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Propanoic acid is treated with reagent X at room temperature. The organic product of the reaction is sodium propanoate. No gas is produced during the reaction. What could be reagent X?
The ionic equation shows iodide ions reacting with manganate(VII) ions in acidic solution.
$$u\text{MnO}_4^- + v\text{H}^+ + w\text{I}^- \rightarrow x\text{Mn}^{2+} + y\text{H}_2\text{O} + z\text{I}_2$$
The letters $u$, $v$, $w$, $x$, $y$ and $z$ all represent whole numbers. Two or more of $u$, $v$, $w$, $x$, $y$ and $z$ are the same as each other.
What is the lowest possible value of $v$?
A piece of rock has a mass of 2.00 g. It contains calcium carbonate, but no other basic substances. It neutralises exactly 36.0 cm3 of 0.500 mol dm−3 hydrochloric acid.
What is the percentage by mass of calcium carbonate in the 2.00 g piece of rock?
L and M are elements in Period 3 of the Periodic Table. Neither element is argon. Information about the Pauling electronegativity values of L and M is given.
[Table_1]
Three statements about elements L and M are given.
1. Element L contains covalent bonds.
2. Element L has a higher atomic number than element M.
3. A compound of L and M contains ionic bonds.
Which statements are correct?
Ammonia reacts with acids to form the ammonium ion.
$\text{NH}_3 + \text{H}^+ \rightleftharpoons \text{NH}_4^+$
Which row is correct?
[Table_1]
Electronegativity differences can be used to help determine the oxidation number of an atom in different species. A number of rules are used which include:
• The more electronegative atom is given a negative oxidation number.
• Hydrogen is more electronegative than Group 1 metals.
• Oxygen is more electronegative than hydrogen.
Which row is correct?
[Table_1]
Which assumptions are made about ideal gases?
1. Ideal gases contain molecules with no mass.
2. Ideal gases contain molecules with no volume.
3. Ideal gases have no intermolecular forces.
A 200 cm3 sample of water has an amount of oxygen gas dissolved in it. This amount of oxygen gas has a volume of 6.00 cm3 when measured at 1.00 × 105 Pa and 35 °C. What is the concentration of oxygen gas in the water? (You should assume that oxygen behaves as an ideal gas.)
Which statement explains why buckminsterfullerene has a lower melting point than graphite?
Which equation represents the reaction whose standard enthalpy change is the standard enthalpy change of formation of water?
Which mixture will react to form exactly one mole of water?
[Table_1]
The enthalpy change for neutralisation of $\text{HNO}_3(aq)$ with $\text{NaOH}(aq)$ is $-57.0$ kJ mol$^{-1}$.
In an experiment, $20.0$ cm$^3$ of $4.00$ mol dm$^{-3}$ $\text{HNO}_3$ is mixed with $30.0$ cm$^3$ of $2.00$ mol dm$^{-3}$ $\text{NaOH}$ in an insulated container. The initial temperature of both solutions is $25.0$ $^\circ$C.
It can be assumed that the heat capacity of the product mixture is $4.2$ J cm$^{-3}$ $^\circ$C$^{-1}$ and that there are no heat losses.
What is the maximum final temperature of the mixture?
Some bond energies are listed.
[Table_1]
One mole of hydrogen reacts with oxygen to give water vapour.
Using the bond energy data, what is the value for the enthalpy change of this reaction?
Which particle contains nitrogen in the same oxidation state as in the ion $N_2O_2^{2-}$?
Sulfur dioxide reacts with oxygen as shown.
$$2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$$
$$\Delta H^\circ = -197 \text{ kJ mol}^{-1}$$
Which change will move the equilibrium position to the right side and change the value of the equilibrium constant, $K_c$?
Solutions X and Y both have a concentration of 0.10 mol dm$^{-3}$. A fixed volume of solution X is added to a conical flask, and solution Y is added from a burette to the conical flask. A titration is performed.
The diagram shows the pH titration curve for the acid-base reaction between the solutions.
What are solutions X and Y?
Which row shows the expected properties of the element astatine when compared to the properties of the element iodine?
