Question

1. the calculation of quantities in a chemical reaction is called stoichiometry.

true
false

1. the molar mass is the mass of one mole of a pure substance.

true
false

1. the international system of units to measure the amount of a substance is called a mole.

true
false

1. in the following equation, what is the ratio of hydrogen molecules to water molecules?

2 h₂ + o₂ -> 2 h₂o
a) 1:1
b) 2:2
c) 2:1

Explanation:

Step1: Recall stoichiometry definition

Stoichiometry is indeed the calculation of quantities in a chemical reaction. So, question 22 is True.

Step2: Recall molar - mass definition

The molar mass is defined as the mass of one mole of a pure substance. So, question 23 is True.

Step3: Recall mole definition

The mole is the SI - unit for the amount of a substance. So, question 24 is True.

Step4: Analyze the chemical equation

In the equation $2H_2 + O_2
ightarrow2H_2O$, there are 2 hydrogen molecules ($H_2$) and 2 water molecules ($H_2O$). The ratio of hydrogen molecules to water molecules is 2:2, which simplifies to 1:1.

Answer:

1. True
2. True
3. True
4. A. 1:1