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Chemistry flashcards- ms > Inorganic I - p1 > Flashcards

Inorganic I - p1 Flashcards

1
Q

Give an equation for the reaction of solid sodium bromide with concentrated sulfuric acid to form bromine.

State one observation made during this reaction.

A

M1 2H2SO4 + 2NaBr → Na2SO4 + SO2 + Br2 + 2H2O

allow ionic and equation forming NaHSO4

3H2SO4 + 2NaBr → 2NaHSO4 + SO2 + Br2 + 2H2O 2H+ + 2Br- + H2SO4 → SO2 + Br2 + 2H2O

not equation from HBr unless formation of HBr shown in separate equation

1

M2 orange/brown fumes/solution

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2
Q

A solution that is thought to contain chloride ions and iodide ions is tested.

  1. Dilute nitric acid is added to the solution.
  2. Aqueous silver nitrate is added to the solution.
  3. A pale yellow precipitate forms.
  4. Excess dilute aqueous ammonia is added to the mixture.
  5. Some of the precipitate dissolves and a darker yellow precipitate remains.

Give a reason for the use of each reagent.

Explain the observations.

Give ionic equations for any reactions.

A

HNO3 removes (hydroxide/carbonate) ions that may give other ppts with AgNO3

1

AgNO3 produces ppts with chloride/iodide/halide

not chlorine/iodine/halogen

1

Ag+(aq) + Cl−(aq) → AgCl(s) OR

Ag+(aq) + I−(aq) → AgI(s)

allow Ag+(aq) + X−(aq) → AgX(s)

state symbols not required but not if wrong

1

NH3 dissolves AgCl (leaving yellow AgI)

allow chloride/iodide salt/ppt

1

AgCl(s) + 2NH3(aq) → Ag(NH3)2+(aq) + Cl−(aq)

allow with Ag+(aq)

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3
Q

State what is observed when silver nitrate solution is added to sodium fluoride solution.

A
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4
Q

State one observation when solid sodium chloride reacts with concentrated sulfuric acid.

Give an equation for the reaction.

State the role of the chloride ions in the reaction.

A

M1 Misty or steamy or white fumes/gas

1

M2 NaCl + H2SO4 → NaHSO4 + HCl OR 2NaCl + H2SO4 → Na2SO4 + 2HCl

M3 Base OR proton acceptor

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5
Q

Give an equation for the redox reaction between solid sodium bromide and concentrated sulfuric acid.

Explain, using oxidation states, why this is a redox reaction.

A

M1 2NaBr + 2H2SO4 → Na2SO4 + Br2 + SO2 + 2 H2O OR

2Br- + 2H+ + H2SO4 → SO2 + Br2 + 2H2O

M1 Allow ionic equations

2Br – + 2H2SO4 → Br2 + SO42– + SO2 + 2H2O OR

2Br – + 4H+ + SO42- → Br2 + SO2 + 2H2O

1

Br changes oxidation state from −1 to 0 and is oxidised

1

S changes oxidation state from +6 to +4 and is reduced

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6
Q

State what is observed when aqueous chlorine is added to sodium bromide solution.

Give an ionic equation for the reaction.

A

M1 Yellow or orange solution
M1 Do not accept brown solution
1
M2 Cl2 + 2 Br – → 2 Cl – + Br2

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7
Q

Chlorine is used to treat water even though it is toxic to humans.

Give one reason why water is treated with chlorine.

Explain why chlorine is added to water even though it is toxic.

Give an equation for the reaction of chlorine with cold water.

A

Reason: sterilise water / disinfect water / kill bacteria / kill microorganisms / kill microbes

1

Explanation: health benefit outweighs risk / only used in small quantities/low concentrations

1

Equation:

Cl2 + H2O ⇌ HCl + HClO

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8
Q

Write the simplest ionic equation for the reaction between chlorine and aqueous potassium bromide.

State what is observed when this reaction occurs.

A

M1 Cl2 + 2Br−> 2Cl- + Br2

Accept a correct equation using ½ Cl2 but no other multiples

M2 solution goes orange / yellow ( from colourless)

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9
Q

Write an equation for the equilibrium reaction that occurs when chlorine gas reacts with cold water.

