Flashcards in Inorganic Deck (63):
State how the element sulfur deviates from the general trend in first ionisation energies across Period 3. Explain your answer (3 marks)
-Two of the electrons in 3p orbital
-Undergo electron pair repulsion
Strongest type of intermolecular force in Hydrogen Sulfide (H2S):
-Dipole-Dipole OR VDW
When H+ ions react with H20 molecules, H30+ ions are formed.
Name the type of bond formed and explain how this type of bond is formed (2 marks)
-Dative covalent bonding
-O donates a lone pair of electrons to the H+ ion
Give the name of a SOLID pollutant which may form when pentane burns incompletely in air ( 1 mark)
Suggest a type of compound that can be manufactured from the alkene in this cracking reaction (1 mark)
Explain briefly how the relative abundance of an ion is measured in a mass spectrometer (2 marks)
-Ion hits detector and forms current
-Bigger current = bigger abundance
What is the bent bond angle?
This sodium halide is a white solid that reacts with concentrated sulfuric acid to give a brown gas
When a solution of this sodium halide is mixed with silver nitrate solution no precipitate is formed.
When this solid sodium halide reacts with conc sulfuric acid, the reaction mixture remains white and steamy fumes are given off
A colourless aqueous solution of this sodium halide reacts with orange bromine water to give a dark brown solution
State a use of magnesium hydroxide in medicine
Explain why strontium has a higher melting point than barium (2 marks)
(Look at periodic table, anomaly question as strontium is higher up/smaller than barium)
-Valence electrons closer to nucleus in Sr
-Which results in a stronger attraction between the nucleus and outer electrons therefore more energy required to overcome
Calcium carbonate is an insoluble solid that can be used in a reaction to lower the acidity of water in a lake.
Explain why the rate of this reaction decreases when the temp of water in the lake FALLS. (3 marks)
-When temperature decreases the energy of the particles (H+) decrease
-Therefore less particles with greater than or equal to the activation energy
-Therefore less successful collisions
Hydrogen is used in the chemical industry.
Tungsten is extracted by passing hydrogen over heated tungsten oxide (WO3)
State the role of hydrogen in this reaction (1 mark)
State a risk of using hydrogen gas in metal extractions
Write an equation for the reaction of magnesium with titanium(IV) chloride:
2Mg+TiCl4---->2MgCl2 + Ti
Suggest a reason why the catalyst may be hot (1 mark)
-To overcome activation energy
Suggest a reason why the catalyst remains hot during the reaction ( 1 mark).
-The reaction is exothermic (releases heat energy)
State the characteristic property of transition metals that enables them to act as
catalysts in redox reactions. (1 mark)
Variable oxidation state
SO2 + V2O5 → SO3 + V2O4
2V2O4 + O2 ---> 2V205
Suggest one reason why poisoning reduces the effectiveness of a heterogeneous
catalyst. (1 mark)
Poison attaches to surface
Suggest how poisoning of a catalyst, used in an industrial process, can be
minimised. ( 1 mark)
State a medical use of barium sulfate and state why it is safe. (2 marks)
-Used in a barium meal
-It is insoluble
Magnesium burns with a bright white light and is used in flares and fireworks.
Use your knowledge of the reactions of Group 2 metals with water to explain why
water should not be used to put out a fire in which magnesium metal is burning. (2 marks)
-Hydrogen / H2 produced
-Risk of explosion
Explain why toxicity of chlorine doesn't stop it being used in water
Used in small amounts / Dilute(Low) concentrations
Reaction of chlorine with cold water:
Cl2 + H2O ----> HCl + HClO
Sodium bromide reacts with concentrated sulfuric acid in a different way from
Write an equation for this reaction of sodium bromide and explain why bromide ions
react differently from chloride ions. (3 marks)
2NaBr + 2H2SO4 -----> Na2SO4 + Br2 + SO2 + 2H2O
Br- ions are bigger than Cl- ions
Therefore Br– ions more easily oxidised (lose an electron more easily)
(NaBr also has the reaction of
NaBr + H2SO4 --> NaHSO4 + HBr) - HBr can go on to react to make reaction above (not including na2so4)
K2Cr2O7 reaction with iron half equations:
Fe2+ goes to Fe3+
Chromium in Cr2O72- ----> Cr3+
Cr2O72- +14H+ +6e- ----------> 2Cr3+ +7H2O
6Fe2+ -----> 6Fe3+ +6e-
KMnO4 Reaction half equation:
Manganate goes to Mn2+ in MnO4-
MnO4- +8H+ +5e- ------> Mn2+ +4H2O
In a titration question, you are asked to work out the mass of FeSO4.7H2O. When calculating Mr, do you count 7(H2O) (7x18) when calculating overall Mr?
Yes count moles of water so FeSO4.7H2O
55.8+32,1+64+7x(18) = 277.9
How many sig figs should you give a calculated titration mass to?
3 sig figs
Explain why sodium oxide forms an alkaline solution when it reacts with water.
