# Expressing concentrations as a percent

• Illyaria
In summary, the concentration of O2 in seawater is 0.01%. The Earth's atmosphere contains 21% O2/L of air, which is significantly higher than the concentration in seawater.
Illyaria
Please post this type of questions in HW section using the template and showing your work.
You measure the concentration of O2 in seawater to be 5.0 mg O2/L H2O. Express this concentration as a percent.

Question 2: The Earth's atmosphere contains 21% O2/L of air. How much more oxygen does the atmosphere hold than seawater from the previous question?

So for question one I got 0.01% which I think is way off. For question 2, I was just going to subtract 21% from the answer from 1. I changed the milligrams to grams for question one.

What was your attempt to solve #1?

Comeback City said:
What was your attempt to solve #1?

I converted the 1 5.0 mg to grams and got 0.005g. Then, I divided that by 50 which is the atomic msss for O2/L H2O I think and multiplied that by 100.

Atomic mass of Oxygen is 16.00 amu, so O2 would be 32.00. Why did you divide by it though and then multiply by 100?

## What does it mean to express concentrations as a percent?

Expressing concentrations as a percent is a way of representing the amount of a particular substance in a solution relative to the total amount of the solution. It is typically expressed as a percentage, with the numerator being the amount of the substance and the denominator being the total amount of the solution.

## What is the formula for calculating percent concentration?

The formula for calculating percent concentration is: (amount of substance / total amount of solution) x 100%. This will give you the percentage of the substance in the solution.

## How is percent concentration different from molarity?

Percent concentration and molarity are two different ways of expressing the concentration of a solution. Percent concentration is based on the percentage of a particular substance in the solution, while molarity takes into account the molecular weight of the substance and the volume of the solution.

## Can percent concentration be greater than 100%?

Yes, percent concentration can be greater than 100%. This would mean that there is more of the substance in the solution than the total amount of the solution itself.

## How is percent concentration used in real life?

Percent concentration is commonly used in fields such as chemistry, biology, and medicine to express the amount of a particular substance in a solution. It is also used in everyday life, such as when reading nutrition labels on food products to determine the percentage of certain ingredients.

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