Name ______
Hour______
Chemistry Packet #2 /
Measurement and Uncertainty /
1

Name ______

Hr ___

Analyzing Data

Section 2.1 Units and Measurement

Notes:

  1. Complete the following table:

SI Base Units
Quantity / Base Unit / Unit Abbreviation
s
Mass
Kelvin
Length
liter
  1. What number do the following prefixes represent:

Giga ______

Mega ______

Kilo ______

Hecto______

Deka______

Deci______

Centi______

Milli______

Nano______

  1. Use a ruler or meter stick and record the following:
  1. Measure this line ______answer in cm ______
  1. Measure this line ______answer in mm______
  1. Measure this line______answer in dm______
  1. Measure your height answer in cm______

answer in m______

  1. Measure the width of your deskanswer in cm______
  1. Measure one floor tileanswer in mm______

2

Metric Conversions &Dimensional Analysis

DIRECTIONS: Solve the following problems by (a) moving the decimal and (b) dimensional analysis. Show the complete set-up for each problem.

  1. Convert 15.9 mm to its equivalent measurement in m.
  2. 15.9 mm = ______m
  1. Convert 0.0982 g to its equivalent measurement in mg.
  2. 0.0982 g = ______mg
  1. Convert 13,455 g to its equivalent measurement in kg.
  2. 13,455 g = ______kg
  1. Convert 32.5 mL to its equivalent measurement in L.
  2. 32.5 mL = ______L
  1. Convert 3.55 mm to its equivalent measurement in km.
  2. 3.55 mm = ______km
  1. Convert 143.75 mL to its equivalent measurement in cm3.
  2. 143.75 mL = ______cm3
  1. Convert 14.0 m to its equivalent measurement in mm.
  2. 14.0 m = ______mm
  1. Convert 35.1 kg to its equivalent measurement in g.
  2. 35.1 kg = ______g
  1. Convert 57 L to its equivalent measurement in mL.
  2. 57 L = ______mL

3

Metric-English Conversions

Notes:

Solve the following problems using dimensional analysis. Show your set up.

1. 5 lb = ____ g

2. 700 mg = ____ g

3. 500 mL = ____ L

4. 2.3 qts = ____ L

5. 7.5 ft = ____ m

6. 60 in = ____ cm

7. 50 mi = ____ km

8. 65.8 cm3 = ____ qts

9. Challenge 100 yds = ____ m

4
Experiment #2-1

Uncertainty

Purpose: Use uncertainty values to find a range for laboratory measurements. Relate the reliability of experimental data to uncertainty and percent error.

Procedure:

  1. Three different graduated cylinders with varying volumes of water are at the designated laboratory station. Record the volume of each sample of water in the data table. Include the range of uncertainty in the values.
  1. Two blocks are provided for measurement at a designated laboratory station. Measure the length, width, and thickness of each block using a metric ruler. Record each dimension and their range of uncertainty on the data sheet.

3.The accepted values for the blocks will be provided by your instructor. Use these values to determine your percent of error in measurement. Perform the calculation for the high, medium, and low values.

Data:Table 1

Graduate Cylinder # / Liquid Volume
(+/- mL)
1
2
3

Table 2

Block 1 / Block 2
Low – uncertainty / Medium / High + uncertainty / Low – uncertainty / Medium / High + uncertainty
Length
(cm)
Width
(cm)
Height
(cm)
Volume
(cm3)

Calculations

Percent Error:

Block / l actual – experimental l *100%
actual
1
2

5

Accuracy and Precision

Notes:

Four basketball players measure the length of the court in three trials. The true length of the court is 28 m. Describe their values in terms of accuracy and precision.

Name / Trial1 / Trial 2 / Trial 3 / Average
Kobe / 20 m / 40 m / 33 m / 31 m
Michael / 28 m / 27 m / 29 m / 28 m
Labron / 29 m / 35 m / 15 m / 26 m
Kevin / 35 m / 33 m / 34 m / 34 m

AccuracyPrecision

Kobe
Michael
Labron
Kevin

What is Kevin’s experimental error of measurement?

6

Significant figures

Notes:

Circle the significant figures in the following numbers:

  1. 1234
  2. 0.023
  3. 890
  4. 91010
  5. 9010.0
  6. 1090.0010
  7. 0.00120
  8. 0.00030
  9. 1020010
  10. 1000
  11. 918.010
  12. 0.0001
  13. 0.00390
  14. 8120

More sig fig practice

How many significant figures in the following numbers?

  1. 573.056_____
  2. 300000.0_____
  3. 34500_____
  4. 0.000302_____
  5. 0.0001_____
  6. 231.000023 _____
  7. 87.0334000_____
  8. 9000_____
  9. 46700.01_____
  10. 4520.430010 _____

Solve with the correct number of significant figures

  1. 25 *3= _____
  1. 12.50/5.5 = _____
  1. 4.012 + 3 = _____

14 5.0 - 0.05 = _____

7

CHEMISTRY LAB #2-2GRAPHING

Purpose: To make accurate measurements and plot data in a graph to determine meaning of slope.

Procedure:

Graph I: Use a 10 ml graduated cylinder and an eyedropper to measure the number of drops needed to obtain the volumes as indicated in the data table.

Sketch of Graph

Drops mL

_____2.0

_____3.0

_____5.0

_____7.0

_____9.0

  1. Plot drops of water versus mL of water. Label your axes with titles and numbers.
  1. Determine the slope of the line (rise over run = (y2 – y1)/ (x2 – x1))
  1. Compare your data with that of another group (record yours and theirs below). Is your slope the same?

Graph II Use a string and ruler to measure the circumference of 5 circles. Measure the diameter of the five circles. Enter your values in the data table.

