Quiz about CHEMICAL REACTIONS - Test

Question 1

Kai is conducting an experiment where he mixes two chemicals in a beaker, and the temperature of the mixture decreases. In this endothermic reaction, heat is ...

Accepted Answer

taken in or absorbed

Answer

given out or released

Question 2

When does a chemical reaction stop?

Accepted Answer

When the limiting reactant is used up

Answer

When the lab is finished

Answer

When the excess reactant is used up

Answer

Chemical reactions never stop

Question 3

Which of the following shows the correct way to balance the chemical equation?
Fe + O₂ -> Fe₂O₃

Accepted Answer

4Fe + 3O₂ -> 2Fe₂O₃

Answer

2 Fe + 3O₂ -> Fe₂O₆

Answer

4 Fe + O₆ -> 2Fe₂O₃

Answer

None of the options are correctly balanced.

Question 4

Balance this equation...
HgO --> Hg + O₂

Accepted Answer

2HgO --> 2Hg + O₂

Answer

It is balanced

Answer

2HgO --> Hg + O₂

Answer

I don't know...Oh well!

Question 5

What happens in ALL chemical changes?

Accepted Answer

A new substance is formed

Answer

Change in state of matter

Answer

Bubbles are produced

Answer

An explosion

Question 6

In reactions, products must be equal to..

Accepted Answer

Reactants

Answer

Products

Answer

Starters

Answer

Enders

Question 7

Water can dissolve many things so it is called the .....

Accepted Answer

universal solvent

Answer

wonderful water

Answer

cohesion

Answer

liquid

Question 8

The thing that does the dissolving

Accepted Answer

Solvent

Answer

Solute

Answer

Colloid

Answer

Solution

Question 9

According to the law of conservation of mass, how does the amount of each element on the product side compare to each element on the reactant side?

Accepted Answer

The amount of atoms on each side is equal

Answer

The amount of atoms on the product side is greater

Answer

The amount of atoms on the reactant side is greater

Answer

Depends on the reaction

Question 10

Which reaction type is the following:

C₅H₁₀ + O₂ --> CO₂ + H₂O

Accepted Answer

Complete Combustion

Answer

Decomposition

Answer

Synthesis

Answer

Double Replacement

Question 11

In chemical reactions, what does the principle of conservation of mass mean?

Accepted Answer

Matter is not created or destroyed.

Answer

The total mass of the reactants is greater than the total mass of the products.

Answer

The total mass of the reactants is less than the total mass of the products.

Answer

Matter is not changed.

Question 12

When materials combine to form new compounds it is a chemical change. Which example is a chemical change?

Accepted Answer

baking powder fizzing

Answer

water boiling

Answer

ice melting

Answer

sugar cube dissolving

Question 13

Which is an example of a chemical reaction?

Accepted Answer

cookies baking in an oven

Answer

paper cut into small pieces

Answer

chocolate melting in a pan

Answer

flour and sugar mixed in a bowl

Question 14

In a chemical equation, it is true that -

Accepted Answer

the coefficients indicate the number of molecules of each reactant used and the number of molecules of each product made

Answer

the reactant side and product side can have different numbers of atoms for each element

Answer

there can be different elements on the reactant side and the product side

Answer

an element or compound must be accompanied by a phase change

Question 15

Which of the following models best demonstrates a balanced chemical equation?

Accepted Answer

F

Answer

G

Answer

H

Answer

J

Question 16

The reactants are on the left side of the chemical equation.

Accepted Answer

True

Answer

False

Question 17

How many atoms in all are in a molecule of serotonin?

C₁₀H₁₂N₂O

Accepted Answer

25

Answer

22

Answer

24

Answer

4

Question 18

Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns?

Accepted Answer

A new substance is produced

Answer

The shape of the coal changes

Answer

Oxygen is present

Answer

Coal is made up of more than one element

Question 19

Which type of chemical reaction has two or more reactants to make one product?

Accepted Answer

synthesis

Answer

combustion

Answer

single displacement

Answer

double displacement

Answer

decomposition

Question 20

Which phrase describes what happens to atoms in a chemical reaction?

