Question

A 250ml aqueous solution contains 45.1microgram of pesticide.express the pesticide concentration in:

Answer 1

Answer:

1. 1.80x10⁻⁵ (w/w %).

2. 1.80x10⁻⁴ parts per thousand

3. 0.18 parts per million

Explanation:

The solution contains 45.1μg / 250mL.

1. Weight percent (100 times mass in grams of solute per gram of solution, as there are 250mL of water = 250g):

45.1x10⁻⁶g / 250g * 100 =

1.80x10⁻⁵ (w/w %)

2. Parts per thousand (mg of solute per g of solution).

45.1μg * (1x10⁻³mg / 1μg) = 0.0451mg.

0.0451mg / 250g =

1.80x10⁻⁴ parts per thousand

3. Parts per million (μg of solute per g of solution):

45.1μg / 250g =

0.18 parts per million