Question 1

1 mark

An atom of element

X

has the same number of occupied electron shells as an atom of Carbon (

Z = 6

), and the same number of valence (outer shell) electrons as an atom of Magnesium (

Z = 12

).

What is the electron configuration of a neutral atom of element

X

?

A. $2,2$
B. $2,8,2$
C. $2,4$
D. $2,8,4$
E. $2,8,8,2$

Answer: A

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Question 2

1 mark

Elements

X, Y,

and

Z

have consecutive atomic numbers

n-1, n,

and

n+1

respectively. Element

Y

is a noble gas. Which of the following statements about these elements must be correct?

A.Elements $X$ and $Z$ are in the same period of the Periodic Table.
B.Element $X$ is a halogen in Group 17.
C.Element $Z$ is an alkali metal in Group 1.
D.The atomic number of the element directly below $Y$ in Group 18 is $n+8$ .
E.The compound formed by the reaction of $X$ and $Z$ has a simple molecular structure.

Answer: C

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Question 3

1 mark

Element

X

is in Period 4, Group 1 of the Periodic Table. Element

Y

is in Period 3, Group 16 of the Periodic Table.

Which of the following correctly classifies element

X

and provides the formula of the compound formed between

X

and

Y

?

A. $X$ is an alkaline earth metal; the formula is $X_2Y$
B. $X$ is an alkali metal; the formula is $XY_2$
C. $X$ is an alkaline earth metal; the formula is $XY$
D. $X$ is an alkali metal; the formula is $X_2Y$
E. $X$ is a transition metal; the formula is $X_2Y$

Answer: D

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Question 4

1 mark

Four elements,

P

,

Q

,

R

, and

S

, are found in the Periodic Table.

P

and

Q

are in Group 2, with

P

in Period 3 and

Q

in Period 4.

R

and

S

are in Group 17, with

R

in Period 3 and

S

in Period 4. Which of the following correctly compares the relative reactivity of these elements?

A. $P$ is more reactive than $Q$ , and $R$ is more reactive than $S$ .
B. $Q$ is more reactive than $P$ , and $S$ is more reactive than $R$ .
C. $P$ is more reactive than $Q$ , and $S$ is more reactive than $R$ .
D. $Q$ is more reactive than $P$ , and $R$ is more reactive than $S$ .
E. $P$ has the same reactivity as $Q$ , and $R$ has the same reactivity as $S$ .

Answer: D

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Question 5

1 mark

A sample of

0.40\,\text{g}

of pure deuterium gas (

^2\text{H}_2

) is reacted completely with an excess of oxygen-18 gas (

^{18}\text{O}_2

) to form heavy water (

^2\text{H}_2^{18}\text{O}

). Given that the atomic number (

Z

) of hydrogen is

1

and oxygen is

8

, and the Avogadro constant

N_A = 6.0 \times 10^{23}\,\text{mol}^{-1}

, what is the total number of neutrons in the nuclei of the product molecules?

A. $6.0 \times 10^{23}$
B. $7.2 \times 10^{23}$
C. $1.2 \times 10^{24}$
D. $1.32 \times 10^{24}$
E. $1.44 \times 10^{24}$

Answer: B

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Question 6

1 mark

A student is asked to identify the correct chemical formula and calculate the relative formula mass (

M_r

) for several common ionic compounds.

Which one of the following rows correctly identifies both the chemical formula and the

M_r

for the named compound?

(Use the following relative atomic masses (

A_r

):

H = 1.0

,

C = 12.0

,

N = 14.0

,

O = 16.0

,

Na = 23.0

,

Mg = 24.0

,

Al = 27.0

,

S = 32.0

,

K = 39.0

,

Ca = 40.0

)

A.Calcium nitrate: $Ca(NO_2)_2$ , $M_r = 132.0$
B.Ammonium sulfate: $(NH_4)_2SO_4$ , $M_r = 132.0$
C.Magnesium hydroxide: $MgOH_2$ , $M_r = 58.0$
D.Aluminium oxide: $Al_3O_2$ , $M_r = 113.0$
E.Potassium carbonate: $K_2CO_3$ , $M_r = 106.0$

Answer: B

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Question 7

1 mark

A piece of calcium metal is added to a beaker of distilled water. After the reaction is complete, the resulting milky mixture is filtered to remove any undissolved solid. A stream of carbon dioxide gas is then bubbled through the clear filtrate, resulting in the formation of a white precipitate. Which of the following balanced chemical equations correctly represents the reaction occurring in the filtrate at

25^\circ\text{C}

and

100\,\text{kPa}

?

