In the laboratory a "coffee cup" calorimeter, or constant pressure calorimeter, is frequently used to determine the specific heat of a solid, or to measure the energy of a solution phase reaction. Water Thermometer Metal sample Stirring rod Since the cup itself can absorb energy, a separate experiment is needed to determine the heat capacity of the calorimeter. This is known as calibrating the calorimeter and the value determined is called the calorimeter constant. One way to do this is to use a common metal of known heat capacity. In the laboratory a student heats 100.00 grams of nickel to 98.10 °C and then drops it into a cup containing 79.36 grams of water at 23.62 °C. She measures the final temperature to be 32.36 °C. Using the accepted value for the specific heat of nickel (See the References tool), calculate the calorimeter constant. Calorimeter Constant = J/°C

In the laboratory a "coffee cup" calorimeter, or constant pressure calorimeter, is frequently used to determine the specific heat of a solid, or to measure the energy of a solution phase reaction. Water Thermometer Metal sample Stirring rod Since the cup itself can absorb energy, a separate experiment is needed to determine the heat capacity of the calorimeter. This is known as calibrating the calorimeter and the value determined is called the calorimeter constant. One way to do this is to use a common metal of known heat capacity. In the laboratory a student heats 100.00 grams of nickel to 98.10 °C and then drops it into a cup containing 79.36 grams of water at 23.62 °C. She measures the final temperature to be 32.36 °C. Using the accepted value for the specific heat of nickel (See the References tool), calculate the calorimeter constant. Calorimeter Constant = J/°C

Chemistry for Engineering Students

4th Edition

ISBN:9781337398909

Author:Lawrence S. Brown, Tom Holme

Publisher:Lawrence S. Brown, Tom Holme

Chapter9: Energy And Chemistry

Section: Chapter Questions

Problem 9.94PAE

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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?
Consider the combustion of propane: C3H8(g)+5O2(g)3CO2(g)+4H2O(l)H=2221KJ Assume that all the heat in Example 7-3 comes from the combustion of propane. What mass of propane must be burned to furnish this amount of energy assuming the heat transfer process is 60.% efficient?
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9.50 When a 13.0-g sample of NaOH(s) dissolves in 400.0 mL of water in a coffee cup calorimeter, the temperature of the water changes from 22.6°C to 30.7C Assuming that the specific heat capacity of the solution is the same as for water, calculate (a) the heat transfer from system to surroundings and (b) H for the reaction NaOH(s)Na+(aq)+OH(aq)
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The reaction SO3(g)+H2O(l)H2SO4(aq) is the last step in the commercial production of sulfuric acid. The enthalpy change for this reaction is 227 kJ. In designing a sulfuric acid plant, is it necessary to provide for heating or cooling of the reaction mixture? Explain.
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?
A sample of ethanol, C2H5OH, weighing 2.84 g was burned in an excess of oxygen in a bomb calorimeter. The temperature of the calorimeter rose from 25.00C to 33.73C. If the heat capacity of the calorimeter and contents was 9.63 kJ/C, what is the value of q for burning 1.00 mol of ethanol at constant volume and 25.00C? The reaction is C2H5OH(l)+3O2(g)2CO2(g)+3H2O(l) Is q equal to U or H?
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What is the difference between the enthalpy of reaction and the enthalpy of formation? For what chemical reaction(s) are the two quantities the same?