Sketch of Graph

Circle / Diameter
(cm) / Circumference
(cm)
1
2
3
4
5
  1. Plot circumference (Y-axis)vs.diameter (x-axis). Label and number your axes.
  1. Determine the slope for the line on the graph.
  1. What does the slope of the line represent?
  1. Compare the slope of your line to the actual value for  by calculating the percent error.

8

Chapter 2 Scientific Notation

Notes:

1. Convert each of the following into scientific notation

727 ______

172,000 ______

0.000984 ______

2,000 ______

0.0014 ______

2,560,000,000 ______

2. Convert each into decimal form

1.56 x 104 ______

3.6 x 10-2 ______

7.369 x 106 ______

5.9 x 10-5 ______

5.9 x 10-10 ______

9

Lab: Determining the Density of Solids

Notes:

Purpose: To determine the density of solid objects by measuring their mass and volume and then using the formula D = m/V.

Procedure:

  1. Find the mass of a wood cube, wood cylinder, aluminum retangle, aluminum cylinder, and an unknown metal cube. Record these masses in the table provided below.
  1. Measure the length, width, and height of the cubes to determine their volume. Measure the volume of the cylinders using volume by displacement with a graduated cylinder alone or with the use of an overflow can. Record all data in the table provided below.
  1. Calculate the density of each object.

Data:

Object / Mass (g) / Length (cm) / Width (cm) / Height (cm) / Volume
(cm3 or mL) / Density= m/V
(g/cm3 or g/mL)
Wood cube
Wood cylinder
Aluminum rectangle
Aluminum cylinder
Unknown metal cube

10

Conclusions:

  1. How do the densities of the wood cube and cylinder compare? The aluminum rectangle and cylinder?
  1. Does shape affect density? Why or why not?
  1. What are two units for volume?
  1. What is the relationship between cm3 and mL (i.e., 1 cm3= ?mL)?
  1. Based on your data, what can you conclude is true of the density of an object that floats in water?
  1. The density of aluminum = 2.7 g/cm3, calculate the percent error for your results for the rectangle and cylinder. Of the two results, which was more accurate and why?
  1. Given your results and the data below, identify your unknown metal and calculate your percent error:

Metal / Density (g/cm3)
Aluminum / 2.7
Brass / 8.5
Copper / 8.96
Iron / 7.87
Lead / 11.3
Stainless steel / 8.03
zinc / 7.14
  1. What clues helped you choose your unknown answer?

1.

2.

3.

11

Lab: Water Density

Purpose: To find the density of five different volumes of water and to compare those five densities.

Procedure:

  1. Mass a 100 mL graduated cylinder
  2. Add 10 mL of water to the graduated cylinder and mass.
  3. Determine the mass of 10 mL of water (massgraduated cylinder & water – massgraduated cylinder)
  4. Repeat steps 2 & 3 for 30 mL, 50 mL, 80 mL, and 100 mL of water.
  5. Calculate the density of water for each trial based on the values of volume and mass.

Data

Massgraduated cylinder & water (g) / Massgraduated cylinder
(g) / Masswater
(g) / Volume
(mL) / Density = m/V
(g/mL)
10
30
50
80
100

Graph:mass(y-axis)vrs volume(x-axis)

Conclusions:

  1. Based on your data, how does mass of water vary as volume increases?
  1. Based on your data, how does density of water vary as volume increases?
  2. Calculate your percent error using the average of your density data and the actual density of water = 1 g/mL:
  1. What does the slope of the graph represent?

12

Chapter 2 Test Review

Things to know:

  1. SI units and measurement
  2. Metric conversions
  3. Reading measurements
  4. Scientific Notation
  5. Significant Figures
  6. Accuracy and Precision
  7. Calculate percent error
  8. Graphing
  9. Calculate Density
  10. Steps of the scientific method
  11. Lab Equipment

Review Questions

  1. What are the base units and abbreviations for:

Temperature

Volume

Time

Mass

Length

  1. Solve the following problems by moving the decimal or dimensional analysis.
  2. Convert 5.70 g =______mg
  3. Convert 4.37 cm = ______m
  4. Convert 783 kg = ______g
  5. Convert 45.3 mm = ______m
  6. Record the following measurements

All in cmMeasure the cylinder using both rulers:

All in ml

13

  1. Write the following numbers in scientific notation

  1. 0.0045834 mm
  2. 0.03054 g
  3. 438,904 s
  4. 7,004,300,000 g

  1. Write the following numbers in decimal form

  1. 8.348 x 106 km
  2. 3.402 x 103 g
  3. 7.6352 x 10-3 kg
  4. 3.02 x 10-5 s

  1. Indicate how many significant figures are present

  1. 0.0004023 g
  2. 405,000 kg
  3. 0.0084 mL
  4. 508 L

  1. Use the terms accuracy and precise to describe the following data. The actual value is 10.

Name / Trial 1 / Trial 2 / Trial 3 / Average
Fred / 15 / 5 / 10 / 10
Wilma / 4 / 25 / 20 / 16.3
Barney / 9.9 / 10.1 / 10 / 10
Betty / 13 / 12 / 13 / 12.7
  1. The accepted density for copper is 8.96 g/mL. Calculate the percent error for each of these measurements.
  2. 8.86 g/mL
  3. 8.92 g/mL
  4. 9.00 g/mL
  5. Graph the following data

Mass(g) / Volume(mL)
1 / 2
2 / 4
3 / 6
4 / 8
  1. A 5 mL sample of water has a mass of 5 g. What is the density of water?
  1. An object with a mass of 7.5 g raises the level of water in a graduated cylinder from 25.1 mL to 30.1 mL. What is the density of the object?
  1. Define and write the steps of the scientific method.