Amount Of Substance

Question 1

What is the equation for relative atomic mass?

Answer 1

1/12 mass of one carbon-12 atom

Question 2

what is the equation for relative molecular mass?

Answer 2

1/12 mass of one carbon-12molecule

Question 3

what is a mole?

Answer 3

the amount of substance that contains 6.022 x10^23

Question 4

what is the Avogadro constant formula?

Answer 4

no. of particles=moles x 6.022 x10^23

Question 5

what is the formula for calculating moles?

Answer 5

mass of substance
————————— = no. of moles
molecular mass

Question 6

what are the units for concentration?

Answer 6

moldm-3

Question 7

how do you calculate moles using concentration?

Answer 7

concentration x volume(dm3)

Question 8

how do you convert cm3 to dm3?

Answer 8

cm3\1000

Question 9

what does the ideal gas equation allow you to find

Answer 9

the no.of moles in a certain volume at any temperature and pressure.

Question 10

what does pV=nRT stand for?

Answer 10

p=pressure(pa)
v=volume
n=no.moles
r=gas constant(8.31klmol-1)
t=temperature in k

Question 11

how do you convert kpa to pa?

Answer 11

kpa x 1000

Question 12

how to you convert degrees to kalvin?

Answer 12

add 273

Question 13

how do you convert cm3 to m3?

Answer 13

cm3 x 10-6

Question 14

how do you balance equations?

Answer 14

• write word equation
• write formulas involved
• balance from left to right

Question 15

how do you write an ionic equation?

Answer 15

• full balanced equation
• split any dissolved ionic species into ions
• take out any ions that appear on both sides

Question 16

how do you calculate how much product you get from a product?

Answer 16

• write out balanced equation
• workout how many moles of reactant you have
• use molar ratio to workout the number of moles of product that will be formed this much reactant
• calculate the mass of that moles of product

Question 17

what is different about calculating gas volumes

Answer 17

once moles of product is found it is put into the ideal gas equation.

Question 18

what is neutralisation?

Answer 18

acid reacts with an alkali you get salt and water

Question 19

what is the empirical formula?

Answer 19

the smallest whole number ratio of atoms in a compound

Question 20

what is the molecular formula?

Answer 20

gives the actual number of atoms in a molecule

Question 21

how do you calculate empirical formula?

Answer 21

• turn percentages into masses
• divide each mole by the smallest one
• apply the ratio number into the formula

Question 22

what is the theoretical yield?

Answer 22

mass of product that should be formed in a chemical reaction

Question 23

how do you calculate theoretical yield?

Answer 23

• workout how many reactant moles
• use equation to workout how many moles you would have of product
• calculate the mass of that many moles in prodcut

Question 24

how do you find the percentage yield?

Answer 24

actual yield
———————— x 100
theoretical yield

Question 25

what is atom economy?

Answer 25

measure of the proportion of reactant atoms that become apart of the desired product

Question 26

what are the advantages of high atom economy

Answer 26

more efficient use of materials means less waste

Question 27

how does yield effect the economy?

Answer 27

produce less waste is better for economy

Question 28

how do you calculate atom economy?

Answer 28

molecular mass of desired product
———————————————————x100
sum of all molecular masses ofreactants