Test #1 for term

Question 1

What is the chemical formula for sodium chloride?

Answer 1

NaCl

Question 2

What is the formula for calcium oxide?

Answer 2

CaO

Question 3

What is the formula for aluminium sulfate?

Answer 3

Al₂(SO₄)₃

Question 4

Calculate the number of particles in 2 moles of any substance.

Answer 4

2 × 6.02 × 10²³ = 1.204 × 10²⁴ particles

Question 5

What is the formula to calculate the number of particles?

Answer 5

Particles = Moles × Avogadro’s number (6.02 × 10²³)

Question 6

Calculate the percentage composition of oxygen in H₂O (H = 1, O = 16).

Answer 6

% O = (16 ÷ 18) × 100 = 88.89%

Question 7

Calculate the number of moles in 12g of carbon (C = 12).

Answer 7

1 mole

Question 8

A sample contains 48g of Mg (Molar mass = 24 g/mol). How many moles are present?

Answer 8

2 moles

Question 9

What is the molar volume of a gas at r.t.p.?

Answer 9

24 dm³ per mole

Question 10

How do you calculate molar mass?

Answer 10

Add the relative atomic masses of all atoms in the formula.

Question 11

Define percentage composition.

Answer 11

The percentage by mass of each element in a compound.

Question 12

State the relationship between mass, molar mass, and moles.

Answer 12

Moles = Mass ÷ Molar Mass

Question 13

What is the mole?

Answer 13

The amount of substance that contains 6.02 × 10²³ particles (Avogadro’s number).

Question 14

State Avogadro’s law.

Answer 14

Equal volumes of gases at the same temperature and pressure contain the same number of particles.

Question 15

Define molar mass.

Answer 15

The mass of one mole of a substance, measured in grams per mole (g/mol).

Question 16

: Balance the equation:
___ Al + ___ O₂ → ___ Al₂O₃

Answer 16

4 Al + 3 O₂ → 2 Al₂O₃

Question 17

Balance the equation:
___ Na + ___ Cl₂ → ___ NaCl

Answer 17

2 Na + 1 Cl₂ → 2 NaCl

Question 18

Balance the equation:
___ H₂ + ___ O₂ → ___ H₂O

Answer 18

2 H₂ + 1 O₂ → 2 H₂O

Question 19

What is the formula for potassium nitrate?

Answer 19

KNO₃

Question 20

What is the formula for magnesium hydroxide?

Answer 20

Mg(OH)₂

Question 21

Number of moles (when mass and rmm is given)

Answer 21

mass of a substance divided by molar mass

Question 22

1 mole is?

Answer 22

the amount of substance that contains as many particles as there are in 12.00 g of Carbon 12

Question 23

Each mole of a substance has how many atoms?

Answer 23

6.022 x 10 to the 23rd power

Question 24

Molar Mass

Answer 24

tells how much mass there is in 1 mole of a substance

Question 25

RAM

Answer 25

Calculated by adding all the rams of the atoms present in a formula unit or molecule

Question 26

Relative atomic mass

Answer 26

the average mass of one atom of an element compared to one-twelfth the mass of an atom of carbon 12

Question 27

Molar Volume

Answer 27

The volume occupied by one mole

Question 28

Standard Temperature and Pressure (STP)

Answer 28

These conditions have a temperature of 0 degrees celcius and a pressure of 101,300 pascals (Pa) and occupies a volume of 22.4 dm3 or 22,400 cm3

Question 29

Room Temperature and pressure (RTP)

Answer 29

These conditions have a temperature 25 degrees celcius and a pressure of 101,300 pascals (Pa) and occupies a volume of 24 dm3 or 24,000 cm3

Question 30

Avogadro's Law

Answer 30

States that equal volumes of gases will contain the same number molecules as long as they are under the same conditions of temperature and pressure.