Chemistry 9

5 steps of scientific method

Ask a question, make a hypothesis, conduct an experiment, make a conclusion, share results

WHMIS stands for

workplace hazardous materials information system

MSDS stands for

material safety data sheet

three qualities of solids

rigid, fixed shape, fixed volume

three qualities of a liquid

not rigid, no fixed shape, fixed volume

three qualities of a gas

not rigid, no fixed shape, no fixed volume

Define matter

anything that has mass and occupies space

physical changes occur in two ways

increase in energy (heating) and decrease in energy (cooling)

Pure substances…

are made up of only one kind of matter and have a unique set of properties that are different from any other type of matter

elements…

cannot be broken down into simpler substances

compounds…

are created when 2 or more elements combine

chemically in fixed proportions

mixtures…

are combinations of pure substances that have not chemically combined to form a compound

how many types of mixtures are there?

four

What are the four types of mixtures?

Mechanical mixtures, solutions, suspensions, colloids

mechanical mixtures

If we looked at it we would be able to see the distinct substances that make it up.

solution

One substance (A) is dissolved into another (B) creating a substance that looks like one substance!

suspension

A cloudy mixture with tiny particles of one substance held within another. These particles CAN be separated out again.

colloid

Cloudy mixture where the particles are so small that they cannot be easily separated from each other.

qualitative

things you use your five senses for

quantitative

things you measure

you can observe both qualitative and quantitative blank

properties of matter

11 examples of physical properties of matter

• Shape/texture

• Colour

• State at room temperature

• Hardness

• Melting/boiling point

` Magnetism

• Density

• Conductivity

• Malleability

• Ductility

• Odour

5 characteristics to consider in chemical properties of matter

• How it reacts when mixed with acids

• Its ability to burn

• How it reacts with water

• Its behaviour in the air

• How it reacts with heat

yellow triangle means

caution

orange diamond means

warning

red hexagon means

danger

when two or more elements combine chemically they form what?

a compound

a pure substance may either be a

compound or element

four types of mixtures

mechanical, solution, suspension, colloid

mechanical mixture

you can visibly see the different substances

solution

substances are not separately visible (homogeneous)

suspension

cloudy mixture where the tiny mixtures can be separated out

colloid

cloudy mixture, cannot be easily separated out

two types of matter

pure substances and mixtures

how do you know chemical change has occured?

a change in colour, odour, state, thermal energy

All chemical reactions involve

energy

Energy is used to break blank in reactants, and energy is released when new blanks form in products

bonds

in terms of energy, there are two types of chemical reactions:

exothermic and endothermic

2 descriptions of endothermic reactions

absorb chemical energy and temperature decreases

two descriptions of exothermic reactions

release chemical energy and temperature increases

exothermic reaction example

burning firewood

endothermic reaction example

freezing an ice pack

blank take place when 2 or more substances combine to form a new substance

chemical reactions

2 parts of a chemical reaction:

reactants and products

Reactants:

the materials present at the start of a reaction

products:

the new materials produced by the reaction

the most common types of chemical reactions are those involving blank

oxygen

three examples of reactions in which oxygen reacts with other substances are:

combustion, corrosion and cellular respiration

combustion:

heat and pressure mixed with oxygen to create a reaction

combustion example

aerosol can react to heat

corrosion:

metal or another substance breaking down due to exposure to air or water

corrosion example:

rusting

cellular respiration

chemical reaction with sugars and air (think reactions within the body)

cellular respiration example

sugars for energy and oxygen to live

the law of conservation mass

states that matter is neither created nor destroyed in a chemical reaction

the total mass of products is always blank to the total mass of the reactants

equal

to prove the conservation law of mass, you must do your reactions in a blank

closed system

closed system

when matter is not allowed to leave or enter

open system

material is open to the atmosphere while reacting

concentration

the relative amount of a given substance contained within a solution or in a particular volume of space; the amount of solute per unit volume of solution

temperature

the degree or intensity of heat present in a substance or object, especially as expressed according to a comparative scale and shown by a thermometer or perceived by touch.

surface area

the outside part or uppermost layer of something (often used when describing its texture, form, or extent).

enzymes

a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.

four factors that can effect the rate of a chemical change

the presence of a catalyst, the concentration of the reactants, the temperature of the reactants, the surface area of the reactants

the greater the concentration of the reactants, the blank the reaction

faster

the more heat added to a reaction the blank it will occur

faster

temperature makes what move faster

atoms

increasing the surface area of the reactants will also

increase the rate of a reaction

Enzymes are not blank during the reaction

consumed

enzymes help reactions go

faster