An insulated jar containing 200 g of solid candle wax is placed on a hot plate that supplies heat energy to the wax at the rate of 220 J/s. The wax temperature is measured every 30 s, yielding the following data: Time (s) Temperature C) 0 20.0 30 31.7 60 42.2 90 55.0 120 64.7 150 70.4 180 70.5 210 70.5 240 70.6 270 70.5 Table 1: Problem 2 data. 300 330 70.4 74.5 What are the specific heat of the solid wax, the melting point, and the wax's heat of fusion? You may need a linear regression, which you may do in a spreadsheet or programming language of your choice.

An insulated jar containing 200 g of solid candle wax is placed on a hot plate that supplies heat energy to the wax at the rate of 220 J/s. The wax temperature is measured every 30 s, yielding the following data: Time (s) Temperature C) 0 20.0 30 31.7 60 42.2 90 55.0 120 64.7 150 70.4 180 70.5 210 70.5 240 70.6 270 70.5 Table 1: Problem 2 data. 300 330 70.4 74.5 What are the specific heat of the solid wax, the melting point, and the wax's heat of fusion? You may need a linear regression, which you may do in a spreadsheet or programming language of your choice.

Chemistry by OpenStax (2015-05-04)

1st Edition

ISBN:9781938168390

Author:Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark Blaser

Publisher:Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark Blaser

Chapter5: Thermochemistry

Section: Chapter Questions

Problem 20E: A 45-g aluminum spoon (specific heat 0.88 J/g C) at 24 C is placed in 180 mL (180 g) of coffee at 85...

See similar textbooks

Similar questions

A 500-g sample of one of the substances listed in Table 7-1 was heated from 25.2C to 55.1C, requiring 133 J to do so. Which substance was it?
How fast (in meters per second) must an iron ball with a mass of 56.6 g be traveling in order to have a kinetic energy of 15.75 J?
The complete combustion of acetylene, C2H2(g), produces 1300. kJ of energy per mole of acetylene consumed. How many grams of acetylene must be burned to produce enough heat to raise the temperature of 1.00 gal water by 10.0c if the process is 80.0% efficient? Assume the density of water is 1.00 g/cm3
The second law of thermodynamics has been called the arrow of time. Explain why this is so.
A cubic piece of uranium metal (specific heat capacity = 0.117 J/C g) at 200.0C is dropped into 1.00 L deuterium oxide ("heavy water;" specific heat capacity = 4.21 I J/C g) at 25.5C. The final temperature of the uranium and deuterium oxide mixture is 28.5C. Given the densities of uranium (19.05 g/cm3) and deuterium oxide (1.11 g/mL). what is the edge length of the cube of uranium?
In the 1880s, Frederick Trouton noted that the enthalpy of vaporization of 1 mol pure liquid is approximately 88 times the boiling point, Tb, of the liquid on the Kelvin scale. This relationship is called Troutons rule and is represented by the thermochemical equation liquid gas H = 88 Tb, joules Combined with an empirical formula from chemical analysis, Troutons rule can be used to find the molecular formula of a compound, as illustrated here. A compound that contains only carbon and hydrogen is 85.6% C and 14.4% H. Its enthalpy of vaporization is 389 J/g, and it boils at a temperature of 322 K. (a) What is the empirical formula of this compound? (b) Use Troutons rule to calculate the approximate enthalpy or vaporization or one mole of the compound. Combine the enthalpy of vaporization per mole with that same quantity per gram to obtain an approximate molar mass of the compound. (c) Use the results of parts (a) and (b) to find the molecular formula of this compound. Remember that the molecular mass must be exactly a whole-number multiple of the empirical formula mass, so considerable rounding may be needed.
A system releases 125 kJ of heal while 104 kJ of work is done on it. Calculate E.
9.86 You make some iced tea by dropping 134 g of ice into 500.0 mL of warm tea in an insulated pitcher. If the tea is initially at 20.0°C and the ice cubes are initially at 0.0°C, how many grams of ice will still be present when the contents of the pitcher reach a final temperature? The tea is mostly water, so assume that it has the same density (1.0 g/mL), molar mass, heat capacity (75.3 J K-1 mol-1), and heat of fusion (6.0 kJ/mol) as pure water. The heat capacity of ice is 37.7 J K-l mol-l.
Which is the least expensive source of energy in kilojoules per dollar: a box of breakfast cereal that weighs 32 ounces and costs $4.23, or a liter of isooctane (density, 0.69 19 g/mL) that costs $0.45? Compare the nutritional value of the cereal with the heat produced by combustion of the isooctane under standard conditions. A 1.0-ounce serving of the cereal provides 130 Calories.
Swimming Pool A swimming pool measuring 20.0m12.5m is filled with water to a depth of 3.75m. If the initial temperature is 18.4°C, how much heatmust be added to the water to raise its temperature to29.0°C? Assume that the density of water is 1.000 g/mL.
A 45-g aluminum spoon (specific heat 0.88 J/g C) at 24 C is placed in 180 mL (180 g) of coffee at 85 C and the temperature of the two become equal. (a) What is the final temperature when the two become equal? Assume that coffee has the same specific heat as water. (b) The first time a student solved this problem she got an answer of 88 C. Explain why this is clearly an incorrect answer.
In the “Chemistry in Focus” segment Firewalking: Magic or Science?, it is claimed that one reason people can walk on hot coals is that human tissue is mainly composed of water. Because of this, a large amount of heat must be transferred from the coals to change the temperature of the feet significantly. How much heat must be transferred to 100.0 g of water to change its temperature by 35 °C?