Question

At stp, a 12.0 liter sample of CH4 has the same total number of molecules as

Answer 1

Option 2: 12.0 L of $CO_{2} (g)$ at STP.

The standard pressure and temperature values are 1 atm and 273.15 K.

Using the ideal gas equation, number of moles of gas can be calculated which is as follows:

PV=nRT...... (1)

Here, P is pressure, V is volume, n is number of moles, R is gas constant and T is temperature.

Also, in 1 mole of any gas there are $6.023\times 10^{23}$ molecules of the gas. This is known as Avogadro's number and denoted by symbol $N_{A}$

Thus,

$N=n\times N_{A}$

Equation (1) can be rewritten as follows:

$PV=\frac{N}{N_{A}}RT$

On rearranging,

$N=\frac{P\times V\times N_{A}}{R\times T}$

Here, all the other terms are constant except volume, thus, gas with volume equal to the volume of $CH_{4}$ will have same number of molecules.

Volume of $CH_{4}$ gas and $CO_{2}$gas is same thus, $CH_{4}$ will have same total number of molecules as  $CO_{2}$ gas.

Answer 2

2 the answer is 12.0 L of CO2(g) at STP