Answer: 2.06X10^-4M
Explanation: Caffeine's molar mass is 194.2 g/mole. 10 mg is 0.010 gram, so (0.01g/194.2 g/mole) = 5.15x10^-5 moles. 250 ml = 0.250 liters.
(5.15x10^-5 moles)/(0.250 liters) = 2.06x10^-4 Molar
5.7m questions
7.5m answers