A. $\text{Ca(OH)}_2(\text{aq}) + \text{CO}_2(\text{g}) \rightarrow \text{CaCO}_3(\text{s}) + \text{H}_2\text{O}(\text{l})$
B. $\text{Ca(OH)}_2(\text{s}) + \text{CO}_2(\text{g}) \rightarrow \text{CaCO}_3(\text{s}) + \text{H}_2\text{O}(\text{l})$
C. $\text{Ca(OH)}_2(\text{aq}) + 2\text{CO}_2(\text{g}) \rightarrow \text{Ca(HCO}_3)_2(\text{aq})$
D. $\text{Ca(OH)}_2(\text{aq}) + \text{CO}_2(\text{g}) \rightarrow \text{CaCO}_3(\text{s}) + \text{H}_2\text{O}(\text{aq})$
E. $\text{Ca(OH)}_2(\text{aq}) + \text{CO}_2(\text{g}) \rightarrow \text{CaCO}_3(\text{aq}) + \text{H}_2\text{O}(\text{l})$

Answer: A

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Question 8

1 mark

Consider the following reversible reaction at equilibrium in a closed container:

\text{CH}_4(\text{g}) + \text{H}_2\text{O}(\text{g}) \rightleftharpoons \text{CO}(\text{g}) + 3\text{H}_2(\text{g}) \quad \Delta H = +206\,\text{kJ}\,\text{mol}^{-1}

Which of the following changes, when applied independently and assuming all other conditions remain constant, will result in an increase in the equilibrium yield of

\text{H}_2(\text{g})

?

1. Increasing the temperature
2. Increasing the total pressure
3. Adding more

\text{CH}_4(\text{g})

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

Answer: D

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Question 9

1 mark

A

4.92\,\text{g}

sample of a hydrated Group 2 metal sulfate,

MSO_4 \cdot x\text{H}_2\text{O}

, is heated until it has completely decomposed into a solid metal oxide,

MO

, and two gases: water vapour and sulfur trioxide,

\text{SO}_3

.

The total mass of the gaseous products collected is

4.12\,\text{g}

.
The mass of the water vapour alone is

2.52\,\text{g}

.

What is the relative molar mass (

M_r

) of the original hydrated metal sulfate?

(

A_r

values:

\text{H} = 1.0; \text{O} = 16.0; \text{S} = 32.0

)

A. $120$
B. $172$
C. $246$
D. $252$
E. $412$

Answer: C

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Question 10

1 mark

A sample of pure water,

\text{H}_2\text{O}

, has a mass of

0.45\,\text{g}

. What is the total number of hydrogen atoms present in this sample?

(Take Avogadro's number as

6.0 \times 10^{23}\,\text{mol}^{-1}

.

A_r

values:

\text{H} = 1.0, \text{O} = 16.0

)

A. $1.5 \times 10^{22}$
B. $3.0 \times 10^{22}$
C. $4.5 \times 10^{22}$
D. $1.5 \times 10^{23}$
E. $3.0 \times 10^{23}$

Answer: B

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Question 11

1 mark

A solid mixture contains

2.5\,\text{kg}

of calcium carbonate (

CaCO_3

) and

1.2\,\text{kg}

of sodium hydroxide (

NaOH

). This mixture is added to an excess of dilute hydrochloric acid, and the following reactions occur:

CaCO_3(\text{s}) + 2HCl(\text{aq}) \rightarrow CaCl_2(\text{aq}) + H_2O(\text{l}) + CO_2(\text{g})

NaOH(\text{s}) + HCl(\text{aq}) \rightarrow NaCl(\text{aq}) + H_2O(\text{l})

What is the total amount, in moles, of water produced by these reactions?

