Science NWIS 6.1,6,2 Revision

Why does the powdering of calcium carbonate increase the speed of its reaction with an acid?

• It increases the mass of calcium carbonate.

• It increases the surface area of the calcium carbonate

• The powder becomes more concentrated.

• The powder floats on top of the acid.

What does the symbol ⇌ mean?

The solvent ethanol is produced by the formation of sugar, using yeast. Which graph correctly shows how the speed of fermentation changes with temperature?

• A

• B

• C

• D

Oxygen is formed when manganese (IV) oxide is added to hydrogen peroxide, H2O2. 2H2O2→ 2H2O + O2 In this reaction, manganese (IV) oxide acts as

• acid

• base

• catalyst

• drying agent

1. When lumps of calcium carbonate react with hydrochloric acid, carbon dioxide gas is released. CaCO3(s) + 2HCl(aq) → CaCl2 (aq) + CO2 (g) + H2O(l) what will the following have on the rate of reaction , Increasing temp

• None of the above

• Slower

• Faster

Which changes of condition slow down the reaction between magnesium and air? 1. Heating the magnesium to a higher temp, 2. using a higher proportion of oxygen in the air, 3. using magnesium ribbon instead of powdered magnesium

• 1

• 2

• 3

• all of the above

How many elements are in the periodic table?

2. When lumps of calcium carbonate react with hydrochloric acid, carbon dioxide gas is released. CaCO3(s) + 2HCl(aq) → CaCl2 (aq) + CO2 (g) + H2O(l) what will the following have on the rate of reaction , adding water to the acid

• faster

• heavier

• slower

• evaporation

Pure zinc sulphate can be prepared by adding an excess of either zinc carbonate or an excess of zinc hydroxide to dilute sulphuric acid. In which form are these zinc compounds used?

• A

• B

• C

• D

Some students investigate the effect of temperature on the rate of the reaction of sodium thiosulfate solution with hydrochloric acid. The students make some predictions. Give the name of the person whose prediction includes a scientific explanation.