Question

Calculate the mass of 112 cm cube of hydrogen at stp

Answer 1

112cm^3 = 112ml = (112/1000)L
= (224/2000)L = (22.4/200)L
= (1/200) mole = 2×(1/200)g = 0.01g

Answer 2

Answer: The mass of hydrogen gas at STP is 0.01 grams.

Explanation:

STP conditions are known as standard temperature and pressure. Temperature as 273 K and pressure at 1 atm.

We are given that the volume of hydrogen gas is $11.2cm^3$

So, by using the conversion factor:

$1L=1000cm^3$

$112cm^3=0.112L$

According to the mole concept:  

22.4 L of volume is occupied by 1 mole of a gas.

So, 0.112L of volume will be occupied by $=\frac{1mol}{22.4L\times 0.112L=0.005mol$

To calculate the mass of hydrogen gas, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of hydrogen gas = 0.005 mol

Molar mass of hydrogen gas = 2 g/mol

Putting values in above equation, we get:

$0.005mol=\frac{text{Mass of hydrogen gas}}{2g/mol}$

Mass of hydrogen gas = 0.01 grams

Hence, the mass of hydrogen gas at STP is 0.01 grams.