Questions on Phase Change and Calorimetry

Front

Why doesn’t the temperature of water change during boiling?

Back

Because the heat energy is used to break the hydrogen bonds between water molecules

Front

What is the heat of vaporization of water, based on the phase-change data table given that 1 calorie = 4.18 J?

Back

2260 J/g

Front

A jeweler pours liquid gold into a mold to make a 6 g wedding ring. How much energy is transferred from the ring when it solidifies? What temperature is the gold at the instant all of its atoms become solid?

Back

The energy transferred is 92.4 cal and the temperature is 1063°C

Front

Which of the following processes are exothermic?

• Combustion of fuels
• Photosynthesis
• Melting of ice
• Evaporation of water

Back

Combustion of fuels

Front

How much energy is required to melt 56 mol of ice given the data in the table?

Back

80,500 cal

Front

If you transfer 5000 cal, how many grams of ethanol can you vaporize?

Back

24.4 grams

Front

Energy conservation in mixing 25.0 g of ice at 0 °C with 100 g of water at 45 °C resulting in a final temperature of 20 °C.

Back

The heat lost by the water is equal to the heat gained by the ice.

Front

What does "ΔT" mean?

Back

A change in temperature

Front

The specific heat of water is 4.18 J/g°C. If 980. J of energy is added to 6.20 g of water at 18.0 °C, what is the final temperature of the water?

Back

55.8 °C

Front

What would be the effect on the particles if more heat is supplied to the system?

Back

They would speed up