Air is made of 80% nitrogen and 20% oxygen by volume. the densities of air and oxygen is 1.29kgm^-3 and 1.43kgm^-3 respectively. what is the density of nitrogen? specify your soultion, you!

Volume % = mole %

Molar mass of oxygen = 32kg/kmol

Molar mass of nitrogen = 28 kg/kmol

Density of nitrogen = Density of oxygen x molar mass of oxygen x molar ratio of air x molar mass of nitrogen

Density of nitrogen = (1.43kgm^-3)(1 kmol O2/32 kg O2)(80 kmol N2/ 20 kmol O2)(28 kg N2/1 kmol O2) = 5.01 kg/m3

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.