measurements and calculations chapter 2. quantitative observation comparison based on an accepted...
TRANSCRIPT
![Page 1: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/1.jpg)
Measurements and
Calculations
Chapter 2
![Page 2: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/2.jpg)
Quantitative Observation Comparison Based on an Accepted Scale
◦ e.g. Meter Stick Has 2 Parts – the Number and the Unit
◦ Number Tells Comparison◦ Unit Tells Scale
![Page 3: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/3.jpg)
Technique Used to Express Very Large or Very Small Numbers
Based on Powers of 10
![Page 4: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/4.jpg)
1. Move the decimal point so there is only one non-zero number to the left of it. The new number is now between 1 and 9
2. Multiply the new number by 10n
◦ where n is the number of places you moved the decimal point
3. Determine the sign on the exponent n◦ If the decimal point was moved left, n is +◦ If the decimal point was moved right, n is –◦ If the decimal point was not moved, n is 0
![Page 5: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/5.jpg)
1 Determine the sign of n of 10n
◦ If n is + the decimal point will move to the right◦ If n is – the decimal point will move to the left
2 Determine the value of the exponent of 10◦ Tells the number of places to move the decimal
point3 Move the decimal point and rewrite the
number
![Page 6: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/6.jpg)
75,000,000
0.0005710
0.0000000011
8,031,000,000
![Page 7: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/7.jpg)
2.75 x 10-7
5.22 x 104
7.10 x 10-5
9.38 x 1012
![Page 8: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/8.jpg)
Change to scientific notation
41080.642
1.8732
Change to standard notation
0.00065 x 106
391 x 10-2
![Page 9: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/9.jpg)
![Page 10: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/10.jpg)
All units in the metric system are related to the fundamental unit by a power of 10
The power of 10 is indicated by a prefix
The prefixes are always the same, regardless of the fundamental or basic unit
![Page 11: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/11.jpg)
![Page 12: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/12.jpg)
![Page 13: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/13.jpg)
SI unit = meter (m)◦ About 3½ inches longer than a yard
1 meter = one ten-millionth the distance from the North Pole to the Equator = distance between marks on standard metal rod in a Paris vault = distance covered by a certain number of wavelengths of a special color of light
Commonly use centimeters (cm)
◦ 1 m = 100 cm◦ 1 cm = 0.01 m = 10 mm◦ 1 inch = 2.54 cm (exactly)
![Page 14: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/14.jpg)
![Page 15: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/15.jpg)
Measure of the amount of three-dimensional space occupied by a substance
SI unit = cubic meter (m3) Commonly measure solid volume in cubic
centimeters (cm3 (cm x cm x cm))◦ 1 m3 = 106 cm3 ◦ 1 cm3 = 10-6 m3 = 0.000001 m3
Commonly measure liquid or gas volume in milliliters (mL)◦ 1 L is slightly larger than 1 quart◦ 1 L = 1 dL3 = 1000 mL = 103 mL ◦ 1 mL = 0.001 L = 10-3 L◦ 1 mL = 1 cm3
![Page 16: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/16.jpg)
![Page 17: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/17.jpg)
Measure of the amount of matter present in an object
SI unit = kilogram (kg) Commonly measure mass in grams (g) or
milligrams (mg)◦ 1 kg = 2.2046 pounds, 1 lbs.. = 453.59 g◦ 1 kg = 1000 g = 103 g, 1 g = 1000 mg = 103 mg◦ 1 g = 0.001 kg = 10-3 kg, 1 mg = 0.001 g = 10-3
g
![Page 18: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/18.jpg)
![Page 19: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/19.jpg)
250 mL to Liters
1.75 kg to grams
88 daL to mL
![Page 20: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/20.jpg)
475 cg to g
328 hm to Mm
0.00075 nL to cL
![Page 21: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/21.jpg)
A measurement always has some amount of uncertainty
Uncertainty comes from limitations of the techniques used for comparison
To understand how reliable a measurement is, we need to understand the limitations of the measurement
![Page 22: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/22.jpg)
To indicate the uncertainty of a single measurement scientists use a system called significant figures
The last digit written in a measurement is the number that is considered to be uncertain
Unless stated otherwise, the uncertainty in the last digit is ±1
![Page 23: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/23.jpg)
Nonzero integers are always significant
◦ How many significant figures are in the following examples: 2753
89.659
0.281
![Page 24: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/24.jpg)
Zeros ◦ Captive zeros are always significant◦ How many significant figures are in the
following examples: 1001.4
55.0702
0.4900008
![Page 25: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/25.jpg)
Zeros ◦ Leading zeros never count as significant figures◦ How many significant figures are in the
following examples: 0.00048
0.0037009
0.0000000802
![Page 26: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/26.jpg)
Zeros ◦ Trailing zeros are significant if the number has a
decimal point◦ How many significant figures are in the
following examples: 22,000 63,850. 0.00630100 2.70900 100,000
![Page 27: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/27.jpg)
Scientific Notation◦ All numbers before the “x” are significant. Don’t
worry about any other rules.◦ 7.0 x 10-4 g has 2 significant figures◦ 2.010 x 108 m has 4 significant figures
![Page 28: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/28.jpg)
If the digit to be removed• is less than 5, the preceding digit stays the
same Round 87.482 to 4 sig figs.
• is equal to or greater than 5, the preceding digit is increased by 1 Round 0.00649710 to 3 sig figs.
![Page 29: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/29.jpg)
In a series of calculations, carry the extra digits to the final result and then round off◦ Ex: Convert 80,150,000 seconds to years
Don’t forget to add place-holding zeros if necessary to keep value the same!!◦ Round 80,150,000 to 3 sig figs.
