Chemistry 4: Change in Matter

ppt. by Robin D. Seamon

M A T T E RMatter: anything that has mass and takes up space• Mass: measure of how much matter is in an

object• Law of conservation of mass- mass is

conserved- the amount of atoms cannot change; nothing is created or destroyed

• Melting point• Boiling point• Electrical

conductivity• Color• Density

• Thermal conductivity

• Ductility• Malleability• shape• smell

Physical properties- anything that can be observed without changing the identity of the substance

methane oxygen water

• Heat of combustion• Reactivity with

water• pH• Oxidation

• flammability• Reactivity to other

chemicals

Chemical properties- the types of changes matter can undergo; the chemical composition of the substance changes; the arrangement of its atoms changes (number stays the same)

Can ONLY be observed AS substances are changing

carbon dioxide

M A T T E R C A N C H A N G E

Physically• Physical reaction• Physical change

Chemically• Chemical reaction• Chemical change

Change in mass, volume, density, state, color, shape

A new substance is made as a result of the reaction; cannot be undone

Special physical changes:

Change of state operations: when object changes state (from solid, liquid, & gas)

Examples: PHYSICAL CHANGES

BoilingFreezingMeltingDissolvingBreakingMaking a mixture

PHYSICAL CHANGE:

Making Orange Juice

Photosynthesis

Cellular respiration

Decomposition

Examples: CHEMICAL CHANGES-change the way the atoms are arranged

Combustion of methane

Combustion of wood

Iron oxidation (rust)

CHEMICAL CHANGES

• Wood burns to create ash and smoke

• Iron oxidizes (rusts)

• Vinegar & baking soda create a gas

Baking sodavinegar +

flammability

reactivity

Evidence of a chemical reaction:1. Formation of gas

2. Formation of precipitate (a solid formed from a chemical reaction; can look cloudy)

3. Change in color

4. Change in energy• Endothermic-

absorbs heat energy(gets cold)

• Exothermic-releases heat energy (gets hot)

5. Change in characteristic property(odor, gives off light)

HOW TO TELL CHEMICAL REACTIONS FROM AN EQUATION:

When the mass of the products does not equal the mass of the reactants. What happened?Gas was produced & lost to environment

UNIT CHECK- Matter ChangesDecide if each is a chemical or physical change.

1. Ice melting 2. cutting paper 3. Burning rocket fuel

6. evaporating puddle

5. bike chain rusting

4. sawing wood

Physical change

Physical change

change

Physical change

Physical change

Chemical change

Chemical change

UNIT CHECK- Matter ChangesDecide if each is a chemical or physical change.

8. dry ice

12. Baking muffins

11. Coloring paper with crayons

10. An egg rotting

7. candle burning

Physical change

Physical change

Physical change

Chemical change

Chemical change

9. Sugar dissolving in water

Chemical change

Chemical Changes LABWrite the chemical equation for each of the three reactions. Then highlight the reactants yellow.

Iron Nail Rusting

Summarize with words what happens in this reaction. Be sure to describe the reactants and products.

Baking Soda and Vinegar reacting

Summarize with words what happens in this reaction. Be sure to describe the reactants and products.

Wood combusting

Summarize with words what happens in this reaction. Be sure to describe the reactants and products.

Visual Depiction of Reaction: (Draw & Label the parts of the demonstration.)

Visual Depiction of Reaction: (Draw & Label the parts of the demonstration.)

Visual Depiction of Reaction: (Draw & Label the parts of the demonstration.)

HEADER:

Chemical Changes LABWrite the chemical equation for each of the three reactions. Then highlight the reactants yellow.

Iron Nail Rusting

Summarize with words what happens in this reaction. Be sure to describe the reactants and products.

Baking Soda and Vinegar reacting

Summarize with words what happens in this reaction. Be sure to describe the reactants and products.

Wood combusting

Summarize with words what happens in this reaction. Be sure to describe the reactants and products.

Visual Depiction of Reaction: (Draw & Label the parts of the demonstration.)

Visual Depiction of Reaction: (Draw & Label the parts of the demonstration.)

Visual Depiction of Reaction: (Draw & Label the parts of the demonstration.)

HEADER:

Sodium bicarbonate

Acetic acid precipitate gas

Balance the following equations.Choose the best answer.

HEADER:

Chemical Changes LAB