Give one reason why chlorine is used for the treatment of drinking water even though the gas is very toxic.

A

M Cl2 + H2O EQ ARROW HClO + HCl

(HOCl)

Equilibrium symbol required in M1

Accept ionic RHS

M2

The (health) benefit outweighs the risk or wtte

OR

a clear statement that once it has done its job, little of it remains

OR

used in (very) dilute concentrations / small amounts / low doses

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10
Q

Sodium bromide reacts with concentrated sulfuric acid in a different way from sodium chloride.

Write an equation for this reaction of sodium bromide and explain why bromide ions react differently from chloride ions.

A

2NaBr + 2H2SO4 -> Na2SO4 + Br2 + SO2 + 2H2O

Allow ionic equation

2Br– + 2H2SO4 Br2 + SO42– + SO2 + 2H2O

1

Br– ions are bigger than Cl– ions

1

Therefore Br– ions more easily oxidised / lose an electron more easily (than Cl– ions)

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11
Q

A colourless solution contains a mixture of sodium chloride and sodium bromide.

Using aqueous silver nitrate and any other reagents of your choice, develop a procedure to prepare a pure sample of silver bromide from this mixture. Explain each step in the procedure and illustrate your explanations with equations, where appropriate.

A

Indicative chemistry content

Stage 1: formation of precipitates

  • Add silver nitrate * to form precipitates of AgCl and AgBr * AgNO3 + NaCl → AgCl + NaNO3 * AgNO3 + NaBr → AgBr + NaNO3

Stage 2: selective dissolving of AgCl

  • Add excess of dilute ammonia to the mixture of precipitates * the silver chloride precipitate dissolves * AgCl + 2NH3 → Ag(NH3)2+ + Cl−

Stage 3: separation and purification of AgBr

  • Filter off the remaining silver bromide precipitate * Wash to remove soluble compounds * Dry to remove water
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12
Q

Does atomic radius increase/decrease down group 2

A

Increases

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13
Q

Does atomic radius increase/decrease down group 2

A

Increases

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14
Q

Do the reactions with water in group 2 increase or decrease down the group

A

Decrease

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15
Q

Group 2 reaction with liquid water - Mg

A

Mg (s) + H2O (l) —> Mg(OH)2 (aq) + H2 (g)

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16
Q

Group 2 reaction with steam - Mg

A

Mg(s) + H2O(g) –> MgO(s) + H2(g)

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17
Q

Observations with Mg and steam

A

white solid - MgO
bright light

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18
Q

Extraction of Ti from TiCl4

A

TiCl4 + 2Mg 2MgCl2 + Ti

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19
Q

Solubility of group 2 hydroxides ….. down the group

A

Increases

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20
Q

Mg and OH- reaction

A

Mg2+(aq) + OH−(aq) à Mg(OH)2(s)

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21
Q

Observation with Mg and OH-

A

white precipitate forms

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22
Q

How to test for the presence of Mg2+ in a solution

A

NaOH (aq)

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23
Q

How to test for the presence of OH- in a solution

A

Mg(NO3)2 (aq)

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24
Q

Use of MgOH

A

Indigestion relief

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25
Q

Use of barium sulphate

A

Taking x-rays of the stomach
Barium meal

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26
Q

How to test for the presence of Ba2+ in a solution

A

H2SO4

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27
Q

How to test for the presence of SO42- in a solution

A

BaCl2

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28
Q

Observation with barium and sulfates

A

white precipitate

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29
Q

Ba2+ and SO42- equation

A

Ba2+(aq) + SO42−(aq) à BaSO4(s)

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30
Q

Solubility of group 2 sulphate …. down the group

A

Decreases

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31
Q

Melting point ….. down group 2

A

Decreases

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32
Q

Flue gas removal

A
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33
Q

Ca(OH)2 use

A

Neutralise soil

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34
Q

State an observation when Mg reacts with steam
Give the equation, including state symbols

A

Bright light / white light / white powder/ash/solid
1
Mg(s) + H2O(g) → MgO(s) + H2(g)

