An unknown substance is obtained by police. The forensics laboratory has determined it is made of nitrogen and oxygen. If 74.66 grams are nitrogen
and the police obtained a 250 gram sample, what is the percent
composition of oxygen in the sample?

70.0 %

Explanation:

Step 1: Given data

Step 2: Calculate the mass of oxygen (mO) in the compound

The mass of the compound is equal to the sum of the masses of the elements that form it.

mNxOy = mN + mO

mO = mNxOy - mN

mO = 250 g - 74.66 g = 175 g

Step 3: Determine the percent composition of oxygen in the sample

We will use the following expression.

%O = mO / mNxOy × 100%

%O = 175 g / 250 g × 100% = 70.0 %

r just means there's a number of carbon in teh chain. for example rcooh means that after x number of carbon, the chain ends with cooh.

explanation:

the molecules move in straight line until they collide with each other or with the walls of the container. collisions are perfectly elastic; when two molecules collide, they change their directions and kinetic energies, but the total kinetic energy is conserved.

explanation: