NSAA 2017 Chemistry D568/11C

• A.none of them
• B.1 only
• C.2 only
• D.3 only
• E.1 and 2 only
• F.1 and 3 only
• G.2 and 3 only
• H.1, 2 and 3

Answer: F

• A.1 and 2 only
• B.1 and 3 only
• C.1 and 4 only
• D.2 and 3 only
• E.2 and 4 only
• F.3 and 4 only

Answer: B

• A.none of them
• B.1 only
• C.2 only
• D.3 only
• E.1 and 2 only
• F.1 and 3 only
• G.2 and 3 only
• H.1, 2 and 3

Answer: H

• A.none of them
• B.1 only
• C.1 or 2 only
• D.1 or 3 only
• E.2 only
• F.2 or 3 only
• G.3 only
• H.1, 2 or 3

Answer: A

Study the chromatogram below showing the spots obtained, labelled (i) to (v), from two sweets and pure samples of the food additives, labelled Q, R and S.

Which of the following statements about the chromatogram is/are correct?

1 Both sweet 1 and 2 contain additives R and S.

2 The $R_f$ value for spot (iv) is half that for spot (iii).

3 The $R_f$ value for spot (v) is 0.7.

• A.none of them
• B.1 only
• C.2 only
• D.3 only
• E.1 and 2 only
• F.1 and 3 only
• G.2 and 3 only
• H.1, 2 and 3

Answer: D

Element X has atomic number 20. Consider only the simple oxide of X.

Which of the following options identifies the formula, the type of bonding and the acid-base character of the oxide of element X?

• A.formula of oxide: X$_2$O, type of bonding in oxide: ionic, acid-base character of oxide: basic
• B.formula of oxide: X$_2$O, type of bonding in oxide: covalent, acid-base character of oxide: basic
• C.formula of oxide: XO, type of bonding in oxide: ionic, acid-base character of oxide: basic
• D.formula of oxide: XO, type of bonding in oxide: covalent, acid-base character of oxide: acidic
• E.formula of oxide: XO$_2$, type of bonding in oxide: ionic, acid-base character of oxide: acidic
• F.formula of oxide: XO$_2$, type of bonding in oxide: covalent, acid-base character of oxide: acidic
• G.formula of oxide: X$_2$O$_3$, type of bonding in oxide: ionic, acid-base character of oxide: basic
• H.formula of oxide: X$_2$O$_3$, type of bonding in oxide: covalent, acid-base character of oxide: acidic

Answer: C

• A.$\text{Cu}^{2+}(\text{aq}) + 2\text{e}^- \rightarrow \text{Cu}(\text{s})$
• B.$2\text{Cu}^{2+}(\text{aq}) + 3\text{PO}_4^{3-}(\text{aq}) \rightarrow \text{Cu}_2(\text{PO}_4)_3(\text{s})$
• C.$2\text{Cu}^{2+}(\text{aq}) + 5\text{PO}_4^{3-}(\text{aq}) \rightarrow \text{Cu}_2(\text{PO}_4)_5(\text{s})$
• D.$3\text{Cu}^{2+}(\text{aq}) + 2\text{PO}_4^{3-}(\text{aq}) \rightarrow \text{Cu}_3(\text{PO}_4)_2(\text{s})$
• E.$3\text{Cu}^{2+}(\text{aq}) + 6\text{Cl}^-(\text{aq}) + 6\text{Li}^+(\text{aq}) + 2\text{PO}_4^{3-}(\text{aq}) \rightarrow \text{Cu}_3(\text{PO}_4)_2(\text{s}) + 6\text{LiCl}(\text{aq})$
• F.$3\text{CuCl}_2(\text{aq}) + 2\text{Li}_3\text{PO}_4(\text{aq}) \rightarrow \text{Cu}_3(\text{PO}_4)_2(\text{s}) + 6\text{LiCl}(\text{aq})$

Answer: D

• A.1 and 2 only
• B.1 and 4 only
• C.1, 2 and 3 only
• D.1, 3 and 4 only
• E.2 and 3 only
• F.3 and 4 only

Answer: D

Consider this electrochemical cell containing an aqueous copper(II) chloride electrolyte:

Which row in the following table identifies the reactions occurring at the electrodes?

• A.cathode (negative electrode): $\text{Cu}^{2+}(\text{aq}) + 2\text{e}^- \rightarrow \text{Cu}(\text{s})$; anode (positive electrode): $\text{Cu}(\text{s}) \rightarrow \text{Cu}^{2+}(\text{aq}) + 2\text{e}^-$
• B.cathode (negative electrode): $\text{Cu}(\text{s}) \rightarrow \text{Cu}^{2+}(\text{aq}) + 2\text{e}^-$; anode (positive electrode): $\text{Cu}^{2+}(\text{aq}) + 2\text{e}^- \rightarrow \text{Cu}(\text{s})$
• C.cathode (negative electrode): $2\text{Cl}^-(\text{aq}) \rightarrow \text{Cl}_2(\text{g}) + 2\text{e}^-$; anode (positive electrode): $\text{Cu}^{2+}(\text{aq}) + 2\text{e}^- \rightarrow \text{Cu}(\text{s})$
• D.cathode (negative electrode): $\text{Cu}^{2+}(\text{aq}) + 2\text{e}^- \rightarrow \text{Cu}(\text{s})$; anode (positive electrode): $2\text{Cl}^-(\text{aq}) \rightarrow \text{Cl}_2(\text{g}) + 2\text{e}^-$
• E.cathode (negative electrode): $\text{Cu}(\text{s}) \rightarrow \text{Cu}^{2+}(\text{aq}) + 2\text{e}^-$; anode (positive electrode): $2\text{OH}^-(\text{aq}) \rightarrow \text{H}_2(\text{g}) + \text{O}_2(\text{g}) + 2\text{e}^-$

