CHM 105 Answer the questions in order in the blue book. You must show your ca I.
ID: 693162 • Letter: C
Question
CHM 105 Answer the questions in order in the blue book. You must show your ca I. What is the mass/volume % of a solution made by dissolving 15.0 g o Exam 3, Sp 2014 calculations for full credit. water? 2. What is th e mass mass % of a solution made by dissolving 12.0 g of NaBr in 85.0 g of water? What is the molarity of a solution obtained by dissolving 5.35 g of NacI in some wa diluting to exactly 250 mL in a graduated flask? 3. 4. How many grams of NaOHl are there in exactly 10.0 mL of a 0.0990 M solution of the compound? 5. What is the molarity of a HCI solution obtained bóy diluting 20.0 mL of a 0.150 M soltion of HCI to exatly 250 mL in a volumetric flask 5. (a) Tell what is meant by: i) osmosis ) osmotic pressure (b) Consider the diagram below with a built ins permeable membrane as shown:Explanation / Answer
1. m/v% = mass of solute present in 100 ml solution.
m/v% = mass of solute/volume of solution *100
= 15/50*100
= 30% (assuming no change in vol of solution.after dissolving solute)
2. m/m% = mass of solute present in 100 g solution.
m/m% = mass of solute/mass of solution*100
= 12/(85+12)*100
= 12.37%
3. Molarity = w/M*1000/V in ml
= (5.35/58.5)*(1000/250)
= 0.366 M
4. NO of mol of NaOH = M*V
= 0.0990*10*10^-3
= 0.00099 mol
Mass of NaOH present in solution = 0.00099*40 = 0.0396 g
5. M1V1 = M2V2
(20*0.15) = (M2*250)
M2 = molarity of dilute solution = 0.012 M