Atoms and reactions

Question 1

give the charge and mass of each subatomic particle in an atom

Answer 1

proton - mass 1, charge +1
neutron - mass 1, charge 0
electron - mass 1/1836 (negligible), charge -1

Question 2

define isotope

Answer 2

atoms of the same element that have the same atomic number but different mass number

Question 3

what is relative atomic mass (Ar)

Answer 3

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

Question 4

what is the use of a mass spectrometer?

Answer 4

-determine relative isotopic mass + relative abundances of isotopes

Question 5

define molar mass and molar gas volume and their units

Answer 5

molar mass- mass per mole ( g mol-1)
molar gas volume-gas volume per mole ( dm3 mol-1)

Question 6

what does anhydrous mean

Answer 6

contains no water, opposite of hydrated

Question 7

percentage yield equation

Answer 7

actual/theoretical X100

Question 8

atom economy equation

Answer 8

mr desired products/mr total products X100

Question 9

formula for nitric acid

Answer 9

HNO3

Question 10

metal + water =
*name type of reaction

Answer 10

metal hydroxide + hydrogen
displacement exothermic

Question 11

metal + acid =
*name type of reaction

Answer 11

salt + hydrogen
(redox)

Question 12

metal oxide + acid =
*name type of reaction

Answer 12

salt + water
(neutralisation)

Question 13

metal hydroxide + acid =
*name type of reaction

Answer 13

salt + water
(neutralisation)

Question 14

metal carbonate + acid =
*name type of reaction

Answer 14

salt + water + carbon dioxide
neutralisation

Question 15

hydrogencarbonate + acid =
*name type of reaction

Answer 15

salt + water + carbon dioxide
neutralisation

Question 16

ammonia + acid =
*name type of reaction

Answer 16

ammonium salt
neutralisation

Question 17

define relative isotopic mass

Answer 17

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

Question 18

define relative molecular mass (MMR/MR)

Answer 18

the average mass (gmol-1) of a molecule compared to the mass of 1/12th of a carbon-12 atom

Question 19

how do you calculate relative formula mass

Answer 19

add up the relative atomic masses of all the atoms/ions in one formula unit of a compound

Question 20

how do you calculate relative atomic mass

Answer 20

sum of (isotopic mass X isotopic abundance) / sum of abundance of all isotopes

Question 21

formula for ethanoic acid

Answer 21

Ch3COOH

Question 22

formula for ammonia

Answer 22

NH3

Question 23

what is a strong acid and give the equation

Answer 23

one that completely dissociates in water to release hydrogen ions and the corresponding anions
HA(aq) - H+(aq) + A-(aq)

Question 24

what is a proton donor

Answer 24

a chemical that releases hydrogen ions / ‘protons’ when dissolved in water, eg acids

Question 25

formula for phosphoric acid

Answer 25

H3PO4

Question 26

what are diprotic and triprotic acids

Answer 26

diprotic - release 2 protons, eg H2SO4 triprotic - release 3 protons, eg H3PO4

Question 27

what is a weak acid and give the equation

Answer 27

one that partially dissociates in water to release some hydrogen ions HA(aq) -/- H+(aq) + A-(aq)

Question 28

what is a base

Answer 28

a chemical that reacts with protons released by acids, ie proton acceptors

Question 29

what is an alkali

Answer 29

a soluble base that releases hydroxide ions (OH-) when dissolved in water BOH(aq) - B+(aq) + OH-(aq) can be weak/strong

Question 30

describe neutralistion reaction and give equation

Answer 30

reaction of an acid and an alkali to form salt and water H+(aq) + OH-(aq) - H2O (l) -type of salt formed depends on the acid used

Question 31

charges on zinc and silver

Answer 31

zinc - Zn2+ silver - Ag+

Question 32

what is avagadro's constant

Answer 32

6.02x10^23

Question 33

what is concentration measured in

Answer 33

moldm^-3

Question 34

give examples of strong bases

Answer 34

KOH NaOH

Question 35

give examples of weak bases

Answer 35

hydroxides methylamine NH3

Question 36

give examples of strong acids

Answer 36

HCl H2SO4 HNO3

Question 37

give examples of weak acids

Answer 37

CH3COOH H2CO3 H2S benzoic acid

Question 38

what is the ideal way gases behave

Answer 38

- no intermolecular forces - continuously flow - exert pressure when they collide - no kinetic energy lost in collisions - when temperature increases, kinetic energy of gas particles increases

Question 39

what does the concentration of a solution mean

Answer 39

amount of solute dissolved in 1dm3 of the solvent

Question 40

what is a standard solution

Answer 40

a solution of a known concentration

Question 41

steps to prepare a standard solution

Answer 41

1- weigh solute then dissolve with a solvent 2- pour solution into volumetric flask 3- rinse beaker w/ distilled water and add to flask 4- add distilled water until the graduation line 5- mix thoroughly (invert)

Question 42

does 100% yield mean 100% atom economy

Answer 42

no, even if all reactants are turned into products, not all of them are the required ones

Question 43

what acid is used to treat acid indigestion

Answer 43

Magnesium hydroxide

Question 44

what acid is used to neutralise acidic soil

Answer 44

Calcium carbonate

Question 45

what is an amphoteric substance

Answer 45

substance that can act as both an acid and an alkali

Question 46

why are products the same when an acid reacts with alkalis or metal oxides

Answer 46

both alkali and metal oxides are bases

Question 47

describe the method to carry out a titration

Answer 47

1. measure volume of a solution with a pipette 2. add solution to conical flask and add a few drops of indicator 3. add other solution to a burette and record the initial volume 4. slowly add solution in burette to conical flask and mix continuously 5. when end point is reached stop and record volume of solution in burette 6. repeat until you produce concordant results

Question 48

describe the indicator methyl orange's colour change

Answer 48

yellow in alkali, red in acid

Question 49

describe the indicator phenolphthalein's colour change

Answer 49

pink in alkali, colourless in acid

Question 50

oxidation of combined oxygen and in peroxides

Answer 50

2- in combined 1- in peroxides

Question 51

oxidation number of combined hydrogen and in metal hydrides

Answer 51

1+ in combined 1- in metal hydrides

Question 52

what are oxyanions and give an example

Answer 52

negative ions with an element along with oxygen, eg NO3-

Question 53

what is a redox reaction

Answer 53

both oxidation (loss of electrons) and reduction (gain of electrons) occurs

Question 54

what is a disproportionation reaction

Answer 54

when an element is both oxidised and reduced in a reaction