Lab Practical Study Guide

1. Be able to read a thermometer, read & use calipers, triple beam balance, and graduated cylinders.

2. A graduated cylinder contains 234 mL of a solution of sugar-water. It has a mass of 428 g. The mass of the empty graduated cylinder is 166 g.
A. Calculate the density of the sugar-water, in g / mL.
B. If all of the water were evaporated from the graduated cylinder, how many pounds of sugar would remain? (1 pound = 453.5 grams)
C. To prepare half a liter of a sugar-water solution that is exactly twice as sugary as this solution, how many grams of sugar would be needed?

3. Practice delivering 1.0 mL, 2.0 mL, and 3.0 mL of water into a plastic cup using a disposable pipet. Check that the weights of your water samples are 1.0 g, 2.0 g, and 3.0 g respectively.

4. Be able to calculate the volume of one drop of ethanol using a calibrated plastic pipet.

5. Be able to distinguish between a substance that has undergone a chemical change vs. a physical change.

6. Be able to identify the solution containing phenolphthalein among a group of other colorless aqueous solutions containing acids and bases.

7. A graduated cylinder contains 96.0 mL of a solution of salt water. It has a mass of 210.7 g. The mass of the empty graduated cylinder is 102.4 g.
A. Calculate the density of the salt water, in g / mL.
B. The salt water in this cylinder was obtained as follows: a 50 mL scoop of salt-sand mixture weighing 66 grams was combined with 200 mL water, and stirred to dissolve the salt. After settling overnight, about half of the salt water was poured into a 100 mL graduated cylinder and weighed.

How much salt is present in the graduated cylinder? ____________________g
C. How many grams of salt were added to 5 lbs. Of sand in order to prepare this salt-sand mixture? Assume that all of the salt in the original salt-sand sample is contained in the graduated cylinder, and that the 50 mL sample accurately represents the larger salt-sand mixture.

___________________grams

8. How many calories would be required to raise the temperature of 150 mL of water at 10 o C to 40 o C? (One calorie is the amount of heat required to raise the temperature of 1 g of water 1 o C.

9. A. Use the calipers to measure the thickness of 5 pennies, to the nearest 0.001 of an inch.
B. Convert this value to cm. (1 inch = 2.54 cm)
C. What is the thickness of ONE penny, in mm? ------------------------------------------
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You have the option for this test to take it either as an individual or as a member of a study group of FOUR students. You may pick the members of your study group.

Q. How will grades be calculated for study group members?

John 62
Jane 84
Elmo 94
Tess 54
___________
Total = 62 + 84 + 94 + 54 = 294

294 / 4 = 73.5

Grades:

John: (62 + 73.5) / 2 = 68
Jane: (84 + 73.5) / 2 = 79
Elmo: (94 + 73.5) / 2 = 84
Tess: (54 + 73.5) / 2 = 64