Chemistry Random Retrieval Y12

At a high temperature in the presence of steam, the alkane C₁₆H₂₄ reacts to form a mixture of ethene, propene and ethane. This is an example of:

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!

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

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 standard enthalpy of combustion of methane is -890 kJ mol^-1. Calculate the energy given out on burning 3.2 g methane.

Using enthalpies of combustion Δ_cH, calculate the enthalpy change for the hydrogenation of propene:

C₃H_6(g) + H_2(g) => C₃H_8(g)

Select the data from theenthalpies of combustion Δ_cH.

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

Calculate the volume of oxygen gas formed on strongly heating 3.40 g sodium nitrate which decomposes according to this equation:

2NaNO_3(s) -> 2NaNO_2(s) + O_2(g)

Assume that the volume of 1 mol of any gas is 24 000 cm³ under the conditions of the experiment.

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.

The ionic equation for a neutralisation reaction is:

What is the concentration of a solution of sodium hydroxide that is made by dissolving 20.0g of the solid in water and making the solution up to 250 cm³? (Relative atomic masses: Na = 23, O = 16, H = 1)

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.

Which of these sets of properties is that of a substance which is molecular?

At room temperature, in the crystal lattice of an ionic compound the ions are:

(i) arranged symmetrically

(ii) uncharged

(iii) held together by electrostatic forces

(iv) stationary

How many chloride ions touch each sodium ion in the crystal structure of sodium 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 molecular formula of a hydrocarbon which consists of 82.8% carbon and has a relative molecular mass estimated in the range 50 and 60.

What is the molar mass of calcium hydroxide?

What is the electronic configuration of sulfide? Enter your answer in the following format 1s2 2s2 etc. (note the space between each sub-shell!) Follow the aufbau order of sub-shell filling.

What is the electronic configuration of bromine? Enter your answer in the following format 1s2 2s2 etc. (note the space between each sub-shell!) Follow the aufbau order of sub-shell filling.

The reaction of nitrogen with hydrogen to form ammonia is exothermic. Which of these changes increases the proportion of ammonia in an equilibrium mixture of nitrogen, hydrogen and ammonia.

(i) raising the pressure at constant temperature

(ii) raising the temperature at constant pressure

(iii) decreasing the volume at constant temperature

(iv) adding a catalyst

Which of these reactions can be reversed by changing the conditions in a typical advanced chemistry laboratory?

(i) CuSO₄.5H₂O_(s) -> CuSO_4(s) + 5H₂O(l)

(ii) 2Mg_(s) + O_2(g) -> 2MgO_(s)

(iii) NH_3(g) + HCl_(g) -> NH₄Cl_(s)

(iv) CH_4(g) + 2O_2(g) -> CO_2(g) + 2H₂O_(l)

Using enthalpies of formation Δ_fH, calculate the enthalpy change for the following esterification reaction.

CH₃COOH_(l) + C₂H₅OH_(l) => CH₃COOCH₂CH_3(l) + H₂O_(l)

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.

Using enthalpies of formation Δ_fH, calculate the enthalpy change for the following hydration process.

Na₂S₂O_3(s) + 5H₂O_(l) => Na₂S₂O₃•5H₂O_(s)

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.

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

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

In which of these molecules do the intermolecular forces arise largely from attractions between temporary dipoles?

What is the electron configuration of a magnesium atom?

What is the oxidation number of OSMIUM in

OsO₄

What is the oxidation number of CARBON in

C₂H₆

Choose one of the following options:

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 functional group isomers of C₄H₈ are there?

Which of the following statements describe molecules that are structural isomers?

(i) molecules whose atoms have the same arrangement in space

(ii) molecules that have the same molecular formula

(iii) molecules in which the atoms are joined to the same neighbouring atoms

(iv) molecules which the same atoms but they are bonded in a different order

Infra-red absorption ranges for some bonds are as follows:

C-H, 2850 - 3300 cm^-1

C=C, 1620 - 1680 cm^-1

C=O, 1680 - 1750 cm^-1

C-O, 1000 - 1300 cm^-1

O-H (alcohols), 3230 - 3550 cm^-1

O-H (acids), 2500 - 3000 cm^-1

The IR spectrum of propanal has one particularly strong absorption peak

This can be expected to be at:

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 is the formula of 2-bromo-3-methylpentane?

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

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