Calculations Involving Specific Heat and Latent Heat of Phase Change

Gap-fill exercise

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   .14      0.38      0.4      0.45      142      164      18      180      1870      20      205      24      410      418      50      83600   
1. How many joules of energy must be absorbed to raise the temperature of 20 grams of water from 25°C to 30°C? The specific heat of water can be found on your periodic table.

Joules


2. An 50 gram sample of an unknown metal warms from 18° to 58° after absorbing 800 joules. What is the specific heat of the metal?

J/(g·°C)


3. The specific heat of carbon (graphite) is 0.71 J/(g·°C). How much energy is given off as a 2 gram piece of graphite cools from 120°C to 20°C?

Joules


4. A sample of mercury has a mass of 500 grams. When it absorbs 280 joules, the temperature is found to have increased from 25°C to 29°C. What is the specific heat of mercury?

J/(g·°C)


5. How much energy must be absorbed by 10 grams of steam in order to raise its temperature by 100°C? The specific heat of steam is 1.87J/(g·°C).

Joules


6. A 50 gram piece of iron warms from 0°C to 40°C while absorbing 900 joules. What is the specific heat of iron?

J/(g·°C)


7. How much energy must be removed from 500 grams of water in order to cool it from 80°C to 40°C? The specific heat of water can be found on your periodic table.

Joules


8. When a 500 gram piece of brass cools from 100°C to 60°C, it is found to have given up 7600 joules of energy. What is the specific heat of the brass?

J/(g·°C)


9. How much energy is required to melt 4 moles of ice at its melting point? Assume that the molar heat of fusion of ice is 6 kJ/mol.

kJ


10. How much energy is required to boil 4 moles of water at its boiling point? Assume that the molar heat of vaporization of water is 41 kJ/mol.

kJ


11. An engineer wants to be able to condense 10 moles of water vapor every minute. Assuming the steam is at 100°C, how much energy must be removed every minute? Assume that the molar heat of vaporization of water is 41 kJ/mol.

kJ


12. How much energy must be removed from 30 moles of liquid water at 0°C in order to convert it to ice? Assume that the molar heat of fusion of ice is 6 kJ/mol.

kJ


13. A sample of ice at 0°C melts after absorbing 300 kJ of heat. How many moles of H2O are contained in the sample? Assume that the molar heat of fusion of ice is 6 kJ/mol.

moles H2O


14. A sample of water at 100°C is converted to steam after absorbing 820 kJ of heat. How many moles of H2O are contained in the sample? Assume that the molar heat of vaporization of water is 41 kJ/mol.

moles


15. How many joules of energy are needed to melt 54 grams of ice at its melting point? Assume that the molar heat of fusion of ice is 6 kJ/mol.

kJ


16. How many joules of energy are needed to boil 90 grams of water at its boiling point. Assume that the molar heat of vaporization of water is 41 kJ/mol.

kJ