Unit 1 - Definitions

Question 1

Valency

Answer 1

The number of bonds an element needs, to have a full outer shell.

Question 2

Ions

Answer 2

An ion is an atom or molecule with a net charge due to the loss or gain of one or more electrons.

Question 3

What is an atom?

Answer 3

The smallest a substance can be and still stable.

Question 4

Atomic number

Answer 4

Atomic number is the number of protons in the nucleus of an atom.

Question 5

Mass number

Answer 5

The number of protons and neutrons in the nucleus of an atom.

Question 6

Neutral atom

Answer 6

Protons and electrons are equal.

Positive charges and negative charges cancel out.

Question 7

Defenition of Isotopes

Answer 7

An isotope is

2 or more atoms (of the same element) with the same atomic number but different mass numbers.

Question 8

Definition of isotopes in terms of particles

Answer 8

2 or more atoms (of the same element) with the same number of protons but different numbers of neutrons.

Question 9

Relative atomic mass

Answer 9

Relative atomic mass is the mass of an element relative to the proportion of each isotope.

Question 10

Solutions and solubility

Answer 10

Solute - the substance that dissolves in the solvent.

Solvent - the liquid that dissolves the solvent

Solution - the substance made from the solute and solvent.

Saturated - when no more solute dissolves in the solvent.

Question 11

What is a catalyst?

Answer 11

Catalysts are substances that speed up a reaction without being used up in reaction.

Question 12

Definition of

Rate of reaction

Answer 12

The rate of a reaction is a measure of how quickly a reactant is used up, or a product is produced.

Question 13

Why do atoms form bonds?

Answer 13

Atoms form bonds to achieve a full stable electron arrangement.

(Like a noble gas)

Question 14

Covalent bond

Answer 14

A covalent bond is an electrostatic force of attraction between the positive nuclei and the shared electrons.

Question 15

Ionic bonds

Answer 15

An ionic bond is an electrostatic force of attraction between positive and negative ions.

Question 16

Molecule

Answer 16

A small number of non-metal atoms covalently bonded together.

Question 17

Electrolysis

Answer 17

Electrolysis is the process of

Separating a compound into its elements using electric current.

Question 18

Gram formula mass

Answer 18

gfm = the relative atomic mass for 1 mole of an atom.

The mass in grams of 1 mole of an element or compound.

Question 19

Universal indicator

Answer 19

Universal indicator is used to tell if something is a acidic, alkali or neutral.

Question 20

pH

Answer 20

pH is the number which indicates how acid or alkaline a substance is.

(pH means power of hydrogen)

Question 21

What are acids?

Answer 21

Acids are solutions containing a greater concentration of hydrogen ions than hydroxide ions.

Question 22

What are alkalis?

Answer 22

Alkalis are solutions containing a greater concentration of hydroxide ions than hydrogen ions.

An Alkali is a soluble base.

Question 23

What are neutral solutions?

Answer 23

Neutral solutions contain an equal amount of hydrogen and hydroxide ions

Question 24

What is a base?

Answer 24

A base is defined as anything that neutralises and acid.

Question 25

How are acids made?

Answer 25

Acids are made when: Soluble non-metal oxides form acids when dissolved in water.

Question 26

How are alkalis made?

Answer 26

Alkalis are made when: Soluble metal oxides form alkalis when dissolved in water.

Question 27

What is pH dependent on?

Answer 27

pH is dependent on the concentration of hydrogen ions in a solution

Question 28

What is a neutralisation reaction?

Answer 28

A neutralisation reaction is a reaction in which a base reacts with an acid to form water. (A salt is also produced)

Question 29

Titration

Answer 29

Titrations are used to calculate the concentration of an unknown solution by reacting it with a solution of known concentration, known as a standard solution.

Question 30

Solute

Answer 30

Solute (substance) dissolves (in the solvent)

Question 31

Solvent

Answer 31

Solvent (the liquid) dissolves the solute

Question 32

Solution

Answer 32

The substance that is made from the solute and solvent | Solute + solvent

Question 33

Saturated

Answer 33

No more solute can dissolve in the solvent

Question 34

Covalent molecule

Answer 34

Have fixed - shapes, sizes and formulae (non-metals)

Question 35

What are delocalised electrons?

Answer 35

Delocalised electrons are electrons that are free to move between the layers. This allows electricity and heat to be conducted.

Question 36

What are charged particles called?

Answer 36

Ions

Question 37

Monatomic

Answer 37

A substance which exists as single, unbonded atoms. E.g. noble gases

Question 38

Ions - metals and non-metals

Answer 38

Non metal form ions by GAINING electrons to form negative ions. Metals form ions by LOSING outer electrons to form positive ions.

Question 39

Ions - Charge and valency

Answer 39

The charge on the ion equals its valency.

Question 40

Types of bonding

Answer 40

Covalent - non metals only Ionic - metals and non metals only Metallic - metals only

Question 41

Number of methods to react/collect gases?

Answer 41

2 methods - they are interchangeable | Diagrams in jotter

Question 42

3 common lab acids

Answer 42

``` Hydrochloric acid (HCl) Nitric acid (HNO3) Sulfuric acid (H2SO4) ```

Question 43

Test for hydrogen gas

Answer 43

Burns with a popping sound. ?

Question 44

Test for carbon dioxide

Answer 44

Carbon dioxide gas turns lime water cloudy.

Question 45

Test for oxygen

Answer 45

Oxygen gas relights a glowing splint.

Question 46

Examples of bases (4) | Neutralisation

Answer 46

- metal oxide - metal hydroxide - metal carbonate - ammonia

Question 47

Describe a diatomic molecule

Answer 47

A molecule made up of only 2 atoms (they can be the same atom or 2 different atoms)

Question 48

Dissociation of water equation

Answer 48

H2O H+(aq) + OH- (aq)

Question 49

Ions in acids and alkalis

Answer 49

Acids contain a higher concentration of H+ ions that OH- ions. Alkalis contain a higher concentration of OH- ions that H+ ions. Neutral substances contain equal concentrations of OH- and H+ ions.

Question 50

Neutralisation equations

Answer 50

Metal oxide + acid ----> water + salt Metal hydroxide + acid ----> water + salt Metal carbonate + acid ----> water + salt + carbon dioxide

Question 51

Spectator ions

Answer 51

A spectator ion is an ion which h is present in a reaction but is not involved. It is 'spectating'.

Question 52

Titration method

Answer 52

An indicator shows the end point. A rough titre is done first to give a rough idea of quantities. It is NEVER used for calculations. A white tile is used to make the colour change clearer. Repeat until results are concordant (within 0.2cm³ of each other) An average titre is calculated from the 2 concordant titres.