my tutor gave me I dont understand how answer this

Question

Air is about 78.0% nitrogen molecules and 21.0% oxygen molecules. Several other gases make up the remaining 1% of air molecules.

What is the partial pressure of nitrogen in air at atmospheric pressure (101 kPa)? Assume ideal behaviour.

Express your answer to three significant figures and include the appropriate units.

i need help with this Q

Answer 1

If the gases are ideal, then the partial pressure of the gas P_g= (n_g/n_T) P_T

where T stands for total and g stands for a particular gas in the mixture. Of course n_g/n_T is the fraction of the gas or the percentage of the gas (given) written as a decimal. It really is that simple.