Chemistry Unit 2: Measurement and Analysis
What is the percent error formula?
% error = (error / accepted value) x 100
The accepted value for a quantity is 5.67. If the measures value is 5.89 g, what is the percent error?
3.88%
Convert 89 degrees Fahrenheit to Celsius and Kelvin
31.7 degrees Celsius, and 305K
Convert 360s to ms
360,000 ms
What is the sum of these values to the appropriate number of significant figures?: 17.358+3.502+20.14=
41.00
Convert 4,800 g to kg
4800000 kg
Write 4 in scientific notation
4x10^1
How many significant figures are in 1.0023
5
How many significant figures are in 60110 x 10^6
5 (because you include digits in scientific notation)
Scientific notation
Can be used to express any number as a number between 1 and 10 (coefficient) multiplied by 10 raised to a power (exponent)
Density formula - g/cm^3 for solids
D=m/V
Base unit
Defined unit in a system of measurement based on an object or event in the physical world
Error
Difference between an experimental value and an accepted value
What is the error formula?
Error = Experimental - Accepted
Percent error
Expresses error as a percentage of the accepted value
Fahrenheit to Celsius conversion
F=1.8 (degrees Celsius) + 32
Significant figures
Include all known digits plus 1 estimated digit
Conversion factor
Is a ratio of equivalent values having different values
Accuracy
Refers to how close a measured value is to an accepted value
Precision
Refers to how close a series of measurements are to one another
Dimensional analysis
Systematic approach to problem solving that uses a conversion factor to move from 1 unit to another
What should you do when rounding addition/subtraction problems?
1. Arrange values so decimal points align 2. Identify value with fewest places after decimal place and round answer to that number of places
Volume
The amount of space occupied by a 3-dimensional figure in cubic meters
Convert 0 Kelvin to Celsius and Fahrenheit
-273 degrees Celsius, -459.4 degrees Fahrenheit
Convert -40 degrees Celsius to Fahrenheit and Kelvin
-40 degrees Fahrenheit, 233 Kelvin
What are the base units?
-Time: Seconds (s) -Length: Meters (m) -Mass: Kilograms (kg) -Temperature: Kelvin (K) -Pressure: Pascal (Pa) -Amount of substance: Moles (mol) -Luminous intensity: Candela (Cd) -Electric current: Ampere (A)
What are the significant figure rules?
1. Nonzero numbers are always significant 2. Zeros between nonzero numbers are always significant 3. All final zeros to the right of the decimal area always significant 4. Placeholder zeros are not significant. To remove placeholder zeros, write it in scientific notation 5. Counting numbers and defined constants have infinite numbers of significant figures
What should you do when rounding multiplication/division problems?
1. You must have the same number of significant figures as measurement with the fewest significant figures
When rounding numbers, what should you do?
To round, find the significant figures in the question. Then look at the number to right of it, if it's less than 5 round down
Meter
Unit of length
Kilogram
Unit of mass equal to 1,000 grams
Kelvin
Unit of temperature
Seconds(s)
Unit of time
Derived unit
Unit that is defined by a combination of base units
Volume formula - Cubic meter (m^3)
V=m/d
How many significant figures are in 0.001
1
Write 12300000 in scientific notation
1.23x10^7
What are the steps to dimensional analysis?
1.Write down what you're given 2. Set up fence post 3. In next section, write conversion factor, continue process until arrived at unit 4. Find product of top and divide by product of bottom
What does 1mL and 1 Liter convert to?
1mL= 1 cubic centimeter (cm^3 or cc) 1L = 1 cubic meter (m^3)
How many significant figures are in 820000
2
The volume of a basketball is 455.9 cm^3. If its mass is 925 grams, what is the density of the basketball?
2.03 g/cm^3.
Convert 100 degrees Celsius to Fahrenheit and kelvin
212 degrees Fahrenheit, 373K
Write 0.002 in scientific notation
2x10^3
How many significant figures are in 0.00575
3
What is the product of these numbers to the appropriate number of significant figures?: 56.2x9.2057=
517
Convert 6800x10^3 cm to km
68,000 km
Convert 72 g to mg
72,000 mg
Celsius to Kelvin conversion
K= Degrees Celsius + 273
What is kilos, centis, millis all worth?
Kilo = 1,000 of a basic unit Centi = 100 of a basic unit Milli = 1,000 of a basic unit
What is volume measured in?
Liters, or milliliters
In scientific notation, numbers less than 1 have what exponents, and numbers greater than 1 have what exponents?
Negative and positive
