temperature scales fahrenheit, celsius & kelvin. temperature is a measure of how hot or cold an...
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Temperature ScalesFahrenheit, 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.
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.
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
Temperature Scales
Fahrenheit, Celsius, and Kelvin reference points for the boiling and freezing points of water.
More About GasesCharles’ LawGay-Lussac’s Law
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.
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
Volume of balloon at
room temperature
Volume of balloon at
room temperature
Volume of balloon at 5°C
Volume of balloon at 5°C
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 = ?
2) Plug in the variables:
3) Cross multiply and solve
(500K)(3.0L) = V2(400K)
V2 = 3.75 L
=
=
3.0L V2
400K 500K
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
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
?
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