-Sodium oxide contains O2- ions
-Which react with water to form OH- ions, making alkaline
pH of Ca(OH)2 solution:
State a reagent used to test for presence of sulfafe ions:
And think of the equation AND ioni c equation:
BaCl2 (aq)+ SO42- ——-> BaSO4 (s)+ 2Cl-
Ba2+ + SO42- —-> BaSO4
Displacement reaction of Cl2 reacting with NaBr
Cl2 + 2NaBr ---> Br2 + 2NaCl
Reaction of sodium chloride with concentrated sulfuric acid:
NaCl(s) + H2SO4(l) ---> NaHSO4(s) + HCl(g)
This reaction can be used to prepare hydrogen chloride gas
Reaction of sodium fluoride with conc sulfuric acid:
NaF(s) + H2SO4(l) ---> NaHSO4(s) +HF(g)
Reaction(s) of sodium iodide with concentrated sulfuric acid:
Black Solid- Iodine
H2S- Bad egg smell
Sulfur- yellow solid
NaI + H2SO4 ---> NaHSO4 + HI
REACTION GOES ON TO:
8H+ +8I- + H2SO4(l) ---> H2S(g) + 4H2O(l) + 4I2 (s)
Reactions of period 3 elements with OXYGEN colours and precipates:
Sodium(Na)- Burns with a yellow flame to produce a WHITE SOLID
Mg, Al, Si and P burn with a white flame to give a WHITE SOLID SMOKE
S (sulphur)- Burns with a blue flame to form an acidic choking gas
What is Al2O3
Amphoteric oxide, can act as an acid and a base
State the type of bonding in magnesium oxide.
And outline a simple experiment to demonstrate that magnesium oxide has this type of bonding.
-And it should conduct elecricity as 'Molten oxide conducts electricity'
By reference to the structure of, and bonding in silicon dioxide, suggest why it is insoluble in water (3 marks)
-Consists of covalent bonding
-Water cannot supply enough energy to break the (strong) covalent bonds *
State how the melting point of phosphorous(V) oxide compares with that of silicon dioxide. Explain your answer in terms of the structure of, and the bonding in, phosphorous(v) oxide (3 marks)
-MP of phosphorous oxide is lower
-As only has simple molecular structure (compared to silicon dioxide macromolecular)
-therefore NOT MUCH ENERGY NEEDED TO BREAK THE WEAK INTERMOLECULAR FORCES *
Magnesium oxide is classified as a basic oxide. Write an equation for a reaction that shows magnesium oxide acting as a base with another reagent (2)
MgO + H2O --> Mg(OH)2 (reagent is water)
Explain in terms of structure and bonding, why sulfur trioxide has a higher melting point than sulfur dioxide.
-SO3 is a larger molecule than SO2
-So greater van der waals forces
i)Some Period 3 oxides have basic properties, state the type of bonding in these oxides.
ii) EXPLAIN WHY THIS TYPE OF BONDING CAUSES THESE OXIDES TO HAVE BASIC PROPERTIES. (2 marks)
ii)-Contains O2-/oxide ions
- O2- ions accept protons to form OH- / hydroxide ions
Some Period 3 oxides have acidic properties, state the type of bonding in these oxides.
Ions are formed when sulfur dioxide reacts with water.
Write an equation.
i)Suggest why sulfur dioxide forms a weakly acidic solution
SO2 +H20 --> HSO3- + H+
i) Reversible reaction therefore partially ionised/dissociated
(Allow reaction doesn't go to completion)
Ions are formed when sulfur trioxide reacts with water.
Write an equation.
SO3 + H20 --> HSO4- + H+
Suggest why silicon dioxide is described as an acidic oxide even though it is insoluble in water.
SiO2 reacts with bases (e.g NaOH, CaO, CaCO3)
Describe what you would observe when magnesium is burned in oxygen (2 marks)
-White fumes/white solid (NOT WHITE PPT, PENALISE)
Describe what you would observe when sulfur burns in oxygen (2 marks)
Aluminium Oxide (Al2O3) Acting as an acid Equation and Ionic equation:
Al2O3(s) +2NaOH(aq) + 3H2O(l) --> 2NaAl(OH)4 (aq)
Al2O3(s) + 2OH- (aq) + 3H2O(l) --> 2Al(OH)4- (aq)
ACIDIC OXIDES REACTING WITH BASES TO FORM SALTS:
Al2O3(s) +2NaOH(aq) + 3H2O(l) --> 2NaAl(OH)4 (aq)
SO2+ 2NaOH --> Na2SO3 + H2O
IONIC: SO2 + 2OH- ---> SO32- + H2O
SO3 +2NaOH --> Na2SO4 + H2O
IONIC: SO2 + 2OH- ---> SO42- + H2O
p4O10 + 12NaOH ---> 4Na3PO4 + 6H2O
P4O10 + 6Na2O ----> 4Na3PO4
SiO2 only reacts with VERY CONCENTRATED NaOH
2NaOH + SiO2 ----> Na2SiO3 + H2O
Suggest one reason why a thin layer of aluminium oxide protects aluminium from corrosion in moist air/
Suggest one property of the aluminum oxide coating that causes aluminium to resist corrision in water.
The oxide is insoluble in water (meaning the MOIST air)
Write an ionic equation to show how aluminium oxide reacts with hydrochloric acid
Al2O3 + 6H+ --> 2Al3+ + 3H2O
Name the type of reaction shown between Na2O and P4O10 (produces Na3PO4)
pH of solutions:
H3PO4 - 0
Suggest why this pure water at 10 °C is not alkaline.