Part 5: Combined Heat Calculations Substance Specific Heat AHfus for H2O: 6.01 kJ/mol H2O (s) 2.1 J/g°C 4.18 J/g C 1.7 J/g C H20 m AHvap for H2O: 40.7 kJ/mol H20 () Question #1: How many kilojoules of heat energy are needed to raise 23.0 g of H2O from -46°C to 109°C? Step 1: Calculate the heat needed to raise the temp of the ice from -46°C to 0°C. Step 2: Calculate the heat needed to melt the ice (solid to liquid). Step 3: Calculate the heat needed to raise the temp of the water from 0°C to 100°C. Step 4: Calculate the heat needed to vaporize the water (liquid to gas). Step 5: Calculate the heat needed to raise the temp of the gas from 100°C to 109°C. Step 6: To get the total amount of heat needed, ADD the amounts of heat calculated in steps 1-5. **Change all the amounts to kJ before you add!!! kJ TOTAL HEAT NEEEDED:

Part 5: Combined Heat Calculations Substance Specific Heat AHfus for H2O: 6.01 kJ/mol H2O (s) 2.1 J/g°C 4.18 J/g C 1.7 J/g C H20 m AHvap for H2O: 40.7 kJ/mol H20 () Question #1: How many kilojoules of heat energy are needed to raise 23.0 g of H2O from -46°C to 109°C? Step 1: Calculate the heat needed to raise the temp of the ice from -46°C to 0°C. Step 2: Calculate the heat needed to melt the ice (solid to liquid). Step 3: Calculate the heat needed to raise the temp of the water from 0°C to 100°C. Step 4: Calculate the heat needed to vaporize the water (liquid to gas). Step 5: Calculate the heat needed to raise the temp of the gas from 100°C to 109°C. Step 6: To get the total amount of heat needed, ADD the amounts of heat calculated in steps 1-5. **Change all the amounts to kJ before you add!!! kJ TOTAL HEAT NEEEDED:

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter6: Thermochemistry

Section: Chapter Questions

Problem 61E: A 5.00-g sample of aluminum pellets (specific heat capacity = 0.89 J/C g) and a 10.00-g sample of...

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A 250-g sample of water at 20.0C is placed in a freezer that is held at a constant temperature of 20.0C. Considering the water as the system, answer the following questions: a What is the sign of qsys for the water after it is placed in the freezer? b After a few hours, what will be the state of the water? c How will the initial enthalpy for the water compare with the final enthalpy of the water after it has spent several hours in the freezer? d What will the temperature of the water be after several hours in the freezer?
A sample of nickel is heated to 99.8C and placed in a coffee-cup calorimeter containing 150.0 g water at 23.5C. After the metal cools, the final temperature of metal and water mixture is 25.0C. If the specific heat capacity of nickel is 0.444 J/C g, what mass of nickel was originally heated? Assume no heat loss to the surroundings.
9.49 Hvap=31.3 kJ/mol for acetone. If 1.40 kg of water were vaporized to steam in a boiler, how much acetone (in kg) would need to be vaporized to use the same amount of heat?
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A sample of 0.562 g of carbon is burned in oxygen in a bomb calorimeter, producing carbon dioxide. Assume both the reactants and products are under standard state conditions, and that the heat released is directly proportional to the enthalpy of combustion of graphite. The temperature of the calorimeter increases from 26.74 C to 27.93 C. What is the heat capacity of the calorimeter and its contents?
You wish to heat water to make coffee. How much heat (in joules) must be used to raise the temperature of 0.180 kg of tap water (enough for one cup of coffee) from 30C to 96C (near the ideal brewing temperature)? Assume the specific heat is that of pure water, 4.18 J/(gC).
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9.57 The heat of combustion of butane is —2877 kJ/mol. Use this value to find the heat of formation of butane. (You may also need to use additional thermochemical data found in Appendix E.)
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In earlier times, ethyl ether was commonly used as an anesthetic. It is, however, highly flammable. When five milliliters of ethyl ether, C4H10O(l)(d=0.714g/mL), are burned in a bomb calorimeter, the temperature rises from 23.5C to 39.7C. The calorimeter contains 1.200 kg of water and has a heat capacity of 5.32 kJ/C. (a) What is qH2o? (b) What is qcal? (c) What is q for the combustion of 5.00 mL of ethyl ether? (d) What is q for the combustion of one mole of ethyl ether?