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35
Q

Describe the bonding in Mg

A

M1: Attraction between (lattice of) Mg2+ ions
M1 attraction between nucleus and delocalised
electrons or between + ions and delocalised
electrons
1
M2: And delocalised electrons

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36
Q

Explain, in terms of bonding and structure why MgCl has a high melting point

A

(Giant) ionic lattice / lots of Mg2+ and Cl–
ions
1
Strong (electrostatic) forces of attraction
1
Between Mg2+ and Cl–
ions
Allow oppositely charged ions

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37
Q

Give a medical use of MgOH

A

Indigestion relief / laxative / neutralise (excess stomach) acid
Allow milk of magnesia

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38
Q

Use of barium sulphate

A

In medicine to produce an X-ray image

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39
Q

Explain why the melting point of Mg is higher than the melting point of Na

A

Mg2+ has a higher charge than Na+
/ Mg2+ ions are smaller / Mg2+ has a
greater charge density / Mg atoms smaller than Na atoms / Mg has more
delocalised electrons than Na
Allow
Mg has a higher nuclear charge
1
Stronger attraction to delocalised sea of electrons / stronger metallic
bonding

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40
Q

Give an equation to show how Mg is used as a reducing agent in the extraction of titanium
Explain, in terms of oxidation states why Mg is the reducing agent

A

2Mg + TiCl4 → 2MgCl2 + Ti
Allow multiples
1
Mg changes oxidation state from 0 to +2 so electrons are lost / Ti changes
oxidation state from +4 to 0 , so gains electrons
Allow
Oxidation state of Mg increases so it is a reducing
agent

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41
Q

Give the observation why dilute, aq NaOH is added to separate solutions of MgCl2 and BaCl2

A

MgCl- white ppt
BaCl2- no visible change/ colourless solution/ no reaction

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42
Q

Give an eqaution for the reaction between titanium chloride and magnesium
state the role of magnesium in this reaction

A

Equation: 2 Mg + TiCl4 → Ti + 2 MgCl2
Allow multiples / ignore ss
1
Role: Reducing agent

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43
Q

Give the full electronic configuration of Ca2+

A
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44
Q

Explain why the second ionisation of calcium is lower than the second ionisation energy of potassium

A

M1 In Ca(+) (outer) electron(s) is further from nucleus
Or Ca(+) loses electron from a higher (energy) orbital
AQA Chemistry A-Level - Group 2 Metals MS PhysicsAndMathsTutor.com
Page 4 of 8
Or Ca(+) loses electron from a 4(s) orbital or 4th energy level or 4th
energy shell and K(+) loses electron from a 3(p) orbital or 3rd energy
level or 3rd energy shell
Must be comparative
Allow converse arguments
1
M2 More shielding (in Ca+
)

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45
Q

Identify the s-block metal with the highest first ionisation energy

A

Be

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46
Q

Give the formula of the hydroxide of the element in group 2, from Mg to Ba that is the least soluble in water

A

Mg(OH)2

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47
Q

Give an equation and two observations made for the reaction that occurs when sodium is heated in oxygen.

A

4Na + O2 → 2Na2O

Yellow/orange flame/light AND

white solid/powder/smoke/fumes/ash

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48
Q

Give an equation and one observation made for the reaction that occurs when phosphorus is heated in oxygen.

A

Equation 4P + 5O2 → P4O10 / P4 + 5O2 → P4O10

white flame/light OR white fumes/smoke/solid/powder/ash

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49
Q

Explain the increase in melting point from sodium oxide to magnesium oxide.

A

Greater/increased charge/charge density on magnesium ion/Mg2+ (specific mention of ion(s) can be scored from M2)

Ignore atomic radius

If mention of molecules, intermolecular forces, metallic bonding then CE=0

Stronger attraction for anions/oxide ion / stronger attraction between oppositely charged ions/ stronger attraction between Mg2+ and O2– / stronger ionic bonding

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50
Q

Explain why the melting point of the oxide of silicon is much higher than that of the highest oxide of phosphorus.

