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You need your calculator and paper to write on

You need your calculator and paper to write on. You will need the chart on page 2 for one of the problems. How many joules of energy is required to change 50mL of liquid water at 85ºC to steam at 115ºC? Some helpful information: ΔH vap (water ) = 40.7 kJ/mol

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You need your calculator and paper to write on

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  1. You need your calculator and paper to write on You will need the chart on page 2 for one of the problems.

  2. How many joules of energy is required to change 50mL of liquid water at 85ºC to steam at 115ºC? Some helpful information: ΔHvap(water) = 40.7 kJ/mol ΔHfus(water) = 6.01 kJ/mol Freezing temperature of water = 0.06ºC Boiling temperature of water = 99.4ºC Answer: 117,000 Approx 7 minutes

  3. An 8.50-gram sample of an unknown metal at 118ºC is placed into a coffee-cup calorimeter containing 35.0 mL of water. The water’s temperature increased from 35.000ºC to 36.793ºC. What is the identity of the metal? [You will need to use your packet chart.] Answer: Brass Approx 7 minutes

  4. A 3-gram sample of heptane, C7H16, is combusted with 1,050 mL of oxygen gas at STP. ΔH = - 4819 J/mol rxn. • Write the balanced reaction. • How much energy will be produced? • The energy is used to heat 90 grams of water originally at 17°C. What is the final temperature of the water? Answers: 2) -20.5 J 3) 17.05°C When you finish, get your packet out and work some extra problems!!! No sitting around! Approx 15 minutes

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