Question

Mass of 112mL of certain gas is 0.22g at STP .How many molecules are there in the sample of gas ? What is the molar mass of the gas.​

Answer 1

Answer:

➜ number of molecules = 30.11 × 10²¹ molecules

➜ molar mass of the gas = 44 g

Explanation:

Given,

mass of the given gas, m = 0.22 g

volume of the given gas, V = 112 ml or 0.112 L

To Find,

☛ number of molecules of the given gas present

☛ molar mass of the gas

Solution,

We know,

$\large\boxed{\sf { No. \ of \ moles = \ \frac {volume}{volume \ of \ gas \ at \ STP}}}$

On substituting the values,

$\large\rm { \frac {0.112}{22.4}}$

M=0.005mol

Now,

1 mol = 6.022 × 10²⁴ atoms / molecules

0.005 mol = 6.022 × 0.005 × 10²⁴

➜ 6.022 × 5 × 10²¹

➜ 30.11 × 10²¹ molecules

$\large\begin{gathered}\\ \\\end{gathered}$

Also,

$\large \begin{gathered}\\\end{gathered}$

No. of moles = Mass given / Molar mass

☛ 0.005 = 0.22 / molar mass

☛ molar mass = 0.22 / 0.005

☛ molar mass = 44 g

$\large\begin{gathered}\\ \\ \\\end{gathered}$