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What are irreversible reactions? Can you

name a few?

CHEMICAL REACTIONS 1. REVERSIBLE AND IRREVERSABLE REACTIONS What are reversible reactions? Can you name a few?

2. CHEMICAL AND PHYSICAL CHANGES

Fill in shape phyical change appearance new reversible

volume size irreversible When there is a ____________________, no new materials are made. Physical changes usually

result in one of the following: change in _____________, ______________, _____________ and

________________. Usually physical changes are also _______________ changes.

Not all physical changes are reversible e.g. if you drop a glass onto the floor and it breaks this is

irreversible.

On the other hand, __________ materials are made when there is a chemical change. Chemical

changes are usually ________________ changes.

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Two examples of physical changes are: _____________________________________________

_____________________________________________________________________________

Two examples of chemical changes are :_____________________________________________

______________________________________________________________________________

Cut the pictures from the last page and paste them in the appropriate box

Physical

Chemical

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3. WORD EQUATIONS Whenever a chemical reaction takes place, scientists use equations in order to show how the

reaction is taking place. Word equations describe chemical reactions by using words.

Word equations have the following pattern:

REACTANT 1 + REACTANT 2 + ... PRODUCT 1 + PRODUCT 2 + ...

.

.

Sometimes heat or energy is needed or formed in a reaction. Heat or energy is included in the

word equation just like any other reactant or product.

Reaction One: Sam mixed together some eggs, milk and flour. When he heated them in a large pan they reacted to form a big pancake!

………………........ + ………………........ + ………………........ Pancake!

Reaction Two: When Katerina dropped a lump of magnesium into a test tube of hydrochloric acid, the chemical magnesium chloride was formed. Katerina also noticed a gas being formed. When a lighted splint was placed in the gas it made a squeaky ‘pop’ sound.

………………............. + Magnesium Magnesium chloride

REACTANTS

(substances we started the reaction with), always go on the

left. A plus sign is used between the reactants when

there is more than one reactant.

PRODUCTS

(substances formed during a reaction), always go to the right

of the arrow. A plus sign is used between the products

when there is more than one product

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Reaction Three: Chelsea was given some nitric acid and some iron oxide. She reacts these together and finds that she makes a solution of iron nitrate and iron water.

…………………………… + ……………………… ………………........ + ………………........ Reaction Four: Raisa was learning about photosynthesis. She looked on the internet and found that in this process, plants take in carbon dioxide gas from the air and water from the ground. Using energy from the sun they can turn these chemicals into a kind of sugar called glucose and the gas oxygen.

………………………… + ………………........ ………………........ + ………………........

Reaction Five: Sean added dilute sodium hydroxide to dilute hydrochloric acid. They reacted to form sodium chloride and water.

…………………………… + ……………………… ………………........ + ………………........

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4. MORE PHYSICAL AND CHEMICAL CHANGES Experiment 1: Mixing copper sulphate and sodium hydroxide solution

Observations:

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Is there a chemical reaction taking place?

______________________________________________________________________________

Is it reversible or not?

______________________________________________________________________________

What are the reactants?

______________________________________________________________________________

What are the products?

______________________________________________________________________________

Write down the word equation.

______________________________________________________________________________

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Experiment 2: Burning magnesium ribbon

Observations:

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Is there a chemical reaction taking place?

______________________________________________________________________________

Is it reversible or not?

______________________________________________________________________________

What are the reactants?

______________________________________________________________________________

What are the products?

______________________________________________________________________________

Write down the word equation.

______________________________________________________________________________

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Experiment 3: Reaction between Hydrochloric acid and Magnesium

Observations:

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Is there a chemical reaction taking place?

______________________________________________________________________________

Is it reversible or not?

______________________________________________________________________________

What are the reactants?

______________________________________________________________________________

What are the products?

______________________________________________________________________________

Write down the word equation.

______________________________________________________________________________

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Experiment 4: Reaction between calcium carbonate and hydrochloric acid

Observations:

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Is there a chemical reaction taking place?

______________________________________________________________________________

Is it reversible or not?

______________________________________________________________________________

What are the reactants?

______________________________________________________________________________

What are the products?

______________________________________________________________________________

Write down the word equation.

_______________________________________________________________

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Experiment 5: Heating ice in a beaker

Observations:

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Is there a chemical reaction taking place?

______________________________________________________________________________

Experiment 6: Burning Ammonium Dichromate

(video: http://www.youtube.com/watch?v=DD6uh01X7Gg )

Observations:

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Is there a chemical reaction taking place?

______________________________________________________________________________

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Experiment 7: Adding copper turning to dilute hydrochloric acid

Observations:

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Is there a chemical reaction taking place?

______________________________________________________________________________

Experiment 8: Reaction between sodium bicarbonate and acetic acid (vinegar)

Observations:

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Is there a chemical reaction taking place?

______________________________________________________________________________

Is it reversible or not?

______________________________________________________________________________

What are the reactants?

______________________________________________________________________________

What are the products?

______________________________________________________________________________

Write down the word equation.

______________________________________________________________________________

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5. RUSTING, PHOTOSYNTHESIS AND RESPIRATION

The mechanic told me that my body is rusting. Can you

please explain to me what is happening?

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_____________________________________________

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_____________________________________________

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_____________________________________________

_____________________________________________

____________

Hey there! My momma told me that I produce my own food

during photosynthesis. Can you please explain how this

happens?

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__________________________________________________

__________________________________________________

__________________________________________________

__________________________________________________

__________________________________________________

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During science class we talked about respiration, but I

did not understand the process. Can you please re-

explain it? Cheers!

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