Chemistry 9701/23 — May/June 2014

Cambridge AS Level · AS Level Structured Questions · worked solutions for every part, with the mark scheme

questions

marks

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Topics Atoms, Molecules and Stoichiometry · Halogen Compounds · Nitrogen and Sulfur · Hydrocarbons · Hydroxy Compounds · Equilibria · +2 more

Q1Atoms, Molecules and StoichiometryHydrocarbonsHalogen CompoundsHydroxy CompoundsFree sample

(a)

Define the term mole.

(b)

$10\text{ cm}^3$ of a gaseous hydrocarbon, $\text{C}_x\text{H}_y$ , was reacted with $100\text{ cm}^3$ of oxygen gas, an excess.

The final volume of the gaseous mixture was $95\text{ cm}^3$ .

This gaseous mixture was treated with concentrated, aqueous sodium hydroxide to absorb the carbon dioxide present. This reduced the gas volume to $75\text{ cm}^3$ .

All gas volumes were measured at $298\text{ K}$ and $100\text{ kPa}$ .

(i)

Write an equation for the reaction between sodium hydroxide and carbon dioxide.

(ii)

Calculate the volume of carbon dioxide produced by the combustion of the hydrocarbon.

volume of $\text{CO}_2$ produced = ................. $\text{cm}^3$

(iii)

Calculate the volume of oxygen used up in the reaction with the hydrocarbon.

volume of $\text{O}_2$ used = ................. $\text{cm}^3$

(iv)

Use your answers to (b)(ii) and (b)(iii), together with the initial volume of hydrocarbon, to balance the equation below.

\text{...........C}_x\text{H}_y + \text{...........O}_2 \rightarrow \text{...........CO}_2 + z\text{H}_2\text{O}

(v)

Deduce the values of $x$ , $y$ and $z$ in the equation in (iv).

$x$ = .................

$y$ = .................

$z$ = .................

(c)

Another hydrocarbon, W, with the formula $\text{C}_4\text{H}_8$ , reacts with hydrogen bromide, $\text{HBr}$ , to give two products X and Y. X and Y are structural isomers of molecular formula $\text{C}_4\text{H}_9\text{Br}$ .

Reaction of X with aqueous alkali produces an alcohol, Z, that has no reaction with acidified dichromate(VI).

(i)

Give the structures and names of the compounds W, X, Y, and Z

Q1_WXYZ

(ii)

When W reacts with hydrogen bromide, more X than Y is produced. Explain why.

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3 more questions

Q2Nitrogen and Sulfur · Atoms, Molecules and Stoichiometry8M
Q3Nitrogen and Sulfur · Equilibria13M
Q4Group 17 · Introduction to Organic Chemistry · Halogen Compounds24M

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