Chemistry Random Retrieval Y13

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Chemistry Year 13 Random Retrieval

This quiz contains all the questions in the year 13 chemistry section. The website will pick 10 questions at random.

1 / 10

Which of the following molecules would you predict to be the most basic?

2 / 10

Which of these molecules does NOT consist of one or more chains of amino acids?

(i) The hormone insulin

(ii) The filaments in muscle fibres

(iii) The enzyme in saliva, amylase

(iv) The genetic material, DNA

3 / 10

Step 5:

4 / 10

In which of these reactions between pairs of reagents is the bond breaking homolytic?

(i) butan-1-ol with sodium bromide and concentrated sulfuric acid

(ii) catalytic cracking of hydrocarbons

(iii) bromine with ethene

(iv) bromine with hexane

5 / 10

What does the symbol [X] represent?

6 / 10

What is the value of the rate constant, k for this reaction at this temperature?

7 / 10

Consider the following reaction:

C4H9Cl(aq) + OH-(aq) => C4H9OH(aq) + Cl-(aq)

The rate equation was found, by experiment:

rate = k [C4H9Cl]

Which of the following statements is/are true?

(i) Increasing the concentrations of all reactants speeds up the nucleophilic substitution reaction

(ii) The mechanism probably has only one step

(iii) There are two particles involved in the rate determining step

(iv) OH- is required for the overall reaction to proceed

 

8 / 10

Which of the following are examples of heterogeneous equilibria?

(i) CaCO3(s) <=> CaO(s) + CO2(g)

(ii) 2CrO42-(aq) + 2H+(aq) <=> Cr2O72-(aq) + H2O(l)

(iii) Ag+(aq) + Fe2+(aq) <=> Ag(s) + Fe3+(s)

(iv) Co2+(aq) + 6NH3(aq) <=> [Co(NH3)6]2+(aq)

9 / 10

These reactions are rapid at 298 K. Which of the reactions goes effectively to completion?

(i) I-(aq) + I2(aq) <=> I3-(aq) Kc = 7.1 x 10-2 mol-1 dm3

(ii) Cu2+(aq) + 4NH3(aq) <=> [Cu(NH3)4]2+(aq) Kc = 1.4 x 1013 mol-4dm12

(iii) 2H2O(l) <=> H3O+(aq) + OH-(aq) Kc = 1.0 x 10-14 mol2 dm-6

(iv) Cu2+(aq) + Zn(s) <=> Cu(s) + Zn2+(aq) Kc = 1 x 1037

10 / 10

What is the value of Eϴcell/V observed for a cell constructed from the following half-cells. (These are the half-cells that are put together in a car battery (6 cells in series)?

PbSO4(s) + 2e- <=> Pb(s) + SO42-(aq) Eϴ/V = -0.36

PbO2(s) + SO42-(aq)+4H(aq) + 2e- <=> PbSO4(s) + 2H2O(l) Eϴ/V = +1.69

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7

Physical Chemistry & Transition Elements Random Retrieval

This quiz contains all the questions in the Physical Chemistry & Transition Elements section. The website will pick 10 questions at random.

1 / 10

Work out the ratio of the species in the following half-equation.

O2 + e- + H+ => H2O

2 / 10

Calculate the value of the enthalpy change associated with the following equation?

N2(g) + 3H2(g) => 2NH3(g)

3 / 10

The lattice enthalpy for magnesium oxide is -3850 kJ mol-1.

The energy needed to break up 0.1 mol MgO into gaseous ions at 298K is:

 

[1] -38.5 kJ mol-1

[2] -385 kJ mol-1

[3] +385 kJ mol-1

[4] +3850 kJ mol-1

4 / 10

What is the enthalpy of solution of lithium bromide given that:

the lattice enthalpy for LiBr = -818 kJ mol-1

enthalpy of hydration of Li+ ions = -559 kJ mol-1

enthalpy of hydration of Br- ions = -309 kJ mol-1

5 / 10

The indicator thymol blue changes from yellow to blue of the pH range 8.0 to 9.6. The indicator could be used to detect accurately the end-point in a titration of roughly 0.1 mol dm-3 solutions of:

(i) ethanoic acid with sodium hydroxide

(ii) hydrochloric acid with ammonia

(iii) hydrochloric acid with sodium hydroxide

(iv) ethanoic acid with ammonia

6 / 10

What is the pH of a 0.01 mol dm-3 solution of methanoic acid given that for this acid: Ka = 1.6 x 10-4 mol dm-3 at 298K ?