A

(SiO2) giant covalent / macromolecular

(P4O10) (simple) molecular

(Covalent) bonds (throughout structure) of SiO2 much stronger than the forces between molecules/intermolecular forces in P4O1

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51
Q

A sample of the highest oxide of phosphorus was prepared in a laboratory.

Describe a method for determining the melting point of the sample.

State how the result obtained could be used to evaluate its purity.

A

M1 Sample in suitable melting point apparatus (e.g. capillary in oil bath/Thiele tube / melting point apparatus)

M2 Heat slowly/gradually/gently (to establish melting point range)

M3 Lower melting point / (broad) range of melting point indicates presence of impurities

OR melting point agrees with/close to data book value / melts sharply/over narrow range / melting point exactly 573K indicates purity

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52
Q

Write an equation for the reaction of phosphorus with an excess of oxygen.

A

P4 + 5 O2 → P4O10

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53
Q

Describe a test you could carry out in a test tube to distinguish between sodium oxide and the product of the reaction in part

A

React with water / add water / solution (of substances in question)

Add litmus paper / universal indicator / measure pH (with pH meter)

pH meter or Universal Indicator: sodium (hydr)oxide (solution) has a higher pH (than phosphorus oxide (solution))

sodium (hydr)oxide pH (12 to 14) and phosphorus oxide (solution) pH (-1 to 2)

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54
Q

State the type of crystal structure shown in silicon dioxide and in sulfur trioxide.

A

Silicon dioxide macromolecular

Sulfur trioxide molecular / (simple) molecule

55
Q

Explain why silicon dioxide has a higher melting point than sulfur trioxide.

A

Covalent bonds (between atoms) in SiO2

1

Van der Waals between molecules / intermolecular forces in SO3

1

Covalent bonds are stronger than van der Waals forces

1

(Covalent bonds) take more energy to be overcome/broken or (Van der Waals) take less energy to be overcome/broken

56
Q

Write an equation for the reaction of sulfur trioxide with potassium hydroxide solution.

A

SO3 + 2KOH → K2SO4 + H2O

57
Q

Write an equation for the reaction of an excess of magnesium oxide with phosphoric acid.

A

3 MgO + 2 H3PO4 → Mg3(PO4)2 + 3 H2O

58
Q

Explain why the atomic radii of the elements decrease across Period 3 from sodium to chlorine.

A

The number of protons increases (across the period) / nuclear charge increases AND same shielding

Therefore, the attraction between the nucleus and electrons increases

59
Q

Explain why the melting point of sulfur (S8) is greater than that of phosphorus (P4).

A

S8 molecules are bigger than P4 molecules

Therefore, van der Waals between molecules are stronger in sulfur

60
Q

Explain why sodium oxide forms an alkaline solution when it reacts with water.

A

Sodium oxide contains O2– ions

1

These O2– ions react with water forming OH– ions

O2– + H2O 2OH–> scores M1 and M2

61
Q

Write an ionic equation for the reaction of phosphorus(V) oxide with an excess of sodium hydroxide solution.

A

P4O10 + 12OH–> 4PO43- + 6H2

62
Q

Element X forms an oxide that has a low melting point. This oxide dissolves in water to form an acidic solution.

(i) Deduce the type of bonding in this oxide of X.
(ii) Identify element X.
(iii) Write an equation for the reaction between this oxide of X and water.

A

i- covalent
ii- Phosphorus/P
iii- P4O10 + 6H2O → 4H3PO4

63
Q

Element Y reacts vigorously with water. An oxide of Y dissolves in water to form a solution with a pH of 14.

(i) Deduce the type of bonding in this oxide of Y.
(ii) Identify element Y.
(iii) Write an equation for the reaction of element Y with water.
(iv) Write an equation for the reaction of this oxide of Y with hydrochloric acid

A

i- ionic
ii- Na/sodium
iii- 2Na + 2H2O → 2Na+ + 2OH- + H2
iv- Na2O + 2HCl → 2NaCl + H2O

64
Q

Write two equations to show the amphoteric nature of the oxide of Z.

