Revision Flashcards
(25 cards)
Acid +metal carbonate –>
(Na2CO3+2HCl)
Salt+Water+Carbon dioxide
(2NaCl+H2O+CO2)
Define relative atomic mass
The weighted mean mass of an atom of an element compared with 1/12th of the mass of an atom of carbon 12
Define Mole
The number of atoms in exactly 12 grams of carbon 12
Define relative isotopic mass
The mass of an atom of an isotope compared with one twelfth of the mass of an atom of carbon 12
Formula triangle of Mr mass moles
M
n|mr
Formula triangle of concentration moles and volume
n
C|V
Formula triangle of volume moles 24
V
n|24
Percentage error =
= glassware error
——————— ×100
quantity measured
Colours of halogens when dissolved in water
Cl2 = pale-green
Br2 = Orange
I2 = brown
Colours of halogens when dissolved in organic solvents
Cl2 = pale green
Br2 = Orange
Iodine = Purple
What are the colours of silver halide precipitates
AgCl = white
AgBr= cream
AgI = yellow
What are AgCl,AgBr,AgI soluble and insoluble in
Silver chloride is soluble in dilute ammonia solution
Silver Bromide is insoluble in dilute ammonia solution but soluble in concentrated ammonia solution
Silver Iodide is insoluble in dilute and and concentrated ammonia solution
Define precipitate
An insoluble solid formed when two solutions are mixed together
Ionic equation and test for carbonate ions [CO3²‐]
Ionic equation = CO3²-[aq] + 2H+[aq] = H2O[l] + CO2[g]
Test = Add HNO3 to the solution
Positive result = effervescence [due to carbon dioxide being produced] [carbon dioxide could be further tested using lime water which would produce a white precipitate]
Ionic equation and test for Sulfate ions [SO4²-]
Ionic equation = Ba²±[aq] + SO4²‐[aq] = BaSO4[s]
Test = Add dilute nitric acid followed by barium nitrate solution to the suspected sulfate solution
Positive result = White precipitate forms insoluble barium sulfate
Ionic equation and test for halide ions [ Cl‐ Br- I- ]
Ionic equation = Ag+[aq] + X‐[aq] =
AgX[s]
Test = Add dilute nitric acid,followed by AgNO3[aq]
Positive result = white/cream/yellow precipitate forming [insoluble silver halide]
Ionic equation and test for Ammonium ions [NH4+]
Ionic equation = NH4+[aq] + OH‐[aq] = NH3[g] + H2O [l]
Test = Add warm dilute aqueous sodium hydroxide [NaOH]
Positive result= Ammonia gas NH3 is produced,ammonia can be detected with moist pH indicator paper which turns blue
Reagent for carbonate test
HNO3
Reagent for sulfate test
Ba(NO3)2
Reagent for halide test
AgNO3
Reagent for Ammonium test
Warm dilute NaOH
What happens to the solubility of group 2 metals down a group
Solubility increases, solutions become more alkaline due to higher OH- concentrations
Trend of group 2 carbonates thermal decomposition down a group
More difficult to decompose as going down the group
Trend of reactivity of group 2 metals down a group
More reactive down group because:
• Atomic radius increases/ more shielding
•nuclear attraction decreases
• less energy needed to remove electrons
