Question

The mass of CO that can be mixed with 70g of dry nitrogen so that both have same partial pressure is
1) 70
2) 25 g
3) 2.5 g
4) 110
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Answer 1

Answer:

partial pressure of N2 = Partial pressure of CO

Ptotal × mole fraction of N2 = Ptotal × mole fraction of CO

mole fraction of N2 = mole fraction of CO

moles of N2 = Moles of CO

70/28 = m/28

m= 70 g

Answer 2

Answer:

The mass of CO mixed with dry nitrogen shoulda be equal to 70grams so that both gases can have same partial pressure.

Explanation:

If the partial pressure of two mixed gases will be equal, then their mole fraction or number of moles will be equal as well.

$P_{CO}=P_{N_{2}}$  ⇒  $x_{CO}=x_{N_{2}}$

Therefore, number of moles of CO = number of moles of N₂

Given mass of dry nitrogen N₂ $=70g$

Number of moles of N₂ $=\frac{mass}{Molar Mass}$

                                   $=\frac{70}{28}=2.5moles$

Number of moles CO $=2.5moles$

The mass of CO = (no. of moles)(Molar mass of CO)

                           $=2.5*28=70g$