Question

13. Find the number of moles of molecules present in the samples given below.
a) 170gNH3 b) 112L NH3 at STP
[Atomic mass N-14, H =1]​

Answer 1

Answer:

hey dude here is your Answer

Explanation:

a)no.of moles=given mass/molar mass

Molar mass NH3=17

No.of moles=170/17

=10moles

b) no. if moles=112/22.4

= 5moles

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Answer 2

Given:

Samples of $\[170\,g\,N{H_3}\]$ and $\[112L\,N{H_3}\]$

To Find: Number of moles of molecules in

(a) $\[170\,g\,N{H_3}\]$

(b) $\[112L\,N{H_3}\]$

Solution:

(a)

Number of moles can be given as:

$\[No.\,of\,moles = \frac{{Mass}}{{Molar\,mass}}\]$

Therefore, the number of moles present in $\[170\,g\,N{H_3}\]$

$\[No.\,of\,moles = \frac{{170\,g}}{{17\,g}}\]$

$\[No.\,of\,moles = 10\]$

Hence, the number of moles of molecules in $\[170\,g\,N{H_3}\]$ is 10.

(b)

The mass of $\[112L\,N{H_3}\]$ can be calculated by the formula:

$\[\frac{{Mass}}{{Molar\,mass}} = \frac{{Given\,Volume}}{{22.4}}\]$

Therefore,

$\[Mass = \frac{{112\,L}}{{22.4}} \times 17\]$

$\[Mass = 85\,g\]$

Thus, the number of moles present in $\[112L\,N{H_3}\]$

$\[No.\,of\,moles = \frac{{85\,g}}{{17\,g}}\]$

$\[No.\,of\,moles = 5\]$

Hence, the the number of moles of molecules in $\[112L\,N{H_3}\]$ is 5.