CHM 1032 Lecture Notes - Lecture 19: 2G, Heat Capacity

47 views2 pages

yellowoyster512

12 Sep 2016

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

The fahrenheit degree is five-ninths the size of a celsius degree. The celsius degree and the kelvin degree are the same size. We can convert between fahrenheit, celsius, and kelvin temperature scales using the following formulas: Heat capacity: the quantity of heat (usually in joules) required to change the temperature of a given amount of the substance by 1 c (also in kelvins). When the amount of the substance is expressed in grams, the heat capacity is called the specific heat capacity (or the specific heat) and has units of joules per gram per degree celsius, j/g c (also in kelvins). Notice that water has the highest specific heat capacity on the list. This data table is needed when solving homework problems. Heat = mass x specific heat capacity x temperature changechange q = m x c x t. Q is the amount of heat in joules. M is the mass of the substance in grams.

Related Questions

Chapter 2 introduced the Kelvin and Celsius temperature scales and related them to the Fahrenheit temperature scale commonly used in the United States.

A. How is the size of the temperature unit (degree) related between the Kelvin and Celsius scale?

B. How does the size of the temperature unit (degree) on the Fahrenheit scale compare to the temperature unit on the Celsius scale?

C. What is the normal freezing point of water on each of the three temperature scales?

D. Convert 27.5^oC to Kelvins and to Fahrenheit degrees.

E. Convert 298.1 K to Celsius degrees and to Fahrenheit degrees.

F. Convert 98.6^oF to Kelvins and to Celsius degrees.

violetwildebeest691

When 0.595 g of biphenyl (C12H10) undergoes combustion in a bomb calorimeter, the temperature rises from 25.4 âC to 29.9 âC.

Part A

Find ÎErxn for the combustion of biphenyl in kJ/mol biphenyl. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 5.86 kJ/âC.

Part B

Learning Goal: To understand the concepts of heat capacity, specific heat, and molar heat capacity. Heat capacity, C, is the amount of energy required to raise the temperature of a substance by exactly 1 degree Celsius. The energy needed to warm an object increases as the mass of that object increases. We see this in our everyday life. For example, we know that it takes much more energy to heat a large tank of water than a small cup. Because of this dependence on mass, experimentally determined heat capacities are always reported in terms of the amount of the substance that is heated. One method is to report how much energy it takes to raise the temperature of one mole of a substance by exactly 1 degree Celsius. This value is the molar heat capacity, which has the symbol Cp.The molar heat capacity is given in the units J/(molâ âC). A second method is to report how much energy it takes to raise the temperature of one gram of a substance by exactly 1 degree Celsius. This value is the specific heat, which has been given the symbol Cs. The units for specific heat are J/(gâ âC). The heat capacity of a substance is therefore related to the energy q needed to raise its temperature by an amount ÎT. That is, q=nCpÎT, where n denotes the number of moles of the substance, or q=mCsÎT, where m denotes the number of grams of the substance.

Part 1

It takes 55.0 J to raise the temperature of an 9.90 g piece of unknown metal from 13.0âC to 24.8 âC. What is the specific heat for the metal?

Express your answer with the appropriate units.

Part 2

The molar heat capacity of silver is 25.35 J/molâ âC. How much energy would it take to raise the temperature of 9.90 g of silver by 16.0 âC?

Express your answer with the appropriate units.

Part 3

What is the specific heat of silver? Express your answer with the appropriate units.

pearcockroach968

Heat Capacity

Learning Goal:

To understand the concepts of heat capacity, specific heat, and molar heat capacity.

Heat capacity, C, is the amount of energy required to raise the temperature of a substance by exactly 1 degree Celsius. The energy needed to warm an object increases as the mass of that object increases. We see this in our everyday life. For example, we know that it takes much more energy to heat a large tank of water than a small cup. Because of this dependence on mass, experimentally determined heat capacities are always reported in terms of the amount of the substance that is heated. One method is to report how much energy it takes to raise the temperature of one mole of a substance by exactly 1 degree Celsius. This value is the molar heat capacity, which has the symbol Cp.The molar heat capacity is given in the units J/(molâ âC). A second method is to report how much energy it takes to raise the temperature of one gram of a substance by exactly 1 degree Celsius. This value is the specific heat, which has been given the symbol Cs. The units for specific heat are J/(gâ âC).

The heat capacity of a substance is therefore related to the energy q needed to raise its temperature by an amount ÎT. That is, q=nCpÎT, where n denotes the number of moles of the substance, or q=mCsÎT, where m denotes the number of grams of the substance.

Part A

It takes 51.0 J to raise the temperature of an 11.1 g piece of unknown metal from 13.0âC to 24.3 âC. What is the specific heat for the metal?

Express your answer with the appropriate units.

Cs =

SubmitHintsMy AnswersGive UpReview Part

Parts B and C

The next two questions pertain to silver. They have nothing to do with unknown metal described in Part A.

Part B

The molar heat capacity of silver is 25.35 J/molâ âC. How much energy would it take to raise the temperature of 11.1 g of silver by 15.8 âC?

Express your answer with the appropriate units.

q =

SubmitHintsMy AnswersGive UpReview Part

Part C

What is the specific heat of silver?

Express your answer with the appropriate units.

SubmitHintsMy AnswersGive UpReview Part

CHM 1032 Lecture Notes - Lecture 19: 2G, Heat Capacity

Document Summary

Get access

Related Documents

PH 122 Chapter Notes - Chapter 18: Thermal Insulation, Thermal Energy, Pressure Measurement

ATOC 181 Lecture Notes - Lecture 4: Cool Air, Thermal Conductivity, Calorie

GEOL 102 Lecture Notes - Lecture 11: Thermodynamics, Black-Body Radiation

Related Questions