Use of Techniques, Apparatus and Materials

Barium carbonate decomposes when heated. The word equation for the reaction is shown.

$$\text{barium carbonate} \rightarrow \text{barium oxide} + \text{carbon dioxide}$$

Plan an experiment to determine the percentage loss in mass when barium carbonate is heated.

Your plan must include the use of common laboratory apparatus and a sample of barium carbonate. No other chemicals should be used.

Your plan must include:

• the apparatus needed
• the method to use and the measurements to take
• procedures to ensure that the percentage determined is as accurate as possible
• how the measurements are used to determine the percentage loss in mass.

You may draw a diagram to help answer the question.

Copper(II) carbonate reacts with dilute sulfuric acid at room temperature.

The word equation for the reaction is shown.

$$\text{copper(II) carbonate} + \text{sulfuric acid} \rightarrow \text{copper(II) sulfate} + \text{carbon dioxide} + \text{water}$$

Plan an experiment to determine the volume of carbon dioxide formed when a known mass of copper(II) carbonate completely reacts with dilute sulfuric acid.

Your plan must include the use of common laboratory apparatus, dilute sulfuric acid and copper(II) carbonate. No other chemicals should be used.

Your plan must include:

• the apparatus needed
• the method to use and the measurements to take
• procedures to ensure that the volume measured is as accurate as possible.

You may draw a diagram to help answer the question.

Argentan is an alloy containing only zinc, nickel and copper.

Zinc and nickel both react with dilute hydrochloric acid. Copper does not react with dilute hydrochloric acid.

Plan an investigation to find the percentage by mass of copper in a powdered sample of argentan.

Your plan must include the use of common laboratory apparatus, argentan and dilute hydrochloric acid. No other chemicals should be used.

Your plan must include:

• the apparatus needed
• the method to use and the measurements to take
• procedures to ensure that the percentage determined is as accurate as possible
• how the measurements are used to determine the percentage by mass of copper in the sample.

You may draw a diagram to help answer the question.

Baking soda is used to make bread rise. When baking soda is heated, it decomposes and carbon dioxide gas is released.

Baking soda also decomposes gradually when it is stored. The longer the baking soda is stored, the less carbon dioxide it releases when it is heated.

Plan an investigation to show which of two different samples of baking soda has been stored for longer.

Your plan should include the use of common laboratory apparatus and the two samples of baking soda. No other chemicals should be used.

Your plan should include:

• the apparatus needed
• the method to use
• the measurements to take
• the variables to control
• how to use the results to determine which sample has been stored for longer.

You may draw a diagram to help you answer the question.

Ammonium sulfate is a salt used in fertilisers.

Ammonium sulfate is prepared by neutralising dilute sulfuric acid with aqueous ammonia.

Plan an experiment to prepare pure dry crystals of ammonium sulfate.

Your plan should include the use of:

• common laboratory apparatus
• dilute sulfuric acid
• aqueous ammonia
• methyl orange indicator.

No other chemicals should be used.

Your plan should include:

• the apparatus needed
• the method to use.

You may draw a diagram to help answer the question.

Copper(II) sulfate is a salt used to kill pests on plant leaves.

Copper(II) sulfate is prepared by neutralising dilute sulfuric acid with solid copper(II) oxide.

Plan an experiment to prepare pure dry crystals of copper(II) sulfate.

Your plan should include the use of:

• common laboratory apparatus
• dilute sulfuric acid
• solid copper(II) oxide.

No other chemicals should be used.

Your plan should include:

• the apparatus needed
• the method to use.

You may draw a diagram to help answer the question.

A student has three colourless organic liquids, W, X and Y.

One is an alkene, one is an alcohol and one is a carboxylic acid but the student does not know which liquid is which.

Describe a series of tests to determine which liquid, W, X or Y, is the alkene, which is the alcohol and which is the carboxylic acid.

Each liquid must be identified by a positive test.

You are provided with:

• separate samples of liquids W, X and Y
• acidified aqueous potassium manganate(VII)
• aqueous bromine
• solid calcium carbonate
• the apparatus normally found in a school laboratory.

In your answer include:

• a description of the tests
• the apparatus needed for the tests
• how the results of the tests are used to identify W, X and Y
• a safety risk that is involved in doing one of the tests and a precaution to avoid the risk.

Calcium carbonate reacts with dilute hydrochloric acid to form carbon dioxide gas.

Describe an experiment to follow the rate of reaction between calcium carbonate and $25\,\text{cm}^3$ $0.10\,\text{mol / dm}^3$ hydrochloric acid at room temperature.

Your method must include the collection of carbon dioxide gas.

You are provided with:

• $2\,\text{g}$ of small pieces of calcium carbonate (an excess)
• $25\,\text{cm}^3$ $0.10\,\text{mol / dm}^3$ hydrochloric acid
• the apparatus normally found in a school laboratory.

Your answer should include:

• a method
• the measurements you need to make during your experiment
• how you will process your results.

You may use a labelled diagram to help explain the method.