Chemistry 3rd Quarter Grade 9

Question 1

Atoms

Answer 1

Building blocks of matter
Are extremely small
Are mostly made up of empty space

Question 2

Element

Answer 2

Are what all matter is made up off
Are pure substances
Are made up of atoms

Question 3

Mole equation

Answer 3

The number of moles in a sample equals the mass of that element/compound over Mr (Molar Mass)

Question 4

Mole

Answer 4

Unit we use to measure the amount of chemical we have.
1 mole we have of any substance is 6.02 x 10(23) particles (avogadros constant)

Question 5

To find mass of element/compound

Answer 5

number of moles in a sample x Mr (Molar mass)

Question 6

To find number of moles

Answer 6

mass of element over Mr

Question 7

To find number of atoms

Answer 7

number of moles x avogadros number (6.022 is x 10(23)

Question 8

1 mole represents

Answer 8

6.022 x 10(23) molecules, ions and atoms

Question 9

How to find number of moles with atoms

Answer 9

number of atoms divided by avogadros number (6.022 x 10(23)

Question 10

moles to grams

Answer 10

moles x the molar mass

Question 11

grams to moles

Answer 11

grams over moles

Question 12

STP

Answer 12

Standard Temperature and Pressure: 0C and 1 ATM

Question 13

At 1 STP, 1 mole of any gas

Answer 13

takes up 22.4 liters of volume

Question 14

To find number of moles in Litres of Gas

Answer 14

Litres divided by 22.4 liters

Question 15

To find volume with moles and gas

Answer 15

number moles x 22.4 liters

Question 16

Conversion factor

Answer 16

example 13 liters of chlorine gas is how many moles?
13L divided by 22.4 equals 0.580

Question 17

Balancing Equations

Answer 17

Reactants to products

Question 18

Law of Conservation of Mass

Answer 18

That mass is neither created nor destroyed in chemical reactions.

Question 19

Stoichiometry

Answer 19

Measuring chemicals that go into and come out go any given reaction.
In greek it means measuring elements.
Allows us to count atoms and molecules by weighing them.

Question 20

Molar mass

Answer 20

in grams
ex: 1 mole of H = 1.008g

Question 21

Relative atomic mass

Answer 21

in AMU

Question 22

Average atomic mass of an element in grams

Answer 22

an elects molar mass

Question 23

Stoichoimetry helps us understand

Answer 23

the proportions of chemicals as they react at the molecular level.