Chapter 9- Stoichiometry

Question 1

What is the mole?

Answer 1

A unit used to measure the amount of a substance

Question 2

What is the mole’s relationship with carbon?

Answer 2

It is the number of carbon atoms in 12 grams of carbon-12

Question 3

What is Avogadro’s number?

Answer 3

6.02×10²³

Question 4

What does Avagadro’s number represent?

Answer 4

The number of atoms in 12 g of carbon.

Question 5

Why do we use moles?

Answer 5

To have a convenient unit to measure substances.

Question 6

What is molar mass

Answer 6

The mass of one mole of a pure substance in grams per mole

Question 7

Molar mas = ______

Answer 7

Atomic mass

Question 8

What is stoichiometry

Answer 8

The relationship between the relative quantities (masses) of elements in a compound and reactions and products

Question 9

How do you go from grams to moles?

Answer 9

Divide by the molar mass

Question 10

How do you go from moles to grams

Answer 10

Multiply by molar mass

Question 11

How do you go from moles to particles

Answer 11

Multiply by 6.02×10²³

Question 12

How do you go from particles to moles

Answer 12

Divide by 6.02×10²³

Question 13

How do you find the percent composition

Answer 13

(Mass of element÷mass of compound) ×100

Question 14

What is the empirical formula

Answer 14

The formula of a compound with the smallest whole number ratio of its elements

Question 15

What is the molecular formula

Answer 15

A multiple of the empirical formula that represents the actual compound

Question 16

What are the steps to find the empirical and molecular formulas

Answer 16

1. Is right percent of each element given as grams
2. Convert to moles by dividing by the molar mass
3. Find the imperical formula ratio by dividing each mole by the smallest number
4. Is calculate the empirical formula mass- the sum of the molar masses
5. Find the molecular formula factor- dividing the given molar mass by the empirical mass
6. Calculate the molecular formula- multiply the empirical formula by the molecular formula factor