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Chemical Equations and Charge

Total questions: 21

Worksheet time: 28mins

Name
Class
Date
1.
The law of conservation of mass states that....
a)
Matter can be made
b)
Matter can be destroyed
c)
Matter can neither be made or destroyed
2.
Is this balanced?...
Al + O2 --> 2Al2O3
a)
Yes!
b)
NO!
3.
Balance this equation...
HgO --> 2Hg + O2
a)
It is balanced 
b)
2HgO --> Hg + O2
c)
2HgO --> 2Hg + O2
4.
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
5.

How many valence electrons does magnesium have?

a)

6

b)

12

c)

2

d)

10

6.

What are valence electrons?

a)

electrons in the outermost energy level

b)

electrons in the innermost energy level

c)

positively charged ions

d)

energy used for attraction in a shell

7.

How many valence electrons does elements in group 16 have?

a)

16

b)

1

c)

6

d)

0

8.

What is an ion?

a)

a positively charged atom

b)

a negatively charged atom

c)

a neutral charged atom

d)

both a and b

9.

What is a cation?

a)

a negatively charged ion

b)

an ion with many charges

c)

a positively charged ion

10.

What defines the octet rule?

a)

Contains element symbol and valence electrons

b)

atoms of main-group elements tend to combine in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.

c)

The electrons in the outermost energy level of an atom that influence how an element will react with other substances

11.

What is an anion?

a)

a positively charged ion

b)

a negatively charged ion

c)

a neutral charged ion

12.

How many protons, neutrons, and electrons does a neutral Selenium (Se) have?

a)

34, 45, 34

b)

34, 34, 45

c)

45, 45, 45

d)

45, 34, 34

13.

Is the equation balanced (yes or no)?  


 Cl2+2KBr  2KCl +Br2Cl_2+2KBr\ \rightarrow\ 2KCl\ +Br_2  


(a)  

14.

When Lead Nitrate reacts with potassium iodide, Yellow precipitate of ............. is formed

a)

PbI2

b)

KNO3

c)

Pb(NO3)2

d)

PbIO3

15.

What does the symbol inside the circle mean?

a)

"yields, or produces"

b)

"dissolved in water"

c)

"forms a precipitate"

d)

"released as a gas"

16.

When balancing this equation, Fe + Cl2 → FeCl3, the correct coefficient for Cl2?

a)

1

b)

2

c)

3

d)

4

17.

Balance this equation, CaCO3(s) → CaO(s) + CO2(g)?

a)

3,1,2

b)

1,1,1

c)

1,3,1

d)

2,6,3

18.
Fill in the blanks with coefficient:
PCl5+_ H2O→_ HCl+H3PO4
a)
4, 5
b)
1, 6
c)
3, 8
d)
2,2
19.

Write a balanced chemical equation for the following reaction.


Iron metal reacts with water to form Fe3O4 and hydrogen gas.

4 lines
20.
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
21.
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