Oxygen

Q.

How can you show that exhaled air contains more water vapor than fresh air?

Q. How much percentage of oxygen is present in the air which we breath out?

1. 21%
2. 10%
3. 16%
4. 30%

Q.

Hydrogen is taken as the standard reference for measuring the atomic mass unit.

1. True

2. False

Q.

What is the percentage of oxygen present in the earth’s atmosphere?

1. 15%

2. 21%

3. 18%

4. 26%

Q.

Joseph Priestley Performed an Experiment in Which - Fill in the Blank - Was Heated By Focusing Sun Rays On It Using a Convex Lens

Q. Dioxygen is a blue-colored gas and is very essential for life.

1. True
2. False

Q. Name of natural indicator ?
chemical formula of Rust iron?

Q.

Oxygen cylinders are used by fire fighters, deep-sea divers, miners, etc. Why?

Q. A compound has vapour density 29. On warming with a solution of iodine in alkali, it gives a yellow precipitate, the compound is---- 1. CH3CH2CHO 2. CH3COCH3 3. CH3CHOHCH3 4. CH2CH2CH2Br

Q.

The person who gave oxygen its name is ……….

Q.

Which of the following property is incorrect about oxygen?

1. Colourless

2. Poisonous gas

3. Heavier than air

4. Odourless

Q.

Oxygen is a chemically active gas.

1. True
2. False

Q.

Who was the first scientist who named the oxygen gas?

1. William Scheele
2. Priestley
3. Antoine Lavoisier
4. None of the above

Q.

Scuba divers carry cylinders with them. Is it necessary for them?

1. Yes

2. No

Q. <!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}--> How are alkaline pyrogallol solution and nitric oxide used to test the presence of oxygen?

Q.

Name the following:

Two sources of occurrence of carbon dioxide.

Q. Joseph Priestley discovered oxygen.

1. True
2. False

Q.

what is the colour of lead oxide

Q. As many as ______ different combinations of water are possible from $H_1^1,H_1^2,H_1^3,O_8^{16},O_8^{17},O_8^{17}$ ?

1. $16$
2. $5$
3. $18$
4. $24$

Q.

In rocks, oxygen is combined with _______ and _______ in the form of oxides.

Q.

Oxygen on liquefication gives bluish liquid at -187^{\circ} C.

1. True

2. False

Q.

28. Why do sea divers carry oxygen cylinders with them?

Q. The proportion of oxygen in the atmosphere is maintained by:

1. plants
2. machines
3. animals
4. human beings

Q.

Which alkaline earth metal is formed by the decay of uranium?

1. Beryllium

2. Strontium

3. Radium

4. Barium

Q.

Write a note on the discovery of carbon dioxide and its occurrence.

Q. What is tidal volume?

Q.

Which gas in air is essential for respiration?

1. Oxygen

2. Nitrogen

3. Carbon dioxide

4. Carbon monoxide

Q.

what is the significance of atomic number in classification element give me answer dont give me link

Q. Which one of the following elements is not detected by Lassaigne's test?

1. Sulphur
2. Nitrogen
3. Oxygen
4. Chlorine

Q. What is magnesium oxide and calcium carbonate?