Question

Two moles of oxygen gas is reacted with hydrogen gas to produce water in this reaction:

2 H2 + O2 → 2 H2O

In the lab you actually made 33.1 grams of water. What is the percent yield?

218.10%

91.80%

45.87%

54.50%

Answer 1

I have no idea cuz in the beginning it says 2 moles of oxygen reacts with hydrogen but the reaction given show that 2 moles of hydrogen reacting with oxygen. little confused '@Photon336 @taramgrant0543664

Answer 2

Is it the second one?

Answer 3

@Rushwr yes in the equation you always use the smallest numbers as coefficients, and shows the relationship of the reactants and products. The info in the problem is telling you how much oxygen the person use in the experiment. It can be 2 moles, 20g, 2.00L depends of the problem. In this case 2 moles of oxygen were used and the reaction produced 33.1g of water. You have to assume that the H2 was in excess and the limiting reactant is the oxygen. Calculate the theoretical yield and then the percentage yield with the amount of water formed.

Answer 4

@anti-chem-hag74 are you sure that that is the answer? how did you got it?

Answer 5

I'm not sure I'm just asking. @Cuanchi

Answer 6

45.87%?

Answer 7

Now you change your answer, which one is your choice and how did you calculate the value?

Answer 8

find out the limiting reagent; you have 2 moles of oxygen so you multiply by the molar ratio to figure out how many moles you need to get the reaction going.

2 moles O2 x ( 2H2/O2)= 4 moles of H2

one of these is going to run out, i would guess that it's probably going to be the oxygen.

so you use the moles of oxygen multiple by the molar ratio of oxygen to water to find your theoretical yield.

you're given experimental yield.

experimental/theoretical x 100%