Students were requested to answer a question at education and to mention what is most important for them to succeed. The one which response stood out from the rest was practice. Successful persons are certainly born successful; they become successful by hard work and determination. This is how you can accomplish your goals. shown below some question and answer examples that you can certainly utilise to develop your knowledge and gain insight that will assist you to keep up your school studies.

## Question:

A solution contains 15 ppm of benzene. The density of the solution is 1.00 g/mL. This means that ________.

the solution is 15% by mass of benzene

1.0 g of the solution contains 15 * 10^-6 g of benzene

there are 15 mg of benzene in 1.0 g of this solution

100 g of the solution contains 15 g of benzene

1.0 L of the solution contains 15 g of benzene

## Answer:

**Answer:**

- second choice:
__1.0 g of the solution contains 15 × 10⁻⁶ g of benzene.__

**Explanation:**

**ppm **is a unit of concentration that means **parts per million**. In grams that is grams of solute per one million (10⁶) grams of solution.

Then, *15 ppm of benzene* means that there are 15 grams of benzen in 1,000,000 grams of solution.

That leads to:

- 1,000,000 g solution / 15 g benzene

Multiplying numerator and denominator by 10⁻⁶ you find:

- 1,000,000 × 10⁻⁶ g solution / (15 × 10⁻⁶ g benzene)

Simplifying:

- 1.0 g solution / (15 × 10⁻⁶ g benzene)

Which is read as 1.0 g of the solution contains 15 × 10⁻⁶ g of benzene, i.e. the second answer choice.

They can certainly hopefully guide the student take care of the question by applying the questions and answer examples. Then could simply have some sharing in a group discussion and also learning with the classmate concerning the topic, so another student also have some enlightenment and still keeps up the school learning.