Temperature Relationships Chapter 18 Temperature Relationships

P,V,T Inversely related P↓V↑ or P↑V↓ Directly related T↑V↑ or T↓V↓ Directly related T↑P↑ or T↓P↓

2L ? °C 1L 27°C heat 327°C 300 K 600 K

Charles' Law “The volume of a quantity of gas, held at constant pressure, varies directly with the Kelvin temperature.” An inflatable pool float may seem quite firm as it sits on a deck in the hot sun.  However, minutes after you toss to float into the cold pool, the same float may seem under-inflated.  You may suspect that the float has developed a slow leak, but that may not be the most likely explanation for the apparent loss of air pressure.  It may be that Charles's law is responsible.   Charles's law, discovered by Jacques Charles, states that the volume of a quantity of gas, held at constant pressure, varies directly with the Kelvin temperature.        Gases expand as they are heated and they contract when they are cooled.  In other words, as the temperature of a sample of gas at constant pressure increases, the volume increases.  As the temperature goes down, the volume decreases as well.  The mathematical expression for Charles's law is shown below: V1/T1 = V2/T2 Remember that Charles's law calculations must be done in the Kelvin scale.

Pressure vs. Temperature The pressure exerted by a gas is directly related to the Kelvin temperature if the volume is constant.

The type of container will determine what factor changes (volume or pressure) when the temperature is altered.

Why does bread rise when baked Why does bread rise when baked? (Hint: CO2 gas is produced by yeast action).

If you can install one thermostat in a two-story house, should it be placed on the first or second floor if a you are trying to save money on your heating bills?

Explain why car owners in severe northern climates often add air to their tires in the winter and release air from them when summer arrives.

225cm3 of gas are collected at 58°C 225cm3 of gas are collected at 58°C. What volume would the gas occupy at standard temperature? 186cm3

667cm3 of a gas at 431 K has the temperature changed to 41°C 667cm3 of a gas at 431 K has the temperature changed to 41°C. What is the new volume of the gas? 486 cm3

Man dies after explosion at party

NEW MILFORD, Conn. --Police were trying to determine who tossed a beer keg into an open fire at an outdoor party early Sunday, causing an explosion that sent shards of shrapnel slicing through a crowd of partygoers, killing one. The explosion, which could be heard miles away, killed Sean M. Caselli, 22, of New Milford. Police say seven other people were taken to New Milford and Danbury hospitals. Caselli died after being struck by a piece of flying metal in the neck, police said. Witnesses told police they saw someone put what appeared to be a quarter-keg of beer into one of the burning barrels just after 3 a.m. Robert Greco, who lives in the area, went to the scene after hearing the explosion. "It was an unbelievable explosion," Greco told the News-Times of Danbury. "It rattled the street."

An empty keg at 15°C and 425torr is thrown on a fire and explodes when the temperature reaches 1157°C. What was the internal pressure in the keg when it exploded? 2110 torr

Homework Worksheet: Temperature Relationships (Will Review in 2 Days.) Summarize the Purpose and Procedure of the “Gas Laws” Lab (Due in 3 Days). Study Guide Chapter 18 (Due in 3 Days).