7 / 10

Consider the following equilibrium:

3Fe(s) + 4H2O(g) Fe3O4(s)+ 4H2(g)

40.0 g of iron wool was placed in a vessel of volume 2.00 dm3. The iron was exposed to 20.0 mol of high pressure steam and the system allowed to settle to equilibrium. At equilibrium, 0.250 mol of hydrogen was found in the vessel. The gauge on the pressure vessel read 1 000 kPa. The volume of iron wool was insignificant.

Calculate the value of Kp (no units) under these conditions.

8 / 10

Consider the following equilibrium:

2SO2(g) + O2(g) <=>2SO3(g)

8.00 mol of SO2 was mixed with 5.00 mol of O2 and the mixture sealed in a heated vessel of volume of 1.00 dm3. The mixture was left until no further observable change in composition took place. The pressure was recorded as 200 kPa. At this point, 2.00 mol of O2 was present in the mixture.

Calculate the value of Kp (in units: kPa-1) under these conditions.

9 / 10

For which of the following equilibria, does raising the pressure favours the formation of products?

(i) H2(g) + C(s) <=> H2(g) + CO(g)

(ii) 4NH3(g) + 5O2(g) <=> 4NO(g) + 6H2O(g)

(iii) 2HCl(g) + I2(g) <=> 2HI(g) + Cl2(g)

(iv) 2SO2(g) + O2(g) <=> 2SO3(g)

10 / 10

These reactions are rapid at 298 K. Which of the reactions goes effectively to completion?

(i) I-(aq) + I2(aq) <=> I3-(aq) Kc = 7.1 x 10-2 mol-1 dm3

(ii) Cu2+(aq) + 4NH3(aq) <=> [Cu(NH3)4]2+(aq) Kc = 1.4 x 1013 mol-4dm12

(iii) 2H2O(l) <=> H3O+(aq) + OH-(aq) Kc = 1.0 x 10-14 mol2 dm-6

(iv) Cu2+(aq) + Zn(s) <=> Cu(s) + Zn2+(aq) Kc = 1 x 1037

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11

Organic Chemistry & Analysis Random Retrieval

This quiz contains all the questions in the Organic Chemistry & Analysis section. The website will pick 10 questions at random.

1 / 10

Which of these statements is true of a solution of a racemic mixture?

(i) It contains asymmetric molecules,

(ii) It is a mixture of enantiomers,

(iii) It contains equal amounts of optical isomers,

(iv) It rotates the plane of polarised light

2 / 10

Which of these compounds can exist in two enantiomeric forms?

(i) 2-methylbutan-1-ol,

(ii) 2-bromo-1-chlorobutane,

(iii) 2-chloropentane,

(iv) 1-chlorobutane

3 / 10

Which of these compounds have E/Z isomers?

(i) pent-2-ene,

(ii) 2-methylpent-2-ene,

(iii) 1,2-dichloropropene,

(iv) hex-1-ene

4 / 10

Which of these compounds are chain isomers of 2-methylpentane

(i) hexane,

(ii) 2,2-dimethylpentane,

(iii) 2,3-dimethylbutane,

(iv) 2,2-dimethylpropane

5 / 10

The reaction of benzene with ethanoyl chloride in the presence of aluminium chloride

(i) involves CH3-CO+ as an intermediate

(ii) forms C6H5-CO-CH3

(iii) is a substitution reaction

(iv) involves nucleophilic attack on benzene

6 / 10

Step 2:

7 / 10

Which of these amino acids are chiral?

(i) CH3CHNH2CO2H

(ii) C6H5CH2CHNH2CO2H

(iii) HOCH2CHNH2CO2H

(iv) CH2NH2CO2H

8 / 10

What is the main organic product when benzene reacts with 2-iodo-2-methylpropane in the presence of aluminium chloride?

9 / 10

The product of the reaction of ethanoic acid and ammonia at room temperature is:

10 / 10

Treating ethanal with hydrogen cyanide in the presence of some KCN and then hydrolysing the product with hot hydrochloric acid (which converts a cyano / nitrile group RCN, to RCOOH) produces:

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