs at thermal equilibrium?

While water is in the process of freezing, what happens to its temperature?

What is most likely to occur if you continuously increase the temperature of a liquid at atmospheric pressure?

In a sauna, why is only a small ladle-full of water poured onto the hot rocks at one time?

Given 352 mL of water at 26 °C in a perfectly heat-insulating container, how much ice at 0 °C (in grams) would have to be added to this water so that after the ice has melted, the overall temperature of the system has been lowered to 5 °C?

If 45.0 mL of ethanol (density = 0.789 g/mL) initially at 9.0 °C is mixed with 45.0 mL of water (density = 1.0 g/mL) initially at 28.2 °C in an insulated beaker, what is the final temperature of the mixture, assuming that no heat is lost?

If 55.0 mL of ethanol (density = 0.789 g/mL) initially at 9.0 °C is mixed with 55.0 mL of water (density = 1.0 g/mL) initially at 28.7 °C in an insulated beaker, what is the final temperature of the mixture, assuming that no heat is lost and the specific heat capacities are 2.44 J/g°C for ethanol and 4.18 J/g°C for water?

Which of the following indicates that thermal energy is no longer being transferred from boiling water to a mug?