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WorksheetsUnit 3 Review
Total questions: 36
Worksheet time: 18mins
The chemical equation shows the mass of the reactants and the products. What is the missing mass of Hydrogen?
Zn + 2HCl --- > ZnCl2 + H2
Mass 2g 6g 4g ?
2 g
3 g
4 g
8 g
Consider the following chemical reaction: 2 NaCl + Ca(OH)2 --- > CaCl2 + 2 NaOH
If the mass of 191 grams NaCl reacted with 74 grams of calcium hydroxide and 80 grams of sodium hydroxide is produced, what mass of calcium chloride is produced?
52.5 g
111 g
91 g
185 g
How many total atoms are found in this molecule? H2C3O4N5
5
14
15
19
Mrs. Oakes needed to count the number of atoms in 2H2SO4. What should her answer be?
H = 2, S = 1, O = 4
H = 4, S = 2, O = 4
H = 2, S = 2, O = 2
H = 4, S = 2, O = 8
KClO3 --- > KCl + O2
If 125 g of KClO3 is heated, what is the total mass of the products?
250 g
100 g
125 g
Cannot be determined from given information
In a chemical reaction, 400 grams of reactant A are combined with 200 grams of reactant B. Both A and B react to completion. How much will the product weigh?
400 g
200 g
600 g
Cannot be determined from given information
Mrs. Holt needs to find out the number of atoms found in 4Pb(NO3)2. What is the breakdown of atoms?
Pb = 4, N = 3, O = 2
Pb = 4, N = 8, O = 24
Pb = 4, N = 24, O = 24
Pb = 8, N = 8, O = 8
How many elements are present in the following chemical formula? C6H12O6
6
1
2
3
Hydrogen & oxygen react chemically to form water. How much water would form if 14.8 grams of hydrogen reacted with 34.8 grams of oxygen? (H2 + O2 = H2O)
49.6 grams
34.8 grams
20 grams
14.8 grams
If 115 g of a substance reacts with 84 g of another substance, what will be the mass of the products after the reaction?
115 g
84 g
185 g
199 g
Which of the following shows a balanced equation?
2AgI + Na₂S → Ag2S + 2NaI
AgI + Na2S → Ag2S + 2NaI
2AgI + NaS → Ag2S + 2NaI
AgI + NaS → Ag2S + 2NaI
Which of the following shows a balance equation?
CO2 + 6 H2O → C6H12O6 + 6 O2
6 CO2 + H2O → C6H12O6 + 6 O2
6 CO2 + H2O → CH12O6 + 6 O2
6 CO2 + 6 H2O → C6H12O6 + 6 O2
In the experiment depicted, the mass of the reactants and the mass of the products are equal. Which statement below best expresses the outcome of this experiment?
The experiment is inaccurate because the product should have been less.
The experiment is inaccurate because the product should have been more since a precipitate was formed.
The experiment supports the law of conservation of mass because matter was not created or destroyed.
The experiment does not support the law of conservation of mass because a precipitate was formed.
Look at the experiment above. The flask was heated and bubbles began to rise. There is nothing covering the top of the bottle, allowing gases to escape. If the beginning mass of the reactants was 98.26 g and no stopper/lid was placed over the flask, what would be the mass of the products if weighed again?
More than 98.26 grams
Less than 98.26 grams
98.26 grams
Which of the following statements are correct concerning the law of conservation of mass in the picture above?
The law of conservation of mass is supported because the mass of the reactants equal the mass of the products.
The law of conservation of mass is not supported because the mass of the reactants and products are equal.
The law of conservation of mass is not supported because the mass of the reactants do not equal the mass of the products.
The law of conservation of mass is not supported because smoke does not have weight.
How many grams of of iron (Fe) was added to sulfur to produce 88 g of iron sulfate (FeS)?
32 g
40 g
50 g
56 g
Which of the following chemical formulas correctly identifies the yellow reactants in the picture?
2Na
Na2
2Na2
Na
Which of the following correctly identifies the red and white reactants?
