Year 1 Definitions And Laws

Question 1

Isotopes

Answer 1

Atoms of the same element with different numbers of neutrons and different masses

Question 2

Relative isotopic mass

Answer 2

Mass of an isotope compared with 1/12 of the mass of an atom of carbon-12

Question 3

Relative atomic mass

Answer 3

Weighted mean mass of an atom of an element compared with 1/12th of the mass of an atom of carbon-12

Question 4

Amount of substance

Answer 4

Number of particles in a substance, measured in miles

Question 5

Mol

Answer 5

The unit for amount of substance

Question 6

Avogadro Constance

Answer 6

The number of particles per mol

6.02 x 10^23 mol^-1

Question 7

Molar mass

Answer 7

Mass in grams per mole of a substance

Units g mol^-1

Question 8

Molar gas volume

Answer 8

The volume of 1 mole of a gas

Units - dm^3 mol ^ -1

Question 9

Empirical formula

Answer 9

The simplest whole number ratio of atoms of each element present in a compound

Question 10

Molecular formula

Answer 10

The number of atoms of each element in a molecule

Question 11

Anhydrous

Answer 11

Contains no water of crystallisation

Question 12

Hydrated

Answer 12

Contains water molecules (water of crystallisation) as part of the crystalline structure

Question 13

Water of crystallisation

Answer 13

The water molecules contained within a crystalline structure

Question 14

Ideal gas equation

Answer 14

pV = nRT

Question 15

Atom economy

Answer 15

Mr of useful products/sum of mr of all products x100

Question 16

Oxidation

Answer 16

Loss of electrons

Increase in oxidation number

Question 17

Reduction

Answer 17

Gain of electrons

Decrease in oxidation number

Question 18

Atomic orbital

Answer 18

Region around the nucleus that can hold up to two electrons, with opposite spin

Question 19

Ionic bonding

Answer 19

The electrostatic attraction between positive and negative ions

Question 20

Covalent bonding

Answer 20

The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 21

Electronegativity

Answer 21

The ability of an atom to attract the bonding pair of electrons in a covalent bond