Answer: D

• A.C$_2$F$_3$
• B.C$_2$F$_5$
• C.C$_3$F$_6$
• D.C$_3$F$_8$
• E.C$_4$F$_6$
• F.C$_4$F$_{10}$

Answer: E

• A.none of them
• B.1 only
• C.2 only
• D.3 only
• E.1 and 2 only
• F.1 and 3 only
• G.2 and 3 only
• H.1, 2 and 3

Answer: E

Magnesium reacts with sulfuric acid according to the following chemical equation:

$\text{Mg}(\text{s}) + \text{H}_2\text{SO}_4(\text{aq}) \rightarrow \text{MgSO}_4(\text{aq}) + \text{H}_2(\text{g})$

Line P on each graph shows how the volume of hydrogen formed changes with time when 1.2 g of magnesium reacts with 40 cm³ of 1.0 mol dm⁻³ sulfuric acid at 20 °C.

(A$_r$ value: Mg=24)

Two further experiments were carried out and the volumes of hydrogen formed were plotted.

Experiment Q: 1.2 g of magnesium + 40 cm³ of 2.0 mol dm⁻³ sulfuric acid at 20 °C

Experiment R: 1.2 g of magnesium + 40 cm³ of 0.5 mol dm⁻³ sulfuric acid at 20 °C

(Image shows two graphs. The left graph is 'experiment Q' and has curves P, 1, 2, 3. The right graph is 'experiment R' and has curves P, 4, 5. Both graphs plot volume of hydrogen vs time.)

Which lines show how the volume of hydrogen formed will change with time in each experiment?

• A.experiment Q: 1, experiment R: 4
• B.experiment Q: 1, experiment R: 5
• C.experiment Q: 2, experiment R: 4
• D.experiment Q: 2, experiment R: 5
• E.experiment Q: 3, experiment R: 4
• F.experiment Q: 3, experiment R: 5

Answer: D

• A.315 kJ mol⁻¹
• B.513 kJ mol⁻¹
• C.644 kJ mol⁻¹
• D.864 kJ mol⁻¹
• E.945 kJ mol⁻¹
• F.1131 kJ mol⁻¹

Answer: E

• A.none of them
• B.1 only
• C.2 only
• D.3 only
• E.1 and 2 only
• F.1 and 3 only
• G.2 and 3 only
• H.1, 2 and 3

Answer: B

Silver nitrate solution reacts with zinc powder in an exothermic reaction:

$2\text{AgNO}_3(\text{aq}) + \text{Zn}(\text{s}) \rightarrow 2\text{Ag}(\text{s}) + \text{Zn}(\text{NO}_3)_2(\text{aq})$

The graph shows the maximum temperature rise as different masses of zinc react with separate 50.0 cm³ samples of 0.100 mol dm⁻³ silver nitrate solution.

(Image of a graph plotting 'temperature rise' on the y-axis against 'mass of zinc' on the x-axis. The graph starts at the origin, rises linearly to a peak point labelled Y, and then becomes a horizontal line.)

What is the mass of zinc at the position labelled Y?

(A$_r$ value: Zn = 65)

• A.0.163 g
• B.0.325 g
• C.0.650 g
• D.1.63 g
• E.3.25 g
• F.6.50 g

Answer: A

• A.27% $^{63}\text{Cu}$ and 73% $^{65}\text{Cu}$
• B.73% $^{63}\text{Cu}$ and 27% $^{65}\text{Cu}$
• C.31% $^{63}\text{Cu}$ and 69% $^{65}\text{Cu}$
• D.69% $^{63}\text{Cu}$ and 31% $^{65}\text{Cu}$
• E.36% $^{63}\text{Cu}$ and 64% $^{65}\text{Cu}$
• F.64% $^{63}\text{Cu}$ and 36% $^{65}\text{Cu}$

Answer: D

The reaction between calcium carbonate and hydrochloric acid was used to measure the effect of changing conditions on the mass of CO$_2$ produced and the rate of CO$_2$ production.

$\text{CaCO}_3(\text{s}) + 2\text{HCl}(\text{aq}) \rightarrow \text{CaCl}_2(\text{aq}) + \text{H}_2\text{O}(\text{l}) + \text{CO}_2(\text{g})$

The experiment was carried out five times with different conditions at a constant temperature.

The following conditions were varied:

CaCO$_3$ as chips or powder

mass of CaCO$_3$

volume of HCl

concentration of HCl

Which experiment (A-E) in the following table will produce 8.8 g of carbon dioxide in the shortest time?

(M$_r$ values: CaCO$_3$ = 100; CO$_2$=44)

• A.CaCO$_3$ type: chips, mass/g: 10, HCl volume/cm³: 400, concentration/mol dm⁻³: 2.0
• B.CaCO$_3$ type: powder, mass/g: 20, HCl volume/cm³: 100, concentration/mol dm⁻³: 2.0
• C.CaCO$_3$ type: chips, mass/g: 20, HCl volume/cm³: 200, concentration/mol dm⁻³: 2.0
• D.CaCO$_3$ type: powder, mass/g: 10, HCl volume/cm³: 200, concentration/mol dm⁻³: 2.0
• E.CaCO$_3$ type: chips, mass/g: 20, HCl volume/cm³: 400, concentration/mol dm⁻³: 1.0

Answer: C

• A.1000
• B.100
• C.10
• D.1
• E.0.1
• F.0.01

Answer: D