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CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306740 Assertion :
Atomicity of oxygen is 2 .
Reason :
1 mole of an element contains $6.023 \times 10^{23}$ atoms.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

The number of atoms present in a molecule of a gaseous element is called its atomicity. For example, $O_{2}$ has two atoms, and hence its atomicity is 2 .
1 mole of an element contains Avagadro number of atoms. So, the option (2) is correct.

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306741 Assertion :
Molar volume of gases change considerably with temperature and pressure.
Reason :
Molar volume of a substance is the volume occupied by 1 mole of that substance.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306742 How many molecules of ammonia gas are present in $67.2 {dm}^{3}$ , measured at S.T.P.?

1

2.0 \times 10^{24}

2

1.0 \times 10^{23}

3

1.8 \times 10^{24}

4

5.0 \times 10^{24}

Explanation:

No.of moles $= \frac{Volume ({dm}^{3}) at STP}{22.4}$
$= \frac{67.2}{22.4} = 3 moles$
No. of molecules $=$ no. of moles $\times 6.023 \times 10^{23}$
$= 3 \times 6.023 \times 10^{23} = 1.8 \times 10^{24}$ molecules

MHTCET - 2021

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306743 What amount of dioxygen (in gram) contains $1 .8 \times 1 0^{22}$ molecules ?

1

0 .960

2

96 .0

3

0 .0960

4

9 .60

Explanation:

$6 .022 \times 1 0^{23}$ molecules are present in 32 g of $O_{2}$ .
$∴ 1 .8 \times 1 0^{22}$ molecules will be present in
$\frac{32}{6 .022 \times 1 0^{23}} \times 1 .8 \times 1 0^{22} g = 0 .960 g o f O_{2}$

KCET - 2014

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306740 Assertion :
Atomicity of oxygen is 2 .
Reason :
1 mole of an element contains $6.023 \times 10^{23}$ atoms.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

The number of atoms present in a molecule of a gaseous element is called its atomicity. For example, $O_{2}$ has two atoms, and hence its atomicity is 2 .
1 mole of an element contains Avagadro number of atoms. So, the option (2) is correct.

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306741 Assertion :
Molar volume of gases change considerably with temperature and pressure.
Reason :
Molar volume of a substance is the volume occupied by 1 mole of that substance.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306742 How many molecules of ammonia gas are present in $67.2 {dm}^{3}$ , measured at S.T.P.?

1

2.0 \times 10^{24}

2

1.0 \times 10^{23}

3

1.8 \times 10^{24}

4

5.0 \times 10^{24}

Explanation:

No.of moles $= \frac{Volume ({dm}^{3}) at STP}{22.4}$
$= \frac{67.2}{22.4} = 3 moles$
No. of molecules $=$ no. of moles $\times 6.023 \times 10^{23}$
$= 3 \times 6.023 \times 10^{23} = 1.8 \times 10^{24}$ molecules

MHTCET - 2021

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306743 What amount of dioxygen (in gram) contains $1 .8 \times 1 0^{22}$ molecules ?

1

0 .960

2

96 .0

3

0 .0960

4

9 .60

Explanation:

$6 .022 \times 1 0^{23}$ molecules are present in 32 g of $O_{2}$ .
$∴ 1 .8 \times 1 0^{22}$ molecules will be present in
$\frac{32}{6 .022 \times 1 0^{23}} \times 1 .8 \times 1 0^{22} g = 0 .960 g o f O_{2}$

KCET - 2014

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306740 Assertion :
Atomicity of oxygen is 2 .
Reason :
1 mole of an element contains $6.023 \times 10^{23}$ atoms.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

The number of atoms present in a molecule of a gaseous element is called its atomicity. For example, $O_{2}$ has two atoms, and hence its atomicity is 2 .
1 mole of an element contains Avagadro number of atoms. So, the option (2) is correct.

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306741 Assertion :
Molar volume of gases change considerably with temperature and pressure.
Reason :
Molar volume of a substance is the volume occupied by 1 mole of that substance.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306742 How many molecules of ammonia gas are present in $67.2 {dm}^{3}$ , measured at S.T.P.?

1

2.0 \times 10^{24}

2

1.0 \times 10^{23}

3

1.8 \times 10^{24}

4

5.0 \times 10^{24}

Explanation:

No.of moles $= \frac{Volume ({dm}^{3}) at STP}{22.4}$
$= \frac{67.2}{22.4} = 3 moles$
No. of molecules $=$ no. of moles $\times 6.023 \times 10^{23}$
$= 3 \times 6.023 \times 10^{23} = 1.8 \times 10^{24}$ molecules

MHTCET - 2021

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306743 What amount of dioxygen (in gram) contains $1 .8 \times 1 0^{22}$ molecules ?

1

0 .960

2

96 .0

3

0 .0960

4

9 .60

Explanation:

$6 .022 \times 1 0^{23}$ molecules are present in 32 g of $O_{2}$ .
$∴ 1 .8 \times 1 0^{22}$ molecules will be present in
$\frac{32}{6 .022 \times 1 0^{23}} \times 1 .8 \times 1 0^{22} g = 0 .960 g o f O_{2}$

KCET - 2014

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306740 Assertion :
Atomicity of oxygen is 2 .
Reason :
1 mole of an element contains $6.023 \times 10^{23}$ atoms.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

Explanation:

The number of atoms present in a molecule of a gaseous element is called its atomicity. For example, $O_{2}$ has two atoms, and hence its atomicity is 2 .
1 mole of an element contains Avagadro number of atoms. So, the option (2) is correct.

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306741 Assertion :
Molar volume of gases change considerably with temperature and pressure.
Reason :
Molar volume of a substance is the volume occupied by 1 mole of that substance.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.

2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.

3 Assertion is correct but Reason is incorrect.

4 Assertion is incorrect but Reason is correct.

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306742 How many molecules of ammonia gas are present in $67.2 {dm}^{3}$ , measured at S.T.P.?

1

2.0 \times 10^{24}

2

1.0 \times 10^{23}

3

1.8 \times 10^{24}

4

5.0 \times 10^{24}

Explanation:

No.of moles $= \frac{Volume ({dm}^{3}) at STP}{22.4}$
$= \frac{67.2}{22.4} = 3 moles$
No. of molecules $=$ no. of moles $\times 6.023 \times 10^{23}$
$= 3 \times 6.023 \times 10^{23} = 1.8 \times 10^{24}$ molecules

MHTCET - 2021

CHXI01:SOME BASIC CONCEPTS OF CHEMISTRY

306743 What amount of dioxygen (in gram) contains $1 .8 \times 1 0^{22}$ molecules ?

1

0 .960

2

96 .0

3

0 .0960

4

9 .60

Explanation:

$6 .022 \times 1 0^{23}$ molecules are present in 32 g of $O_{2}$ .
$∴ 1 .8 \times 1 0^{22}$ molecules will be present in
$\frac{32}{6 .022 \times 1 0^{23}} \times 1 .8 \times 1 0^{22} g = 0 .960 g o f O_{2}$

KCET - 2014