Chemical Reactions

Question 1

A rusting bicycle is a

Accepted Answer

chemical change

Question 2

What are the reactant(s) in this equation?

Accepted Answer

Copper and Oxygen

Question 3

Looking at the picture, what is a sign that a chemical reaction took place.

Accepted Answer

Precipitate formation

Question 4

Spoiling food is a

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Chemical change

Question 5

The metal salt copper chloride was burnt in a flame. The flame changed to which colour?

Accepted Answer

Green

Question 6

A chemical change is a change where

Accepted Answer

one or more new substances are formed

Question 7

In the compound Na2SO4, which statement is true?

Accepted Answer

2 Na atoms are present

Question 8

Photosynthesis and Cold packs are an example of what type of reaction?

Accepted Answer

Endothermic

Question 9

Which of the following is NOT a sign of a chemical reaction

Accepted Answer

change of state (e.g. solid to liquid)

Question 10

A change where the properties of a substance change, but the substance is still the same

Accepted Answer

Physical change

Question 11

How do you know a chemical reaction has taken place?

Accepted Answer

Gas bubbles

Question 12

Substances you start with in a chemical reaction are called

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Reactants

Question 13

Magnesium can be burned in air to produce magnesium oxide. Which is the correct word equation?

Accepted Answer

magnesium + oxygen -------> magnesium oxide

Question 14

What are the product(s) in this reaction?

Accepted Answer

H2O

Question 15

Melting butter for popcorn is a

Accepted Answer

Physical change

Question 16

Combustion (burning) is an example of a

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Exothermic

Question 17

H is the symbol for which element?

Accepted Answer

Hydrogen

Question 18

Sodium reacts with chlorine (a smelly gas) to produce sodium chloride (salt). Which is correct?

Accepted Answer

sodium + chloride -------> sodium chloride

Question 19

In an exothermic reaction...

Accepted Answer

energy is released to the surroundings, the products are hotter than their surroundings

Question 20

This diagram represents...

Accepted Answer

The law of conservation of mass

Question 21

N is the chemical symbol for which element?

Accepted Answer

Nitrogen

Question 22

Glass breaking is a

Accepted Answer

physical change

Question 23

Mixing cordial in water is a

Accepted Answer

Physical change

Chemical Reactions

Questions 23

Chemical Reactions

Questions 23