You react ammonia and oxygen, and at the end of the experiment you find that you produced 20.7 g of water and have 8.52 g of ammonia left over. Determine the mass of oxygen reacted.

To find the mass of oxygen reacted, we need to determine the mass of ammonia that reacted first.

The mass of water produced (20.7 g) and the mass of ammonia remaining (8.52 g) allow us to find the mass of ammonia reacted.

1. Calculate the mass of ammonia reacted:
Mass of ammonia reacted = Initial mass of ammonia - Mass of ammonia remaining
= Initial mass of ammonia - 8.52 g

2. Determine the initial mass of ammonia:
Since you have not provided the initial mass of ammonia, we cannot determine the amount of ammonia reacted. Please provide the initial mass of ammonia used in the reaction.

Once we have the initial mass of ammonia, we can proceed to find the mass of oxygen reacted using the balanced chemical equation.

To determine the mass of oxygen reacted in the reaction between ammonia and oxygen, we need to first find the initial mass of ammonia reacted and then use the principle of conservation of mass.

Given that we have 20.7 g of water and 8.52 g of ammonia left over, we can find the initial mass of ammonia reacted by subtracting the amount of ammonia left over from the total mass of ammonia used. Let's denote the initial mass of ammonia as x.

Total mass of ammonia = mass of ammonia reacted + mass of ammonia left over
x = mass of ammonia reacted + 8.52 g

Next, we know that ammonia (NH3) reacts with oxygen (O2) to produce water (H2O) according to the balanced chemical equation:

4NH3 + 3O2 -> 6H2O

From this equation, we can see that the ratio of ammonia to oxygen is 4:3. Therefore, the ratio of the masses of ammonia to oxygen is also 4:3.

We can setup a proportion to find the mass of oxygen reacted:

(4 g ammonia / x g ammonia) = (3 g oxygen / mass of oxygen reacted)

Cross-multiplying and solving for the mass of oxygen reacted:

4 * (mass of oxygen reacted) = 3 * x
mass of oxygen reacted = (3 * x) / 4

Now we can substitute the value of x, which we found earlier:

mass of oxygen reacted = (3 * 8.52 g) / 4

Calculating this expression provides the mass of oxygen reacted.

A stoichiometry problem in reverse. Just follow the steps of this example.

http://www.jiskha.com/science/chemistry/stoichiometry.html