BMST - Basic Math and Science Chemical Reactions and Stoichiometry Questions and Answers 2

Question 1

In a balanced chemical equation, what is conserved?

Accepted Answer

Mass and the number of atoms of each element

Answer

The law of conservation of mass requires that atoms are neither created nor destroyed in a chemical reaction.

Question 2

What is the molar mass of water (H₂O)?

Accepted Answer

18 g/mol

Answer

H₂O = 2(1.008) + 16.00 = approximately 18 g/mol.

Question 3

What type of reaction is: 2H₂ + O₂ → 2H₂O?

Accepted Answer

Synthesis (combination)

Answer

Two or more reactants combine to form a single product, which defines a synthesis reaction.

Question 4

How many moles are in 44 grams of CO₂?

Accepted Answer

1 mole

Answer

Molar mass of CO₂ = 12 + 2(16) = 44 g/mol. So 44g ÷ 44g/mol = 1 mole.

Question 5

What is a catalyst?

Accepted Answer

A substance that speeds up a reaction without being consumed

Answer

Catalysts lower the activation energy of a reaction, increasing its rate without being permanently changed.

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