WorksheetsCounting atoms, Balancing, Law of Conservation of Mass Review
Total questions: 32
Worksheet time: 36mins
How many Hydrogen atoms are there in 3H2O?
2
3
5
6
In CO2, how many Carbon's are there?
1
2
3
infinite solution
In H2O + CO2 + O2, how many O's are there?
1
2
3
5
In the compound 4Mg(OH)2, how many Hydrogen's are there?
2
4
6
8
In NH3, how many Nitrogen's are there?
1
2
3
4
Does this equation follow the law of conservation of mass?
Yes
No
Sometimes
According to the law of conservation of mass, which statement is true?
The atoms of the reactants and products are different
The atoms of the reactants and products are equal
The subscripts must be the same
The compounds must be the same
Salt is combined with water to make salt water. What are the reactants?
Salt
Water
Salt and water
Salt water
Salt is combined with water to make salt water. What are the products?
Salt
Water
Salt and water
Salt water
How many grams of products should there be?
30 g
275 g
300 g
305 g
If there is 200 g of reactants, how many grams of products should there be?
Less than 200 g
Equal to 200 g
More than 200 g
Does this follow the law of conservation of mass?
Yes, because there are the same number of atoms.
Yes, because there are not the same number of atoms.
No, because there are the same number of atoms.
No, because there are not the same number of atoms.
Does this equation follow the law of conservation of mass?
Yes, because the mass is the same.
Yes, because the mass is not the same.
No, because the mass is the same.
No, because the mass is not the same.
Which equation follows the law of conservation of mass?
Na + Cl2 --> NaCl
Na + Cl2 --> 2NaCl
2Na + Cl2 --> NaCl
2Na + Cl2 --> 2NaCl
10g of H2 + 20 g of Cl2 --> 30 g of 2HCl. What are the reactants?
H2 + HCl
H2 + Cl2
HCl
Cl2 + HCl
10g of H2 + 20 g of Cl2 --> 30 g of 2HCl. What are the products?
H2 + HCl
H2 + Cl2
HCl
Cl2 + HCl
20 g of water decomposes into 12 g of oxygen and an unknown amount of hydrogen. How much hydrogen was there?
32 g
20 g
12 g
8 g
In 6CO2, identify the subscript.
C
O
6
2
In 6CO2, identify the coefficient.
C
O
6
2
This chemical equation represents what happens when a nail rusts: 4Fe + 3O2 –› 2Fe2O3. The total mass after the reaction is
not considered before the reaction.
5 times less than before the reaction.
exactly the same as before the reaction.
about twice as much as before the reaction.
Which of the following best describes the mass of the iron oxide that is produced during a chemical reaction when a fixed amount of iron combines completely with a fixed amount of oxygen?
equal to the mass of the iron plus the mass of the oxygen
greater than the combined mass of the iron and the oxygen
equal to the mass of the iron minus the mass of the oxygen
less than the mass of the iron but greater than the mass of the oxygen
Suppose 20 g of liquid hydrogen peroxide is heated so it completely breaks down into liquid water and oxygen gas. Which best describes the total mass of the water and oxygen that was produced?
more than 20 g because of the addition of heat
more than 20 g because there are now two substances
less than 20 g because oxygen gas is very light
20 g because no matter is added or removed
Iron chloride is formed when 44 g of iron and 56 g of chlorine react completely. What is the expected mass of iron chloride?
12 g
44 g
56 g
100 g
Which of the following equations is balanced?
C2H4 + O2 --> CO2 + H2O
2C2H4 + 2O2 --> CO2 + 3H2O
C2H4 + 3O2 --> 2CO2 + 2H2O
2C2H4 + 3O2 --> 2CO2 + 3H2O
What are the products in the following chemical equation?
NaCl + AgF → NaF + AgCl
NaCl, NaF
NaCl, AgF
NaF, AgCl
AgF, AgCl
What are the reactants in the following chemical equation?
NaCl + AgF → NaF + AgCl
NaCl, NaF
NaCl, AgF
NaF, AgCl
AgF, AgCl
When acetic acid and baking soda are mixed together, carbon dioxide, water, and sodium acetate are formed. What are the products of this reaction?
acetic acid and baking soda
baking soda and carbon dioxide
acetic acid and sodium acetate
carbon dioxide, water, and sodium acetate
When acetic acid and baking soda are mixed together, carbon dioxide, water, and sodium acetate are formed. What are the reactants of this reaction?
acetic acid and baking soda
baking soda and carbon dioxide
acetic acid and sodium acetate
carbon dioxide, water, and sodium acetate
Evaluate this equation. What is the problem? 4Al + O2 → 2Al2O3
There is one missing oxygen atom in the reactants.
There are two missing oxygen atoms in the reactants.
There are four missing oxygen atoms in the reactants.
There is an extra aluminum atom in the product.
Evaluate this equation. What is the problem? H2 + O2 → 2H2O
There is one missing oxygen atom in the reactants.
There are two missing oxygen atoms in the reactants.
There is an extra hydrogen atom in the reactants.
There are two missing hydrogen atoms in the reactants.
What coefficient should be placed in the ? spot in the equation to balance it:
C+?H2-->CH4
1
2
3
4
What coefficient should be placed in the ? spot in the equation to balance it:
P4+?O2-->P4O6
1
2
3
4
