New
New
Year 10
OCR
Foundation

Adapting a multistep chemical procedure for making a pure dry salt

I can describe and explain adaptations to a multistage chemical procedure to alter or improve the quality of the product.

New
New
Year 10
OCR
Foundation

Adapting a multistep chemical procedure for making a pure dry salt

I can describe and explain adaptations to a multistage chemical procedure to alter or improve the quality of the product.

Lesson details

Key learning points

  1. Gently heating the acid speeds up the reaction, ensuring all acid reacts.
  2. The salt should be dried using an appropriate method (using filter paper, or in the oven).
  3. A pure sample should be prepared with equipment washed with distilled water to avoid contamination.
  4. Reacting a metal hydroxide with an acid also produces a salt and water.
  5. Reacting a metal carbonate with an acid can produce a desired salt with water, as well as carbon dioxide gas.

Common misconception

Pupils can sometimes mistake the excess base for the salt formed as it is a solid.

Emphasise at the beginning of the experiment what soluble means and that the salt will be initially obtained dissolved in water.

Keywords

  • Method - Describes how an experiment is carried out; it is a step-by-step procedure.

  • Apparatus - A piece of equipment that is designed for a particular use.

  • Evaluate - To evaluate something is to make a judgement about it with respect to a particular purpose.

  • Adapt - To make suitable for use or purpose, e.g. equipment or steps in an experimental procedure.

Get the pupils to explain to each other why they are performing each step of the method. They need to understand why each step is performed.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
What is a pure salt formed in a chemical reaction?
two reactants of the reaction
two products of the reaction
the salt that has been made dissolved in water
Correct answer: a solid sample of the salt that has been made
Q2.
The chemical reaction between an acid and a metal oxide, which makes a salt and water, is an example of a reaction.
Correct Answer: neutralisation, neutralization
Q3.
How do we know for sure that the reaction between an acid and an insoluble metal oxide is complete?
there is no fizzing
there is some insoluble metal oxide on the bottom of the reaction vessel
Correct answer: pH paper dipped into the solution shows pH7
the colour of solution does not change when more insoluble metal oxide is added
Q4.
What is the general name given to a solid caught in filter paper after a filtration?
An image in a quiz
Correct Answer: residue
Q5.
Evaporating water from a salt solution to leave a pure salt is called .
Correct Answer: crystallisation, crystallising, crystallization, crystallizing
Q6.
Match the following words, used to describe how to make pure salt samples, to their definitions.
Correct Answer:crystallisation,forming solid crystals from saturated solution by evaporating solvent

forming solid crystals from saturated solution by evaporating solvent

Correct Answer:filtration,a technique to separate insoluble solids from a liquid mixture

a technique to separate insoluble solids from a liquid mixture

Correct Answer:insoluble,when a substance does not dissolve in a particular solvent

when a substance does not dissolve in a particular solvent

Correct Answer:neutralisation,reaction of acid and base, producing solution of metal salt and water

reaction of acid and base, producing solution of metal salt and water

Correct Answer:precipitate,an insoluble solid formed when two solutions react together

an insoluble solid formed when two solutions react together

6 Questions

Q1.
What is the pH of a base?
less than 7
exactly 7
close to 7
Correct answer: more than 7
Q2.
What are the products of a reaction between a metal carbonate and an acid?
salt + water
Correct answer: salt + water + carbon dioxide
salt + water + hydrogen carbonate
salt + water + metal
Q3.
What are the main steps required to produce a pure salt when reacting a soluble base (alkali) with an acid?
Correct answer: crystallisation
distillation
filtration
heating
Correct answer: neutralisation
Q4.
What are the main steps required to produce a pure salt when reacting an insoluble base with an acid?
Correct answer: crystallisation
distillation
Correct answer: filtration
heating
Correct answer: neutralisation
Q5.
Adding an insoluble base to an acid in helps make sure that all of the acid has reacted to produce a neutral solution.
Correct Answer: excess, in excess
Q6.
What helps to ensure that the salt produced in a reaction between an insoluble base and an acid is very pure?
Correct answer: using pH paper to confirm the solution made is neutral
testing the melting point of the salt produced
Correct answer: washing all glassware with distilled water before use
adjusting the pH by adding acid drop by drop near the neutralisation point
Correct answer: avoiding overfilling filter paper