Tag: chemistry

Quizzes (490) Questions (9892)

Questions Related to chemistry

Multiple choice chemistry air and atmosphere natural cycles and resources constituents of air component of air - nitrogen

Which of following statements is true?

  1. The salinity of rivers increases with time

  2. The salinity of rivers decreases with time

  3. The salinity of seas increases with time

  4. The salinity of seas decreases with time
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A falling of rain on earth causes breaking up of rocks and transferring their minerals to the ocean, the ocean becomes saltier and by evaporation, water evaporates leaving salt in the oceans.


So, by this, we can say that salinity of increases with time.

Hence, the correct option is $\text{C}$

Multiple choice chemistry air and atmosphere natural cycles and resources constituents of air component of air - nitrogen

Almost all the water on the earth is contained in the:

  1. seas and oceans

  2. rivers, lakes, ice caps

  3. as ground water and in the atmosphere

  4. all of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Almost all the water on the earth is contained in the oceans, seas, rivers, lakes, ice caps, as ground water and in atmosphere as water vapour.

Option (D) is the correct answer.

Multiple choice chemistry air and atmosphere natural cycles and resources constituents of air component of air - nitrogen

The main source of water for perennial rivers is in the form of:

  1. lakes

  2. rain water

  3. snow

  4. dams
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Perennial rivers flows continuously throughout the year irrespective of seasons. Mostly they originates from the mountain and water is fed by melting of glaciers. These river get water by rain in rainy season, melting of ice in summer and by snow in winter.

Multiple choice chemistry air and atmosphere natural cycles and resources constituents of air component of air - nitrogen

Which of the following elements would give water on burning?

  1. Hydrogen

  2. Oxygen

  3. Carbon

  4. Nitrogen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In a flame of pure hydrogen gas, burning in air, the hydrogen (H$ _2$) reacts with oxygen (O$ _2$) to form water (H$ _2$O) and releases energy. If carried out in atmospheric air instead of pure oxygen, as is usually the case, hydrogen combustion may yield small amounts of nitrogen oxides, along with the water vapour.


Hence, the correct option is $\text{A}$

Multiple choice chemistry water and air and their importance natural cycles and resources constituents of air component of air - nitrogen

All the plants require nitrogen for:

  1. reproduction

  2. photosynthesis

  3. transpiration

  4. growth
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
All the plants require nitrogen for growth. Nitrogen is found in healthy soils and give plants the energy to grow and produce fruit or vegetables. Nitrogen is part of the chlorophyll molecule, which gives plant their green colour and is involved in  creating food for the plant through photosynthesis.
So, the correct answer is 'growth'
Multiple choice chemistry water and air and their importance natural cycles and resources constituents of air component of air - nitrogen

Gas used as a refrigerant is:

  1. Nitrogen

  2. Oxygen

  3. Hydrogen

  4. Water gas
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

NITROGEN is used as a refrigerant. Nitrogen is a liquid at temperatures below 196.5 C and is used as a refrigerant for such things as preservation of blood and cooling of large computer systems, as well as some industrial uses. Being a liquid, it is more convenient to use for low temperature cooling than dry ice. Liquid nitrogen is also used in oil wells to build up pressure in order to force crude oil upward.