000 chemical and physical properties.notebook

000_Chemical and Physical Properties.notebook

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What is Chemistry?

Chemistry is the study of matter, its properties and its changes or transformations.

Matter is anything that has mass and takes up space.

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• All matter has physical and chemical properties.

Physical properties are the characteristics of a substance.

Examples are colour, texture, odour, luster, hardness, malleability, ductility, melting point, boiling point, solubility, viscosity, density

A physical change involves a change of state. The matter itself doesn‛t change, just its form (solid, liquid or gas). Most physical changes are easy to reverse.


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A chemical property is a characteristic behaviour that occurs when a substance changes to a new substance. A chemical change is generally very difficult to reverse.

When a chemical change occurs it is called a chemical reaction. The reactants (original substances) react together to form products (new substances that were not present originally).

Examples:

Combustibility - Ability of a substance to react

with oxygen to produce CO2, water and energy.

Reaction of a metal with Acid – the metal reacts with the acid to form hydrogen gas and a soluble salt.

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Physical and Chemical PropertiesChemistry is the study of maer.

Maer is anything that has mass, and takes up space.

How do you know a chemical is a CHEMICAL in Science?By its... properes

There are two types of properes: physical and chemical.

PHYSICAL properes are used to describe or explain the object.

These characteriscs are descripons.


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Property Description Example

HardnessMeasure of resistance of solid to being scratched/dented

Diamonds very hard Chalk very soft

Odour The smellApples sweet Oxygen gas odourless

Malleability Ability to be hammered into a sheet

Playdough is malleable.

A boulder is not

Ductility Ability to be pulled into a wire

An elastic is ductile, a paper is not

Melting Point Temp. at which it melts Ice melts at 0

Boiling point Temp. At which it boils Water boils at 100

Solubility Ability to dissolve Sugar dissolves in water

Viscosity How a substance flows

Honey is very viscous (flows slowly)

Density Ratio of mass to volume

Oil is less dense than waterWater has a density of 1g/cm3

Colour Is it black, white, red, etc. Banana is yellow

Brittleness Does it break when bent

Uncooked spaghetti is brittle. Cooked spaghetti is not brittle

State Solid liquid or gas At 30

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chemical properes describes how a substance will react or combine with another substance.

Examples Include:

1. Combusbility (will it burn?)

2. Reacts with AIR /O2

3. Reacts with Water /Acid


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Place a P (for physical property) or C (for chemical property) beside each of the following statements:

1. The sulfur was yellow

2. The corn syrup flows slowly

3. The magnesium burned

4. The metal felt smooth

5. The mercury transmied the electricity

6. Water freezes at 0⁰C

7. A nail sinks in water

8. Iron rusts in air

9. The sulfur breaks easily

10. Sodium explodes in water


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Types of changes in Chemistry

In a physical change the substance involved remains the same.

« Changes of state and size are physical changes.

« dissolving is also a physical change.

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In a chemical change the original substance is changed into one or more different substances that have different properties

« chemical changes always involve the production of new substances

« most chemical changes are difficult to reverse

Burning, cooking, and rusting are all examples

How can you tell if a chemical change has occurred?

The following suggest that a new substance has been produced.

1. Colour Change

2. Gas produced (bubbles)

3. Heat released or absorbed

4. Light released

5. Odour change

6. Precipitate forms from 2 liquids


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Pracce Quesons:

1. Which one of the following is an example of a physical change?

a. Iron rusng

b. A steak cooking

c. Sugar dissolving in water

d. A candle burning

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2. A physical change means that no new substance is formed A. True B. False


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3. Breaking water up by separang it into hydrogen and oxygen is an example of a ...

A. Physical B. Chemical

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4. Melng and boiling causes a ... A. Physical change B. Chemical change


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5. A change in size or shape is a... A. Physical change B. Chemical change

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6. A chemical change means that a new substance with new properes is formed.

A. True B. False


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7. The fact that sugar is white is a A. Physical property B. Chemical Property

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8. Iron rusts when exposed to air. This is a A. Physical property B. Chemical Property


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9. Which one is not a physical property of hydrogen?

A. It is a gas B. It is explosive C. It is colourless

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10. Which one of the following is not a physical change?

A. Clothes drying in the dryer

B. Making a cup of coffee

C. Chopping Wood

D. Boiling an egg


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Chemical and Physical Changes Pracce

For each of the following determine if it is a Chemical or a Physical change. Give a specific reason for your choice.

1. A hot dog is cooked. Physical or Chemical (circle)

Explain:

2. Thousand Island dressing is mixed with Mayonnaise to make a special sauce. Physical or Chemical (circle)

Explain:

3. Water is boiled in preparaon for making pasta. Physical or Chemical (circle)

Explain:

4. Old hamburger goes bad in the fridge. Physical or Chemical (circle)

Explain:

5. You get a taoo. Physical or Chemical (circle)

Explain:

.

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Change Physical or Chemical? Clue

ice melts

sulfur is burned

glass breaks

a match is struck

mercury is heated to produce mercury vapourwax hardens on a candle

silver tarnishes

leaves change colour and fallnail polish remover evaporates

a dish rag dries

wood is hammered together to build a playhouse

sugar dissolves in tea

vinegar is added to baking sodamuddy water is allowed to settle

an egg is fried

butter is melted for popcornsand is separated from gravellemonade powder is mixed in water

the lawn is mowed

metal rusts

hair is bleached

fireworks explode

oranges are squeezed to make orange juiceleaves change colour and fall


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Bill Nye the Science Guy

Chemical Reactions

1. When do chemical reactions occur? when electrons hook together

2. Why did the steel wool react so much better in the plastic container full of oxygen? there was more oxygen available to keep the reaction

going

3. Why did the carbon dioxide fire extinguisher put out the ‘tornado of fire‛? the carbon dioxide replaces the air around the fire so there

is no more oxygen for it to keep burning (reacting)

4. What gas is produced when you mix baking soda and vinegar together? carbon dioxide is produced (CO2)

5. What is the chemical formula for water? H2O

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6. What two pieces of information does this formula give us? the types of atoms (elements) in a water molecule

the number of each atom (element) in the water molecule

7. What would happen if you were to breath chlorine gas? you would be killed

8. What happens when sodium is put in water? bubbles and turns on fire and then explodes

9. What is formed when sodium and chlorine react together? table salt (sodium chloride NaCl)


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10. What is the name given to people who work with fireworks? pyrotechnician

11.How do fireworks get their different colours? different metals are used

12. What else besides carbon dioxide is also created when vinegar and baking soda are mixed together? heat

13. How many natural elements are there? 92

14. What chemical did Alfred Nobel discover? dynamite (TNT – trinitro toluene)

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15. What award has been named after Alfred Nobel? the Nobel Prize (for peace, for art, and for different

sciences)

winner is given $1 million

16. How does a cold pack work? it has 2 chemicals in it

when the barrier inside the pack is broken the two chemicals react together

the reaction takes up more heat than it gives off and so it feels cold

17. How are elements grouped together on the Periodic Table?

they are grouped by similar chemical reactions


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000 chemical and physical properties.notebook

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