Chemistry Random Retrieval Y13

Ethyl ethanoate is heated under reflux with excess aqueous sodium hydroxide. The resulting solution is distilled. The distillate contains:

Which of the following molecules would you predict to be the least nucleophilic?

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

Which of these characteristics of polymers accounts for the difference between low density and high density poly(ethene)?

[1] the average length of the polymer chains

[2] the type of intermolecular (interchain) forces

[3] the number and size of bulky side groups

[4] the extent of chain branching

The nitrating agent for benzene is a mixture of concentrated sulfuric and nitric acids. This mixture produces:

When ethene reacts with bromine in the presence of aqueous sodium chloride the organic products include:

(i) CH₂BrCH₂Br

(ii) CH₂BrCH₂Cl

(iii) CH₂ClCH₂Br

(iv) CH₂ClCH₂Cl

Consider the following reaction.

O_3(g) + Cl_(g) => O_2(g)+ ClO_(g)

The rate equation was found, by experiment.

rate = k [O₃] [Cl]

Which of the following statements is/are true?

(i) Doubling [O₃] has no effect on the rate of the reaction

(ii) The mechanism probably has more than one step

(iii) There is one particle involved in the slowest step

(iv) The mechanism probably has only one step

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

A mixture of 1 mol ethanoic acid and 1 mol ethanol was allowed to reach equilibrium at a constant temperature. Analysis of the equilibrium mixture showed that it contained ¹/₃ mol ethanoic acid and ¹/₃ mol ethanol:

CH₃CO₂H_(l) + C₂H₅OH_(l) <=> CH₃CO₂C₂H_5(l) + H₂O_(l)

What is the value of K_c?

For which of these compounds would expect the best agreement between the values of the lattice energy derived from experimental data (with the help of the Born-Haber cycle) and the values calculated from theory on the assumption that the bonding in the crystals is purely ionic?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Which chemical species is reduced most easily?

Thinking carefully about the definitions of anode and cathode in electrochemical cells, an anode is defined as (CARE!):

In the anti-cancer complex compound [Pt(NH₃)₂Cl₂]

(i) the Pt, N and Cl atoms lie in one plane

(ii) the N-Pt-N angle is 180^o

(iii) the Cl-Pt-Cl angle is 90^o

(iv) the coordination number of platinum is zero

What enthalpy change is represented by the following equation?

Cl_(g) + e^-=> Cl^-_(g)

For which of these changes is the enthalpy change the standard enthalpy of atomisation of bromine?

Which of these are examples of acid-base reactions according to the Bronsted-Lowry theory.

(i) ZnO_(s)+2H₃O⁺_(aq)->Zn²⁺_(aq)+3H₂O_(l)

(ii) H₂O_(l)+H₂O_(l)->H₃O⁺ _(aq)+ OH^-_(aq)

(iii) NH_3(g)+HBr_(g)->NH₄Br _(s)

(iv) SO_2(g)+H₂O_(l)->H₂SO_3(aq)

Consider the following reaction:

2N₂O_5(g) => 4NO_2(g)+ O_2(g)

The rate equation was found, by experiment:

rate = k [N₂O₅]

Which of the following statements is/are true?

(i) Doubling the concentration N₂O₅ caused the rate of production of 4NO₂ to increase by 4 times

(ii) Tripling the concentration N₂O₅ caused the rate of production of O₂ to increase by 3 times

(iii) There are two particles of N₂O₅ involved in the rate determining step

(iv) The mechanism is probably multi step

Consider the following reaction:

2NO_(g) + 2H_2(g) => N_2(g) + 2H₂O_(g)

The rate equation was found, by experiment:

rate = k [NO]²[H₂]

Which of the following statements is/are true?

(i) The mechanism has more than one step

(ii) Doubling [NO₂] quadruples the rate of the reaction

(iii) H₂ is consumed in more than one of the steps

(iv)The mechanism has only one step

The reaction of bromine with propanone in acid solution is zero order with respect to bromine, first order with respect to propanone and first order with respect to hydrogen ions.

At a given temperature, the rate of disappearance of bromine is 1.20 x 10^-4 mol dm^-3 when

[CH₃COCH₃] = 0.30 mol dm^-3

[Br₂] = 0.05 mol dm^-3

[H+] = 0.10 mol dm^-3

What is the rate of disappearance bromine when

[CH₃COCH₃] = 0.10 mol dm^-3

[Br₂] = 0.10 mol dm^-3 and [H+] = 0.05 mol dm^-3?

What does the symbol [X] represent?

How many peaks would you expect to see in the ¹³C spectrym of 2,5-dimethyltetrahydrofuran?

If an amino acid is written as RCHNH₂CO₂H, in which of these amino acids is R a polar group?

(i) HSCH₂CHNH₂CO₂H

(ii) C₆H₅CH₂CHNH₂CO₂H

(iii) HOCH₂CHNH₂CO₂H

(iv) CH₃CHNH₂CO₂H

Which of these compounds are solids at room temperature?

(i) propane

(ii) propanoic acid

(iii) propylamine

(iv) 2-aminopropanoic acid

Which of these formulae represent glycine in aqueous solution at pH 9?

If the molecule shown below is hydrolysed in hot sodium hydroxide, what are the main organic products?

Which of the following molecules is/are examples of 2^o amines?

(i) 

(ii)

(iii) 

(iv) 

What are the reagents and conditions for converting benzene to bromobenzene?

Ethyl ethanoate is heated under reflux with excess aqueous sodium hydroxide. The resulting solution is distilled. The distillate contains:

The reagent which converts ethanoic acid to ethanoyl chloride is:

A compound P, C₄H₈O, gave on oxidation an acid C₄H₈O₂. Which of the following are possible structures for P?

(i)CH₃CH₂CH₂CHO

(ii)CH₃COCH₂CH₃

(iii) (CH₃)₂CHCHO

(iv) CH₃CH=CHCH₂OH