A

Al2O3 + 6HCl → 2Al3+ + 6Cl- + 3H2O

Al2O3 + 2NaOH + 3H2O → 2Na+ + 2[Al(OH)4]

65
Q

Write an equation for the reaction that occurs when magnesium is heated in steam.
Describe what you would observe when this reaction occurs.

A

Equation Mg + H2O → MgO + H2_

Observations

White solid / powder / ash / smoke

(Bright) white light / flame

66
Q

Write an equation for the reaction that occurs when sodium is heated in oxygen.
Describe what you would observe when this reaction occurs.

A

Equation 4Na + O2 → 2Na2O

Observations

white / yellow solid / ash / smoke

orange / yellow flame

67
Q

Explain, in terms of structure and bonding, why sodium oxide has a high melting point.

A

Ionic lattice / giant ionic

Strong attraction between oppositely charged ions / Na+ and O2−

lots of energy required to separate / overcome attraction between oppositely charged ions / Na+ and O2

68
Q

Why the melting point of sufur oxide is different from phosphorus(V) oxide

A

SO2 smaller (molecule) (than P4O10) (or converse)

vdW forces between molecules are weaker / require less energy to separate molecules

69
Q

Write an equation for the reaction of sulfur(IV) oxide with water.

Suggest the pH value of the resulting solution.

A

Equation

SO2 + H2O → H2SO3

pH value 1 (allow 1-3

70
Q

Silicon(IV) oxide is insoluble in water.

Explain, using an equation, why silicon(IV) oxide is classified as an acidic oxide.

A

Reacts with / neutralises bases / alkalis

SiO2 + 2NaOH à Na2SiO3 + H2O

71
Q

Describe what you would observe when, in the absence of air, magnesium is heated strongly with water vapour at temperatures above 373 K. Write an equation for the reaction that occurs.

A

White powder / solid / ash / smoke

Bright / white light / flame

Mg + H2O → MgO + H2

72
Q

Explain why magnesium has a higher melting point than sodium.

A

Mg2+ / magnesium ion has higher charge than Na+

Attracts delocalised / free / sea of electrons more strongly / metal–metal bonding stronger / metallic bonding stronger

73
Q

State the structure of, and bonding in, silicon dioxide. Other than a high melting point, give two physical properties of silicon dioxide that are characteristic of its structure and bonding.

A

Structure: Macromolecular / giant molecule / giant covalent

Bonding: Covalent / giant covalent

Physical Properties:

Any two from: Hard/ Brittle / not malleable Insoluble Non conductor

74
Q

Give the formula of the species in a sample of solid phosphorus(V) oxide. State the structure of, and describe fully the bonding in, this oxide.

A

Formula: P4O10

Mention of ionic or metallic, can score M1 only

Structure: Molecular

If macromolecular, can score M1 & M3 only

Bonding: Covalent / shared electron pair

van der Waals’ / dipole–dipole forces between molecules

75
Q

Sulfur(IV) oxide reacts with water to form a solution containing ions.
Write an equation for this reaction.

A

SO2 + H2O → H+ + HSO3

76
Q

Write an equation for the reaction between the acidic oxide, phosphorus(V) oxide, and the basic oxide, magnesium oxide.

A

P4O10 + 6MgO → 2Mg3(PO4)

77
Q

State the type of bonding in magnesium oxide. Outline a simple experiment to demonstrate that magnesium oxide has this type of bonding.

A

Type of bonding MgO is ionic

Experiment

Melt it

(Molten oxide) conducts electricity

78
Q

By reference to the structure of, and the bonding in, silicon dioxide, suggest why it is insoluble in water.

A

Macromolecular

Covalent bonding

Water cannot (supply enough energy to) break the covalent bonds / lattice

79
Q

State how the melting point of phosphorus(V) oxide compares with that of silicon dioxide. Explain your answer in terms of the structure of, and the bonding in, phosphorus(V) oxide.

A

Melting point in comparison to silicon dioxide lower _

Explanation Molecular with covalent bonding

1

Weak / easily broken / not much energy to break intermolecular forces OR weak vdW / dipole-dipole forces of attraction between molecules

80
Q

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.

