Topic 4 Acids and alkalis Flashcards Preview

Edexcel GCSE Combined Science (Chemistry) HIGHER > Topic 4 Acids and alkalis > Flashcards

Flashcards in Topic 4 Acids and alkalis Deck (70)
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1

1. What term describes a substance that attacks metals, stonework and skin?

corrosive

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2. Name an acidic solution found in the kitchen.

vinegar or fruit juice, etc.

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3. Name an alkaline solution used in the kitchen.

bleach or oven cleaner or soap, etc.

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4. What type of substance turns litmus paper red?

acid

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5. How does an indicator show the acidity or alkalinity of solutions?

by changing colour

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6. What pH values represent alkaline solutions?

above 7 or 8 to 14

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7. What happens in all chemical reactions?

new substances are formed

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8. What kind of reaction occurs between an acid and an alkali?

neutralisation

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9. What do you call a solution that is neither acidic nor alkaline.

neutral

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10. Give the name and formula of a common laboratory acid.

hydrochloric acid (HCl) or nitric acid (HNO3) or sulfuric acid (H2SO4), etc.

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11. Which ion is in excess in all acidic solutions?

hydrogen ions or H+ ions

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12. Which ion is in excess in all alkaline solutions?

hydroxide ions or OH ions

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13. What scale is used for measuring acidic and alkaline properties?

the pH scale

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14. Name three examples of acid/alkali indicators apart from universal indicator.

litmus, methyl orange and phenolphthalein

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15. What would you use to measure pH to one decimal place?

a pH meter

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16. What pH values are acidic?

below 7

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17. What colour is phenolphthalein in a solution with a pH of 2?

colourless

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18. What happens to the pH as the H+ ion concentration increases?

it decreases

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19. If a solution has the same concentration of hydrogen ions as hydroxide ions, how is it described?

neutral or pH = 7

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20. If 2 g of salt is dissolved in 250 cm3 of solution, what is its concentration in g dm–3?

8 g dm–3

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21. What word describes a solution that contains a large amount of solute in a small volume of solvent?

concentrated

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22. How can a solution be made more dilute?

by adding solvent/water

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23. If 24 g of acid is dissolved in 600 cm3 of solution, what is its concentration in g dm–3?

40 g dm–3

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24. What happens when strong acid molecules dissolve in water?

they dissociate completely into ions

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25. What kind of reaction occurs between an acid and a base?

neutralisation

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26. What happens to the pH of an acid as it reacts with a neutraliser?

pH increases

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27. What is formed when an acid reacts with a base like a metal oxide?

salt + water

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28. What acid would be used to make zinc sulfate from zinc oxide?

sulfuric acid (sulphuric acid makes sulphates!)

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29. What process can be used to separate an insoluble solid from a liquid?

filtration

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30. How can a sample of a dissolved salt be obtained from a salt solution?

evaporation of the water