C3 Acids & Bases OCR Gateway (9-1)

  • Created by: Aleena
  • Created on: 11-04-18 18:47
What is an Acid?
A substance that has a pH less than 7 and forms hydrogen ions in water
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Hydrogen ions are also called?
Protons
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What is a Base?
Chemicals which can neutralise acids to produce a salt & water.Also, they have a pH greater than 7.
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What is an Alkali?
Bases that are soluble in water & produce hydroxide ions in an aqueous solution(i.e.when in water forms OH- ions)
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What state symbol do we use for Acids & Alkalis in chemical equations?
(aq)
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What is the relationship between the pH value & the hydrogen ions concentration?
The pH value is inversely proportional to the hydrogen ions concentration. As the pH decreases, hydrogen ions concentration increases-becomes more acidic
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What are the 2 ways you can measure the pH of a solution?
Use universal indicator or a pH probe attached to a pH meter
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How would you measure pH value using Universal Indicator?
Add few drops of universal indicator to the solution & compare the colour formed in solution to a pH chart for the universal indicator-which tells you the corresponding pH
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How would you measure pH value using a pH probe attached to a pH meter?
This technique measures the pH electronically. wash the pH probe with deionised water put the end of the probe into the solution record the reading(numerical value) on the pH meter
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Which of these 2 methods is more accurate way of measuring the pH value of a solution?
The pH probe because indicator gives a colour which have to use to judge the pH , this might vary for different people as different people have different quality of vision, so pH value can differ
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When using the pH probe what 2 things must you always do?
Make sure probe is calibrated correctly by setting it to read pH 7 in a sample of pure water & rinse the probe with deionised water in between readings
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What happens during Neutralisation?
An acid & a base react to form a salt and water - which neutralises them
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What are the proportions of the concentration of hydrogen and hydroxide ions at pH 7?
at pH 7 the concentration of hydrogen ions equals the concentration of hydroxide ions
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Why do we carry out Titrations?
Titrations are used to work out how much of an acid is used to neutralise a base of an unknown concentration(or vice versa).
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What type of graph shows Neutralisation?
Titration curves are used to show where neutralisation happens during a titration. There's a vertical point in the curve which is where the solution is neutral-this is called the end point of the titration
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Give some examples of bases?
Copper Oxide and Iron(III) Hydroxide
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Give an example of an alkali?
Sodium Hydroxide
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Salts contain Anions and Cations.Where does the salt get the 2 ions from?
Salts get Cations from the alkali/base. Salts get Anions from the acid.
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What ions does hydrochloric acid produce?
Chloride ions
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What ions does sulfuric acid produce?
Sulfate ions
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What ions does nitric acid produce?
nitrate ions
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Other cards in this set

Card 2

Front

Hydrogen ions are also called?

Back

Protons

Card 3

Front

What is a Base?

Back

Preview of the front of card 3

Card 4

Front

What is an Alkali?

Back

Preview of the front of card 4

Card 5

Front

What state symbol do we use for Acids & Alkalis in chemical equations?

Back

Preview of the front of card 5
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