C2.3 How Much?

Question 1

What is the relative mass of a proton?

Answer 1

1

Question 2

What is the relative mass of a neutron?

Answer 2

1

Question 3

What is the relative mass of an electron?

Answer 3

1/2000

Question 4

What does the mass number mean?

Answer 4

The number of protons + the number of neutrons

Question 5

What is an isotope?

Answer 5

Atoms with the same number of protons and electrons but different number of neutrons

Question 6

What is relative atomic mass?

Answer 6

The mass of an atom compared to 1/12 of an atom of carbon-12

Question 7

What is relative atomic mass measured in?

Answer 7

Grams

Question 8

What is the relative formula mass (Mr) of CO2

Answer 8

12 + 16 + 16 = 44

Question 9

What is the relative formula mass (Mr) of MgO?

Answer 9

24 + 16 = 40

Question 10

What is the percentage by mass of magnesium in magnesium oxide?

Answer 10

24 / 40 x 100 = 60%

Question 11

Give two benefits of using instrumental methods such as gas chromatography?

Answer 11

Highly accurate/Sensitive
Quicker
Can detect small samples

Question 12

Give two disadvantages of using instrumental methods such as gas chromatography?

Answer 12

Very expensive
Require specialist training to interpret
Can only identify samples by comparing with data of known substances

Question 13

In what part is the relative molecular mass of a substance measured?

Answer 13

The mass spectrometer

Question 14

What is the retention time?

Answer 14

The time from when a substance enters a gas chromatogram, to when it leaves.

Question 15

Describe the similarities and differences between atoms of oxygen-16 and oxygen-18

Answer 15

Both have the same number of protons (8)
Both have the same number of electrons (8)
Oxygen-18 has 10 neutrons
Oxygen-16 has 8 neutrons
Have different number of neutrons