Intermolecular forces

This question is about polymers.

A section of the polymer PVC is shown.

Name the monomer used to make PVC.

Draw the structure of the monomer used to make PVC.

Structure

State why PVC is not biodegradable.

Diisobutyl phthalate (DIBP) is a plasticiser added to PVC to modify its properties.

State how the properties of PVC are modified by the addition of DIBP.

An incomplete equation for the reaction used to make DIBP is shown.

Complete the equation.

Give the name of the mechanism for this reaction.

Deduce the empirical formula of DIBP.

Empirical formula of DIBP

A different plasticiser, DEHA, is added to PVC used for food packaging.

The structure of DEHA is

Identify the organic compound that would react with hexanedioic acid to form DEHA.

DEHA can be absorbed into food from PVC packaging.

In an investigation, 1 kg samples of three different foods are stored in PVC packaging for 30 days.

Table 1 shows the water content, fat content and mass of DEHA in each type of food after 30 days.

Use your knowledge of intermolecular forces to explain these results.

The polymer nylon 6,6 can be made from hexanedioyl dichloride and hexane-1,6-diamine.

Figure 2 shows an incomplete mechanism for the first steps in this reaction.

Draw the missing intermediate in the box in Figure 2.

Complete Figure 2 by adding the curly arrows and any relevant lone pairs of electrons involved in these steps in the mechanism.

The polymer nylon 6 can be made by heating caprolactam with water.

Figure 3 shows the species involved in the first three steps of the mechanism for this reaction.

Complete Figure 3 by adding the curly arrows and any relevant lone pairs of electrons involved in these steps in the mechanism.

Which compound forms the greatest number of hydrogen bonds per molecule in the liquid state?

Which statement correctly describes a trend down Group 7 from C l to I ?

X represents C l, Br or I

The diagram shows a gas chromatogram for a sample containing four isomers with

The carrier gas is nitrogen and the stationary phase is polar.

Which of the four isomers in this sample is the most abundant?

The molar enthalpy of vaporisation (H_vap) of a liquid is the enthalpy change when one mole of liquid is converted to vapour at the boiling point of the liquid.

A student does an experiment to determine H_vap for water.

The student:

• places a large beaker on a balance

• pours 500 cm³ of water into the beaker

• uses a 2.4 kW heater to raise the temperature of the water to 100 C

• records the mass of the beaker and hot water

• uses the 2.4 kW heater to boil the water for 100 s

• records the mass of the beaker and remaining water.

The loss in mass is 103 g

Calculate H_vap for water.

Table 2 shows some data about three compounds that all contain the same number of electrons.

All three compounds in Table 2 are polar. Ethanol is the most polar and ethylamine is the least polar.

Explain why all three molecules are polar and why ethylamine is the least polar. In your answer refer to the shapes around, and relative electronegativities of, the most electronegative atoms.

Explain the trend in the boiling points of the three compounds. Refer to the intermolecular forces in all three compounds in your answer.

This question is about Period 3 elements and their compounds.

Which is not a correct statement about magnesium hydroxide?

Tick (✓) one box.

Give an equation for the reaction of aluminium oxide with sulfuric acid.

Identify a reagent or test that could be used to distinguish between aqueous solutions of sulfur dioxide and sulfur trioxide with the same concentrations.

State the observation in each case.

Observation with sulfur dioxide solution

Observation with sulfur trioxide solution

The mass spectrum of the element phosphorus has a peak at = 124

Give the formula of the species responsible for this peak.

Give an equation for the reaction of phosphorus(V) oxide with sodium hydroxide solution.

Draw the displayed formula of the molecule formed when phosphorus(V) oxide reacts with water.

Table 4 shows the melting points of three substances.

Explain why the melting points of these substances are different.

You should refer to the structure of and bonding in each substance.

Which statement about (CH₃)₂CHCH₂COOH is correct?

The melting point of XeF₄ is higher than the melting point of PF₃

Explain why the melting points of these two compounds are different.

In your answer you should give the shape of each molecule, explain why each molecule has that shape and how the shape influences the forces that affect the melting point.

This question is about structure and bonding.

Draw a diagram to show the strongest type of interaction between two molecules of ethanol (C₂H₅OH) in the liquid phase.

Include all lone pairs and partial charges in your diagram.

Methoxymethane (CH₃OCH₃) is an isomer of ethanol.

Table 5 shows the boiling points of ethanol and methoxymethane.

In terms of the intermolecular forces involved, explain the difference in boiling points.

Draw the shape of the POCl₃ molecule and the shape of the ClF₄^– ion. Include any lone pairs of electrons that influence the shapes.

In a POCl₃ molecule the oxygen atom is attached to the phosphorus atom by a double bond that uses two electrons from phosphorus.

Name each shape.

Suggest a value for the bond angle in ClF₄ ̄

Shape of POCl₃ Shape of ClF₄ ̄

Name of shape of POCl₃

Name of shape of ClF₄ ̄

Bond angle in ClF₄ ̄ 11

Isomers X and Y have the molecular formula C₅H₈O

Give the IUPAC name for isomer X.

Explain how and why isomers X and Y can be distinguished by comparing each of their

• boiling points

•¹³C NMR spectra

• infrared spectra.

Use data from Tables A and C in the Data Booklet in your answer.

Which statement is not correct about the trends in properties of the hydrogen halides from HC l to HI ?