Chemistry Question

Question

How much caffeine will need to be weigh out and diluted to 250mL to prepare a concentration of 0ppm, 20ppm, and 40ppm?

Answer 1

ppm is the same as mg / L

For 250 ml, that is 0.250 L

0 ppm = 0 mg caffeine in 250 ml

20 ppm = 20 mg / L x 0.250 L = 5 mg caffeine in 250 ml

40 ppm = 40 mg / L x 0.250 L = 10 mg caffeine in 250 ml