Atmosphere

Earth's current atmosphere is

• 78% nitrogen, 21% oxygen, 0.9% argon and 0.037% carbon dioxide
• 78% oxygen, 21%nitrogen, 0.9% argon, 0.037% carbon dioxide
• 78% nitrogen, 21% argon, 1% oxygen
• 78% oxygen, 21% nitrogen, 1% carbon dioxide

The rapid combination between oxygen and the elements producing heat and light is called......

• burning

• respiration

• oxidation

The hydrogen peroxide is decomposed in the presence of manganese dioxide into .......

• water and hydrogen

• water and oxygen

• oxygen and hydrogen

.......gas does not burn ,but it helps in burning.

• Nitrogen

• Oxygen

• Carbon dioxide

Iron oxide is formed as a result of combination between.......

• iron and hydrogen

• iron and oxygen

• iron and carbon dioxide

............is used as a catalyst in the preparation of oxygen in lab .

• Hydrogen peroxide

• Manganese dioxide

• Manganese oxide

Oxygen is collected by the .........

• downward displacement of water

• upward displacement of water

• No correct answer

..........causes corrosion of ironware such as bridges' pillars .

• Iron rusting

• ozone gas

• combustion

Oxygen gas is scacely (rarely) soluble in .........

• hydrogen

• water

• Nitrogen

Oxygen gas is .......than air , so it can replace air.

• heavier

• lighter

• No correct answer