Chemistry 9701/13 October/November 2019: question paper and mark scheme

Question

The diagram shows the Boltzmann distribution of energies in a gas. The gas undergoes a reaction with an activation energy, Ea. The peak of the distribution is labelled P. P proportion of molecules with energy E 0 0 Ea molecular energy, E If the same reaction is carried out in the presence of a catalyst, which statement is correct? A The peak P is at a lower height and the position of Ea moves to the left. B The peak P is at a lower height and the position of Ea moves to the right. C The peak P remains at the same height and the position of Ea moves to the left. D The peak P remains at the same height and the position of Ea moves to the right.

Question

Diamond is a pure form of carbon. The mass of a diamond can be measured in carats. One carat is 0.200 g of carbon. Which expression gives the number of carats that contain 6.02 × 1023 carbon atoms? A 0.200 × 12.0 B 0.200 12.0 C 12.0 0.200 0.200 D × 12.0 6.02 × 1023

Question

Which molecule or ion contains the smallest bond angle? A C2 H 4 B CH3COCH3 C NH4+ D NH3

Question

Four compounds are shown. C2H4 C2H5OH CH3CHO CH3CO2H How many of these compounds have an odd number of σ bonds? A 1 B 2 C 3 D 4

Question

Ethanal, CH3CHO, ethanol, C2H5OH, and methoxymethane, CH3OCH3, are three organic compounds. Which compound has the highest boiling point and what is the interaction that causes this boiling point to be the highest? highest boiling point interaction A methoxymethane permanent dipole-dipole forces B ethanal hydrogen bonds C ethanol hydrogen bonds D ethanal permanent dipole-dipole forces

Question

What is the oxidation number of sulfur in each species? H2S SO2 H2SO3 A –2 +4 +4 B –2 +4 +6 C +2 –4 +4 D +2 –4 +6

Question

The following data are needed for this question. (N2H4(l)) = 50.6 kJ mol–1 (N2O4(g)) = 9.2 kJ mol–1 (H2O(g)) = –241.8 kJ mol–1 Hydrazine, N2H4(l), reacts with dinitrogen tetraoxide, N2O4(g), to form nitrogen gas and water vapour. 2N2H4(l) + N2O4(g) → 3N2(g) + 4H2O(g) What is the enthalpy change for this reaction? A –1077.6 kJ mol–1 B –856.8 kJ mol–1 C –301.6 kJ mol–1 D –182.0 kJ mol–1

Question

Sodium burns in oxygen giving out heat energy and forming the compound Na2O. The equation for this reaction is shown. 2Na(s) + 1 2 O2(g) → Na2O(s) Which statement about the reaction is correct? A ∆H o for the reaction is equal to twice the bond energy of the Na–O bond. B ∆H o for the reaction is positive. C The equation represents the standard enthalpy change of combustion of sodium. D The equation represents the standard enthalpy change of formation of sodium oxide.

Question

In the chemical equation, w, x, y and z are all whole numbers. wCl O3– + xMnO4– + yH+ → wCl O4– + xMnO2 + zH2O When the equation is balanced, what are w, x and y? w x y A 1 1 2 B 2 2 2 C 2 3 8 D 3 2 2

Question

Two compounds X and Y react to produce compound Z. The reaction is reversible. X + Y Z When X and Y are mixed together in a closed system a dynamic equilibrium is gradually established. Which graph could represent the change in the rates of the forward and reverse reactions over time? A B key rate of forward rate rate reaction rate of reverse reaction 0 time 0 time C D rate rate 0 time 0 time

Question

The reaction between sulfur dioxide and oxygen is reversible. 2SO2(g) + O2(g) 2SO3(g) Kc = 280 mol–1 dm3 at 1000 K In an equilibrium mixture at 1000 K the sulfur dioxide concentration is 0.200 mol dm–3 and the oxygen concentration is 0.100 mol dm–3. What is the sulfur trioxide concentration? A 1.058 mol dm–3 B 1.120 mol dm–3 C 2.366 mol dm–3 D 5.600 mol dm–3

Question

Which oxide will cause an increase in pH when added to water? A MgO B Al 2O3 C SiO2 D SO2

Question

X, Y and Z are consecutive elements in Period 3 of the Periodic Table. Element Y has the highest first ionisation energy and the lowest melting point of these three elements. What are the identities of X, Y and Z? X Y Z A Na Mg Al B Mg Al Si C Al Si P D Si P S

