Temperature Scales

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Temperature Scales Fahrenheit, Celsius & Kelvin

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Temperature Scales. Fahrenheit, Celsius & Kelvin. 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. - PowerPoint PPT Presentation

Transcript of Temperature Scales

Page 1: Temperature Scales

Temperature ScalesFahrenheit, Celsius & Kelvin

Page 2: Temperature Scales

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.

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Celsiusa unit of temperature in the metric system

Water freezes at 0° C. Water boils at 100° C. Normal body temperature is

37° C Room temperature is 21° C.

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Kelvinanother unit of temperature in the metric system.

The lowest possible temperature is 0 Kelvin (-273 ° C). This is Absolute Zero.

To convert from Celsius to Kelvin:

K = C°+ 273

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Temperature Scales

Fahrenheit, Celsius, and Kelvin reference points for the boiling and freezing points of water.

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More About GasesCharles’ LawGay-Lussac’s Law

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Charles’ LawJacques Charles determined the relationship between temperature and volume of a gas.He measured the volume of air at different temperatures, and observed a behavior pattern which led to his law.During his experiments pressure of the system and amount of gas were held constant.

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Temperature

The temperature of a gas is generally measured with a thermometer in Celsius. All calculations involving gases should be made after converting the Celsius to Kelvin temperature.

Kelvin = C° + 273

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Volume of balloon at

room temperature

Volume of balloon at

room temperature

Volume of balloon at 5°C

Volume of balloon at 5°C

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Charles’ Law

Example: A gas has a volume of 3.0 L at 127°C. What is its volume at 227 °C? V1 V2

T1 T2

=

T1 = 127°C + 273 = 400K

V1 = 3.0 L

T2 = 227°C + 273 = 500K

V2 = ?

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2) Plug in the variables:

3) Cross multiply and solve

(500K)(3.0L) = V2(400K)

V2 = 3.75 L

=

=

3.0L V2

400K 500K

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Gay-Lussac’s Law: P and T

In Gay-Lussac’s Law

the pressure exerted by a gas is directly related to the Kelvin temperature.

Volume and the amount of gas are constant.

P1 = P2

T1 T2

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Calculation with Gay-Lussac’s Law

A gas has a pressure at 2.0 atm at 18°C. What is the new pressure when the temperature is 62°C? (Volume and the amount of gas are constant)

1. Set up the problem:

P1 = 2.0 atm P2 =

T1 = 18°C + 273 T2 = 62°C + 273 = 291 K = 335 K

?

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Calculation with Gay-Lussac’s Law (continued)

2. Solve Gay-Lussac’s Law for P2:

P1 = P2

T1 T2

P2 = P1 x T2

T1

P2 = 2.0 atm x 335 K = 2.30 atm 291 K