Accuracy
How close a measurement is to the true value
Precision
A measure of how close a series of measurements are to one another
Percent Error
(Experimental Value - True Value) / True Value x 100
If the density of water is reported as 0.998754 g/mL, and you calculate the density of water to be 0.9956312 g/mL, what is the percent error of your measurement? Report your answer to three significant figures.
0.313%
You have compiled all the data from the above experiment, and have reported all values as measurement � uncertainty. The four pieces of data are represented below:
Method A 5.0�0.1
Method B 9.9�0.3
Method C 7.2�0.2
Method D 6.7�0.5
Which data set (A,B,C,D
Method A
What is the tolerance of this graduated cylinder?
10
What is the volume � uncertainty of liquid in this graduated cylinder?
14 � 1 mL
How many significant figures are in the following measured value?
248.22
5
How many significant figures are in the following measured value?
30,000
1
How many significant figures are in the following measured value?
1.00
3
How many significant figures are in the following measured value?
0.002560
4
Report the answer to the following calculation to ONE significant figure.
65.22 / 782.2
0.08
Report the answer to the following calculation to the correct number of significant figures.
9884.225 / 24.1
410.
Report the answer to the following calculation to the correct number of significant figures.
17.6 + (23.66 / 0.322)
91.1
Calculate the mean and standard deviation for the following data set. Report the mean in the first blank and the standard deviation in the second blank.
21.552
21.556
20.556
20.556
21.1 � 0.6
You measure a total volume of 75mL to make a solution, and are interested in calculating the error in that volume. The data below describes how the volume was measured.
30-mL was delivered 2 times using a 100-mL grad cylinder (graded every 1mL)
15-mL was
75.0 � 0.7 mL
You are tasked with calculating the concentration of a NaCl solution. The procedure you used to prepare the solution is below:
Moles of NaCl: 0.0655 mol � 0.0008 mol
Volume of water: 0.500 L � 0.005 L
Small amount of water added to 500-mL volumetric flask
0.131 � 0.002 M
Tolerance
half the graduation on a device
The objectives of this lab are to identify which of the following pieces of glassware will provide the most accurate measurement and which will provide the most precise measurement. How will you determine the piece of glassware that provides the most prec
(B) smallest uncertainty
You transfer 25.00 - mL of water to a glass beaker sitting on a balance. The resulting mass of the beaker and the water is 60.031 - g. If the mass of the beaker is 33.662 - g, what is the density of the solution?
1.055
Rapunzel and Eugene are calculating the area of Rapunzel's new art studio. Rapunzel measures the length of the room and Eugene measures the width. They take the measurements a few times, and then average their measurements.
The average length of the room
8,880 � 300