1.1 and 1.3 (formulae and chemical equations)

Question 1

what does aqueous mean?

Answer 1

dissolved in water

Question 2

What is the difference between copper sulphide and copper sulphate?

Answer 2

copper sulphate also has oxygen

Question 3

Define compound

Answer 3

two or more different elements that are chemically bonded in a fixed proportion

Question 4

What oxidation state (charge) does group 1 always have?

Answer 4

+1 oxidation state

Question 5

What oxidation state (charge) does group 2 always have?

Answer 5

+2 oxidation state

Question 6

What oxidation state (charge) does group 0 always have?

Answer 6

0 as they don’t react so don’t form ions

Question 7

What oxidation state (charge) does group 7 always have?

Answer 7

-1 oxidation state

Question 8

What oxidation state (charge) do transition metals have?

Answer 8

they have different oxidation states
eg Fe(II) and Fe(III)

Question 9

what does an oxidation agent do?

Answer 9

they will oxidise the other compound in the reaction

Question 10

what does a reducing agent do?

Answer 10

they will reduce the other compounds in the reaction

Question 11

what is the definition of electronegativity?

Answer 11

the ability of an element to attract a pair of electrons in a covalent bond

Question 12

what is ionic bonding?

Answer 12

the electrons transfer from metal to non-metal

Question 13

what is covalent bonding?

Answer 13

shared between atoms

Question 14

what is metallic bonding?

Answer 14

delocalised electrons

Question 15

when is the oxidation state of oxygen different?

Answer 15

in hydrogen peroxide and the xodiation state is -1

Question 16

what is the oxidation state of flourine always?

Answer 16

always -1

Question 17

what is meant by an isotope?

Answer 17

isotopes occur when atoms of the same element have different masses (i.e same number of protons, different number of neutrons)

Question 18

How do you calculate the percentage composition calculations?

Answer 18

mass of element ÷ mass of compound x 100

Question 19

define a mole

Answer 19

a mole is the amount of a substance in grams which has the same number of particles as there are atoms

Question 20

what is avogadro’s constant?

Answer 20

6.02 x 10^23

Question 21

what is the equation to work out mols?

Answer 21

mass divided by mr

Question 22

define the term atom economy

Answer 22

a measure of the amount of starting materials that end up as useful products

Question 23

how do you calculate the percentage atom economy?

Answer 23

relative formula mass of useful products divided by relative formula mass of all products x100

Question 24

how much is 1 tonne in kg?

Answer 24

1000kg

Question 25

how much is 1 tonne in g?

Answer 25

1,000,000g

Question 26

define density

Answer 26

measures the amount of mass per unit of volume in a substance

Question 27

what are the three steps when converting density to concentration?

Answer 27

step 1 - no. of mols that you have in a solution n= m÷mr

step 2 - volume that the no. of mols is dissolved in
v= m ÷ d

step 3 - concentration
c= n ÷ v

Question 28

what does the volume always have to be in when working out solutions?

Answer 28

dm3

Question 29

define concentration

Answer 29

the amount of a substance dissolved in another substance

Question 30

how do you get from gdm-3 to moldm-3?

Answer 30

÷mr

Question 31

how do you get from moldm-3 to gdm-3?

Answer 31

xmr

Question 32

how do you convert from the empirical formula to the molecular formula?

Answer 32

mr÷empirical mr

Question 33

when working out calculations involving solutions what are the two equations you must remember and what are all the units?

Answer 33

m = n x mr
g = mol x no unit
n = c x v
mol = moldm-3 x dm3

Question 34

what are some sources of error when reading the burette/pipette in titrations?

Answer 34

ensure you read the solution at eye level
allow the pipette to drain via gravity

Question 35

what are some sources of error when using indicators?

Answer 35

people percieve colours differently

Question 36

what are some sources of error when weighing solids?

Answer 36

residue could be left on the weighing scale/boat
may be spillage

Question 37

what is the accuracy of a burette and how do you calculate the percentage error for it?

Answer 37

+/- 0.05cm3
2x0.05 / titre x100

Question 38

what is the accuracy of a 2 d.p mass balance and how do you calculate the percentage error for it?

Answer 38

+/- 0.005g
0.005/mass x100

Question 39

what is the accuracy of a 3 d.p balance and how do you calculate the percentage error for it?

Answer 39

+/- 0.0005g
0.0005/mass x 100