Chemical and Physical Changes Notes

Warm - Up What are the three states of matter? Which state of matter is most easily compressed? Which state(s) of matter have a definite volume? What is the definition of a heterogeneous mixture?

Objective Today I will be able to: Describe the classification of matter Differentiate between a chemical and physical change

Homework Chemical and Physical Changes WS Wear Closed Toe Shoes Tuesday

Agenda Warm – Up Classification of Matter Notes Sorting Activity Chemical and Physical Changes Notes Sorting Activity Chemical and Physical Changes Worksheet Classification of Matter Review Game

The Rules 5 minutes or all of the examples One person goes at a time, in order Classify the substance as element, compound, heterogeneous mixture or homogeneous mixture Player may pass I keep score

hydrogen

element

atmosphere

heterogeneous mixture

sugar

compound

pitcher of Kool-Aid

homogeneous mixture

silicon

element

lithium

element

brass (alloy)

homogeneous mixture

ocean

heterogeneous mixture

salad

heterogeneous mixture

titanium

element

titanium alloy

homogeneous mixture

baby food (in a jar)

homogeneous mixture or heterogeneous mixture

sodium

element

salt

compound

saline solution for contact lenses

solution = homogeneous mixture

pizza

heterogeneous mixture

carbon

element

bromine

element

glass (silicon dioxide)

compound

aluminum

element

black coffee (brewed)

homogeneous mixture

graphite

element (form of carbon)

water

compound

gold

element

Lucky Charms

heterogeneous mixture

diamond

element (form of carbon)

sulfur

element

methane

compound

blood

homogeneous mixture

milk

homogeneous mixture

potassium

element

lithium chloride

compound

salad dressing

heterogeneous mixture

air in a SCUBA tank

homogeneous mixture

uranium

element

calcium carbonate (sea shells)

compound

bronze

homogeneous mixture

sucrose

compound

lead

element

Chemical and Physical Changes Notes

Physical Properties Description of a substance undergoing a physical change Intensive Properties – do not depend on the amount of matter present (density, boiling point, freezing point, color, odor) Extensive Properties – depend on the amount of matter that is present (mass, volume, pressure, length)

Chemical Properties Enables a substance to change into a brand new substance, and they describe how a substance reacts with other substances

Changes in Matter Through experimentation and natural occurrences, matter tends to change in either of two ways - Physical Changes - Chemical Changes

Physical Changes Only physical properties change The form of matter changes, but the identity of the matter remains the same Examples: change in state (phase change), breaking a pencil, tearing paper

Physical Changes Phase Change – physical process in which one state of matter is transformed into another

Physical Changes

During a change of state, the temperature remains constant, but energy must be continually transferred because the particles that make up the sample have different quantities of potential energy before and after the change

Physical Changes

Chemical Changes Properties of original substance disappear as new substances with different properties are formed Change in chemical composition Cannot return to original form Can be detected through – energy changes (temperature), change in color, emission of gas, solid formed Examples – wood burning, iron rusting, sour milk

Examples – Chemical or Physical Change? A match lights when struck Wood is placed into a chipper A lump of gold is pounded into a large, thin sheet Baking powder bubbles and gives off CO 2 when it is moistened A pan of water boils on the stove Hydrogen Sulfide gas causes silver to tarnish

Reactions Involving Energy Most chemical reactions, physical changes of state, and dissolving processes involve energy changes Energy can be released or absorbed Exothermic Reactions Endothermic Reactions

Reactions Involving Energy Exothermic Reactions – reactions that release energy into their surroundings - Results in a temperature increase - Feels warm to the touch Example Reaction – Combustion of Propane - C 3 H 8(g) + 5 O 2(g)  3 CO 2(g) + 4 H 2 O (g) kJ

Reactions Involving Energy Endothermic Reactions - reactions that absorb energy from their surroundings - Results in a temperature decrease - Feels cold to the touch Example Reaction – Photosynthesis - Sunlight + 6 CO 2(g) + H 2 O (l)  C 6 H 12 O 6(aq) + 6 O 2(g)

Exit Ticket Write down an original example of: A heterogeneous mixture A homogeneous mixture A compound An element