Asolution 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

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:

Multiplying numerator and denominator by 10⁻⁶ you find:

Simplifying:

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

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72