A

MgO + 2HCl → MgCl2 + H2O (2)

81
Q

Phosphorus(V) oxide is classified as an acidic oxide.
Write an equation for its reaction with sodium hydroxide.

A

P4O10 + 12NaOH → 4Na3PO4 + 6H2O

82
Q

Explain, in terms of structure and bonding, why sodium oxide has a high melting point.

A

Na2O is an ionic lattice / giant ionic / ionic crystal

With strong forces of attraction between ions

83
Q

Explain, in terms of structure and bonding, why sulfur trioxide has a higher melting point than sulfur dioxide.

A

SO3 is a larger molecule than SO2

Allow greater Mr / surface area

So van der Waals’ forces between molecules are stronger

84
Q

Some Period 3 oxides have basic properties.

State the type of bonding in these basic oxides. Explain why this type of bonding causes these oxides to have basic properties.

A

Ionic

Contains O2− ions / oxide ions

These / O2− ions (accept protons to) form OH− / hydroxide / water (must score M2 to gain M3)

85
Q

Ions are formed when sulfur dioxide reacts with water. Write an equation for this reaction.

A

SO2 + H2O → H+ + HSO3−

86
Q

With reference to your equation from part (d)(i), suggest why sulfur dioxide forms a weakly acidic solution.
EQ- SO2 + H2O → H+ + HSO3

A

Reaction is an equilibrium / reversible reaction displaced mainly to the left / partially ionised / dissociated

87
Q

Suggest why silicon dioxide is described as an acidic oxide even though it is insoluble in water.

A

SiO2 reacts with bases / NaOH / CaO / CaCO3 (1)

88
Q

Suggest why white phosphorus is stored under water.

A

To prevent it coming into contact/reacting with oxygen/air

89
Q

Phosphorus(V) oxide is known as phosphorus pentoxide. Suggest why it is usually represented by P4O10 rather than by P2O5

A

One molecule contains 4P and 10O/the molecular formula is P4O10

90
Q

Explain why phosphorus(V) oxide has a higher melting point than sulfur(VI) oxide.

A

P4O10 is a bigger molecule (than SO3)/greater Mr/more electrons/ greater surface area

91
Q

Write an equation for the reaction of P4O10 with water to form phosphoric(V) acid. Give the approximate pH of the final solution.

A

P4O10 + 6H2O ⟶ 4H3PO4

pH must be in the range –1 to +2

92
Q

Write an equation for the reaction between phosphoric(V) acid and magnesium oxide.

A

3MgO + 2H3PO4 → Mg3(PO4)2 + 3H2O

93
Q

Explain why an excess of magnesium oxide can be used for this neutralisation.

A

MgO is sparingly soluble/insoluble/weakly alkaline

94
Q

Explain why the use of an excess of sodium hydroxide to neutralise the phosphoric(V) acid solution might lead to environmental problems in the lake.

A

An excess of NaOH would make the lake alkaline /toxic /kill wildlife

95
Q

In terms of structure and bonding, explain why

(i) sodium oxide has a high melting point

A

Ionic lattice / solid / giant ionic

Strong (electrostatic) forces/attraction between ions

96
Q

In terms of structure and bonding, explain why sulfur dioxide has a low melting point.

A

Molecular/molecules

Weak dipole-dipole and/or van der Waals forces between molecules

97
Q

Explain why the melting point of P4O10 is higher than the melting point of SO2

A

P4O10 bigger molecule/has larger surface area than SO2

van der Waals forces between molecules stronger

98
Q

Write an equation for the acid–base reaction that occurs when Na2O reacts with P4O10 in the absence of water.

A

6Na2O + P4O10 -> 4Na3PO4

99
Q

Describe what you would observe when magnesium burns in oxygen. Write an equation for the reaction that occurs. State the type of bonding in the oxide formed.

A

white flame / white light

solid / powder / smoke / ash / white fumes

2Mg + O2 → 2MgO

ionic

100
Q

Describe what you would observe when sulfur burns in oxygen. Write an equation for the reaction that occurs. State the type of bonding in the oxide formed.

