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PROPERTIES OF OPERATIONS ON

INTEGERS

Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings

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Temperature

Temperature

• is a measure of how hot or cold an object is compared to another object.

• indicates that heat flows from the object with a higher temperature to the object with a lower temperature.

• is measured using a thermometer.

Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings

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Temperature Scales

Temperature Scales

Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings

• are Fahrenheit, Celsius, and Kelvin.

• have reference points for the boiling and freezing points of water.

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A. What is the temperature of freezing water?

1) 0°F 2) 0°C 3) 0 K

B. What is the temperature of boiling water?

1) 100°F 2) 32°F 3) 373 K

C. How many Celsius units are between the boiling and freezing points of water?

1) 100 2) 180 3) 273

Learning Check

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A. What is the temperature of freezing water?

2) 0°C

B. What is the temperature of boiling water?

3) 373 K

C. How many Celsius units are between the boiling and freezing points of water?

1) 100

Solution

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• On the Fahrenheit scale, there are 180°F between the freezing and boiling points and on the Celsius scale, there are 100°C.

180°F = 9°F = 1.8°F 100°C 5°C 1°C

• In the formula for the Fahrenheit temperature, adding 32 adjusts the zero point of water from 0°C to 32°F.

TF = 9/5 TC + 32

or

TF = 1.8 TC + 32

Fahrenheit Formula

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• TC is obtained by rearranging the equation for TF.

TF = 1.8TC + 32

• Subtract 32 from both sides.

TF - 32 = 1.8TC ( +32 - 32)

TF - 32 = 1.8TC

• Divide by 1.8 = °F - 32 = 1.8 TC

1.8 1.8

TF - 32 = TC

1.8

Celsius Formula

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Solving A Temperature Problem

A person with hypothermia has abody temperature of 34.8°C. What is that temperature in °F?

TF = 1.8 TC + 32

TF = 1.8 (34.8°C) + 32° exact tenth's exact

= 62.6 + 32° = 94.6°F tenth’s Copyright © 2005 by Pearson Education, Inc.

Publishing as Benjamin Cummings

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The normal temperature of a chickadee is 105.8°F. What is that temperature on the Celsius scale?

1) 73.8°C

2) 58.8°C

3) 41.0°C

Learning Check

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3) 41.0 °C

TC = (TF - 32°) 1.8

= (105.8 - 32°) 1.8

= 73.8°F = 41.0°C 1.8°

Solution

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A pepperoni pizza is baked at 455°F. What temperature is needed on the Celsius scale?

1) 423°C

2) 235°C

3) 221°C

Learning Check

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A pepperoni pizza is baked at 455°F. What temperature is needed on the Celsius scale?

2) 235°C

TF - 32° = TC 1.8

(455 - 32°) = 235°C 1.8

Solution

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On a cold winter day, the temperature is –15°C.What is that temperature in °F?

1) 19°F

2) 59°F

3) 5°F

Learning Check

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3) 5°F

TF = 1.8 TC + 32

TF = 1.8(–15°C) + 32°= – 27 + 32°= 5°F

Note: Be sure to use the change sign key on your calculator to enter the minus – sign. 1.8 x 15 +/ – = –27

Solution

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The Kelvin temperature scale• has 100 units between the freezing and boiling points

of water. 100 K = 100°C or 1 K = 1°C

• is obtained by adding 273 to the Celsius temperature.

TK = TC + 273

• contains the lowest possible temperature, absolute zero (0 K).

0 K = –273°C

Kelvin Temperature Scale

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Temperatures

TABLE 2.5

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What is normal body temperature of 37°C in Kelvins?

1) 236 K

2) 310. K

3) 342 K

Learning Check

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What is normal body temperature of 37°C in kelvins?

2) 310. K

TK = TC + 273

= 37°C + 273

= 310. K

Solution