[Table_1]
The rate of an exothermic reaction is followed by measuring the concentration of a reactant at regular time intervals.
During the experiment the temperature of the reaction mixture is not controlled.
Which graph shows the change in concentration of reactant against time?
For a particular reversible reaction the backward reaction is endothermic. The activation energy of the backward reaction is 160 kJ mol–1. It can be assumed that the backward reaction proceeds by a mechanism that is the exact reverse of the mechanism for the forward reaction. Which statement about the activation energy of the forward reaction is correct?
HCN has been detected in interstellar gas. The molecules below have also been detected in interstellar gas.
Which molecule contains the same total number of valence shell (outer shell) electrons as HCN?
The diagram shows the Boltzmann distribution of the energy of gaseous molecules at a particular temperature.
Which statement is correct?
The elements magnesium and phosphorus are reacted separately with an excess of oxygen to form their oxides. Each oxide is then added separately to water and the pH values of the resulting solutions are measured.
The same two elements are reacted separately with an excess of chlorine to form their chlorides. Each chloride is then added separately to water and the pH values of the resulting solutions are measured.
Which row is correct?
[Table_1]
Equal volumes of saturated solutions of magnesium hydroxide, calcium hydroxide and strontium hydroxide are completely neutralised with dilute sulfuric acid. The water is gently evaporated from each of the resulting solutions, leaving the corresponding solid sulfates. These solid sulfates are completely dissolved in the minimum volume of water needed to produce saturated solutions. Which statement about the volumes of water needed to dissolve the sulfates is correct?
Which statement about the halogens is correct?
When concentrated sulfuric acid is added to solid sodium bromide, bromine gas is produced, along with a number of other products. However, when concentrated sulfuric acid is added to solid sodium chloride, only hydrogen chloride and sodium hydrogensulfate are produced. What is the reason for this difference?
Which statement about the oxides of nitrogen is correct?
Structural isomerism and stereoisomerism should be considered when answering this question.
2-bromopentane is heated with an excess of ethanolic sodium hydroxide.
How many different hydrocarbons are produced?
Which compound is a secondary alcohol that can be dehydrated to form an alkene with $M_r = 70$?
The conversion of propan-1-ol into propan-2-ol can be completed in a two-stage synthesis.
The first stage is to heat the propan-1-ol with concentrated sulfuric acid.
Which reagent would be needed to complete the second stage?
Which type of reaction happens during the hydrolysis of 2-bromopropane?
A mixture of ethane and an excess of chlorine is exposed to UV light.
How many different products, each containing only two carbon atoms and at least one chlorine atom per molecule, can be formed?
When 1-methylcyclohexene reacts with $\text{Br}_2$ the product is X.
When 1-methylcyclohexene reacts with HBr the \textit{major} product is Y.
Which statement is correct?
T is an organic compound which contains 66.7\% by mass of carbon. T also contains one atom of oxygen per molecule.
T reacts with alkaline I$_2$(aq) to produce a yellow precipitate.
What is T?
Which statement about butanone is correct?
Methylbut-2-ene reacts with HBr at room temperature to produce compound X as a major product.
Compound X reacts with KCN in ethanol to produce compound Y.
Compound Y is hydrolysed with acid to produce compound Z.
What is compound Z?
Compound Q can be hydrolysed by HCl(aq). The two products of this hydrolysis have the same empirical formula.
What could Q be?
An unsaturated carboxylic acid reacts with alcohol X to form an ester. The structure of the ester is shown.
Which geometrical isomer is shown in this ester and to which class of alcohol does X belong?
[Table_1]
Which two-step process converts cyclohexanol into cyclohexane-1,2-diol?
In polymer G every carbon atom in the polymer chain is bonded to one hydrogen atom and one methyl group. Which alkene could be polymerised to make polymer G?
The mass spectrum of compound X has M, M+1 and M+2 peaks. Other peaks are also present.
Peak M is the molecular ion peak, $M^+$. Peak M has a relative abundance fifteen times that of peak M+1.
Peaks M and M+2 are of equal height.
What could be compound X?