Concentration question.

o.0

Oh, I thought it was another type of concentration...

What kind of concentration are you going to find in a chemistry forum?

Zishi: it has do somthing with the fact that Nitrogen is a gas ....and always occurs as N2 gas (a diatomic molecule). So when they say 15g on Nitrogen is there ..THEY MEAN 15g of N2 gas is there !!!!!!...so the Molecular weight of N2 is ~28g/mol....so that's why it is 3.5g/[28 g/mol].

Hope that helps!!!!!!!!!!

It shouldn't.... it's wrong

fertilizer contains 15% N (15g in every 100g)

You use 14g fertilizer you use 14 x 15/100 g nitrogen

But you need moles of ATOMS = 14/14 x 15/100 = 0.15

You put this into 5 litres and the concentration is 0.15/5 = 0.03 mol dm^-3

But THAT is the ratio, so that isn't the actual mass of nitrogen in the fertilizer.

Read the question carefully:

" ... the ratio per 100g of fertilizer"

If it were only N, P and K it would be a pretty horrendous mixture to put on plants...

N is a gas (Nitrogen) it would escape into the air
P is phosphorus it would burst into flames spontaneously and produce toxic acidic clouds of phosphorus pentoxide
K is potassium, which would burst into flames as it came into contact with any moisture in the soil...

You gonna stuff them together into a bag?

LOL! So 'per' represents that they're present in exact quantities in 100g of Fertilizer as in the ratio, right?

yes, 'per' means 'in'