Question

A 5.00 g sample of an anhydrous Group 2 metal nitrate loses 3.29 g in mass when heated strongly. Which metal is present? A magnesium B calcium C strontium D barium

Question

Solutions P and Q each contain a different Group 2 ion at the same concentration. One contains Mg2+, the other contains Ba2+. Tests are carried out on separate 5 cm3 samples of P and Q. test 1: add 1 cm3 of 0.1 mol dm–3 Na2SO4(aq) test 2: add 1 cm3 of 0.1 mol dm–3 NaOH(aq) What are the results of these tests? results in test 1 results in test 2 A more precipitate with Ba2+ more precipitate with Ba2+ B more precipitate with Ba2+ more precipitate with Mg2+ C more precipitate with Mg2+ more precipitate with Ba2+ D more precipitate with Mg2+ more precipitate with Mg2+

Question

Chlorine and bromine have different volatilities. Which row identifies the more volatile of the two elements, and gives the correct explanation? identity of the explanation for the more volatile element difference in volatility A bromine instantaneous dipole-induced dipole forces are greater in bromine than they are in chlorine B bromine instantaneous dipole-induced dipole forces are greater in chlorine than they are in bromine C chlorine instantaneous dipole-induced dipole forces are greater in bromine than they are in chlorine D chlorine instantaneous dipole-induced dipole forces are greater in chlorine than they are in bromine

Question

Sodium azide, NaN3, is dissolved in water. Acidified silver nitrate is added to the solution and a white precipitate forms. Aqueous ammonia is then added to the white precipitate. The azide ion, N3–, has similar chemical properties to the Cl – ion. Which row of the table can be predicted from this information? formula of observation on adding white precipitate aqueous ammonia A AgN3 colourless solution formed B AgN3 precipitate remains C Ag3N colourless solution formed D Ag3N precipitate remains

Question

Which type of reaction occurs when solid ammonium sulfate is heated with an excess of sodium hydroxide solution? A acid-base B precipitation C redox D thermal decomposition

Question

Catalytic converters are fitted in the exhaust systems of many cars. Which gas: ● causes acid rain if it is released into the air ● is removed from car exhaust fumes by a catalytic converter? A carbon dioxide B carbon monoxide C hydrocarbon vapour D nitrogen dioxide

Question

Which substance reacts with trichloroethene to give a chiral product? A Br2 B HCl C NaCN D NaOH

Question

Alkanes are saturated hydrocarbons. Which type of reaction are alkanes most likely to undergo? A electrophilic addition B electrophilic substitution C free radical substitution D nucleophilic addition

Question

An alkene reacts with hot, concentrated, acidified potassium manganate(VII) to produce a single organic product as shown. hot, concentrated, O O acidified KMnO4(aq) alkene OH What is the structure of the alkene? A B C D

Question

A tertiary bromoalkane, indicated here by C–Br , reacts with aqueous NaOH. The mechanism has the reaction pathway shown. X C–Br + OH– Y energy C–OH + Br – progress of reaction Which point in the diagram is correctly identified? A X is C+ – B X is HO C Br C Y is C+ – D Y is HO C Br

Question

Bromoethane and chloroethane are added separately to water. Hydrolysis reactions occur. Which compound hydrolyses more rapidly and what is the mechanism? compound that mechanism hydrolyses more rapidly A bromoethane electrophilic substitution B bromoethane nucleophilic substitution C chloroethane electrophilic substitution D chloroethane nucleophilic substitution

Question

Alcohol X is oxidised to form compound Y. The composition of Y is 54.54% carbon, 36.36% oxygen and 9.10% hydrogen. The Mr of Y is 88.0. What could be the structure of alcohol X? A CH3CH2CH(OH)CH3 B CH3CH2CH2CH2CH2OH C CH3CH2CH2CH2OH D CH3CH2CH(OH)CH2CH3

Question

The diagram shows the structure of compound Z. Z O O What is the product of the reaction between compound Z and an excess of NaBH4? A B C D OH OH OH OH O O O OH

Question

Compound Q shows the following reactions. ● It gives an orange precipitate with 2,4-dinitrophenylhydrazine. ● It gives a red-brown precipitate with Fehling’s reagent. ● It gives a pale yellow precipitate with alkaline aqueous iodine. What could be the identity of Q? A ethanal B propan-2-ol C propanal D propanone

Question

Tartaric acid, HO2CCH(OH)CH(OH)CO2H, is found in many plants. A sample of tartaric acid reacts with an excess of LiAl H4 to form the organic product J. What happens when NaOH(aq) is added to separate samples of tartaric acid and J? A Both tartaric acid and J react. B Only tartaric acid reacts. C Only J reacts. D Neither tartaric acid nor J react.

