Molecules

Q. (a) What is the difference between monatomic ions and polyatomic ions?
(b) Give two examples of trivalent metal ions.

Q. The ratio by mass of hydrogen and oxygen atoms in a water molecule is:

1. $1:2$
2. $1:8$
3. $2:1$
4. $1:16$

Q.

The atomicity of a compound ${\text{C}}_{\text{a}}{\text{H}}_{\text{b}}$ is 6. If the ratio of carbon and hydrogen in the given compound is 1:2, then its empirical and molecular formula is _____ and ______ respectively.

Q.
Differentiate between molecular mass and formula unit mass.

Q. Can one atom be called an element also? Can one molecule having more than one type of atom be called a compound also?

Q. Question 4 (ii)
How many atoms are present in a:
$\left(ii\right)P{O}_4^{3-}ion$

Q. What is the molecular mass of carbon dioxide?

Q.
Differentiate between molecular mass and formula unit mass.

Q.

The mass ratio of hydrogen to oxygen in water is :

1. 1:8

2. 8:1

3. 2:3

4. 3:2

Q. Name the separation techniques that you will apply for the separation of following mixtures?

(i) Small dirt pieces from grain seeds
(ii) Paddy seeds from stalks
(iii) Fine mud particles in water
(iv) Potassium chloride and ammonium chloride
(v) Common salt and water
(vi) Wheat grains from husk
(vii) Small pieces of metal in the engine oil of a car
(viii) Draining water from a pot of noodles
[8 Marks]

Q.

(a) What is the significance of a chemical formula?

(b) Define polyatomic ions with an example?

Q. How many atoms are present in one molecule of ozone?

Q. What is the molecular mass of carbon dioxide?

Q. Burst the bubble for the molecules having atomicity 2

1. HCl
2. $P_4$
3. He
4. $O_3$
5. $H_2$
6. CO
7. $C{l}_2$
8. FeO

Q.

(a) What is the significance of a chemical formula?

(b) Define polyatomic ions with an example?

Q.

Which of the following exists as molecules?

(i) Oxygen gas

(ii) Argon

(iii) Ammonia

(iv) Helium

(v) Water

(vi) Sugar

1. i, iii, v, vi
2. i, iv, ii
3. iii, v, vi
4. ii, iv, v

Q. The valency of Argon is
[TEXTBOOK QUESTION- I(5)]

Q. Calculate the molar mass of Ethyne ( $C_2{H}_2$).

Q. Burst the bubble for the molecules having atomicity 2

1. HCl
2. $P_4$
3. He
4. $O_3$
5. $H_2$
6. CO
7. $C{l}_2$
8. FeO

Q.

Which of the following exists as molecules?

(i) Oxygen gas

(ii) Argon

(iii) Ammonia

(iv) Helium

(v) Water

(vi) Sugar

1. i, iii, v, vi
2. i, iv, ii
3. iii, v, vi
4. ii, iv, v

Q.

Which of the following exists as molecules?

(i) Oxygen gas

(ii) Argon

(iii) Ammonia

(iv) Helium

(v) Water

(vi) Sugar

1. iii, v, vi
2. i, iv, ii
3. i, iii, v, vi
4. ii, iv, v

Q. Is it true that atoms form molecules, molecules form elements/compounds

Q.

Assertion: Chlorine is an element.​
Reason: Chlorine is made up of different kinds of atoms.​

1. Both (A) and (R) are true and, (R) is not the correct explanation of (A).​
2. (A) is false, but (R) is true.​
3. (A) is true, but (R) is false.​

4. Both (A) and (R) are true and (R) is the correct explanation of (A).​

   ​

Q. Which amongst the following pairs is not an example of molecule?

1. Oxygen gas and water
2. Sodium and potassium
3. Oxygen gas and ammonia
4. Hydrochloric acid and water

Q. Explain:
The basic unit of an element is atom, whereas the basic unit of a compound is molecule.