C2.3 How Much? Flashcards Preview

GCSE Chemistry AQA > C2.3 How Much? > Flashcards

Flashcards in C2.3 How Much? Deck (15):
1

What is the relative mass of a proton?

1

2

What is the relative mass of a neutron?

1

3

What is the relative mass of an electron?

1/2000

4

What does the mass number mean?

The number of protons + the number of neutrons

5

What is an isotope?

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

6

What is relative atomic mass?

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

7

What is relative atomic mass measured in?

Grams

8

What is the relative formula mass (Mr) of CO2

12 + 16 + 16 = 44

9

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

24 + 16 = 40

10

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

24 / 40 x 100 = 60%

11

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

Highly accurate/Sensitive
Quicker
Can detect small samples

12

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

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

13

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

The mass spectrometer

14

What is the retention time?

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

15

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

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