Amount of substance

Question 1

What is an isotope?

Answer 1

Atoms of the same element with the same number of protons but a different number of neutrons

Question 2

What is the atomic number?

Answer 2

The number of protons in the nucleus

Question 3

What is the relative isotopic mass?

Answer 3

Mass of 1 isotope compared to 1/12 mass of 1 atom of C-12

Question 4

What is the relative atomic mass?

Answer 4

Mass of 1 atom compared to 1/12 mass of 1 atom of C-12

Question 5

What is the relative molecular mass?

Answer 5

Average mass of a molecule compared to 1/12 mass of 1 atom of C-12

Question 6

What is mass spectroscopy for?

Answer 6

It is used to determine the mass of the atoms and molecules by measuring masses of components.

Question 7

What are the steps of mass spectroscopy?

Answer 7

1. Vapourisation
2. Ionisation
3. Acceleration - cations attracted to negative plates
4. Deflection - size depends on ratio of ions mass to charge
5. Detection - current generated - proportional to abundance of each ion

Question 8

What is the empirical formula?

Answer 8

The simplest ratio of atoms of each element in a substance

Question 9

What is the molecular formula?

Answer 9

The number of atoms of each element in 1 molecule