FUNDAMENTAL Physics – Matters : 2.1 Matter and Density

Matter and Density

Learning Objectives What are the three states of matter How do particles behave in the three states of matter Name and describe the processes of changing state. Recall and use the formula for density Describe how to determine the density of regular solids, irregular solids,

liquids and gases.

The 3 states of matterThe 3 states of matter are …solid…….. , …liquid…….. and …gas…….

Solid Liquid Gas

Particle arrangement

Closely …packed…….

…Regular.. arrangement (lattice)

Closely …packet….No fixed/no regular arrangement. …Randomly…. arranged.

…Spread…. outLarge ..Spaces. between particles. …randomly.. arranged.

Particle movement

…vibration…. only Move randomly but with limited …… .Slide past each other

Particles are free to move. Particles move ……… at high speed. Particles ………. off each other and the walls, which exerts a force.

Forces between particles

Strong, spring-like forces.Fixed in place

Strong forces of attractions

Zero (Ideal gas)

Particles in all states of matter are constantly ……in motion……...

This is called the …kinetic…. THEORY of matter.

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FUNDAMENTAL Physics – Matters : 2.1 Matter and Density

Changing State

……sublimation……..

…melting.... …evaporation..….

Solid Liquid Gas

…freezing../…solidification… …condensation…..

… deposition……

We need to describe:

MeltingMelting is the change of state where a …solid.… becomes a …liquid… at the …melting.. point. The …melting. Point is the temperature at which the solid melts.

Boiling Boiling is the change of state where a …liquid…… becomes a …gas… at the …boiling….. point. The …boiling…. Point is the temperature at which the liquid boils.

EvaporationEvaporation is the change of state where a …liquid… becomes a …gas… at a temperature …hotter….. than the boiling point.

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FUNDAMENTAL Physics – Matters : 2.1 Matter and Density

Density

Density is a measure of how much ………… is present in each unit …………… .

Density = mass / volume

(kg/m3) (Kg) (m3)Or (g/cm3) (g) (cm3)

The symbol for density is the Greek letter ρ ‘Roe’

So ρ = mass / volume

We will conduct experiments to determine the density of:

a. Regular solids

b. Irregular solids

c. Liquids

d. Gases

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FUNDAMENTAL Physics – Matters : 2.1 Matter and Density

A. How to determine the Density of a regular object.

Method1. Measure mass on a balance

2. Measure dimensions using Vernier callipers.

3. Repeat measurements and calculate average dimensions

4. Calculate volume

5. Calculate density

Eg 1. Density of a …aluminum…. cuboid:

1. Mass measure by a balance = ...22.44… g

2. Dimensions; length = …1.82... cm, width = ….1.82… cm, height = …1.82... cm

3. Volume = l x w x h = …1.82….. x …1.82… x ……1.82…. = …6.03… cm3 (3.s.f)

4. Density = mass / volume = …22.4…. / …6.03…. = …3.71…. g/cm3 (3.s.f)

Eg 2. Density of a brass sphere:

1. Measure mass by a balance = …26.10….. g

2. Dimensions; diameter = …1.62… cm, radius = … 0.81 .. cm

3. Volume = 4/3 x π x r3 = 4/3 x π x ……….3 = ……………. cm3

4. Density = mass / volume = ………. / …………. = ………. g/cm3

Homework: P 17 Q 1- 9

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Safety.

Careful with sharp points on Vernier callipers.

FUNDAMENTAL Physics – Matters : 2.1 Matter and Density

B – Determine Density of an Irregular Solid

Method1. Measure mass using top-pan balance

2. Measure Volume by displacement of water. (the Ureka moment), using one of these techniques:

2a. For small objects measure displaced volume using a measuring Cylinder.

Measure accurately approximately 50cm3 of water in a measuring cylinder.

Submerge object

Measure new volume

Displaced Vol = new vol – original vol

2b. For larger objects measure displaced volume using a displacement can.

Fill a displacement can to overflowing.

Submerge object

Measure displaced volume using a measuring cylinder

Note - if the object floats, press it down with a tiny stick to fully submerge it.

3. Repeat displaced volume measurement to get an average.

4. Calculate Density using

Density = Mass / volume

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New Vol

Orig. Vol

Safety.

Beware of spills which are a slip hazard.

FUNDAMENTAL Physics – Matters : 2.1 Matter and Density

C. Determine Density of a Liquid.

Method

1. Place an empty measuring cylinder on a top pan balance

2. Hit TARE to zero reading.

3. Add approx 50cm3 of the liquid.

4. Record the mass.

5. Accurately measure the volume.

6. Calculate the density using:

Density = mass / volume

7. Repeat and calculate an average.

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Safety.

Beware spills which are a slip hazard.

In particular, oil spills must be wiped up immediately.

50.00g00.00g

Read to the ……….…….. of the meniscus.

FUNDAMENTAL Physics – Matters : 2.1 Matter and Density

D. Determine Density of a Gas, eg Carbon Dioxide

Method

1. Place conical flask with limestone chips and beaker of 0.2M HCl on a top pan balance

2. Hit TARE to zero reading.

3. Add approx 10ml of acid to excess of limestone chips.

4. Accurately measure volume of gas by downward displacement of water, once bubbles have stopped being released.

5. Remove the delivery tube and record the mass loss from reactants.

6. Calculate the density using:

Density of gas = mass lost / volume collected

7. Repeat and calculate an average.

Homework P19, Q1-2 and P20, Q 1 - 2

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Safety.

Acids are corrosive

Use safety goggles

00.00g

0.2MHCl

Limestone Chips

FUNDAMENTAL Physics – Matters : 2.1 Matter and Density

Extension:

Does an egg float:

http://www.youtube.com/watch?v=fqLCwuKMBMA

It depends ……

1. On the liquid…..2. On the egg …..

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