Structure 1. Models of the particulate nature of matter

1.1 Introduction to the particulate nature of matter

1.2 The nuclear atom

1.3 Electron configurations

1.4 The mole

1.5 Ideal gases

Structure 2. Models of bonding and structure

2.1 The ionic model

2.2 The covalent model

2.3 The metallic model

2.4 From models to materials

Structure 3. Classification of matter

3.1 The periodic table

3.2 Functional groups: Organic compounds

Reactivity 1. What drives chemical reactions?

1.1 Measuring enthalpy changes

1.2 Energy cycles

1.3 Energy from fuels

Reactivity 2. How much, how fast and how far?

2.1 Amount of chemical change

2.2 Rate of chemical change

2.3 Extent of chemical change

Reactivity 3. What are the mechanisms of chemical change?

3.1 Proton transfer reactions

3.2 Electron transfer reactions

3.3 Electron sharing reactions (Radicals)

3.4 Electron-pair sharing reactions

IB Chemistry SL 1.2 Energy cycles Question Bank

[Maximum number: 3]

Ethyne, $\mathrm{C}_{2} \mathrm{H}_{2}$ , reacts with oxygen in welding torches.

(a)

Ethyne reacts with steam.

Two possible products are:

[ 3 ]

(i)

Determine the enthalpy change for the reaction, in kJ , to produce A using section 11 of the data booklet.

[ 3 ]

(a)

The students repeated the experiment using 6.16 g of solid hydrated magnesium sulfate, $\mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O}(\mathrm{s})$ , and $50.0 \mathrm{~cm}^{3}$ of water. They found the enthalpy change, $\Delta H_{2}$ , to be $+18 \mathrm{~kJ} \mathrm{~mol}^{-1}$ .

The enthalpy of hydration of solid anhydrous magnesium sulfate is difficult to determine experimentally, but can be determined using the diagram below.

\mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O}(\mathrm{~s}) \xrightarrow[\text { water }]{\Delta H_{2}} \mathrm{Mg}^{2+}(\mathrm{aq})+\mathrm{SO}_{4}^{2-}(\mathrm{aq})

[ 1 ]

(i)

Determine the enthalpy change, $\Delta H$ , in $\mathrm{kJ} \mathrm{mol}^{-1}$ , for the hydration of solid anhydrous magnesium sulfate, $\mathrm{MgSO}_{4}$ .

[ 1 ]

[Maximum number: 3]

Ethane-1,2-diol, $\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{OH}$ , has a wide variety of uses including the removal of ice from aircraft and heat transfer in a solar cell.

(a)

Ethane-1,2-diol can be formed according to the following reaction.

2 \mathrm{CO}(\mathrm{~g})+3 \mathrm{H}_{2}(\mathrm{~g}) \rightleftharpoons \mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{OH}(\mathrm{~g})

[ 3 ]

(i)

Calculate the enthalpy change, $\Delta H^{\ominus}$ , in kJ , for this reaction using section 11 of the data booklet. The bond enthalpy of the carbon-oxygen bond in CO(g) is $1077 \mathrm{~kJ} \mathrm{~mol}^{-1}$ .

[ 3 ]

[Maximum number: 3]

Methanoic acid can be produced by the hydrogenation of carbon dioxide according to the equilibrium

\mathrm{CO}_{2}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g}) \rightleftharpoons \mathrm{HCOOH}(\mathrm{~g})

(a)

Bond enthalpies are a useful way of finding approximate enthalpy changes for reactions.

[ 3 ]

(i)

Determine the enthalpy change, $\Delta H^{\ominus}$ , of this reaction, using section 11 of the data booklet.

[ 3 ]

[Maximum number: 1]

What is correct about energy changes during bond breaking and bond formation?

Bond breaking

Bond formation

exothermic and $\Delta H$ positive

endothermic and $\Delta H$ negative

exothermic and $\Delta H$ negative

endothermic and $\Delta H$ positive

exothermic and $\Delta H$ negative

endothermic and $\Delta H$ negative

exothermic and $\Delta H$ positive

[Maximum number: 1]

Consider the following reactions:

\begin{array}{ll} \mathrm{Fe}_{2} \mathrm{O}_{3}(\mathrm{~s})+\mathrm{CO}(\mathrm{~g}) \rightarrow 2 \mathrm{FeO}(\mathrm{~s})+\mathrm{CO}_{2}(\mathrm{~g}) & \Delta H^{\ominus}=-3 \mathrm{~kJ} \\ \mathrm{Fe}(\mathrm{~s})+\mathrm{CO}_{2}(\mathrm{~g}) \rightarrow \mathrm{FeO}(\mathrm{~s})+\mathrm{CO}(\mathrm{~g}) & \Delta H^{\ominus}=+11 \mathrm{~kJ} \end{array}

What is the $\Delta H^{\ominus}$ value, in kJ , for the following reaction?

