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Chemistry - reactions & balancing

Total questions: 64

Worksheet time: 1hrs 1mins

Name
Class
Date
1.

What coefficients does ____H2 + ____O2 -> ____H2O need to be balanced?

a)

1,1,1

b)

2,2,2

c)

2,1,2

d)

none of the above

2.

How many hydrogen atoms?

a)

1

b)

2

c)

6

d)

not enough information

3.

Balance the equation ___Fe(s) + ___CuSO4(aq) -> ____FeSO4(aq) + ____Cu(s)

a)

1,2,2,1

b)

2,3,6,3

c)

2,4,2,4

d)

already balnced

4.

What happens to the atoms in a chemical reaction?

a)

they are created

b)

they are converted to energy

c)

they are destroyed

d)

they are rearranged

5.

How many nitrogen atoms are on the reactants side of 3Mg(NO3)2 + 2K3PO4 -> Mg3(PO4)2 + 6KNO3?

a)

6

b)

3

c)

18

d)

1

6.

Balance the equation Fe3O4+H2−>Fe+H2O.Balance\ the\ equation\ Fe_3O_4+H_2->Fe+H_2O.  

a)

3,1,4,2

b)

1,4,3,4

c)

2,8,6,8

d)

none of the above

7.

What forces us to balance chemical equations?

a)

The Law of Balanced Equations

b)

The Law of Conservation of Mass

c)

The Law of Conservation of Energy

d)

The Law of Science

8.
What happens to matter during a chemical reaction?
a)
matter is neither destroyed or created
b)
some matter is destroyed
c)
some matter is created
d)
some matter is destroyed and some is created
9.
Which of the following is TRUE for all chemical reactions?
a)
the total mass of the reactants increases
b)
the total mass of the products is greater than the total mass of the reactants
c)
the total mass of the products is less than the total mass of the reactants
d)
the total mass of the reactants equals the total mass of the products
10.
True or False: When balancing chemical equations the subscripts can change.
a)
true
b)
false
11.
Which of the following is evidence of a chemical reaction?
a)
fizzing
b)
water changing to ice
c)
saltwater
d)
paper being cut in half
12.
How many atoms of aluminum are on each side of the following equation: 4Al + 3O2 --> 2Al2 O3
a)
2
b)
6
c)
1
d)
4
13.
What is the part of the chemical equation in green called? 
Fe + S --> FeS
a)
products
b)
reactants
c)
yield
d)
chemical formula
14.
A reaction that gives off heat to its surroundings is...
a)
exothermic
b)
endothermic
c)
endergonic
d)
none of these
15.
Which type of reaction will feel cold?
a)
exothermic
b)
exergonic
c)
endothermic
d)
none of these
16.
At the end of chemical reactions, what is the total mass of the reactants compared to the total mass of the products?
a)
the product is doubled
b)
the product is half the mass of the reactants
c)
the mass is the same
d)
the mass changes depending on the reaction
17.
The red numbers in the image below represent ________
a)
subscripts
b)
coefficients
c)
I don't know, and don't want to try
d)
None of the answers are correct
18.
The blue numbers in the image below represent ________
a)
I don't know, and don't want to try
b)
coefficients
c)
subscripts
d)
none of the answers are correct
19.
When balancing equations a ____ can be placed to the left of a formula of a substance to make the equations balanced
a)
charge
b)
subscript
c)
random number
d)
coefficient
20.
Number of C's in 2Na₂CO₃
a)
1
b)
2
c)
3
d)
5
21.
How many Elements are in the compound C2H8O ?
a)
2
b)
1
c)
3
d)
0
22.
How many total atoms are in the compound C2H8O ?
a)
11
b)
2
c)
8
d)
1
23.

Balance the following equation by filling in the blank:

N2 + 3H2 → _NH3

(a)  

24.

The mass number of an element tells you

a)

The number of protons and neutrons

b)

The number of protons and electrons

c)

The number of neutrons and electrons

d)

The number of neutrons only

25.

The atomic number tells you

a)

The number of electrons

b)

The number of protons

c)

The number of neutrons

d)

The number of nucleons

26.
Which of the following is NOT a property of metals?
a)
Malleable
b)
Lustre
c)
Good electrical conductivity
d)
Brittle
27.
Which subatomic particles are located in the nucleus?
a)
Electrons only
b)
Electrons and neutrons
c)
Protons and electrons
d)
Protons and neutrons
28.
What is the total number of atoms present in the formula H2SO4 ?
a)
1
b)
3
c)
6
d)
7
29.
An atom has an atomic number of 17. How many electrons would there be on each shell? (From inner to outer shell)
a)
2, 10, 5
b)
8, 8, 1
c)
2, 8, 7
d)
8, 7, 2
30.

An atom has no net charge due to

a)

Its subatomic particles carrying no electrical charge

b)

The positively charged protons cancel out the negatively charged neutrons

c)

The positively charged neutrons cancel out the negatively charged electrons

d)

The positively charged protons cancel out the negatively charged electrons

31.

Why is it called a chemical "equation"?

a)

The number of atoms of the elements before the reaction is equal to the number of atoms after the reaction

b)

The total mass of the reacting elements would be the same as the total mass of whatever products are formed

c)

The reaction produces an equal number of products to the number of elements which react

d)

You MUST write an equals sign

32.

