Grade 4 Science Quiz

Which processes decrease the amount of carbon dioxide in the air?

• burning fossil fuels

• photosynthesis in plants

• respiration in animals

• respiration in plants

What is a harmful effect of an increase in carbon dioxide in the atmosphere?

• It allows more heat from the Sun to enter the Earth's atmosphere.

• It decreases the rate at which organisms respire.

• It increases the rate at which plants photosynthesize.

• It prevents reflected heat from leaving the Earth's atmosphere.

The equation for the reaction between zinc and dilute hydrochloric acid is Zn + 2HCl → ZnCl₂ + H₂. What is the volume of hydrogen gas produced by 3.25 g of zinc?

• 1.2 dm³

• 2.4 dm³

• 4.8 dm³

• 24.0 dm³

Which metal can only be extracted by electrolysis of a molten compound?

• copper

• sodium

• iron

• zinc

In which test-tube does the iron nail rust most quickly?

• boiled water

• tap water

• pure oxygen gas

• iron

During the manufacture of sulfuric acid by the Contact process, sulfur trioxide is produced. The sulfur trioxide is dissolved in concentrated sulfuric acid. Which statement explains why sulfur trioxide is not dissolved in water?

• The reaction is too endothermic.

• The reaction is too exothermic.

• The reaction is too slow.

• The reaction needs a high pressure.

Which statement describes the properties of solid metals?

• They are brittle and good thermal conductors.

• They are brittle and poor thermal conductors.

• They are malleable and good thermal conductors.

• They are malleable and poor thermal conductors.

Sulfur dioxide, nitrogen monoxide and carbon monoxide are common pollutants in air. Which row shows a method of reducing the emissions of these pollutants into the air?

• A

• B

• C

• D

Aluminium oxide, Al2O3, nitrogen monoxide, NO, and sulfur trioxide, SO3, are each tested with dilute hydrochloric acid and with aqueous sodium hydroxide. Which oxides are neutral oxides?

• Al2O3 and NO

• Al2O3 and SO3

• NO only

• SO3 only

Zinc oxide is an insoluble base. It reacts with dilute hydrochloric acid to produce zinc chloride. Zinc chloride is soluble in water. Which statement about the preparation of zinc chloride crystals is correct?

• Once the reaction is complete there is no need to filter the reaction mixture.

• The reaction mixture is neutral at the point that no more zinc oxide reacts.

• Zinc chloride crystals are obtained by evaporation to dryness.

• Zinc chloride precipitates when the solution becomes neutral.