(

A_r

values:

H = 1

;

C = 12

;

O = 16

;

Na = 23

;

Ca = 40

)

A. $25\,\text{mol}$
B. $30\,\text{mol}$
C. $55\,\text{mol}$
D. $80\,\text{mol}$
E. $0.055\,\text{mol}$

Answer: C

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Question 12

1 mark

A sample of a hydrocarbon

X

contains

87.5\%

carbon by mass. When

0.050\,\text{mol}

of

X

is completely combusted in an excess of oxygen, it reacts with exactly

12.0\,\text{dm}^3

of oxygen gas (measured at room temperature and pressure, where the molar volume of a gas is

24.0\,\text{dm}^3\,\text{mol}^{-1}

).

What is the molecular formula of

X

?

(

A_r

values:

\text{C} = 12.0

;

\text{H} = 1.0

)

A. $\text{C}_4\text{H}_6$
B. $\text{C}_7\text{H}_{12}$
C. $\text{C}_8\text{H}_8$
D. $\text{C}_9\text{H}_{12}$
E. $\text{C}_{14}\text{H}_{24}$

Answer: B

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Question 13

1 mark

Iron is extracted from iron(III) oxide by reduction with carbon according to the following balanced chemical equation:

2\text{Fe}_2\text{O}_3(\text{s}) + 3\text{C}(\text{s}) \rightarrow 4\text{Fe}(\text{s}) + 3\text{CO}_2(\text{g})

A mixture is prepared containing

32.0\,\text{g}

of iron(III) oxide and

4.50\,\text{g}

of carbon. Assuming the reaction goes to completion, what is the maximum mass of iron that can be produced?

(

A_r

values:

\text{C} = 12

;

\text{O} = 16

;

\text{Fe} = 56

)

A. $11.2\,\text{g}$
B. $16.8\,\text{g}$
C. $21.0\,\text{g}$
D. $22.4\,\text{g}$
E. $28.0\,\text{g}$

Answer: D

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Question 14

1 mark

A

0.54\,\text{g}

sample of a metal

M

(relative atomic mass

A_r = 27

) reacts completely with an excess of dilute sulfuric acid,

\text{H}_2\text{SO}_4

, to produce

720\,\text{cm}^3

of hydrogen gas,

\text{H}_2

. The volume of gas was measured at room temperature and pressure (RTP). Which of the following is the correctly balanced equation for this reaction?

(Assume that

1\,\text{mol}

of gas occupies

24\,\text{dm}^3

at RTP.)

A. $M + \text{H}_2\text{SO}_4 \rightarrow \text{MSO}_4 + \text{H}_2$
B. $2M + \text{H}_2\text{SO}_4 \rightarrow M_2\text{SO}_4 + \text{H}_2$
C. $2M + 3\text{H}_2\text{SO}_4 \rightarrow M_2(\text{SO}_4)_3 + 3\text{H}_2$
D. $M + 2\text{H}_2\text{SO}_4 \rightarrow M(\text{SO}_4)_2 + 2\text{H}_2$
E. $3M + 2\text{H}_2\text{SO}_4 \rightarrow M_3(\text{SO}_4)_2 + 2\text{H}_2$

Answer: C

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Question 15

1 mark

A student is required to prepare

500\,\text{cm}^3

of an aqueous solution of sodium carbonate,

\text{Na}_2\text{CO}_3

, with a concentration of

0.050\,\text{mol dm}^{-3}

.

What mass of anhydrous sodium carbonate is needed to prepare this solution?

(

A_r

values:

\text{C} = 12

;

\text{O} = 16

;

\text{Na} = 23

)

A. $1.33\,\text{g}$
B. $2.65\,\text{g}$
C. $5.30\,\text{g}$
D. $10.6\,\text{g}$
E. $26.5\,\text{g}$

Answer: B

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ESAT Mock Chemistry Esat-chem-bank-1

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

Question 15