Labpaq Lab Techniques and Measurements

Only available on StudyMode
  • Download(s) : 713
  • Published : March 4, 2013
Open Document
Text Preview
Title: Observations of Chemical Changes
Purpose: To learn about the international system of units (SI), to become familiar with common lab equipment and techniques, to gain proficiency in determining volume, mass, length, and temperature of a variety of items using common laboratory measurement devices, to learn to combine units to determine density and concentration, and to use laboratory equipment to create serial dilutions and determine the density and concentration of each dilution. Procedure: Measure the volume, mass, length and temperature of a variety of items. Create dilution of sugar water.

Data Tables and Observation: Fill out the data sheet (below) for the experiment and submit with this form. Recording data carefully and accurately is very important. Be sure to keep notes of experimental errors or difficulties during this experiment.

Exercise 1
Length Measurements:

For the measurement below carefully read the ruler to the best degree of accuracy. The reading you make in centimeters should have two decimals. In other words can you estimate the difference between 10.1 cm and 10.2 cm? If so, you would report 10.10 cm or 10.15 cm whichever your eyes see. If you see 10 cm, than you would report 10.00 cm. The mm reading may be estimated to +/- 0.1 mm. Refer to the lab for more information. You can obtain an accurate ruler from the web, if you don’t have one.

Record the measurement to the correct number of significant figures. (1 point)
Data Table 1: Length Measurements
Object
Length (cm)
Length (mm)
Length (m)

CD or DVD
12.0 cm
120.0 mm
0.12 m

Key
5.0 cm
50.0 mm
0.05 m

Spoon
15.0 cm
150.0 mm
0.15 m

Fork
15.5 cm
155.0 mm
0.155 m

Temperature Measurements: Look closely at the thermometer and record to the best number of significant figures, +/- 0.1 oC. In other words report, for example 24.0 oC, not 24 oC. Calculate the last 2 columns. (1 point)

Data table 2: Temperature measurements
Object
Temperature (oC)
Temperature (oF)
Temperature (K)

Hot from tap
41.0
105.8
314.15

Boiling
98.0
208.4
371.15

Boiling for 5 minutes
99.0
210.2
372.15

Cold from tap
17.0
62.6
290.15

Ice water – 1 min
2.0
35.6
275.15

Ice water – 5 min
1.0
33.8
274.15

Mass measurements: Take some time to study the balance and notice the correct number of decimals and sig figs. For example 5 grams would read 5.0 g so you must report 5.0 g. (1 point)

Data Table 3: Mass Measurements
Object
Estimated Mass (g)
Actual Mass (+/- 0.1 g)
Actual Mass (kg)

Pen or Pencil
8.0 g
11.6 g
0.0116 kg

3 Pennies
6.0 g
8.1 g
0.0081 kg

1 Quarter
5.0 g
5.7 g
0.0057 kg
2 Quarters,
3 Dimes
25.0 g
18.2 g
0.0182 kg
4 Dimes,
5 Pennies
18. 0 g
22.7 g
0.0227 kg
3 Quarters,
1 Dime,
5 Pennies
35.0 g
32.9 g
0.0329 kg

Key
4.0 g
8.1 g
0.0081 kg
Key, 1 Quarter,
4 Pennies
20.0 g
24.9 g
0.0249 kg

Exercise 2

Volume and Density Measurements
(0.5 point) volume should be to +/- 0.1 mL. In other words report for example, 5.0 mL, not 5 mL.

Data Table 4: Liquid Measurements

Mass A
Mass B
Mass B - A

Liquid
Volume (mL)
Graduate Cylinder (g)
Graduate Cylinder with liquid (g)
Liquid (g)
Density (g/mL)
% Error

Water
5 mL
15.8 g
20.8 g
5.0 g
1.0 g/mL
0.00%

Isopropyl alcohol
10 mL
15.8 g
19.8 g
4.0 g
0.4 g/mL
49.12%

Calculate the density of the tap water using significant figures and units carefully. In addition determine the % error. For full credit, show your work. (1.5 points)

20.8g (graduated cylinder w/ water in it)-15.8 g (empty, clean, dry graduated cylinder)=5.0 g (water)

5.0g (mass of water)/5 mL (water volume)=1.0g/mL

Calculate the density of the isopropyl alcohol using significant figures and units carefully. In addition determine the % error. For full credit, show your work. (1.5 points)

19.8g (graduated cylinder w/ rubbing alcohol in it)- 15.8 g (empty,...
tracking img