Energy Requirements for the Changes of State

I. VIDEO ON ENERGY REQUIREMENT

A. For Specific Heat of Matter

B. For Changes of State (Molar Heat of Fusion & Vaporization)

II. NOTES FOR ENERGY REQUIREMENT

A. Diagram for heating curve

III. EXERCISE FOR ENERGY REQUIREMENT

1. A 466-g sample of water is heated from 8.50C to 74.60C. Calculate the amount of heat absorbed (in kilojoules) by the water. (specific heat of water= 4.184 J/g C)

2. An iron bar of mass 869 g cools from 94C to 5C. Calculate the heat released (in kilojoules) by the metal. (specific heat of iron =0.444 J/g C)

3. A piece of silver of mass 362 g has a heat capacity of 85.7 J/C. What is the specific heat of silver?

4. Calculate the amount of energy (in kJ) needed to heat 346 g of liquid water from 0C to 182C. Assume that the specific heat of water is 4.184 J/g C over the entire liquid range and the specific heat of steam is 1.99 J/g C. The molar heat of vaporization of water is 40.79 kg/mol.

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