% Error : % Error A quantitative comparison between your value (determined in an experiment) and an accepted value.
How to Calculate % Error : How to Calculate % Error % Error = | Theoretical value - Experimental value | Theoretical value _________________________________ Theoretical value might also be called literature value
Theoretical value might also be called the accepted value X 100%
Example of % Error : Example of % Error A + B C We calculate that if all goes well, we should isolate 2.23 grams of C.
Theoretical value = 2.23 g Now we actually do reaction but we isolate 1.26 g of C
Experimental value = 1.26 % Error = (2.23 g - 1.26 g) 2.23 g _____________ X 100%
Example of % Error : Example of % Error A + B C We calculate that if all goes well, we should isolate 2.23 grams of C.
Theoretical value = 2.23 g Now we actually do reaction but we isolate 1.26 g of C
Experimental value = 1.26 % Error = 0.97 g 2.23 g _____________ X 100%
Example of % Error : Example of % Error A + B C We calculate that if all goes well, we should isolate 2.23 grams of C.
Theoretical value = 2.23 g Now we actually do reaction but we isolate 1.26 g of C
Experimental value = 1.26 % Error = X 100% 0.4349775 % Error = 43.49775 % 43.5 %
Sample Problems : Sample Problems Vicky made a mistake when measuring the volume of a container. She found the volume to be 70 liters. The actual
value for the volume is 45 liters. What is the percent error
calculated in percentage? Experimental Data: 4.0 g, 4.2 g, 4.1 g
The actual value is reported to be 4.23 g.
What is the percent error?
1. Linear Relationships(Directly Proportional) : 1. Linear Relationships(Directly Proportional) When the line of best fit is linear (a straight line), the variables are directly proportional to each other.
The equation y = mx + b defines the line.
m represents slope
b represents the y-intercept
As one variable increases, so does the other. y = mx + b
2. Non-Linear Relationships:Inverse Relationship : 2. Non-Linear Relationships:Inverse Relationship y = k/x
As one variable increases, the other variable decreases
“k” is called a constant:
…k is whatever number “fixes” the equation and makes it true for x and y.
Density : Density D = M
V D = density (g/ml)
M = mass (g)
V = volume (ml or cm3) Object 2
Mass: 20 g
Volume: 2 ml Object 1
Mass: 5.0 g
Volume: 3.0 cm3 Object 3
Mass: 7.0 g
Volume: 10 ml Object 4
Density: .820 g/ml
Volume: 15.0 ml