CHEM 110 Quiz 4 (Answer all questions. Show all your works for questions 1 and 2. Total points 25) 1. When 100 milligram (mg) of an unknown substance is dissolved in 100 mL of an aqueous solution, the...

Chemisty


CHEM 110 Quiz 4 (Answer all questions. Show all your works for questions 1 and 2. Total points 25) 1. When 100 milligram (mg) of an unknown substance is dissolved in 100 mL of an aqueous solution, the concentration of that solution has a molarity, 0.1 M. Calculate the molar mass of that unknown substance? (6 points) 2. What is the molality, m of a solution containing 300 grams of potassium nitrate (KNO3), a strong electrolyte in 1800 grams of water? (6 points) 3. (i) Write the conjugate acids of the following bases: (4 points) (a) H2PO3 2— (b) HSO3– (c) NH3 (d) CN— (ii) Write the conjugate bases for the following acids: (3 points) (e) HS— (f) H2SO4 (g) HCO3— 4. (a) Write the equation for the dissociation of the weak acid, HCN in water. (3 points) (b) Write the acid dissociation expression, Ka for hydrogen sulfite, HSO3— . (3 points)