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Which sample contains the same number of the named species as the number of molecules in 35.5 g of chlorine?
Mixture R consists of one mole of $C_3H_6$ and one mole of $C_4H_6$.
What is the minimum number of moles of oxygen molecules needed for complete combustion of mixture R?
Which statement about the electrons in a ground state carbon atom is correct?
For the element sulfur, which pair of ionisation energies has the largest difference between them?
How many \( \sigma \) bonds are present in one \( \text{H--C}\equiv\text{C--C(CH}_3\text{)=CH(CH}_3\text{)} \) molecule?
Which molecule has an equal number of bonding electrons and lone-pair electrons?
The table shows properties of four solids held together by different types of bonding.
Which row correctly describes the properties of a solid with a giant covalent structure?
[Table_1]
The carbonate of an s-block element is reacted with an excess of hydrochloric acid.
0.833 g of the carbonate releases 200 $cm^{3}$ of gas, measured under room conditions.
What is the identity of the metal carbonate?
The enthalpy changes of formation, $\Delta H_f^\circ$, of both PCl$_3$ and PCl$_5$ are exothermic.
PCl$_3$ reacts with chlorine.
$$\text{PCl}_3(l) + \text{Cl}_2(g) \rightarrow \text{PCl}_5(s) \hspace{1cm} \Delta H_{\text{reaction}}^\circ = -124 \text{kJ mol}^{-1}$$
Which pair of statements is correct?
A student mixes 25.0 cm3 of 0.350 mol dm–3 sodium hydroxide solution with 25.0 cm3 of 0.350 mol dm–3 hydrochloric acid. The temperature increases by 2.5°C. No heat is lost to the surroundings.
The final mixture has a specific heat capacity of 4.2 J cm–3 K–1.
What is the molar enthalpy change for the reaction?
Ammonium ions are converted into nitrate ions by bacteria.
What is the change in the oxidation number of nitrogen?
Sodium dichromate(VI), Na\textsubscript{2}Cr\textsubscript{2}O\textsubscript{7}, reacts with hydrogen peroxide, H\textsubscript{2}O\textsubscript{2}, producing Cr\textsuperscript{3+} ions, water and oxygen.
What is the correctly balanced ionic equation for this reaction?
In which equilibrium reaction is the position of equilibrium moved to the right-hand side by increasing the temperature and also by decreasing the pressure?
Ethanol is produced industrially by reacting ethene and steam.
$$\text{C}_2\text{H}_4(g) + \text{H}_2\text{O}(g) \rightleftharpoons \text{C}_2\text{H}_5\text{OH}(g)$$
$K_p$ has a value of $1.8 \times 10^{-5}$ and the partial pressures of the reactants at equilibrium are shown.
[Table_1]
Which row is correct?
A large excess of magnesium ribbon is added to dilute hydrochloric acid and the volume of hydrogen gas produced is measured as the reaction proceeds. The reaction is exothermic.
The results are shown.
Which row explains the changes in the rate of reaction between points P and Q and between points Q and R?
Measurements are made to determine the activation energy, $E_a$, of a reaction.
The diagram shows $E_a$ on the Boltzmann distribution at temperature $T_1$.
Measurements are then made at a higher temperature, $T_2$.
Which diagram correctly shows the Boltzmann distribution and $E_a$ at $T_2$?
The electrical conductivities of two compounds, Y and Z, are shown.
[Table_1]
What are compounds Y and Z?
Which row describes the relative sizes of the ionic radii of $\text{Na}^+$, $\text{Mg}^{2+}$ and $\text{S}^{2-}$?
The oxides BaO, CaO, MgO and SrO all produce alkaline solutions when added to water. Which oxide produces the saturated solution with the highest pH?
Which row is correct?
[Table_1]
Which statement about Group 17 elements and compounds is correct?
Chlorine is bubbled through 100 cm³ of hot 4.0 mol dm⁻³ sodium hydroxide until the reaction is complete.
$$6\text{NaOH(aq)} + x\text{Cl}_2\text{(aq)} \rightarrow y\text{NaCl(aq)} + z\text{NaClO}_3\text{(aq)} + 3\text{H}_2\text{O(l)}$$
Which row is correct?
[Table_1]
Which statement about ammonia or the ammonium ion is correct?
Sulfur dioxide can be catalytically oxidised by an oxide of nitrogen in the atmosphere. Which reaction shows how the catalyst is reformed?
Separate 1.0 g samples of $\text{Na}_2\text{O}$, MgO, $\text{Al}_2\text{O}_3$, SiO$_2$, NaCl, MgCl$_2$, $\text{Al}_2\text{Cl}_6$ and SiCl$_4$ are added to separate beakers containing water and stirred.
The number of beakers containing a white solid is Q.
An excess of NaOH(aq) is then added to each beaker and stirred.
The number of beakers now containing a white solid is R.
Which row is correct?
[Table_1]
Which pair of alcohols are isomers of each other?
How many chiral carbon atoms are there in one molecule of 2,2,4,5-tetramethylhexan-3-ol?
Which pair of reagents react together in a redox reaction?
The structure of santonin is shown.
Santonin is first treated with warm dilute $\text{H}_2\text{SO}_4$. The product of this reaction is treated with cold dilute acidified $\text{KMnO}_4$. A final product, Q, is obtained.
How many atoms of hydrogen in each molecule of product Q will react with sodium metal?
Compound R can be formed from 1-bromopropane using a nucleophilic substitution reaction followed by an oxidation reaction. What is the identity of R?
Three colourless liquids with the following formulae are contained in separate unlabelled bottles.
CH$_3$CH$_2$CO$_2$H CH$_3$CH(OH)CO$_2$H CH$_3$COCO$_2$H
Which two tests, carried out on separate samples of each liquid, will successfully identify each liquid?
[Table_1]
An alcohol, X, reacts with a dicarboxylic acid, Y, to form a double ester, Z. The diagram shows the structure of the ester.
Which row about the reactants forming ester Z is correct?
[Table_1]
W reacts with alkaline \( I_{2(aq)} \) to form a yellow precipitate and \( CH_3CH_2CO_2^- \) ions. Which row identifies W and the yellow precipitate? [Table_1]
Ethanol reacts with hydrogen cyanide in the presence of KCN to produce a hydroxynitrile.
What is the first step in the mechanism of this reaction?
Structural isomerism and stereoisomerism should be considered when answering this question.
How many isomeric compounds with molecular formula $C_5H_6O_4$ contain two $-CO_2H$ groups and one $C=C$ double bond?
Compound X reacts with ethanoic acid in the presence of an $H^+$ catalyst to produce the compound shown.
What is the molecular formula of compound X?
2-bromopropane reacts with hot ethanolic sodium hydroxide. Which substance is the major product of this reaction?
Which compounds can be used to make Y in a single-step reaction?
The monomer buta-1,3-diene can undergo addition polymerisation in various ways. Two of the polymers that can be made are called cis-poly(buta-1,3-diene) and trans-poly(buta-1,3-diene). In these names cis and trans have their usual meanings.
What is the structure of the repeat unit of cis-poly(buta-1,3-diene)?
In the mass spectrum of a compound, Z, the relative abundances of the M and M+1 peaks are in the ratio 13:1. What is compound Z?