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13.1 Atomic Theory of Matter Based on analysis of chemical reactions

Brownian motion 1827 – first observed in pollen grains 1905 – Einstein explains motion and

calculates the average atomic diameter to be ~10-10 m

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13.2 Temperature and Thermometers

Variations result in changes to the size/shape and electrical resistance of materials.

Calibration using water – why?

Problems concerning pressure

Mercury vs. Alcohol

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13.4 Thermal Expansion The separation of atoms in a material is

related to its temperature.

ΔL = αLoΔT for solids

ΔV = βVoΔT for solids, liquids, gases

Applications: thermostats, Pyrex glass, bridges, sidewalks, sea levels

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13.4 Thermal Expansion

Water contracts when warmed from 0°C to 4°C then expands.

Fish, water pipes, road repair in the northern US

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13.6 The Gas Laws and Absolute Temperature The volume of a gas depends on

pressure and temperature. Equation of State and equilibrium

Boyle’s Law: PV = constant (T = constant)

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13.6 The Gas Laws and Absolute Temperature Charles’s Law: V/T = constant (P =

constant) Absolute zero and the Kelvin scale

Gay-Lussac’s Law: P/T = constant (V = constant)

Example: a closed container that is heated or cooled.

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13.7 The Ideal Gas Law Combining the previous gas laws and

including the amount of gas, we find that

PV α mT → PV = nRT

n is the number of moles of a gas

R is the universal gas constant 8.314 J/(mol K)

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13.9 Avogadro’s Number The ideal gas law can also be written in

terms of the number of molecules in the gas.

PV = NkT

N = nNA with NA = 6.02 x 1023 molecules/mol

k is the Boltzmann constant 1.38 x 10-23 J/K

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In class: Problems 10, 29 Other problems ↓

3

3

1.00 10 kg

1.00 m

M

V

6 o 3 o o 2 3

0 210 10 C 1.00 m 94 C 4 C 1.89 10 mV V T

33

3 2 3

1.00 10 kg981kg m

1.00 m 1.89 10 m

M

V

11. The density at 4oC is

When the water is warmed, the mass will stay the same, but the volume will increase according to Equation 13-2.

The density at the higher temperature is

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5 3 3

22

23

22 6 4 18 3

Earth

223 3

3 18 3

1.01 10 Pa 2.0 10 m 4.9 10 molecules

1.38 10 J K 300 K

Atmospheric volume 4 4 6.38 10 m 1.0 10 m 5.1 10 m

Galileo molecules 4.9 10 molecules9.6 10 molecules m

m 5.8 10 m

PVPV NkT N

kT

R h

3 33

3

# Galileo molecules molecules 2.0 10 m molecules9.6 10 19

breath m 1 breath breath

45. We assume that the last breath Galileo took has been spread uniformly throughout the atmosphere since his death. Multiply that factor times the size of a breath to find the number of Galileo molecules in one of our breaths.