[Caperi]

I'm doing an assignment right now so I guess I'll be updating this on the go.

For this one, I just don't understand the wording:

Bacterial digestion is an economical method of sewage treatment.

5CO2(g) + 55NH4+(aq) + 76O2(g) ->
C5H7O2N(s) [Bacterial Tissue] + 54NO2-(aq) + 52H2O(l) + 109H+(aq)
      
The above reaction is an intermediate step in the conversion of the nitrogen in organic compounds into nitrate ions. What mass of bacterial tissue is produced in a treatment plant for every 1.0 multiplied by 104 kg of wastewater containing 6.0% NH4+ ions by mass?

I got that, it was 6.8e4g. Now the second part of the question...

Assume that 98% of the ammonium ions are consumed by the bacteria.

What does it mean by 'consumed'?



Then I'm having trouble with this:

Consider the following unbalanced reaction.

P4(s) + F2(g) -> PF3(g)
What mass of F2 is needed to produce 112 g of PF3 if the reaction has a 83.5% yield?

I figured that since %yield = actual yield/theoretic yield * 100%, that I just plug in the %yield and then plug in 48.4g for the theoretical yield (that's what I got when going from 112g of PF3 to g of F2). After solving that, I got 40.4g, which is incorrect. What am I doing wrong?

[Arctic-Nation]

Consumed means the amount of reactant that reacts relative to the total amount present. If, in your case, the bacteria contain a small equilibrium amount of ammonium, they will be unable to process any amount of ammonium beyond that equilibrium.

For your second problem, first write down a balanced reaction equation. From that, calculate the theoretical yield (first in grams, then in moles), and combine the result with the reaction equation to find the amount of fluorine you need. Remember that you don't add 83.5% of fluorine to the reaction mixture, but 100%.