Grade Nine Science

Properties of Matter II

Day 2: Handouts to Review

Matter concept map.

Blackline master 1.2 “Properties of Matter”.

Identify the property that best fits.

1.5 Density

• Which is heavier: a 12 inch bar of gold or a pillow full of feathers?

• A 12 inch bar of gold weighs more than a pillow full of feathers even though the pillow takes up more space. Why?

• Gold is more dense. It has more matter per unit volume.

1.5 Density

• Density is the amount of matter per unit volume of that matter.

• Density(D) = Mass(m) / Volume(V)• If you know any two of the three variables

(D,m, or V), you can solve for the third. m = D x V V = m / D

Sample density question #1

If a rock has a mass of 49 g and occupies a volume of 7 cm3, what is the density?

D = m / V = 49 g / 7 cm3

= 7.0 g/ cm3

Solve these sample density questions

1. An object has a mass of 250 g and occupies a volume of 14.5 cm3, what is the density?

2. A piece of wood occupies a volume of 46 cm3 and it has a mass of 100 g. What is the density of the wood?

3. An unknown metal has a density of 2.6 g/cm3 and a mass of 15 g. How much volume does this piece of metal occupy?

4. A sample of a particular liquid has a density of 6.85 kg/L and it occupies a volume of 3.4 L. How much does this particular sample weigh?

Answer to question #1

D = m / V = 250 g / 14.5 cm3

= 17.24 g/ cm3

Answer to question #2

D = m / V = 100g / 46 cm3

= 2.17 g/ cm3

Answer to question #3

D = m / VV = m / D = 15 g / 2.6 g/cm3 = 5.77 cm3

Answer to question #4

D = m / VM = D x V = 6.85 kg/L x 3.4 L = 23.29 kg

** Note that volume can be expressed as cm3, m3, ml or even L.

Approximate Densities of Some Common Materials

Substance Den sitykg/m3 g/cm3

Gold 19300 19.3Silver 10500 10.5Aluminum 2700 2.7Ice 920 .92Wood (birch) 660 .66Distilled Water 1000 1.0

Water is more dense than ice!

• Why is this so important?– It means that ice floats in water instead of

sinking. Think of the poor fish if this was the not the case.

• Why is ice less dense than water?– When water freezes, it expands which means

that the same mass of water is spread over a greater volume.

Homework

• Answer questions 2,3,4 on page 25 of the text.

Day 3: Lab #1 Identifying Substances