2 - amount of substance

Question 1

relative atomic mass

Answer 1

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

Question 2

relative molecular mass

Answer 2

the mass of a molecule compared to 1/12th the mass of an atom of carbon-12

Question 3

how can you find the relative molecular mass

Answer 3

by adding up all the relative atomic masses of all the atoms present in the molecule

Question 4

why is the term relative formula mass used for ionic compounds

Answer 4

as they dont exist as molecules

Question 5

what is avogadros constant

Answer 5

the number of atoms in 12g of carbon-12

Question 6

what is avogadros constant as a number

Answer 6

6.022 x10^23

Question 7

what is a mole

Answer 7

the amount of substance that contains 6.022 x 10^23 particles

Question 8

how many moles do the relative molecular mass of an element in grams contain

Answer 8

1

Question 9

number of molecules formula

Answer 9

number of moles x mass of 1 mole = mass

Question 10

what is a solutioon

Answer 10

a solvent with a solute dissolved in it

Question 11

unit for concentration

Answer 11

moldm^-3

Question 12

number of moles in solution equation

Answer 12

no. of moles = concentration x volume / 1000

Question 13

boyles law

Answer 13

the product of pressure and volume is a constant as long as the temperatures remain constant

Question 14

boyles law equation

Answer 14

pressure x volume = constant

Question 15

charles law

Answer 15

the volume is proportional to the temperature as long as the pressure remains constant

Question 16

charles law equation

Answer 16

volume/ temperature = constant

Question 17

gay-lussacs law

Answer 17

the pressure is proportional to the temperature as long as the volume remains constat

Question 18

gay lussacs law equation

Answer 18

pressure/temperature = constant

Question 19

ideal gas equation

Answer 19

pressure x volume = number of moles x gas constant x temperature
PV=nRT

Question 20

What can you work out using the idle gas equation

Answer 20

you can calculate the volume of one mole of gas at any temperature and pressure

Question 21

how can you find the relative molecular mass of a gas

Answer 21

if you know the number of moles present in a given mass of gas you can find the mass of one mole of gas and this tells us the relative molecular mass

Question 22

empirical formula

Answer 22

the formula that represents the simplest whole ratio of atoms of each element present in a compound

Question 23

how do you find empirical formula

Answer 23

1. find the masses of each of the element present in a compound
2. work out the number of moles of each element
3. convert the number of moles of each element into a whole number ratio

Question 24

molecular formula

Answer 24

gives us the actually number of atoms of each element in one molecule of the compound

Question 25

what do equations represent

Answer 25

what happens when chemical reactions take place

Question 26

what are equations based on

Answer 26

experimental evidence

Question 27

reactants

Answer 27

the starting material

Question 28

products

Answer 28

the final material

Question 29

the stoichiometry of the reaction

Answer 29

the ratio in which the reactants react and products are produced

Question 30

balanced symbol equations

Answer 30

use the formulae of reactants and products, there are the same number of atoms of each element on both sides of the arrow. tells us the amounts of substances that react togeter and are produces

Question 31

state symbols

Answer 31

tell us what state the reactants and products are in

Question 32

what are the 4 state symbols

Answer 32

S,L,G,Aq

Question 33

ionic equations

Answer 33

considers the ions present, includes the ions that dont take place in the reactions

Question 34

spectator ions

Answer 34

ions that dont take part in a reaction

Question 35

what can you use the balanced symbol equation to work out

Answer 35

how much product is produced from a reaction

Question 36

what can titrations be used to find

Answer 36

the concentration of a solution

Question 37

steps of a titration

Answer 37

1. fill a burette with the acid of a known concentration 2. Accurately measure a amount of the alkali using a calibrated pipette and pipette filler 3. add the alkali to a conical flask with a few drops of a suitable indicator 4. run in acid from the burette until the colour just canges, showing the solution in the conical flask is now neutral 5. repeat the procedure, adding the acid dropwise as you approach the end point, until two values of the volume of acid used at neutralisation are the same within experimental error

Question 38

atom economy

Answer 38

% of the desired product achieved from the reaction

Question 39

atom economy equation

Answer 39

mass of desired product/ total mass of reactants x 100

Question 40

percentage yield

Answer 40

tells us how much product is lost in a reaction