Composition of Air

Q.

An aerosol can contain 400ml of compressed gas at 5.2atm pressure. When gas is sprayed into a large plastic bag, the bag inflates to a volume of 2.14L. What is the pressure of a gas inside the plastic bag?

Q.

A mixture of 95 % oxygen and 5 % carbon dioxide called _____________.

Q.

If you pour water over a sample of soil, you can observe ___ .

1. Nothing is observed.

2. Water changes to water vapour.

3. Bubbles coming out of soil

4. CO₂ gas is released.

Q.

State true or false;
We can survive without greenhouse gases.

1. Carbon dioxide

2. Methane

Q. Mountaineers carry oxygen cylinders with them because :

1. oxygen supports combustion
2. none of these
3. air becomes thinner as we go higher
4. air is denser as we go higher

Q.

Write the composition of air.

Q.

oojho took an empty plastic bottle, turned it upside down and dipped its open mouth into a bucket filled with water. He then tilted the bottle slightly and made the following observations.​

​(i) Bubbles of air came out from the bottle.​

(ii) Some water entered the bottle.​

(iii) Nitrogen gas came out in the form of bubbles and oxygen gets dissolved in water.​

(iv) No bubbles formed, only water entered the bottle​

​Which observations is/are correct?

1. (i) and (ii)
2. (iv) only
3. (iii) and (iv)
4. (i) only

Q. What is the composition of air?

Q.

Which of the non-metal is used as a refrigerant?

1. Nitrogen

2. Chlorine

3. Hydrogen

4. Oxygen

Q.

One litre of a gas weighs $2g$at $300K$and $1atm$ pressure. If the pressure is made $0.75atm$ at what temperatures will one litre of the same gas, weigh one gram?

Q.

Why does a balloon filled with hydrogen gas rise to the ceiling?

Q. The air is a mixture of a number of gases. The major components are oxygen and nitrogen with the approximate proportion of $20$% is to $79$% by volume at $298K$. The water is in equilibrium with air at a pressure of $10$ atm. At $298K$ if the Henry's law constant for oxygen and nitrogen at $298K$ are $3.30\times {10}^{7}mm$ and $6.51\times {10}^{7}mm$ respectively. Calculate the composition of these gases in water.

Q. Usha took a lump of dry soil in a glass and added water to it till it was completely immersed. She observed bubbles coming out. The bubbles contain

1. water vapour
2. only oxygen gas
3. air
4. none of these

Q.

Mention the significance of carbon to living beings.

Q.

Write the chemical properties of nitrogen and its uses.

Q.

What are different constituents of air.

Q. Two forms of oxygen found in the atmosphere are:

1. water and oxygen
2. oxygen and carbon dioxide
3. oxygen and ozone
4. carbon dioxide and water

Q. The percentage of nitrogen in air is:

1. 0.1%
2. 21%
3. 54%
4. 78%

Q. Match Column-I with Column-II and select the correct answer.
$\begin{array}{cc}ColumnI& ColumnII\\ A.Helium& P.Growthofplantsandanimals\\ B.Nitrogen& Q.Signboards\\ C.Neon& R.Weatherballoons\\ D.Argon& S.Electricbulbs\end{array}$

1. A-S, B-R, C-Q, D-P
2. A-S, B-Q, C-R, D-P
3. A-R, B-P, C-Q, D-S
4. A-Q, B-P, C-S, D-R

Q.

___ is the combination of smoke and fog.

Q. Write the composition of air.

Q. The third most abundant gas in Earth's atmosphere is:

1. carbon
2. nitrogen
3. oxygen
4. argon

Q.

What are the main uses of nitrogen ?

Q. Among the gases present in air, which one supports burning of a substance?

1. Oxygen
2. Nitrogen
3. Carbon dioxide
4. Water vapour

Q.

112 cm³ of nitrogen is collected at a pressure of 720 mm of mercury. If the temperature remains constant, find its volume when pressure is:

The pressure drops by 40 % of initial pressure.

Q.

Write true or false for the following statement:
Chips, Namkeen, etc., are generally packed in a nitrogen-free atmosphere.

1. True
2. False

Q. Dinitrogen and dioxygen are main constituents of air, but these do not react with each other to form oxides of nitrogen because:

1. the reaction is endothermic and requires very high temperature
2. the reaction can be initiated only in presence of a catalyst
3. oxides of nitrogen are unstable
4. $N_2$ and $O_2$ are unreactive

Q. Percentage of oxygen in atmosphere of earth is :

1. $35.94$%
2. $25.94$%
3. $20.94$%
4. $42.94$%

Q. Choose the wrong statements.

1. Smoke is present in our atmosphere.
2. There is no smoke present in our atmosphere.
3. Smoke is a mixture of gases and is often harmful.
4. Smoke is a single gas and is often harmful.

Q.

The process of nitrogen-fixation by bacteria does not take place in the presence of:

1. The molecular form of hydrogen

2. The elemental form of oxygen

3. Water

4. The elemental form of nitrogen