Chemistry Random Retrieval Y12

Why is ethanol a liquid while propane is a gas? (Relative atomic masses: C = 12, H = 1, O = 16)

What is the product when methanol and propanoic acid are mixed and warmed in the presence of a few drops of acid?

Which of these alcohols is a tertiary alcohol?

(i) CH₃CH₂CHOHCH₃

(ii) CH₃CH(CH₃)CHOHCH₃

(iii) CH₃C(CH₃)₂CH₂CHOHCH₃

(iv) (CH₃)₃COH

The mass spectrum of copper has two significant peaks. The peak at 63 has a relative abundance of 69 and the peak at 65 has a relative abundance of 31.

This shows that the relative atomic mass of copper is:

An element which consists of a giant structure of atoms held together by covalent bonding is:

The oxidising agent used to extract bromine from sea water in a displacement reaction is:

The total O.N. of all the halogen atoms in these compounds ClO^-, BrO^-, ICl, XeF₄ is:

Hydrazine burns according to this equation: N₂H_4(g) + O_2(g) -> N_2(g) + 2H₂O_(l)

Calculate the standard enthalpy change for the combustion of hydrazine given that the standard enthalpy of formation of hydrazine is +51 kJmol^-1 and of water is -286 kJ mol^-1

The standard enthalpy change of formation of N₂O_(g) is +82 kJ mol^-1. This shows that

Which of these statements are true for the hydrides of group 5: NH₃, PH₃, AsH₃ and SbH₃:

(i) the molecules decrease in size down the group

(ii) the boiling point of ammonia is higher than expected from the general trend in values down the group

(iii) none of the molecules is polar

(iv) only ammonia is affected by hydrogen bonding

Which of these conversions are reductions?

(i) CrO₄^2- to Cr₂O₇^2-

(ii) CrO₄^2- to Cr³⁺

(iii) CrO₄^2- to CrO₃

(iv) CrO₃ to Cr₂O₃

The amount in moles of iodide ions oxidised by one mole of chlorine molecules is:

Which of these true statements can help to explain why magnesium has a higher melting point than sodium:

(i) magnesium atoms/ions are smaller than sodium atoms/ions

(ii) the metallic bonds are stronger in magnesium than in sodium

(iii) a magnesium atoms contributes two bonding electrons not one

(iv) the first ionisation energy is higher for magnesium than for sodium.

Which of these statements is true of a metallic crystal?

(i) It consists of atoms strongly held together by metallic bonding.

(ii) It consists of a regular array of positive ions in a sea of negative electrons.

(iii) The crystal is held together by the attraction between positive metal ions and electrons.

(iv) The crystal is negatively charged.

Zinc conducts electricity because:

(i) the metal is polycrystalline

(ii) the atoms are close-packed

(iii) the atoms are in contact with neighbouring atoms

(iv) the bonding electrons are delocalised.

Which of these molecules are overall polar?

(i) CH₃Cl

(ii) CH₂Cl₂

(iii) CHCl₃

(iv) CCl₄

Which of these materials consist of a giant structure of ions?

(i) magnesium oxide

(ii) silicon dioxide

(iii) potassium fluoride

(iv) silicon chloride

Typically ionic compounds:

(i) are soluble in water

(ii) conduct electricity when dissolved in water

(iii) are insoluble in liquid hydrocarbons

(iv) decompose when they dissolve in water

What is the electron configuration of an oxide ion?

For which of these equilibria does a change in pressure have no effect on the yield of substances on the right-hand side of the equation?

(i) CH_4(g) + H₂O_(g) <=> 3H_2(g) + CO_(g)

(ii) 2HI_(g) <=> H_2(g) + I_2(g)

(iii) 2SO_2(g) + O_2(g) <=> 2SO_3(g)

(iv) H₂O_(g) + CO_(g) <=> H_2(g) + CO_2(g)

Each of these statements is true. From which statement is it possible to predict, by application of Le Chatelier's principle that the solubility of sodium hydroxide increases with temperature?

Using enthalpies of combustion Δ_cH, calculate the enthalpy change for the cracking of butane:

C₄H_10(g) => C₂H_6(g) + C₂H_4(g)

Select the data from the 'Selection of Enthalpies of Formation and Combustion' shown above.

If this question was generated from Random Retrieval, this data can also be found in TOOLS>Data Sheets.

Calculate the enthalpy change for the formation of one mole of hydrogen chloride gas from its elements given these average bond enthalpies: H-H bond enthalpy = 435 kJ mol^-1, Cl-Cl bond enthalpy = 243 kJ mol^-1 and H-Cl bond enthalpy = 432 kJ mol^-1

A solution of Br₂ and KI were mixed. Then shaken with cyclohexane. Which is correct?

(i) the bromine is reduced

(ii) the cyclohexane layer goes brown

(iii) the cyclohexane layer goes purple

(iv) the iodine is reduced

The carbonates of group 2 metals (M):

(i) have the formula of the form MCO₃

(ii) are insoluble in water

(iii) become more difficult to decompose on heating down the group

(iv) decompose on heating to the metal and carbon dioxide

What is the oxidation number of SULFUR in

SO₄^2-

What is the oxidation number of BROMINE in

BrO^-

Which of these statements about atomic and ionic radii are true?

(i) Atomic radii increase down group 2

(ii) Ionic radii increase down group 7

(iii) Atomic radii decrease across period 3

(iv) In period 3 the ionic radii are smaller than the atomic radii

In the periodic table a periodic pattern is:

Choose one of the following options:

How many structural isomers of C₄H₈O are there?

It's really difficult to get all of these structures, so don't panic if you miss some. Just spend some time sketching out all the possibilities and remembering some simple rules, e.g carbon forms 4 bonds, oxygen forms 2 etc. Be creative!

How many structural isomers of C₆H₁₄ are there?

The mass spectrum of chlorine includes three peaks at mass-to-charge ratios of 70, 72 and 74.

The order of the heights of these peaks is:

What are the conditions for converting 1,2-dichlorethane into ethane-1,2-diol?

What is the product when methanol and propanoic acid are mixed and warmed in the presence of a few drops of acid?

What type of reaction takes place on passing the vapour of ethanol over hot aluminium oxide? (Water and an alkene are produced)

What is the product of the reaction of but-2-ene with steam in the presence of a phosphoric acid catalyst?

The reagent which converts hex-1-ene to dibromohexane is:

Which of these alkenes will produce the largest %yield of 2-bromopentane when it is reacted with hydrogen bromide?