Keywords: Making salts, Metals, Acids, IGCSE, Prescribed Practical, Soluble salts, Insoluble salts, Filtration, Evaporation, Crystallization, Bunsen burner

Introduction: Making salts is an important part of chemistry, and there are several methods that can be used to produce different salts. In this practical investigation, we will be reacting different metals with acids to produce different salts. The two types of salts that will be produced are soluble salts and insoluble salts. A pure, dry sample of each type of salt will be produced using different methods.

Equipment:

Bunsen burner Test tubes Metal strips (e.g. zinc, iron, copper) Dilute hydrochloric acid Dilute sulfuric acid Sodium carbonate solution Filter paper Funnel Evaporating dish Tripod stand Gauze mat Crystallizing dish Glass rod

Method – Producing a Pure Dry Sample of a Soluble Salt:

• Place a metal strip in a test tube.
• Add enough dilute hydrochloric acid to cover the metal.
• Heat the test tube gently using a Bunsen burner.
• When the metal has dissolved, add sodium carbonate solution to the test tube until the fizzing stops.
• Filter the mixture using filter paper and a funnel.
• Collect the filtrate in an evaporating dish and heat gently to evaporate some of the water.
• Once some water has evaporated, allow the rest of the water to evaporate slowly in a warm place until crystals start to form.
• Transfer the crystals to a crystallizing dish and leave to dry.

Method – Producing a Pure Dry Sample of an Insoluble Salt:

• Place a metal strip in a test tube.
• Add enough dilute sulfuric acid to cover the metal.
• Heat the test tube gently using a Bunsen burner.
• When the metal has dissolved, filter the mixture using filter paper and a funnel.
• Collect the filtrate in an evaporating dish and heat gently to evaporate some of the water.
• Allow the rest of the water to evaporate slowly in a warm place until crystals start to form.
• Transfer the crystals to a crystallizing dish and leave to dry.

Calculations and Expected Findings: The expected findings from this investigation are that different metals will react with acids to produce different salts. Soluble salts will be produced using sodium carbonate solution to remove any excess acid and insoluble salts will be produced by filtering the mixture to remove excess acid. The purity of the samples can be assessed by checking their melting points against the expected values.

Conclusion: The results of this investigation demonstrate that different metals can be reacted with acids to produce different types of salts. Soluble salts can be produced by adding a carbonate to remove excess acid, while insoluble salts can be produced by filtering the mixture to remove excess acid. The purity of the samples can be assessed by checking their melting points. This technique has important applications in many areas of chemistry.

Questions:

1. What is a salt?
2. What is the difference between a soluble salt and an insoluble salt?
3. How are soluble salts produced?
4. How are insoluble salts produced?
5. How can the purity of a salt sample be assessed?

Answers:

1. A salt is a compound formed by the reaction of an acid with a base.
2. A soluble salt is a salt that dissolves in water, while an insoluble salt is a salt that does not dissolve in water.
3. Soluble salts are produced by reacting a metal with an acid and then adding a carbonate to remove excess acid.
4. Insoluble salts are produced by reacting a metal with an acid and then filtering the mixture to remove excess acid.
5. Melting point analysis and flame tests.

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