Question

Part A

Potassium cyanide is a toxic substance, and the median lethal dose depends on the mass of the person or animal that ingests it. The median lethal dose of KCN for a person weighing 145 lb (65.8 kg ) is 7.27×10−3 mol . What volume of a 0.0820 M KCN solution contains 7.27×10−3 mol of KCN?

Part B

Gastric acid pH can range from 1 to 4, and most of the acid is HCl. For a sample of stomach acid that is 2.21×10−2 M in HCl, how many moles of HCl are in 15.2 mL of the stomach acid? Express the amount to three significant figures and include the appropriate units.

Answer 1

molarity = molar mass molarity = number of moles/volume (L) mass 1 000 molar mass volume (ml) melay ma_C - KCN = 6C. 2 8mol. molarity = 0.0820m number of moles= mass = 7.27 X108 molar mass = 0.0820M = 7.27 x 103 ml volume (L) volume = (J. 27 x 103) / 0.0820m = 0.08866 L Answer: 88.7 mL mol.

part B: number of moles volume & Litres) mole 2.21 x 10²m moles of Hd 1000 ml -3. X 15.2 X10 L -2 2.21 X 10 M 15.2 mL x ! L moles of Hl = 2.21 x 10²m x 15.2 x 103 L = 3.36X104 moles. Answer: 3.36x104 mol.