Cambridge AS Chemistry 9701 w14 12

In which reaction does hydrogen behave as an oxidising agent?

• H₂ + Cl₂ → 2HCl
• C₂H₄ + H₂ → C₂H₆
• N₂ + 3H₂ → 2NH₃
• 2Na + H₂ → 2NaH

Ethanol is increasingly being used as a fuel for cars.
The standard enthalpy change of formation of carbon dioxide is –393 kJ mol^–1.
The standard enthalpy change of formation of water is –286 kJ mol^–1.
The standard enthalpy change of formation of ethanol is –277 kJ mol^–1.
What is the standard enthalpy change of combustion of ethanol?

• -1921 kJ mol^–1
• -1367 kJ mol^–1
• -956 kJ mol^–1
• -402 kJ mol^–1

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NGSS.HS-PS1-4

NGSS.HS-PS3-1

Which solid-line curve most accurately represents the distribution of molecular energies in a gas
at 500 K if the dotted-line curve represents the corresponding distribution for the same gas at
300 K?

• A
• B
• C
• D

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NGSS.HS-PS3-2

NGSS.HS-PS3-4

Two glass vessels M and N are connected by a closed valve.
M contains helium at 20 °C at a pressure of 1 × 10⁵
Pa. N has been evacuated, and has three
times the volume of M. In an experiment, the valve is opened and the temperature of the whole
apparatus is raised to 100 °C.
What is the final pressure in the system?

• 3.18 × 10⁴Pa
• 4.24 × 10⁴Pa
• 1.25 × 10⁴Pa
• 5.09 × 10⁴Pa

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NGSS.HS-PS3-4

Question on image

• A
• B
• C
• D

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NGSS.HS-PS1-1

Aluminium carbide, Al ₄C₃, reacts readily with aqueous sodium hydroxide. The two products of the
reaction are NaAlO₂ and a hydrocarbon. Water molecules are also involved as reactants.
What is the formula of the hydrocarbon?

• CH₄
• C₂H₆
• C₃H₈
• C₆H₁₂

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NGSS.HS-PS1-1

NGSS.HS-PS1-2

In an experiment to calculate the enthalpy change of combustion of a fuel, 1.5 g (0.0326 mol) of the fuel was used to heat 200 g of water. The temperature of the water rose from 25 °C to 55 °C. The specific heat capacity of water is 4.18 J g^–1 K^–1.
There is significant heat loss in this experiment. Therefore, the experimental value for the enthalpy change of combustion, ΔHc, of the fuel will be different from the theoretical value.
Using the information above, what is the experimental value for the enthalpy change of combustion, ΔHc, of the fuel?

• –1410 kJ mol^–1
• -769 kJ mol^–1
• -30.7 kJ mol^–1
• -16.7 kJ mol^–1

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NGSS.HS-PS1-4

NGSS.HS-PS3-1

The reaction pathway diagram below illustrates the energies of the reactants, the products and the transition state of a reaction.
Which expression represents the activation energy of the forward reaction?

• E₁-E₂
• E₂-E₁
• E₂-E₃
• E₃-E₂

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NGSS.HS-PS1-4

Methylpropan-1-ol and butan-1-ol are structural isomers. Methylpropan-1-ol has a lower boiling point.
Which statement explains why the boiling point of methylpropan-1-ol is lower than that of butan-1-ol?

• Methylpropan-1-ol cannot form hydrogen bonds.
• Methylpropan-1-ol has weaker covalent bonds than butan-1-ol.
• Methylpropan-1-ol has weaker van der Waals’ forces than butan-1-ol.
• Methylpropan-1-ol molecules have more surface area than butan-1-ol molecules.

For which equation is the enthalpy change correctly described as an enthalpy change of formation?

• C(g) + O₂(g) → CO₂(g)
• C(s) + 1/2 O₂(g) → CO(g)
• 2N(g) + 4O(g) → N₂O₄(g)
• 2NO(g) + O₂(g) → 2NO₂(g)

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NGSS.HS-PS1-4

NGSS.HS-PS3-1