Unit 1

Question 1

list 4 factors that can speed up the rate of a reaction

Answer 1

1. increasing concentration
2. increasing surface area - decrease particle size
3. increase temperature
4. use a catalyst

Question 2

formula for rate of reaction

Answer 2

Average rate = change in quantity/change in time

Question 3

why does that average rate of a reaction decrease over time?

Answer 3

the reactants are being used up so the concentration of reactants are decreasing

Question 4

what is a catalyst?

Answer 4

a substance that speeds up a chemical reaction but is not used up by the reaction

Question 5

how are elements arranged in the periodic table?

Answer 5

in order of increasing atomic number

Question 6

how are elements in the same group similar?

Answer 6

• they have the same number of outer electrons
• they have similar chemical properties
• they have the same valency

Question 7

describe an atom

Answer 7

a nucleus containing protons and neutrons with electrons in orbit

Question 8

what is the mass number of an atom?

Answer 8

the number of protons + neutrons

Question 9

what is the atomic number of an atom?

Answer 9

the number of protons

Question 10

how do you work out the number of neutrons in an atom?

Answer 10

mass number - the atomic number

Question 11

what is the mass of an electron?

Answer 11

an amount so small its not worth working out

Question 12

what is the charge of an electron?

Answer 12

-1

Question 13

what is the mass of a proton?

Answer 13

1 atomic mass unit

Question 14

what is the charge of a proton?

Answer 14

+1

Question 15

what is the mass of a neutron?

Answer 15

1 atomic mass unit

Question 16

what is the charge of a neutron?

Answer 16

0

Question 17

what are isotopes?

Answer 17

atoms with the same atomic number but different mass number ( they have different numbers of neutrons)

Question 18

what is the relative atomic mass of an element?

Answer 18

the average mass of an element

Question 19

what is a covalent bond?

Answer 19

a shared pair of electrons holding non-metal atoms together

Question 20

how are atoms in a covalent bond held together?

Answer 20

by the attraction between the positive nuclei and the shared pair of electrons

Question 21

list the 7 diatomic elements

Answer 21

• nitrogen
• oxygen
• fluorine
• hydrogen
• iodine
• bromine
• chlorine

Question 22

what does diatomic mean?

Answer 22

two atoms covalently bonded

Question 23

what shape would a molecule with the formula XY have?

Answer 23

linear

Question 24

what shape would a molecule with the formula XY^2 have?

Answer 24

angular

Question 25

what shape would a molecule with the formula XY^3 have?

Answer 25

trigonal pyramidal

Question 26

what shape would a molecule with the formula XY ^4 have?

Answer 26

tetrahedral

Question 27

what is an ion?

Answer 27

an atom that has gained or lost electrons in charge ( they do this to be stable like the noble gasses)

Question 28

ionic compounds are usually made from a metal and non-metal. which ion will be positively charged?

Answer 28

metal ion = positive | non-metal ion = negative

Question 29

what is an ionic bond?

Answer 29

an electrostatic attraction between positive and negative ions

Question 30

what structure do ionic compounds have?

Answer 30

crystal lattice | - each positive ion surrounded by a negative ion and each negative ion surrounded by positive ions

Question 31

in general, do ionic substances have high or low melting and boiling points?

Answer 31

high | because strong bonds must be broken which requires a lot of energy

Question 32

why do ionic substances only conduct electricity when heated until a liquid or in a solution?

Answer 32

because when they are liquid or are in a solution ions are free to move so the substance can conduct electricity

Question 33

what happens at the electrodes when an ionic compound is electrolysed?

Answer 33

at the electrode the ion gains or loses electrons | the ion is drawn to the oppositely charges electrode

Question 34

do ionic compounds usually dissolve in water?

Answer 34

yes

Question 35

what type of bonding is present in substances that can conduct electricity without decomposing?

Answer 35

metallic

Question 36

why can metals conduct electricity?

Answer 36

the electrons are delocalised so they are free to move

Question 37

do covalently bonded substances usually conduct energy?

Answer 37

no | because there are no free charged particles free to move

Question 38

what is the usual ending for a compound containing only 2 elements?

Answer 38

...ide | iron chloride

Question 39

what does the compound ending in ...ate or ...ite mean?

Answer 39

oxygen is present

Question 40

what is pH?

Answer 40

a measure of hydrogen ion concentration in a solution

Question 41

what pH would a solution of equal concentrations of hydrogen and hydroxide ions have?

Answer 41

pH 7

Question 42

what pH would a solution with a higher concentration of hydrogen ions than hydroxide ions have?

Answer 42

pH 1-6 (acid)

Question 43

what pH would a solution with a higher concentration of hydroxide ions than hydrogen ions have?

Answer 43

pH 8-14 (alkaline)

Question 44

why is water neutral? (pH 7)

Answer 44

when the molecules separate it makes equal concentrations of hydrogen and hydroxide ions

Question 45

what pH will a solution of a soluble non-metal oxide be?

Answer 45

less than 7

Question 46

what pH will a solution of soluble metal oxides be?

Answer 46

more than 7

Question 47

what are bases?

Answer 47

a substance that can react with acids and neutralise them

Question 48

what is an alkali?

Answer 48

a base that dissolves in water

Question 49

what is a neutralisation reaction?

Answer 49

the reaction of an acid with a base that results in the pH moving towards 7.

Question 50

complete the equation | metal oxide + water =

Answer 50

metal hydroxide

Question 51

complete the equation | metal oxide + acid =

Answer 51

salt + water

Question 52

complete the equation | metal hydroxide + acid =

Answer 52

salt + water

Question 53

complete the equation | metal carbonate + acid =

Answer 53

salt + water + carbon dioxide

Question 54

which salts are made from - hydrochloric acid - nitric acid - sulphuric acid - ethanoic acid

Answer 54

- chloride - nitrate - sulphate - ethanoate

Question 55

what effect on pH does adding water to an acid have?

Answer 55

increases it

Question 56

what do you get when an acid reacts with a metal?

Answer 56

salt + hydrogen

Question 57

what effect on pH does anything water to an alkili have?

Answer 57

decreases it