Question

Why is chemistry chemistry?​

Answer 1

The concentration in ppm = 125,000 ppm

Further explanation

The concentration of a substance can be expressed in several quantities such as moles, percent (%) weight / volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.

ppm or parts per million (ppm) :

For water solvent = 1 ppm ⇒ 1 mg/L(1 kg=1 L,ρ water=1 kg/L)

In percent mass = 1 ppm ⇒ 1 mg/ 1 kg

Solution contains 0.25 kg of lead in 2 kg of water :

Solvent = water = 2 kg = 2 L

Solute= lead=0.25 kg=250000 mg

So the concentration in ppm :

$\tt ppm=\dfrac{250,000~mg}{2~L}=\boxed{\bold{125,000~ppm}}$