Exam #1 Review

Sig Figs

100

0.200 x 0.010 = 

0.0020

200

150 / 10 = 

20

300

36.800 + 1.2 = 

38.0

400

(13.4 + 0.85) x 1.6 = 

23

500

(23.458 / 3.46) + 12.1 = 

18.9

IMFs

100

Ammonia engages in what type of IMF?

H bonding 

200

Which would be harder to boil?  CH4 or C8H18

C8H18

300

If two molecules A and B are reported to have a vapor presssure of 23 torr and 65 torr, respectively, which one has STRONGER IMFs?

B

400

Why is it harder to boil salt water versus pure water?

Entropy! and competing eq

Solution Calculations

100

What is the M of 23.5 g of NaCl dissolved into 250 mL total solution? 

1.6 M

200

How many grams of glucose (180.14 g/mol) are in 2.00 kg of a 0.250 molal solution? 

90.1 g 

300

What volume (in mL) of a soft drink that is 10.5% sucrose by mass contains 78.5 g of sucrose.  (density of solution= 1.04 g/mL) 

719 mL

400

What is the molarity of a 6.56% by mass glucose solution? The density of the solution is 1.03 g/mL and the molar mass of glucose is 180.16 g/mol

0.375 M

500

How would you make a 1.20 M solution of NaCl?  What do you weigh out, what glassware do you need, etc

70.1 g NaCl etc

FP/BP/Vapor Pressure

100

Why is it harder to freeze salt water versus pure water?

Entropy! (and competing eq)

200

Which of these solutions will have the highest BP?

a. 1.25 M C₆H₁₂O₆

b. 1.25 M KNO₃

C. 1.25 M Ca(NO₃)₂

D. They will all have the same BP

C

300

What mass of glucose should be dissolved in 10.0 kg of water to obtain a solution with a freezing point of -4.2^oC? Kf = 1.86 ^oC/m 

4.1 kg

400

A solution contains a mixture of A (P^o = 87 mmHg) and B (P^o = 122 mmHg), both of which are volatile.  The mole fraction of A is 0.35.  What is the total vapor pressure of the solution?

110 mmHg