Chemical and Physical

Properties

Cake Survey

• Vanilla or chocolate? Why?

• Why does a vanilla cake taste different than a

chocolate cake? They are both cakes aren’t they?

Property

• Property: a characteristic that describes a substance

(e.g. colour, reactivity, taste, smell, hardness).

• Pure gold properties:

-yellow

-very soft

• Iron properties:

-silver coloured

-very hard

• Both are metals yet have different properties. Why?

• All matter is made up of different types and combinations of

particles. The particles of gold (Au) are different than the

particles of Iron (Fe).

Classifying Matter

Property: a characteristic

that describes a substance

(e.g. colour, reactivity, taste,

smell, hardness).

Physical Property:

describes a characteristic of a

substance that can be

observed or measured without

changing the substance.

Chemical Property:

describes the ability of

a substance to change into

a new substance or substances.

More on Physical Properties• Physical Change: the physical properties of a

substance can change without changing what

the substance actually is (which is a picture of

water?).

heat heat

Physical Properties

• Colour

• Lustre

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

This coin is the colour of Gold

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

This coin is shiny Concrete is dull

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

A copper wire allows

electricity to flow

through it (conductor).

A fur coat traps all of my

body heat to stop me

from getting cold

(Insulator)

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

Copper is a metal that can be

stretched into long wire.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

Quartz scratches calcite

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

Aluminum (and play doh) can be

pounded or rolled into sheets. It can

be shaped without breaking.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

Water flows more (quicker) than

maple syrup.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

The bottle above is transparent and

green.

Some more on Clarity

• Transparent (clear): Substances that you can see through very clearly (window glass).

• Translucent (clear):

Substances that you

can see through but not

as clearly (stain glass

windows).

• Opaque (not clear):

Substances that you

cannot see through at

all.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

Water begins to evaporate at 100 ºC.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Melting point, boiling point, freezing point

Ice can float on liquid water due to

this property.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Hardness

• Malleability

• Viscosity

• Clarity

• Brittleness

My glass vase shattered into several

pieces when I dropped it.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Odour

• Malleability

• Viscosity

• Clarity

• Brittleness

This man’s urine smells like

asparagus. Note the way he is

“wafting”.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Ductility

• Odour

• Malleability

• Taste

• Clarity

• Brittleness

The lemon is sour. Why will we not

use this property very often in our

labs?

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Form (shape)

• Odour

• Malleability

• Taste

• Clarity

• Brittleness

Corn starch is an amorphous power.

Salt has a cube-shaped crystalline

structure.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Density

• Form (shape)

• Odour

• Malleability

• Physical state

• Clarity

• Brittleness

The Corn starch is solid.

Physical Properties

• Colour

• Lustre (shine)

• Conductivity

• Solubility

• Form (shape)

• Odour

• Malleability

• Physical state

• Clarity

• Brittleness

I can dissolve sugar (or sweetener) into my

coffee with a little bit of stirring.

More on Solubility

1) No new substances are formed when dissolving sugar in coffee. The coffee molecules surround the sugar molecules.

2) It is a mixture of two substances that are not chemically combined (coffee remains coffee and sugar remains sugar).

Quantitative Qualitative

Physical properties: Quantitative or

Qualitative (summary)

-Density: in g/ml

-Solubility: how much of a substance

can dissolve in a certain amount of

solvent.

-Melting/freezing/boiling point: in ºC

-Mass: in grams (g)

-Volume: in mL or L

-Colour/Lustre: Colour and shine

-Brittleness: Does it shatter?

-Texture/Form: Amorphous/Crystalline?

-Physical State: Solid, liquid, gas

-Odour: How does it smell?

-Taste: Salty/Sour/Bitter/Sweet?

-Malleability: Pounded into sheets?

-Ductility: Stretched into wire?

-Clarity: Transparent/Translucent/Opaque

-Hardness: Hard substances scratch soft.

-Conductivity: Conducts electricity/heat.

Property: a characteristic

that describes a substance

(e.g. colour, reactivity, taste,

smell, hardness).

Physical Property:

describes a characteristic of a

substance that can be

observed or measured without

changing the substance.

Chemical Property:

describes the ability of

a substance to change into

a new substance or substances.

More on Chemical Properties• Chemical properties can only be observed when a

chemical change (new substance is formed)occurs.

• Chemical changes occur during chemical reactions. In this case the change in physical properties occurs due to the formation of a new substance!

• Chemical reaction: Interaction between substances that results in the formation of new substances.

Chemical Properties

• Absorbs heat during reaction

• Combustible

• Forms gas

• Reacts with acid

• Reacts with water

• Emits heat during reaction

• Forms a precipitate (solid) in a solution

Absorbs heat during a reaction

• Endothermic reaction:

• Absorbs heat during a

reaction.

Chemistry of Cold Packs

• The chemical cold pack is filled with water.

• It also contains a small bag or tub full of chemicals.

• The inner compartment keeps its contents separated from the water until it is time to use the cold pack.

• When the inner bag is popped open, the chemicals within mix with the water in the cold pack.

• The reaction removes heat from the surroundings and so feels cold to the touch.

How it works?Membrane separating a

chemical from the water

Water

Chemical

Emits heat during a reaction

• Exothermic reaction:

• Emits heat during a

reaction.

Emits Light During a Reaction

When luciferin (a chemical in fireflies)

reacts with oxygen,

a reaction occurs and light is emitted.

Luciferin + O2 � Oxyluciferin + light

Forms a gas when

heated

• When baking powder is

heated, a reaction occurs

and carbon dioxide gas is

produced.

• In cooking, this helps lift the

cake and make it light/fluffy.

-Forms a

precipitate (solid)

in a solution.

-The precipitate

is a new

substance.

Combustibility

• The ability of a substance to react quickly with

oxygen to produce heat and light. When you

light a BBQ, propane gas reacts with oxygen to

produce carbon dioxide gas, water, and heat

(often seen as large explosions)!

Evidence of a chemical change

• 1) Colour change

• 2) Temperature change

• 3) Precipitate formation inside a liquid

• 4) Odour/taste change

• 5) Production of a new gas

Chemical Reactions

Reactant (s) � Product (s)A substance that undergoes a

chemical reaction (left)

A new substance that is formed

in a chemical reaction (right)

Evidence of Chemical Reactions

• 1) Colour Change: Lugol’s iodine solution.

• Is dissolving blue cool-aid into water to

give a blue coloured drink a chemical

change?

Lugol’s

Iodine

solution

Evidence of Chemical Reactions

• Temperature change (without you having to

add heat in or take heat out).

Evidence of Chemical Reactions

• Precipitate formation: Formation of a NEW

solid inside a liquid.

-Example:

• Ice water � Liquid water = chemical

change?.

-Forms a

precipitate (solid)

in a solution.

-The precipitate

is a new

substance.

KI(l) + PbNO3(l) � PbI(s) + KNO3(l)

New substance

formed (precipitate)

Evidence of Chemical Reactions

• Odour/Flavour Change: e.g. when milk

spoils

Evidence of chemical reactions

• Production of a new gas.

When

vinegar and

baking soda

react, a new

gas (CO2) is

formed.

How do we know if it is a chemical

change or a physical change?• The product is a different substance than the reactant!

Different

Heat

Heat Heat

Heat Heat

Liquid waterIce water

Heat Heat HeatHeat

Heat Heat

Liquid waterIce water