Question

A) Select all the processes below that are SPONTANEOUS.

		Freezing of water at 10°C
		Corrosion of iron metal (rust)
		Expansion of gas to fill the available volume
		Boiling of gasoline at 25°C and 1 atm pressure

B) What is the Q (IP) when 287 mL of 0.068 M solution of Na₂CO₃(aq) are mixed with 211 mL of 0.075 M solution of BaCl₂(aq). The solid product is BaCO₃. Express your answer in scientific notation.

Answer 1

A) Corrosion of iron metal (rust), Expansion of gas to fill the available volume

B) Na2CO3 (aq) + BaCl2 (aq) -----> 2 NaCl (aq) + BaCO3 (s)

Moles of Na2CO3 = 0.068*287 = 19.516 millimoles

Moles of BaCl2 = 211*0.075 = 15.825 millimoles

So, BaCl2 is limiting reagent

Therefore, 15.825 milllimoles of BaCO3 (ppt) is formed

BaCO3 ==== Ba2+ + CO3 2-

ionic product = [Ba2+] [CO3 2-] = (15.825/498) * (15.825/498) = 1.01*10^-3 (as total volume = 211+287 =498 ml)