Unit 3 Review

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