Accepted Answer

never lost or gained, just rearranged

Answer

sometimes lost, never rearranged

Answer

sometimes lost, gained, or rearranged

Answer

lost or gained, never rearranged

Question 21

Which of the following is a compound?

Accepted Answer

sodium chloride (NaCl)

Answer

zinc (Zn)

Answer

magnesium (Mg)

Answer

potassium (K)

Question 22

Which of the following is an element?

Accepted Answer

carbon (C)

Answer

potassium chloride (KCl)

Answer

water (H₂O)

Answer

calcium carbonate (CaCO₃)

Question 23

What is the role of a catalyst in a chemical reaction?

Accepted Answer

It speeds up the reaction without being consumed

Answer

It increases the temperature of the reaction

Answer

It decreases the temperature of the reaction

Answer

It is consumed in the reaction

Question 24

What is the main difference between a mixture and a compound?

Accepted Answer

A compound is chemically bonded, a mixture is not

Answer

Neither is chemically bonded

Answer

Both are chemically bonded

Answer

A mixture is chemically bonded, a compound is not

Question 25

Abigail is conducting an experiment in her chemistry class. She heats aluminum hydroxide, Al(OH)₃, and observes it breaking down into aluminum oxide, Al₂O₃, and water, H₂O. What type of chemical reaction is this one?

Accepted Answer

Decomposition

Answer

Single Replacement

Answer

Synthesis

Answer

Combustion

Question 26

James is learning about diatomic elements in his chemistry class. His teacher asks, "If an element is diatomic, it should have a subscript of___"

Accepted Answer

2, only when it is by itself

Answer

2, always

Answer

it shouldn't have a subscript, it should have a coefficent

Answer

unknown

Question 27

Abigail is conducting an experiment in her chemistry class. She adds a piece of sodium to a beaker of water. A metal hydroxide and a gas are produced. Which of the following is correct?

Accepted Answer

NaOH and H₂ will be produced

Answer

NaOH and H₂O will be produced

Answer

Na₂O + H₂ will be produced

Answer

NaOH will be produced

Question 28

Arjun is conducting a science experiment in his school laboratory. He needs to write a chemical equation that produces hydrogen gas. What is the correct representation of hydrogen gas?

Accepted Answer

H2

Answer

2H

Answer

H

Answer

OH

Question 29

Hannah is conducting an experiment in her chemistry class. She burns hexane (C₆H₁₄) in the presence of oxygen. What type of reaction is this?

2 C₆H₁₄ + 19 O₂ --> 12 CO₂ + 14 H₂O

Accepted Answer

Combustion

Answer

Single Replacement

Answer

Double Replacement

Answer

Decomposition

Question 30

Aiden is conducting an experiment in his chemistry class. He wants to know what the products of this reaction are:

C₂H₄ + O₂ -->

Accepted Answer

CO₂ + H₂O

Answer

C₂O₂ + H₄

Answer

CO₂ + H₂+ O₂

Answer

No Reaction

Question 31

Sophia is conducting an experiment in her chemistry class. She needs to label a beaker containing a substance dissolved in water. What symbol should she use?

Accepted Answer

(aq)

Answer

(s)

Answer

(l)

Answer

(g)

Question 32

Emma is conducting a chemistry experiment in her lab. She needs to balance the following chemical equation to proceed with her experiment. Help her find the correct coefficient that would be in front of Na₂SO₄.

___Na₃PO₄ + ___ ZnSO₄ -----> ___ Na₂SO₄ + ___ Zn₃(PO₄)₂

Accepted Answer

3

Answer

1

Answer

2

Answer

4

Question 33

Priya is conducting a chemistry experiment. She wants to know what the products of this reaction are when using the +2 ion for copper.

Cu+ AgNO₃-->

Accepted Answer

Cu(NO₃)₂+Ag

Answer

CuAg+NO3

Answer

CuNO₃ + Ag

Answer

Cu+ AgNO₃

Question 34

During an endothermic reaction, what happens to energy in relation to the surroundings?

Accepted Answer

absorbed from

Answer

released to

Answer

mixed with

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