H2O
2H2O
2HO
H2O2
Which of the following correctly identifies the products in the picture?
2H₂O + 2Na₂
H₂O + 2Na
2NaOH + H₂
H₂O₂
Which chemical equation supports the law of conservation of mass?
CH4 + 2O2 → CO2 + 2H2O
Zn + HCl ---> ZnCl2 + H2
C5H12 + O2 ---> CO2 + H2O
C5H12 + O2 ---> 5CO2 + H2O
Which of the pictures accurately depicts the chemical reaction: Zn + 2HCl ---> ZnCl2 + H₂
The Law of Conservation of Mass states
mass can be created but not destroyed
mass can be destroyed but not created
mass cannot be created or destroyed
Which series of words correctly fills in the blanks in the correct order?
In a chemical reaction, the atoms of the reactants just get ___________ to form the products. You must have the same _______ and ________ of atoms on both sides of the equation.
lost, number, type
destroyed, number, quantity
rearranged, number, type
When cheical reactions occur,
new substances are always formed
there is always an explosion
there is always a bad smell
new substances are never formed
The substances formed in a chemical reaction may have properties that are ____________ from the original substances.
exactly the same
totally different
some the same, while others different
Count the atoms in the following chemical formula: 6H2SO4
H = 6, S = 6, O = 6
H = 12, S = 6, O = 8
H = 6, S = 1 O = 24
H = 12, S = 6, O = 24
Count the atoms in the following chemical formula: 2Na(OH)2
Na = 2, O = 4, H = 4
Na = 2, O = 2, H = 2
Na = 2, O = 4, H = 2
Na = 4, O = 4, H = 4
Does the following equation support the Law of Conservation of Mass?
2H2 + O2 → 2H2O
Yes, there is an equal number of hydrogen atoms and oxygen atoms on the reactant and product sides of the equation.
No, there is not an equal number of hydrogen atoms and oxygen atoms on the reactant and product sides of the equation
Does the following equation support the Law of Conservation of Mass?
CH4 + O2 → CO2 + H2O
Yes, you have the same number of carbon, hydrogen and oxygen atoms on both the reactant and product side of the equation.
No, although there is an equal number of carbon atoms on each side of the quation, there are unequal numbers of hydrogen and oxygen atoms.
3Fe + 4H2O → Fe3O4 + 4H2
Which substances are the reactants?
3Fe + 4H2O
Fe3O4 + 4H2
3Fe + 4H2O → Fe3O4 + 4H2
Which substances are the products?
3Fe + 4H2O
Fe3O4 + 4H2
If 153 g of iron reacted with 22 g of oxygen gas to form iron oxide, how much iron oxide would be produced if no reactants were left over?
22 g
153 g
175 g
200 g
In an experiment, students started with 176.3 grams of reactants. In a totally closed system, what will be the mass of the products?
176.3 g
170 g
180 g
not enough information to answer the question
AgI + Na2S 🡪 Ag2S + NaI
What is wrong with the equation above?
There is an extra silver (Ag) atom on the reactant side and a missing sulfur (S) atom on the product side.
There is an extra silver (Ag) atom on the reactant side and an extra sodium (Na) atom on the product side.
There is a missing silver (Ag) atom on the reactant side and a missing sodium (Na) atom on the product side.
There is an extra iodine (I) atom on the reactant side and a missing sodium (Na) atom on the product side.
Evaluate the image above. Does it represent an equation that supports the LOCOM?
Yes, there are gray and white circles on both sides of the equation
Yes, there are four circles on the reactant side of the equation and four circles on the product side.
No, there is one gray circle on the reactant side and two gray circles on the product side. You can't create matter, so we should have the same number of gray circles on both sides.
Why in an open system does it sometimes appear that the LOCOM has been broken?
If one of the products is a gas, it can escape, leaving people to assume that matter was destroyed
If one of the products is a precipitate, it won't weigh as much if the system is open
There's not enough information to answer correctly.
