2.1

Question 1

isotope

Answer 1

one of more forms of an element with the same number of protons but different numbers of neutrons and therefore different masses

Question 2

relative isotopic mass

Answer 2

mass of an atom of an isotope of an element compared to 1/12th of the mass of an atom of carbon-12

Question 3

relative atomic mass

Answer 3

average mass of an atom of an element compared to 1/12th of the mass of an atom of carbon-12

Question 4

what do chemists mean by amount of substance

Answer 4

the amount of substance is the number of particles. it is called the mole and given symbol n

Question 5

empirical formula

Answer 5

smallest whole ratio of atoms of each element in a compound

Question 6

molecular formula

Answer 6

the actual number of atoms of each element in a compound

Question 7

explain terms anhydrous, hydrated and water of crystallisation

Answer 7

anhydrous salts don’t contain any water of crystallisation., hydrated salts do contain water of crystallisation, water of crystallisation is the water contained within an ionic lattice

Question 8

Can you describe the techniques and procedures required during experiments requiring the measurement of mass, volumes of solutions and gas volumes?

Answer 8

Masses are measured using a balance. When making up a standard solution, all of the solid should be transferred into the volumetric flask by washing the container several times and transferring the washings into the flask. When measuring volumes, the volume should be read from the bottom of the meniscus at eye level. Volumetric flasks must be stoppered and inverted several times to ensure the contents are mixed thoroughly before using. Gas volumes can be measured using a gas syringe or an upturned measuring cylinder over a trough of water.

Question 9

Can you describe the benefits for sustainability of developing chemical processes with a high atom economy?

Answer 9

A high atom economy means that little waste is produced, which is better for the environment. Reactions with high atom economy are more sustainable. It makes sense to use raw materials efficiently, so they last as long as possible as often they are in limited supply. There are economic benefits from using high atom economy processes as waste products don’t need to be separated from the desired ones.