Question

When CH2(OH)CH=CHCO2H is warmed with a little concentrated sulfuric acid, a cyclic compound is formed. What is the skeletal formula of the cyclic compound? A B C D O O O O O O O O O

Question

The infra-red spectrum of compound P is shown. 100 transmittance /% 50 0 4000 3000 2000 1500 1000 500 –1 wavenumber / cm What could be compound P? A methyl ethanoate B propanal C propanoic acid D propan-2-ol Section B For each of the questions in this section, one or more of the three numbered statements 1 to 3 may be correct. Decide whether each of the statements is or is not correct (you may find it helpful to put a tick against the statements that you consider to be correct). The responses A to D should be selected on the basis of A B C D 1, 2 and 3 1 and 2 2 and 3 1 only are only are only are is correct correct correct correct No other combination of statements is used as a correct response. Use of the Data Booklet may be appropriate for some questions.

Question

A particular atom of germanium, Ge, has a nucleon number of 70. Which statements about a 70 32 Ge atom are correct? 1 It has the same number of electrons as a 79 34 Se 2+ ion. 2 It has the same number of neutrons as an atom of 68 30 Zn. 3 It has half as many protons as an atom of 160 64 Gd.

Question

The first ionisation energy of chlorine is greater than that of sulfur. Which factors contribute to this? 1 Chlorine has more protons in its nucleus than sulfur does. 2 Chlorine has greater electron shielding than sulfur does. 3 The covalent bonds in chlorine molecules are stronger than those in sulfur molecules. The responses A to D should be selected on the basis of A B C D 1, 2 and 3 1 and 2 2 and 3 1 only are only are only are is correct correct correct correct No other combination of statements is used as a correct response.

Question

Liquids X and Y do not react with one another. They have identical boiling points. When a particular volume of X is shaken with a similar volume of Y, they form a liquid mixture Z. The average intermolecular forces in liquid Z are stronger than the average of the forces in X and the forces in Y. Which deductions from this information are correct? 1 The mixing of X and Y is exothermic. 2 The vapour pressure of liquid Z will be less than that of either liquid X or liquid Y at the same temperature. 3 The boiling point of liquid Z will be lower than that of either liquid X or liquid Y at the same pressure.

Question

The stoichiometry of a catalysed reaction is shown by the equation below. P (g) + Q (g) R (g) + S (l) Two experiments are carried out in which the amount of R is measured. The results are shown in the diagram. experiment 1 amount experiment 2 of R 0 0 time Which changes in the conditions could explain the results shown? 1 A lower pressure was used in experiment 2. 2 A different catalyst was used in experiment 2. 3 Product S was continuously removed from the reaction vessel in experiment 2.

Question

Which statements are correct? 1 Chloride ions are oxidised when concentrated sulfuric acid is added to NaCl (s). 2 A disproportionation reaction takes place when chlorine is added to cold NaOH(aq). 3 An acidic solution forms when chlorine is added to water.

Question

Nitrogen gas is unreactive, whereas oxygen gas and chlorine gas are reactive. Which statements help to explain this difference? 1 The two N atoms in an N2 molecule are held together by a very strong triple bond. 2 The triple bond between two N atoms is not polar. The bonds in O2 and Cl 2 are polar. 3 The atoms in N2 have a full outer shell of electrons. The atoms in O2 and Cl 2 do not have a full outer shell of electrons.

Question

The structure of tiglic acid is CH3CH=C(CH3)CO2H. Which statements about the properties of one molecule of this acid are correct? 1 It contains two π bonds. 2 It contains four lone pairs of electrons. 3 It has all its atoms in the same plane.

Question

Which compounds, on heating with an excess of concentrated sulfuric acid, produce only one product with molecular formula C7H10? 1 2 3 OH OH OH OH OH OH

Question

Hydrogen cyanide reacts with propanone in the presence of potassium cyanide. Which statements about this reaction are correct? 1 The cyanide ion is a catalyst for the reaction. 2 This is an addition reaction. 3 The intermediate behaves as a base. The responses A to D should be selected on the basis of A B C D 1, 2 and 3 1 and 2 2 and 3 1 only are only are only are is correct correct correct correct No other combination of statements is used as a correct response.

Question

Which compounds produce three different organic products when hydrolysed? 1 2 3 O O O O O O O O O O O O