1. How many Joules of energy are required to raise the temperature of 75 g of water from 20.0 o C to 70.0 o C? Heat =75 g x 50.0 o C x 4.18 J/g o C Heat= mass x ∆T x specific heat Heat = 15675 J~ 16,000 J= 16 kJ

2. A 250.0 g metal bar requires 5.866 kJ to change its temperature from 22 o C to 100.0 o C. What is the specific heat of the metal? Heat = mass x ∆T x specific heat 5.866 kJ = 250.0 gx 78 o Cx C p C p = 5.866 kJ = 250.0 g x 78 o C 0.00030 kJ g o C = 0.30 J g o C

3. The specific heat of zinc is 0.096 cal/g o C. Determine the energy required to raise the temperature of 250.0 g of zinc from room temperature (24 o C) to 150.0 o C. x 0.096 cal/g o CHeat =250.0 g x 126 o C Heat = mass x ∆T x specific heat = 3.0 x 10 3 cal = 3.0 kcal Heat = 3024 cal

4. A 20.0 g piece of metal at 203 o C is dropped into 100.0 g of water at 25.0 o c. The water temperature rises to 29.0 o C. Calculate the specific heat of the metal(J/g o C). Assume that all of the heat lost by the metal is transferred to the water and no heat is lost to the surroundings. Heat = mass x ∆T x specific heat Heat lost by metal = Heat gained by water

5. Heat = mass x ∆T x specific heat Heat lost by metal = Heat gained by water Heat lost by metal: Heat gained by water: Heat =100.0 gx (29.0 – 25.0) o C x 4.18 J/g o C = 1672 J= 1700 J 1700 J =20.0 g x 174 o C x Cp Cp = 1700 J = 20.0 g x (203 – 29.0) o C.49 J/g o C