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Acids and alkalis

The pH scale and indicators

The pH scale and indicators

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Tutor: Alexander

Summary

The pH scale and indicators

In a nutshell

The pH scale shows whether a solution is acidic or alkaline and the degree of acidity and alkalinity. An indicator is something that changes colour based on the solution's pH. 



The pH scale​​

  • The pH scale ranges from 000​ to 141414​​
  • A pH of 777​ is neutral
  • Acids range from 000​ to 777​, with closer to 000​ being more acidic
  • Alkalis range from 777​ to 141414​, with closer to 141414​ being more alkaline


Science; Acids and alkalis; KS3 Year 7; The pH scale and indicators
1.
More acidic
2.
Neutral
3.
More alkaline



Indicators change colour depending on pH

Litmus paper is a common indicator and can tell whether a solution is an acid or alkali but not the how strong it is. Acid turns litmus paper red and alkalis turn it blue. 


Science; Acids and alkalis; KS3 Year 7; The pH scale and indicators
1.
Litmus paper strips
2.
Acidic litmus test result
3.
Alkaline litmus test result


Universal indicator shows us whether a solution is acidic or alkaline and how strong it is. The colour given by universal indicator matches that of the pH chart. 

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Properties of the three states of matter

Unit 1

Properties of the three states of matter

Physical and chemical properties

Unit 2

Physical and chemical properties

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The pH scale and indicators

Unit 3

The pH scale and indicators

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FAQs - Frequently Asked Questions

What does the pH scale show?

The pH scale shows the acidity / alkalinity of a solution.

What is the pH range for acids?

The pH of acids ranges from 0 to 7.

What is the range for the pH scale?

The pH scale ranges from 0 - 14.

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