Thermochemistry Practice

Based on this graph, what is the heat of fusion?

Note: X axis is energy in calories and Y axis is temperature in degrees Celsius.

• 200 calories, as measured along line BC

• 250 calories, as measured along line BC

• 400 calories, as measured along line DE

• 800 calories, as measured along line DE

The boiling point of the substance is

• 10°C

• 60°C

• 120°C

• 180°C

The graph below was constructed by a student to show the relationship between temperature and time as heat was uniformly added to a solid below its melting point. What is the total length of time that the solid phase existed with the liquid phase?

• 6 min

• 10 min

• 8 min

• 4 min

A student obtained the following data while cooling a substance. The substance was originally in the liquid phase at a temperature below its boiling point. What is the freezing point of the substance?

• 70°C

• 59°C

• 53°C

• 48°C

What is the total number of Joules of heat absorbed by 65.0 grams of water when the temperature of the water is raised from 25°C to 40°C?

• 63.00 J

• 105.0 J

• 4075.5 J

• 6846 J

The temperature of 15 grams of water is increased by 3.0 Celsius degrees. How much heat was absorbed by the water?

• 21 J

• 50 J

• 76 J

• 189 J

A sample of water is heated from 10.0°C to 15.0°C by the addition of 126 Joules of heat. What is the mass of the water?

• 5.00 g

• 6.00 g

• 30.0 g

• 150.0 g

As a 15.1-gram sample of a metal absorbs 48.75 J of heat, its temperature increases 25.0K. What is the specific heat capacity of the metal?

• 0.129 J/g°K

• 1.95 J/g°K

• 3.23 J/g°K

• 7.74 J/g°K

What is the total amount of heat required to completely melt 347 grams of ice at its melting point?

• 334 J

• 1,450 J

• 116,000 J

• 784,000 J

When 20.0 grams of a substance is completely melted at its melting point, 820. Joules are absorbed. What is the heat of fusion of this substance?

• 41.0 J/g

• 800. J/g

• 840. J/g

• 16,400 J/g