Acidic foods can be identified by what taste?
salty
sour
bitter
sweet
A beaker full of acid is steadily added to a beaker full of base. The pH of the base will:
increase
decrease
stay the same
change constantlly
Which substance has the lowest pH?
milk
pure water
soap solution
lemon juice
An unknown substance is added to a solution and the pH increases. The substance is:
acidic
neutral
alkaline
a solvent
A piece of magnesium is dropped into a test-tube containing dilute hydrochloric acid.
Why does the test-tube become warm?
A. Hydrogen is produced.
B. The magnesium neutralises the acid.
C. The reaction is endothermic.
D. The reaction is exothermic.
The diagram shows an experiment to compare the speed of reaction when limestone chips are added to acid.
In which test-tube is the reaction most rapid?
A.
B.
C.
D.
Which element reacts with dilute sulphuric acid to produce hydrogen?
A. carbon
B. chlorine
C. copper
D. zinc
For which pH change is there the largest increase in acidity?
The diagram shows how hydrated copper(II) sulfate crystals can be made by reacting copper(II) oxide with dilute sulfuric acid.
Why is the sulfuric acid heated in stage 1?
A. So it will react faster with the copper (III) sulfate crystals.
B. Because copper (III) sulfate crystals will not react with cold dilute sulfuric acid.
C. To make the copper (III) sulfate crystals dissolve faster.
D. So that more copper (III) sulfate can dissolve.
Why do crystals form when the hot saturated solution is cooled in stage 5?
A. Because the solubility of copper(iii) sulfate increases with temperature.
B. Because the solubility of copper(iii) sulfate decreases with temperature.
C. Because the solubility of copper(iii) sulfate decreases with temperature, and some copper (iii) sulfate will start to precipitate as the mixture cools.
D. Because the copper(II) sulfate and sulfuric acid molecules need to slow down before they can have successful collisions.
Which type of reaction always forms a salt and water?
A. exothermic
B. neutralisation
C. oxidation
D. decomposition
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