Heat Problems

1. Heat Problems

2. The specific heat of lead is 0.129 J/g°C. Find the amount of heat released when 497.28 g of lead are cooled from 37.2°C to 22.5°C.

3. 225.0 J of heat are applied to an 87.0 g sample of water. If the sample’s temperature was initially 18.9 °C , what will it’s final temperature be? The specific heat of water is 4.184J/g °C .

4. While taking a relaxing bubble bath one evening, Cindy wonders how much heat would be needed to convert a tub full of 50.5 L of water at 46.8 °C to steam at 100.0 °C. She knows that ΔHvap = 40.7kJ/mol for water and that Cwater = 4.184 J/g °C. Can you tell Cindy how much heat would be needed? • Then Cindy began to wonder if she could accomplish this task by burning Honey Buns. According to the nutrition label, each Honey Bun is equal to 650,000 J of energy!! Can you tell Cindy how many Honey Buns she would need to burn to turn the tub water into steam?

5. Cice= 2.108 J/g°CCwater= 4.186 J/g°CCsteam= 1.996 J/g°C ∆Hfus = 6.02 kJ/mol∆Hvap= 40.7 kJ/mol What is the change in enthalpy when 10.00 g of ice at -15.00°C is converted to liquid water and heated to 25°C? What is the change in enthalpy when 17.50 mL of water at 60.00°C is converted to steam and heated to 112.00°C ?

6. Cice= 2.108 J/g°CCwater= 4.186 J/g°CCsteam= 1.996 J/g°C ∆Hfus = 6.02 kJ/mol, ∆Hvap = 40.7 kJ/mol 1. What is the change in enthalpy when 32.00 g of ice at -5.00°C is converted to steam and heated to 122.00°C? 2. What is the change in enthalpy when 20.0 g of steam at 107°C is condensed into a liquid and cooled to 35°C? 3. What is the change in enthalpy when 85.0 g of water at 78°C freezes and cools to a solid at -

7. Cice= 2.108 J/g°CCwater= 4.186 J/g°CCsteam= 1.996 J/g°C∆Hfus = 6.02 kJ/mol, ∆Hvap = 40.7 kJ/mol • What is the change in enthalpy when 15.25g of ice at -25.0°C is heated to liquid water at 19.0°C? • What is the change in enthalpy when 23.4g of steam at 112°C is cooled to a solid at -21°C?