chapter 2 and 3

Question 1

mass of electron

Answer 1

1/1836

Question 2

mass of neutron

Answer 2

1

Question 2

mass of proton

Answer 2

1

Question 3

what do neutrons do

Answer 3

neutrons act as a glue that holds the nucleus together despite the electrostatic repulsion between protons

Question 4

what is the mass number

Answer 4

the neutrons plus the number of protons

Question 5

what is the atomic number

Answer 5

the atomic number is the number of protons an atom holds

Question 6

what is relative isotopic mass

Answer 6

relative isotopic is the mass of an isotope relative to 1/12 the mass of carbon 12

Question 7

what is relative atomic mass

Answer 7

relative atomic mass is the weighted mean mass of an atom relative to 1/12th the mass of carbon 12

Question 8

What equipment is used to find percentage abundances

Answer 8

with a spectrometer

Question 9

how does a spectrometer work

Answer 9

sample placed on the mass spectrometer
sample is vaporised
ions are accelerated heavier ions move quicker and are harder to deflect
this way the ions of each isotope are separated
ion is detected by the mass spectrometer and adds to the signal stronger signal = greater abundance

Question 10

what is the mass to charge ratio

Answer 10

relative mass of ion /relative charge on ion = mass to charge ratio

Question 11

ammonium charge NH4

Answer 11

1+

Question 12

hydroxide charge OH

Answer 12

1-

Question 13

nitrate ion charge NO3

Answer 13

1-

Question 14

nitrite ion charge NO2

Answer 14

1-

Question 15

hydrogen carbonate charge HCO3

Answer 15

1-

Question 16

permanganate charge MnO4

Answer 16

1-

Question 17

carbonate charge CO3

Answer 17

2-

Question 18

sulfate charge SO4

Answer 18

2-

Question 19

sulfite charge SO3

Answer 19

2-

Question 20

dichromate charge Cr2O7

Answer 20

2-

Question 21

phosphate charge PO4

Answer 21

3-

Question 22

what is avogadros constant

Answer 22

6.02 * 10^23

Question 23

how to calculate empirical formula

Answer 23

convert mass into moles
divide by smallest whole number
write empirical formula

Question 24

what is the empirical formula of a compound

Answer 24

simplest whole number ratio of of atoms in each element in a compound

Question 25

what is the molecular formula

Answer 25

the molecular formula is the number of atoms of each element in the molecule

Question 26

equation linking mole mass and mr

Answer 26

moles = mass/mr

Question 27

how to calculate molecular formula

Answer 27

convert percentage by mass into moles using moles = mass/mr find the empirical formula write mr of empirical formula find number of the empirical formula by doing total mr/mr of empirical formula times that number with all small number on the empirical formula to get the molecular formula

Question 28

equation that link moles concentration and volume

Answer 28

moles = concentration * volume us e decimetre cubes for the volume so divide by 1000 after finished to convert to cm cubed

Question 29

how to convert between moles and gas volume

Answer 29

for volume in cm^3 divide volume by 24000 for volume in dm^3 divide by 24 to get moles

Question 30

what is the ideal gas equation

Answer 30

the ideal gas equation is an equation used when wanting to find the volume of a gas not at room temperature and normal atmosphere

Question 31

what equation is used links pressure volume moles ideal gas constant temperature and moles

Answer 31

the ideal gas equation: pv = nrt

Question 32

what does the p in in pv = nrt stand for and what unit does it have to be in

Answer 32

p stands for pressure and has to be in Pa

Question 33

what does the v in pv=nrt stand for and what are its units

Answer 33

v stands for volume and has theh values of metres cubed

Question 34

what does the n in pv = nrt stand for and what are its units

Answer 34

the n stands for moles and its units are mol

Question 35

what does the r in pv = nrt stand for and what are its units

Answer 35

the r is the ideal gas constant and is usually 8.31Jmol ^-1K-1

Question 36

what does the t in pv = nrt stand for and what are its units

Answer 36

t stands for temperature and is measured in kelvins

Question 37

how to convert between degrees celcius and Kelvin

Answer 37

+273

Question 39

What is stoichiometry

Answer 39

stoichiometry is the ratio of the amount of moles of a substance in an equation

Question 40

What is the equation for percentage yield

Answer 40

(Actual yield / theoretical yield)*100

Question 41

What is the limiting reagent

Answer 41

The limiting reagent is the reactant that is not in excess

Question 42

What is the equation for atom economy

Answer 42

(Mr of all desired products / molar mass of all products) * 100