A sample is found to contain 2.98x10^-10 g of salt. Express this quantity in nanograms.

This quantity = 0.298 nanograms(ng)

Mass is one of the principal quantities, which is related to the matter in the object

The main mass unit consists of 7 units of other than other units of mass such as quintals, tons, pounds, ounces:

Kilogram, kg

Hectogram, hg

Decagram, dag

gram, g

Desigram, with

centigram, cg

milligram, mg

Each unit descends then multiplied by 10, and if one unit increases then divided by 10

Conversion of other mass units:

10⁻³ g ⇒mg-milligrams

10³ g ⇒kg-kilograms

10⁻⁶ g ⇒µg-micrograms (mcg)

10⁶ g ⇒Mg-megagrams (tons)

10⁻⁹ g ⇒ng-nanograms

10⁹ g ⇒Gg-gigagram

10⁻¹² g ⇒pg-pikogram

2.98 x 10⁻¹⁰ g to nanograms(ng)

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.

the answer is b & c i believe : )