Atoms and Molecules Test

Result

Atoms and Molecules Test - 18

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Which has maximum number of atoms?

A
24 g of C (12)

B
56 g of Fe (56)

C
27 g of Al (27)

D
108 g of Ag (108)

Solution

12 g of C contains $$N_A$$ number of atoms.
Therefore, 24 g of C contains 2$$N_A$$ number of atoms.

Similarly, 56 g of Fe, 27 g of Al and 108 g of Ag contain $$N_A$$ number of atoms.

Therefore, maximum number of atoms is present in 24 g of C.
Question 2
1 / -0

Avogadro's number is the number of molecules present in:

A
1 g of molecule

B
1 atom of molecule

C
1 mole

D
1 litre of molecule

Solution

The Avogadro constant is defined as the number of constituent particles per mole of a given substance. It is equal to $$6.022\times 10^{23}$$.
Question 3
1 / -0

Cation and anion present (if any) in NaCl is :

A
Anion: $$Cl^{2-}$$ Cation: $$Na^+$$

B
Anion: $$Cl^{-}$$ Cation: $$Na^{2+}$$

C
Cation: $$Cl^{-}$$ Anion: $$Na^+$$

D
Anion: $$Cl^{-}$$ Cation: $$Na^+$$

Solution

Separate the compound into its cation and anion.
$$NaCl \rightarrow Na^+ + Cl^-$$
Cation$$\rightarrow Na^+$$
Anion $$\rightarrow Cl^-$$
Question 4
1 / -0

Which of the following is used as standard for determination of atomic mass unit?

A
$$O^{16}$$

B
$$C^{12}$$

C
$$H^{1}$$

D
$$O^{17}$$

Solution

Atomic mass of a compound is measured in atomic mass units abbreviated as amu or u. One atomic mass unit is defined as $$\frac{1}{12}^{th}$$ of mass of a single carbon-12 atom.
Question 5
1 / -0

Calculate the molecular mass of the lime stone.

A
$$CaCO_2 = 84 g mol^{-1}$$

B
$$CaCO_3 = 100 g mol^{-1}$$

C
$$Ca_2CO_3 = 140 g mol^{-1}$$

D
$$CaCO = 68 g mol^{-1}$$

Solution

Formula for lime stone is $$CaCO_3$$. Molar mass $$= 40 + 12 + (3 \times 16) = 100 g mol^{-1}$$
Question 6
1 / -0

Which of the following property of an element never changes?

A
Valency

B
Atomic weight

C
Both A and B

D
None of the above

Solution

The atomic weight is a characteristic property of an element and can never vary.

The valency of an element can vary. For example, when the ion is in +2 and +3 oxidation state, its valency is 2 and 3 respectively.
Question 7
1 / -0

Calculate the molecular mass of the baking powder.

A
$$NaHCO_2 = 68 g mol^{1}$$

B
$$Na_2HCO_3 = 107 g mol^{1}$$

C
$$NaHCO_3 = 84 g mol^{1}$$

D
none of these

Solution

Baking powder (sodium bicarbonate) - $$NaHCO_3$$
Molar mass - $$23 + 1 + 12 + (3 \times 16) = 84 g mol^{-1}$$
Question 8
1 / -0

The formula and molecular mass of caustic soda is :

A
$$NaOH = 40 g mol^{-1}$$

B
$$Na_2OH = 63 g mol^{-1}$$

C
$$Na(OH)_2 = 57 g mol^{-1}$$

D
none of the above

Solution

Sodium has valency $$+1$$ and is represented as $$Na,$$ and hydroxyl has a valency of$$ -1$$ and is represented as $$OH^-$$. Caustic soda is $$NaOH.$$ Molar mass = $$23+16+1 = 40 g mol^{-1}$$.
Question 9
1 / -0

The value of 1 amu is equal to:

A
$$1.66\times 10^{-8}g$$

B
$$1.66\times 10^{-4}g$$

C
$$1.66\times 10^{-16}g$$

D
$$1.66\times 10^{-24}g$$

Solution

One an amu is $$\dfrac{1}{12}$$ of the mass of one carbon-12 atom.

It is equal to $$ \dfrac{1}{N_A} $$

$$= \dfrac{1}{6.022\times10^{23}} = 1.66 \times 10^{-24} g$$.
Question 10
1 / -0

Cations and anions present (if any) in $$H_2$$ are:

A
$$H^+$$

B
$$H^-$$

C
$$H^{2+}$$

D
None of the above

Solution

$$H_2$$ molecule is formed by covalent bond and hence, it does not have any cations and anions.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Atoms and Molecules Test - 18

Result

Atoms and Molecules Test - 18

Score

-

Rank

-

SHARING IS CARING

Question 1

24 g of C (12)

56 g of Fe (56)

27 g of Al (27)

108 g of Ag (108)

Solution

Question 2

1 g of molecule

1 atom of molecule

1 mole

1 litre of molecule

Solution

Question 3

Anion: $$Cl^{2-}$$ Cation: $$Na^+$$

Anion: $$Cl^{-}$$ Cation: $$Na^{2+}$$

Cation: $$Cl^{-}$$ Anion: $$Na^+$$

Anion: $$Cl^{-}$$ Cation: $$Na^+$$

Solution

Question 4

$$O^{16}$$

$$C^{12}$$

$$H^{1}$$

$$O^{17}$$

Solution

Question 5

$$CaCO_2 = 84 g mol^{-1}$$

$$CaCO_3 = 100 g mol^{-1}$$

$$Ca_2CO_3 = 140 g mol^{-1}$$

$$CaCO = 68 g mol^{-1}$$

Solution

Question 6

Valency

Atomic weight

Both A and B

None of the above

Solution

Question 7

$$NaHCO_2 = 68 g mol^{1}$$

$$Na_2HCO_3 = 107 g mol^{1}$$

$$NaHCO_3 = 84 g mol^{1}$$

none of these

Solution

Question 8

$$NaOH = 40 g mol^{-1}$$

$$Na_2OH = 63 g mol^{-1}$$

$$Na(OH)_2 = 57 g mol^{-1}$$

none of the above

Solution

Question 9

$$1.66\times 10^{-8}g$$

$$1.66\times 10^{-4}g$$

$$1.66\times 10^{-16}g$$

$$1.66\times 10^{-24}g$$

Solution

Question 10

$$H^+$$

$$H^-$$

$$H^{2+}$$

None of the above

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.