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Some Basic Concepts of Chemistry

185938 Which of the following represents $180 g$ of water correctly ?

1

5 m o l e s

of water

2

1 m o l e

of water

3

6.023 \times 10^{23}

molecules of water

4

6.023 \times 10^{24}

molecules of water

Explanation:

$n = \frac{180}{18} = 10$
no. of molecule $= 10 \times 6.02 \times 10^{23}$
$= 6.02 \times 10^{24}$

Some Basic Concepts of Chemistry

186133 $510$ milli $g m$ of a liquid on vapourisation in Victor Mayer's apparatus displaces $510 C . C .$ of dry air (at $N T P)$ . The molecular weight of liquid is

1

0.224

2

2.24

3

224

4

22.4

Explanation:

$\frac{510 \times 10^{- 3} g}{M_{W}} = \frac{510 c m^{3}}{22400 c m^{3}}$

Some Basic Concepts of Chemistry

186134 The empirical formula of a compound is $C H$ . Its molecular weight is $78$ . The molecular formula of the compound will be

1

C_{2} H_{2}

2

C_{3} H_{3}

3

C_{4} H_{4}

4

C_{6} H_{6}

Explanation:

Molecular formula $=$ (empirical formula) $_{n}$
$∴ n = \frac{78}{13} = 6$

Some Basic Concepts of Chemistry

186135 Which of the following pairs of substances illustrates the law of multiple proportions?

1

C O

and

C O_{2}

2

N a C l

and

N a B r

3

H_{2} O

and

D_{2} O

4

M g O

and

M g (O H)_{2}

Explanation:

In $C O :$ $C$ $O$
$12 :$ $16$
In $C O_{2}$ $12 :$ $32$

Some Basic Concepts of Chemistry

185938 Which of the following represents $180 g$ of water correctly ?

1

5 m o l e s

of water

2

1 m o l e

of water

3

6.023 \times 10^{23}

molecules of water

4

6.023 \times 10^{24}

molecules of water

Explanation:

$n = \frac{180}{18} = 10$
no. of molecule $= 10 \times 6.02 \times 10^{23}$
$= 6.02 \times 10^{24}$

Some Basic Concepts of Chemistry

186133 $510$ milli $g m$ of a liquid on vapourisation in Victor Mayer's apparatus displaces $510 C . C .$ of dry air (at $N T P)$ . The molecular weight of liquid is

1

0.224

2

2.24

3

224

4

22.4

Explanation:

$\frac{510 \times 10^{- 3} g}{M_{W}} = \frac{510 c m^{3}}{22400 c m^{3}}$

Some Basic Concepts of Chemistry

186134 The empirical formula of a compound is $C H$ . Its molecular weight is $78$ . The molecular formula of the compound will be

1

C_{2} H_{2}

2

C_{3} H_{3}

3

C_{4} H_{4}

4

C_{6} H_{6}

Explanation:

Molecular formula $=$ (empirical formula) $_{n}$
$∴ n = \frac{78}{13} = 6$

Some Basic Concepts of Chemistry

186135 Which of the following pairs of substances illustrates the law of multiple proportions?

1

C O

and

C O_{2}

2

N a C l

and

N a B r

3

H_{2} O

and

D_{2} O

4

M g O

and

M g (O H)_{2}

Explanation:

In $C O :$ $C$ $O$
$12 :$ $16$
In $C O_{2}$ $12 :$ $32$

Some Basic Concepts of Chemistry

185938 Which of the following represents $180 g$ of water correctly ?

1

5 m o l e s

of water

2

1 m o l e

of water

3

6.023 \times 10^{23}

molecules of water

4

6.023 \times 10^{24}

molecules of water

Explanation:

$n = \frac{180}{18} = 10$
no. of molecule $= 10 \times 6.02 \times 10^{23}$
$= 6.02 \times 10^{24}$

Some Basic Concepts of Chemistry

186133 $510$ milli $g m$ of a liquid on vapourisation in Victor Mayer's apparatus displaces $510 C . C .$ of dry air (at $N T P)$ . The molecular weight of liquid is

1

0.224

2

2.24

3

224

4

22.4

Explanation:

$\frac{510 \times 10^{- 3} g}{M_{W}} = \frac{510 c m^{3}}{22400 c m^{3}}$

Some Basic Concepts of Chemistry

186134 The empirical formula of a compound is $C H$ . Its molecular weight is $78$ . The molecular formula of the compound will be

1

C_{2} H_{2}

2

C_{3} H_{3}

3

C_{4} H_{4}

4

C_{6} H_{6}

Explanation:

Molecular formula $=$ (empirical formula) $_{n}$
$∴ n = \frac{78}{13} = 6$

Some Basic Concepts of Chemistry

186135 Which of the following pairs of substances illustrates the law of multiple proportions?

1

C O

and

C O_{2}

2

N a C l

and

N a B r

3

H_{2} O

and

D_{2} O

4

M g O

and

M g (O H)_{2}

Explanation:

In $C O :$ $C$ $O$
$12 :$ $16$
In $C O_{2}$ $12 :$ $32$

Some Basic Concepts of Chemistry

185938 Which of the following represents $180 g$ of water correctly ?

1

5 m o l e s

of water

2

1 m o l e

of water

3

6.023 \times 10^{23}

molecules of water

4

6.023 \times 10^{24}

molecules of water

Explanation:

$n = \frac{180}{18} = 10$
no. of molecule $= 10 \times 6.02 \times 10^{23}$
$= 6.02 \times 10^{24}$

Some Basic Concepts of Chemistry

186133 $510$ milli $g m$ of a liquid on vapourisation in Victor Mayer's apparatus displaces $510 C . C .$ of dry air (at $N T P)$ . The molecular weight of liquid is

1

0.224

2

2.24

3

224

4

22.4

Explanation:

$\frac{510 \times 10^{- 3} g}{M_{W}} = \frac{510 c m^{3}}{22400 c m^{3}}$

Some Basic Concepts of Chemistry

186134 The empirical formula of a compound is $C H$ . Its molecular weight is $78$ . The molecular formula of the compound will be

1

C_{2} H_{2}

2

C_{3} H_{3}

3

C_{4} H_{4}

4

C_{6} H_{6}

Explanation:

Molecular formula $=$ (empirical formula) $_{n}$
$∴ n = \frac{78}{13} = 6$

Some Basic Concepts of Chemistry

186135 Which of the following pairs of substances illustrates the law of multiple proportions?

1

C O

and

C O_{2}

2

N a C l

and

N a B r

3

H_{2} O

and

D_{2} O

4

M g O

and

M g (O H)_{2}

Explanation:

In $C O :$ $C$ $O$
$12 :$ $16$
In $C O_{2}$ $12 :$ $32$