Which is correct...

a)

Most of the mass of an atom is concentrated towards the outside

b)

That the mass of an atom is equally distributed

c)

The the mass of an atom is concentrated in the centre of the atom

d)

The masses of atoms are so small that are not important

33.

A negative ion...

a)

Has an equal number of protons and electrons

b)

It has more electrons than protons

c)

It has a different number of neutrons

d)

It has more protons than electrons

34.

An atom can be changed to an ion by...

a)

Changing its atomic number

b)

Losing or gaining electrons

c)

Losing or gaining alpha particles

d)

Being hit with a gamma ray

35.
A chemical reaction is...
a)
when a substance is mixed with another substance
b)
when a substance undergoes a change to form a new substance
c)
when a substance is dissolved into another substance
d)
when a substance is heated or exposed to another substance
36.
A precipitate is...
a)
a solid that falls out of a liquid solution
b)
a reactant in a reaction
c)
a clear substance
d)
the mass of a product
37.

True or False: In a complete chemical equation, there must be the same number of atoms of each element on the reactants and products side.

a)

True

b)

False

38.

Why are chemical equations always balanced? Select ALL that apply.

a)

Matter cannot be created.

b)

Matter cannot be destroyed.

c)

Matter can only be rearranged/conserved.

d)

Matter doesn't matter.

39.
All of the following are physical properties of matter EXCEPT
a)
mass
b)
color
c)
melting point
d)
ability to rust
40.

True or false?

A chemical reaction is a chemical change that occurs when two substances combine to form a new substance.

a)

True

b)

False

41.

Group 1 elements are very reactive

a)

false

b)

true

42.

The following elements are members of group 7 EXCEPT for one.

a)

chlorine

b)

hydrogen

c)

fluorine

d)

iodine

43.

Which of the following characteristics is similar for fluorine and iodine?

a)

Number of Protons

b)

Number of Neutrons

c)

Number of Orbitals

d)

Number of Valence Electrons

44.

Which statement would be most helpful in identifying an element?

a)

The element has 36 protons

b)

The element has 6 neutrons

c)

The element has 8 valence electrons

d)

The element has properties similar to nitrogen

45.

Which statement would be most helpful in determining an element’s reactivity?

a)

The element has the same number of electron shells as iodine

b)

The element has the same number of valence electrons as cesium

c)

The element has 47 neutrons

d)

The element is a metal

46.

USE THE PERIODIC TABLE

Find the element that has 5 Valence Electrons and 4 energy levels.

a)

Arsenic - As

b)

Selenium - Se

c)

Calcium - Ca

d)

Vanadium - V

47.

An atom that gains or loses an electron becomes

a)

an isotope

b)

a new element

c)

an ion

d)

a molecule

48.

a change to a substance that happens without forming a new substance

a)

physical change

b)

chemical change

c)

double replacement reaction

d)

combustion

49.
The number of atoms you begin with in a chemical reaction ...
a)
must be the same as the number of  atoms you end with
b)
must be an even number
c)
can be different to the number you finish with
d)
changes depending on how much energy is formed
50.

Which one shows that a chemical reaction has occurred?

a)

dissolving

b)

melting

c)

formation of a gas

d)

bending

51.
One of the signs of a chemical reaction taking place is:
a)
Bubbles are produced 
b)
Reactants are not combining
c)
Products are not forming
d)
Color is not changing
52.
Which of the following describes a precipitate?
a)
a liquid forms when a block of metal is heated
b)
a solid forms when one liquid is poured into another
c)
a gas forms when a solid is placed in a liquid
d)
bubbles form when an acid is poured on a rock
53.
You know you a chemical reaction has occurred if 
a)
there is a precipitate.
b)
there is a color change.
c)
there is a temperature change.
d)
All of these answers are evidence.
54.
Four students performed four different investigations by combining different substances. Which of the observations is most indicative of a chemical reaction?
a)
investigation 1
b)
investigation 2
c)
investigation 3
d)
investigation 4
55.

What type of bonding does this picture show?

a)

Ionic

b)

Covalent

56.

Generally, atoms form bonds so that _______________.

a)

Each atom loses its electrons

b)

Each atom has a stable electron configuration

c)

Each atom has an unstable electron configuration

d)

Each atom gains electrons

57.
Where are the nonmetals located on the periodic table? 
a)
Blue
b)
Red
c)
Green
58.

This refers to the tendency of atoms to prefer to have eight electrons in the valence shell

a)

Octet rule

b)

Valence electron

c)

Electronegativity

d)

Lewis symbol

59.

If an atom loses two electrons what charge will it have?

a)

-1

b)

-2

c)

+1

d)

+2

60.

Which particle is responsible for bonding?

a)

Electrons

b)

Protons

c)

Nucleus

d)

Neutrons

61.

Why do elements bond?

a)

To be friends

b)

To create a new element

c)

To become stable

d)

To get bigger

62.
If an atom gains two electrons what charge will it have?
a)
-2
b)
-1
c)
+1
d)
+2
63.

An atom with a different number of electrons than it should have (more or less) is called an ---

a)

isotope

b)

valence electron

c)

ion

d)

octet

64.
How many electrons can the first energy level hold?
a)
1
b)
2
c)
8
d)
0

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