atmospheric air

the percentage of oxygen gas in the atmosphere is ..........................

• 12%

• 78%

• 21%

• 33%

the most abundant gas in the atmosphere is ................. gas.

• oxygen

• carbon dioxide

• nitrogen

• water vapor

The least percentage in the atmosphere is a mixture of ......................

• oxygen and carbon dioxide

• carbon dioxide, water vapour and other gases.

• nitrogen

• sulfur

which of the following gases is not part of the atmospheric air?.........................

• oxygen

• nitrogen

• carbon dioxide

• ammonia

The atmosphere protect the earth, because .....................

• it absorbs infrared rays

• it has oxygen gas

• it absorbs ultraviolet radiation

• it has oxygen gas

the chemical substance that decomposes into water and oxygen.

• hydrogen peroxide

• hydrogen chloride

• calcium carbonate

• manganese dioxide

what is the scientific term?

the chemical substance remains without any change in its quantity and properties during the chemical reaction.

• reactant

• product

• catalyst

• acid

oxygen is collected by..................

• upward displacement of air

• upward displacement of water

• downward displacement of water

oxygen ...................... dissolves in water

• rarely

• always

• on Saturdays

• only

when lightened magnesium ribbon is inserted in a cylinder filled with oxygen

• white matter is produced

• grey matter is produced

• green matter is produced

• yellow matter is produced