A

blue flame

fumes or misty or pungent/choking/smelly gas

S + O2 → SO2

covalent

101
Q

State the type of bonding in sodium oxide. Explain why sodium oxide reacts to form an alkaline solution when added to water.

A

ionic

O2– + H2O → 2OH–

102
Q

Outline an experiment that could be used to show that aluminium oxide contains ions.

A

(heat until) molten

conducts electricity

103
Q

Suggest one reason why a thin layer of aluminium oxide protcts aluminium from corrosion in moist air.

A

insoluble (in water)

104
Q

Write an ionic equation in each case to show how aluminium oxide reacts with the following
(i) hydrochloric acid

A

Al2O3 + 6H+ à 2Al3+ + 3H2O

105
Q

Write an ionic equation in each case to show how aluminium oxide reacts with the following
aqueous sodium hydroxide.

A

Al2O3 + 2OH– +3H2O → 2Al(OH)4-

106
Q

In terms of crystal structure and bonding, explain in each case why the melting points of sodium oxide and silicon dioxide are high.

A

Higher

Li+ (or Li ion) smaller than Na+

Attracts O2– ion more strongly

107
Q

Predict whether the melting point of lithium oxide is higher than, the same as, or lower than the melting point of sodium oxide and explain your prediction.

A

Higher

Li+ (or Li ion) smaller than Na+

Attracts O2– ion more strongly

108
Q

Phosphorus(V) oxide has a lower melting point than sodium oxide.

(i) State the structure of and bonding in phosphorus(V) oxide.

A

Molecular

Covalent bonds (between P and O) atoms

109
Q

Explain why the melting point of phosphorus(V) oxide is low.

A

Weak van der Waals’ forces and/or dipole-dipole forces between molecules

110
Q

Separate samples of phosphorus(V) oxide and sodium oxide were reacted with water. In each case, predict the pH of the solution formed and write an equation for the reaction.

A

Allow –1 to +2

P4O10 + 6H2O → 12H+ + 4PO43– (or 4H3PO4)

Allow 12 to 14

Na2O + H2O → 2Na+ + 2OH-

111
Q

Write an equation for the reaction between Na2O and P4O10 State the general type of reaction illustrated by this example.

A

Macromolecular

Covalent bonding (between atoms)

Many/strong bonds to be broken (or lots of energy required)

112
Q

In terms of its structure and bonding, explain why silicon dioxide has a high melting point.

A

Macromolecular

Covalent bonding (between atoms)

Many/strong bonds to be broken (or lots of energy required)

113
Q

Write an equation for the reaction of aluminium with oxygen.

A

2Al + 3/2O2 → Al2O3

114
Q

Suggest one property of the aluminium oxide coating that causes aluminium to resist corrosion in water.

A

Insoluble/impermeable/non-porous

115
Q

Sodium metal is not resistant to corrosion in water, despite having a surface coating of sodium oxide. Write an equation to show how sodium oxide reacts with water.

A

Na2O + H2O → 2NaOH

116
Q

Write an equation for the reaction between aluminium oxide and hydrochloric acid.

A

Al2O3 + 6HCl → 2AlCl3 + 3H2O

117
Q

Write an equation for the reaction between aluminium oxide and an excess of aqueous sodium hydroxide.

A

Al2O3 + 2NaOH + 3H2O → 2NaAl(OH)4

118
Q

Silicon dioxide does not react with hydrochloric acid but it does react with sodium hydroxide. State one property of silicon dioxide that can be deduced from this information and write an equation for its reaction with sodium hydroxide.

A

SiO2 acidic/

SiO2 + 2NaOH → Na2SiO3 + H2O

119
Q

Write an equation for the reaction between

Write an equation for the reaction between

(i) MgO and HNO3
(ii) SiO2 and NaOH
(iii) Na2O and H3PO4

A

Write an equation for the reaction between

1- MgO + 2HNO3 → Mg(NO3)2 + H2O
2- 2NaOH + SiO2 → Na2SiO3 + H2O
3- 3Na2O + 2H3PO4 → 2Na3PO4 + 3H2O

120
Q

Explain, in terms of their type of structure and bonding, why P4O10 can be vaporised by gentle heat but SiO2 cannot.

