Lecture 1 Flashcards
Celsius to Fahrenheit
F=1.8C+32
Celsius to Kelvin
K=C+273
2^-1
2^-1=1/(2^-1)=1/2
g/cm^3
g/cm^3=g • cm^-3
10^3 • 10^-4
When powers are multiplied, the exponents are added.
10^3 • 10^-4 = 10^-1
cm^3/cm
When powers are divided, the exponents are subtracted
cm^3/cm= cm^2
Express in scientific notation
11,000,000
1.1 x 10^7
Express in scientific notation
0.0000000045
4.5 x 10^-9
Express in a regular number
1.02 x 10^-3
0.00102
Express in a regular number
4.26 x 10^4
42600
Express in a regular number
6.02 x 10^23
602000000000000000000000
(4.8 x 10^-6)/(1.2 x 10^3)(2.0 x 10^-8)
2.0 x 10^ -1 or 0.2
Water boils
212F or 100C
Water freezes
32F or 0C
Charles Law
V/T=k
Volume or gas is directly proportional to the temperature (when pressure is constant
Boyles law
Volume and pressure are inversely proportional when temperature is constant
PV=k
Physical properties
A physical property can be observed or measured without changing the chemical make up of a substance
A physical change occurs without producing a new chemical substance
Precision
The consistency and reproducibility of a test (reliability)
Increased precision = decreased standard deviation
Accuracy
The trueness of test measurements (validity)
Improving accuracy
Improved by making replicate measurements and taking the average
Percent error
Accuracy is assessed by calculating the percent error
%error=( (measured value-“true” value)/(“true” value) )x 100%
Improving precision?
Improved by careful lab technique and or using instruments with more significant figures. More significant figures imply greater precision
Standard deviation
Precision is quantified by standard deviation
Standard deviation= £(measurements-average of measurement)^2/(number of measurements - 1)
Length
Meter (m)