![Page 30: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/30.jpg)
Count the number of significant figures in each measurement
Round the result so it has the same number of significant figures as the measurement with the smallest number of significant figures
14.593 cm x 0.200 cm =
3.7 x 103 x 0.00340 =
![Page 31: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/31.jpg)
Calculators/computers do not know about significant figures!!!
Exact numbers do not affect the number of significant figures in an answer
Answers to calculations must be rounded to the proper number of significant figures◦ round at the end of the calculation
![Page 32: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/32.jpg)
Exact Numbers are numbers known with certainty
Unlimited number of significant figures They are either
◦ counting numbers number of sides on a square
◦ or defined 100 cm = 1 m, 12 in = 1 ft, 1 in = 2.54 cm 1 kg = 1000 g, 1 LB = 16 oz 1000 mL = 1 L; 1 gal = 4 qts. 1 minute = 60 seconds
![Page 33: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/33.jpg)
Many problems in chemistry involve using equivalence statements to convert one unit of measurement to another
Conversion factors are relationships between two units
Conversion factors generated from equivalence statements◦ e.g. 1 inch = 2.54 cm can give or
![Page 34: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/34.jpg)
Arrange conversion factor so starting unit is on the bottom of the conversion factor
You may string conversion factors together for problems that involve more than one conversion factor.
![Page 35: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/35.jpg)
Find the relationship(s) between the starting and final units.
Write an equivalence statement and a conversion factor for each relationship.
Arrange the conversion factor(s) to cancel starting unit and result in goal unit.
![Page 36: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/36.jpg)
Check that the units cancel properly
Multiply all the numbers across the top and divide by each number on the bottom to give the answer with the proper unit.
Round your answer to the correct number of significant figures.
Check that your answer makes sense!
![Page 37: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/37.jpg)
28.5 inches to feet
4.0 gallons to quarts
48.39 minutes to hours
155.0 pounds to grams
2.00 x 108 seconds to hours
![Page 38: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/38.jpg)
682 mg to pounds
3.5 x 10-4 L to cm3
0.091 ft2 to inches2
47.1 mm3 to kL
![Page 39: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/39.jpg)
25 miles per hour to feet per second
4.70 gallons per minute to mL per year
5.6 x 10-6 centiliters per square meter (cL/m2) to cubic meters per square foot (m3/ft2)
![Page 40: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/40.jpg)
Fahrenheit Scale, °F◦ Water’s freezing point = 32°F, boiling point = 212°F
Celsius Scale, °C◦ Temperature unit larger than the Fahrenheit◦ Water’s freezing point = 0°C, boiling point = 100°C
Kelvin Scale, K◦ Temperature unit same size as Celsius◦ Water’s freezing point = 273 K, boiling point = 373
K
![Page 41: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/41.jpg)
Fahrenheit to Celsius oC = 5/9(oF -32)
Celsius to Fahrenheit oF = 1.8(oC) +32
Celsius to Kelvin K = oC + 273
Kelvin to Celsius oC = K – 273
![Page 42: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/42.jpg)
![Page 43: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/43.jpg)
![Page 44: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/44.jpg)
![Page 45: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/45.jpg)
![Page 46: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/46.jpg)
86oF to oC
-5.0oC to oF
352 K to oC
12oC to K
248 K to oF
98.6oF to K
![Page 47: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/47.jpg)
Density is a property of matter representing the mass per unit volume
For equal volumes, denser object has larger mass For equal masses, denser object has small
volume Solids = g/cm3
◦ 1 cm3 = 1 mL Liquids = g/mL Gases = g/L Volume of a solid can be determined by water
displacement Density : solids > liquids >>> gases In a heterogeneous mixture, denser object sinks
Volume
MassDensity
![Page 48: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/48.jpg)
Volume
MassDensity
Density
Mass Volume
Volume Density Mass
![Page 49: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/49.jpg)
![Page 50: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/50.jpg)
![Page 51: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/51.jpg)
What is the density of a metal with a mass of 11.76 g whose volume occupies 6.30 cm3?
What volume, in mL, of ethanol (density = 0.785 g/mL) has a mass of 2.04 lbs?
What is the mass (in mg) of a gas that has a density of 0.0125 g/L in a 500. mL container?
![Page 52: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/52.jpg)
![Page 53: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/53.jpg)
To determine the volume to insert into the density equation, you must find out the difference between the initial volume and the final volume.
A student attempting to find the density of copper records a mass of 75.2 g. When the copper is inserted into a graduated cylinder, the volume of the cylinder increases from 50.0 mL to 58.5 mL. What is the density of the copper in g/mL?
![Page 54: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/54.jpg)
Percent error – absolute value of the error divided by the accepted value, multiplied by 100%.
% error = measured value – accepted value x 100%
accepted value Accepted value – correct value based on
reliable sources. Experimental (measured) value – value
physically measured in the lab.
![Page 55: Measurements and Calculations Chapter 2. Quantitative Observation Comparison Based on an Accepted Scale ◦ e.g. Meter Stick Has 2 Parts – the Number](https://reader035.vdocuments.net/reader035/viewer/2022062518/56649e155503460f94aff5c4/html5/thumbnails/55.jpg)
In the lab, you determined the density of ethanol to be 1.04 g/mL. The accepted density of ethanol is 0.785 g/mL. What is the percent error?
The accepted value for the density of lead is 11.34 g/cm3. When you experimentally determined the density of a sample of lead, you found that a 85.2 gram sample of lead displaced 7.35 mL of water. What is the percent error in this experiment?