A

P4O10 is a molecular (structure) (1) Weak intermolecular forces or van der Waals forces (between molecules) (1) SiO2 is a macromolecule / giant covalent / giant molecule (1)

(Strong) covalent bonds (between atoms) must be broken (1)

121
Q

Which property would you expect the element radium, Ra, to possess?
A It forms a soluble sulfate.
B It does not react with water.
C It is a good conductor of
electricity.
D It forms a covalent fluoride.

A
122
Q

Which statement is not correct?
A Strontium has a lower first ionisation energy than
calcium.
B Strontium has a larger ionic radius than calcium.
C Strontium reacts less vigorously with water than
calcium.
D Strontium hydroxide is more soluble in water
than calcium hydroxide.

A
123
Q

Which property of the Group 2 elements, Ca to Ba, increases with increasing
atomic number?
A Atomic Radius
B Electronegativity
C First ionisation energy
D Melting Point

A
124
Q

What is the correct observation when barium metal is added to an excess of
water?
A Forms a colourless solution only
B
Forms a colourless solution and
effervesces
C Forms a white precipitate only
D
Forms a white precipitate and
effervesces
(Total 1 mark)

A
125
Q

Q9.
An aqueous solution of a salt gives a white precipitate when mixed with aqueous
silver nitrate and when mixed with dilute sulfuric acid.
Which could be the formula of the salt?
A BaCl2
B (NH4)2SO4
C KCl
D Sr(NO3)2

A
126
Q

Which substance is used to reduce titanium(IV) chloride in the extraction of
titanium metal?
A Magnesium
B ManganesWhich statement about barium sulfate is correct?
A It is soluble in water at a temperature of 100 °C.
B It is used in medicine because it does not dissolve in
body fluids.
C It is a pale yellow solid.
D It reacts with acidified barium chloride
C Vanadium
D Zinc

A
127
Q

Which compound is used to treat the symptoms of indigestion?
A MgO
B Mg(OH)2
C CaO
D Ca(OH)2

A
128
Q

Explain why the second ionisation energy of calcium is lower than the
second ionisation energy of potassium.

A
129
Q

A colourless solution contains a mixture of sodium chloride and sodium bromide.
Using aqueous silver nitrate and any other reagents of your choice, develop a
procedure to prepare a pure sample of silver bromide from this mixture.
Explain each step in the procedure and illustrate your explanations with equations,
where appropriate.

A

Indicative chemistry content
Stage 1: formation of precipitates
* Add silver nitrate
* to form precipitates of AgCl and AgBr
* AgNO3 + NaCl → AgCl + NaNO3
* AgNO3 + NaBr → AgBr + NaNO3
Stage 2: selective dissolving of AgCl
* Add excess of dilute ammonia to the mixture of
precipitates
* the silver chloride precipitate dissolves
* AgCl + 2NH3 → Ag(NH3)2
++ Cl−
Page 13
Stage 3: separation and purification of AgBr
* Filter off the remaining silver bromide precipitate
* Wash to remove soluble compounds
* Dry to remove water

130
Q

Sodium bromide reacts with concentrated sulfuric acid in a different way from
sodium chloride.
Write an equation for this reaction of sodium bromide and explain why bromide ions
react differently from chloride ions.
Equation
Explanation

A

2NaBr + 2H2SO4 Na2SO4 + Br2 + SO2 + 2H2O
Allow ionic equation
2Br– + 2H2SO4 Br2 + SO42– + SO2 + 2H2O
1
Br–
ions are bigger than Cl–
ions
1
Therefore Br–
ions more easily oxidised / lose an electron more easily (than Cl–
ions)

131
Q

Give a reason why chlorine is not formed when solid potassium chloride reacts with conc H2SO4

A

Chloride ions cannot reduce sulphuric acid
(Or chloride ions are weak reducing agents
Or sulphuric acid is not a strong enough oxidising agent
Or sulphuric acid is a weaker oxidising agent than chlorine)

132
Q
A
133
Q
A

Chemistry flashcards- ms (14 decks)

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