Introduction to the Particulate Nature of Matter (SL IB Chemistry)

A sample of pure solid sulfur dioxide was slowly heated from –100 °C, which is below its melting point, to 0 °C, which is above its boiling point. Its temperature is measured every minute and the results are represented on the graph.

SO₂ (s) ....................

Using the graph in part (a), complete the table by comparing the separation and movement of the molecules in regions A to B with those in C to D

Explain why the temperature remains constant between B and C.

Solid iodine has the structure shown below.

Under standard conditions (298.15 K and 100 kPa) it will undergo sublimation

Explain why gaseous iodine occupies a significantly greater volume than solid iodine.

State two physical differences between solid iodine and gaseous iodine.

During the manufacture of a commercial drink, a batch containing water, sugar, dyes and flavouring concentrates became contaminated with an unknown solid during the mixing process.

Once the flavourings have been separated chromatography is used to identify them. The sample was labelled X.

A, B and C are reference flavourings used in this process.

Describe how an increase in temperature affects the movement of particles in a liquid.

Carbon is an element in Group 14.

C₆₀ (s) → C₆₀ (g)

Diamond also sublimes but only above 3800 K.

C_diamond (s) → C (g)

Explain, with reference to their structure and properties, why C₆₀ and diamond sublime at such different temperatures.

0.144 g of C₆₀ is placed in a 100 x 10^-6 m³ container of hydrogen gas at a temperature of 25 °C and a pressure of 100 kPa.

The container is heated to make the C₆₀ and hydrogen gas react. The reaction occurs as shown in the equation.

After the reaction, the container is allowed to cool to 25 °C. The pressure decreases to 20.8 kPa. All of the C₆₀ has reacted. 

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An ink is a mixture of coloured substances dissolved in water.

A sample of ink, K, is known to contain three different coloured substances.

Discuss the use of the following methods to separate the coloured substances in the sample of ink, K.

• chromatography
• crystalisation
• filtration
• fractional distillation
• simple distillation

Chromatography can be used to separate a mixture of ions from different transition element compounds.

Two solutions, Y and Z were placed on a piece of chromatography paper.

Four samples, R, S, T and U, each containing transition element ions, were also placed on the same piece of chromatography paper.

The results of the chromatography are shown.

 

12.2 g of hydrated iron(II) sulfate, FeSO₄.xH₂O were dissolved in acidic solution and made up to a volume of 500 cm³.  A 25.0 cm³ sample of this solution was titrated against 0.0200 mol dm^-3 potassium manganate(VII) solution.  21.95 cm³ of this solution were required.

The following reaction took place:

5Fe²⁺+ MnO₄^- + 8H⁺ → 5Fe³⁺ + Mn²⁺ + 4H₂O

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Krypton is a gas at room temperature. Krypton atoms, are spread far apart and move in a random manner at high speed. Krypton is shipped as a liquid.

Compare the movement and arrangement of the molecules in liquid krypton to those in krypton gas.

A sealed container contains krypton gas. 

Explain why the pressure inside the container increases when the temperature is increased.

Explain why gases expand to fill their containers.