Review of Types of ChangeReview of Types of Change

Types of ChangeTypes of Change

Reactants: Zn + IReactants: Zn + I22 Product: Zn IProduct: Zn I22

Types of ChangeTypes of Change::At the conclusion of our time together, At the conclusion of our time together,

you should be able to:you should be able to:

1.1. List the 3 types of change and List the 3 types of change and define each.define each.

2.2. Classify a change as to Classify a change as to nuclear, chemical or physical.nuclear, chemical or physical.

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4. Don't listen to critics, just get on with 4. Don't listen to critics, just get on with what has to be done. what has to be done.

Nuclear Chemical Physical

Types of Change

Protons&

Neutronschange

Bondsmade/ broken

Electrons exchanged

No change in atoms a phase change a density change

Change can be identified by their atoms.

Nuclear

Nuclear Change

Change in the Gain or lose Protons , Neutrons,

Alpha, Beta particle Fission, Fusion, RadiationWe looked at these in the last unit

Proton Neutron

nucleus

Physical

Physical Change

No change in atoms/molecules Phase change (gas, liquid, solid) Light emission/absorption Dissolving Electrons passing through metals

Chemical

Chemical Change

Bonds are made / broken Change in oxidation states

Cl-1 Cl-1

21

Li +1

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Evidence of Chemical Change:

development of a gas formation of precipitate change in color

NOT a Chemical Change:

sublimation crystalizationfluorescence

Chemical Properties are Determined by Observing Chemical

Changes

Reactivity

Combustibility

Gas formation

Precipitate

Color change

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Chemical or Physical

Ice cubes float in water because:

a. The ice is losing mass through the melting processb. The colder ice is more densec. Liquid water is less dense than ice cubesd. The molecules of ice are arranged in an orderly way so that there is an unusually large amount of empty space in the ice cubes.e. None of the above

A hot air balloon rises because:1. molecules become lighter when heated. 2. molecules move faster and farther apart when heated. 3. molecules are less attracted by gravity when heated. 4. molecules become charged and repel each other when heated.

Chemical or Physical

The solid, liquid, and gaseous states of water The solid, liquid, and gaseous states of water differ from each other in:differ from each other in:

the mass of the individual atoms. the mass of the individual atoms. the size of the individual atoms. the size of the individual atoms. the net electrical charge of the individual the net electrical charge of the individual

molecules. molecules. the average speed of movement of the the average speed of movement of the

individual molecules. individual molecules.

Chemical or Physical

If you saw an ice cube sink after it was placed in what you thought was a glass of water, which question should you probably ask?1. What kind of liquid is in the glass? 2. Will the ice melt slower or quicker? 3. How fast did the ice cube sink? 4. How soon would the ice cube start to float?

Chemical or Physical

Interesting Signs:Interesting Signs:

What will happen if you mix vinegar and baking What will happen if you mix vinegar and baking soda?soda?1.1. It will explode. It will explode. 2.2. Nothing will happen. Nothing will happen. 3.3. It will bubble up rapidly. It will bubble up rapidly. 4.4. It will turn bright red. It will turn bright red.

Chemical or Physical

When a gas forms a liquid, which process is taking place?

1. freezing 2. condensation 3. boiling 4. evaporation

Chemical or Physical

Based on the melting points shown in the table, which material would still be a solid at 400°C?

1. beeswax 2. gold 3. lead 4. oxygen

Substance Melting Point (°C)

Beeswax 62

Gold 1,063

Lead 327

Oxygen –218

Chemical or Physical

A chemical change for a piece of metal would be

1. being bent in half. 2. getting cut into two pieces. 3. being painted. 4. getting rusty.

Design a Hypothesis

Types of ChangeTypes of Change::

Let’s see if you can:Let’s see if you can:

1.1. List the 3 types of change and List the 3 types of change and define each.define each.

2.2. Classify a change as to Classify a change as to nuclear, chemical or physical.nuclear, chemical or physical.

You get up in the morning and make toast for breakfast. You notice the color changes from light to dark. Later on that day in science class, your teachers asks for every day examples of physical and chemical changes.

Should you volunteer your toast as an example of a physical or chemical change?

Why?

Chemical or Physical

Lucy noticed that her coin collection had begun to tarnish. Some of the metal in the coins had begun to change color. The formation of tarnish is most similar to which of the following changes?

1. shredding a piece of paper into hundreds of tiny strips 2. dropping a dinner plate on the floor 3. melting ice cubes in a glass of juice 4. burning a piece of paper to ashes in a fireplace

Chemical or Physical

Mr. T performed a chemical reaction for the class. Which of these does NOT show evidence that a chemical reaction has occurred ?

Change in color

Change in shape

Formation of gas

Formation of a precipitate

Which picture shows only a physical change in the wood?

Which action would result in a chemical change?

crumpling several sheets of paper pounding a nail into a piece of wood peeling and slicing a carrot making blueberry muffins

What Kind of a Change is This?Precipitate is the formation of

insoluble molecular compounds.

Does NOT dissolve in water.Chemical

A different chemical substance is formed when a:

piece of cloth is cut.

cup breaks.

candle burns.

piece of chalk breaks.

Which is an example of a chemical change?

• ice melting • salt crystals being ground to powder • water evaporating • wood burning

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