\mathrm{Fe}_{2} \mathrm{O}_{3}(\mathrm{~s})+3 \mathrm{CO}(\mathrm{~g}) \rightarrow 2 \mathrm{Fe}(\mathrm{~s})+3 \mathrm{CO}_{2}(\mathrm{~g})

-25

-14

+19

[Maximum number: 1]

This question is about compounds of sodium.

(a)

Sodium peroxide is used in diving apparatus to produce oxygen from carbon dioxide.

2 \mathrm{Na}_{2} \mathrm{O}_{2}(\mathrm{~s})+2 \mathrm{CO}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{~s})+\mathrm{O}_{2}(\mathrm{~g})

[ 1 ]

(i)

Outline why bond enthalpy values are not valid in calculations such as that in (c)(i).

[ 1 ]

[Maximum number: 1]

Which combination will give you the enthalpy change for the hydrogenation of ethene to ethane, $\Delta H_{3}$ ?

\begin{aligned} 2 \mathrm{C}(\mathrm{~s})+ & 3 \mathrm{H}_{2}(\mathrm{~g}) \xrightarrow{\Delta \mathrm{H}_{2}} \mathrm{C}_{2} \mathrm{H}_{4}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g}) \xrightarrow{\Delta \mathrm{H}_{3}} \mathrm{C}_{2} \mathrm{H}_{6}(\mathrm{~g}) \\ & +2 \mathrm{O}_{2}(\mathrm{~g}) \longrightarrow 2 \mathrm{CO}_{2}(\mathrm{~g})+3 \mathrm{H}_{2}(\mathrm{~g}) \xrightarrow[+2 \mathrm{O}_{2}(\mathrm{~g})]{\Delta H_{4}} \end{aligned}

$-\Delta H_{2}+\Delta H_{1}-\Delta H_{4}$

$\Delta H_{2}-\Delta H_{1}+\Delta H_{4}$

$\Delta H_{2}+\Delta H_{1}-\Delta H_{4}$

$-\Delta H_{2}-\Delta H_{1}+\Delta H_{4}$

[Maximum number: 1]

Which combustion reaction releases the least energy per mole of $\mathrm{C}_{3} \mathrm{H}_{8}$ ?

Approximate bond enthalpy / $\mathrm{kJ} \mathrm{mol}^{-1}$

$\mathrm{O}=\mathrm{O}$	500
$\mathrm{C}=\mathrm{O}$	800
$\mathrm{C} \equiv \mathrm{O}$	1000

$\mathrm{C}_{3} \mathrm{H}_{8}(\mathrm{~g})+5 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 3 \mathrm{CO}_{2}(\mathrm{~g})+4 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})$

$\mathrm{C}_{3} \mathrm{H}_{8}(\mathrm{~g})+\frac{9}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_{2}(\mathrm{~g})+\mathrm{CO}(\mathrm{g})+4 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})$

$\mathrm{C}_{3} \mathrm{H}_{8}(\mathrm{~g})+4 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{CO}_{2}(\mathrm{~g})+2 \mathrm{CO}(\mathrm{g})+4 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})$

$\mathrm{C}_{3} \mathrm{H}_{8}(\mathrm{~g})+\frac{7}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 3 \mathrm{CO}(\mathrm{g})+4 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})$

[Maximum number: 3]

The following shows some compounds which can be made from ethene, $\mathrm{C}_{2} \mathrm{H}_{4}$ .

\text { ethene }\left(\mathrm{C}_{2} \mathrm{H}_{4}\right) \rightarrow \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl} \rightarrow \mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O} \rightarrow \mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}

(a)

(i)

Determine the enthalpy of combustion of the organic product in (b), in $\mathrm{kJ} \mathrm{mol}^{-1}$ , using data from section 11 of the data booklet.

[ 3 ]

0 selected

Question 1

Question 1(c)

Question 1(c)(iii)

Question 1

Question 1(c)

Question 1(c)(i)

Question 1

Question 1(a)

Question 1(a)(iii)

Question 2

Question 2(c)

Question 2(c)(i)

Question 13

Question 13

Question 3

Question 3(c)

Question 3(c)(ii)

Question 14

Question 14

Question 3

Question 3(c)

Question 3(c)(ii)