High School Chemistry : Using SI Units
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Example Questions
Example Question #1 : High School Chemistry
What unit will be used to denote temperature in thermochemistry?
Joules
Kelvin
Celsius
Celsius or Kelvin
Fahrenheit
Kelvin
Temperature is the measure of the average kinetic energy of a system. Kelvin is the SI unit for temperature, and must be used because it is the only scale that does not have any negative numbers possible. At zero Kelvin (absolute zero) and there is absolutely no movement in the system, down to the atomic level.
While temperature is a means of measuring energy in a system, actual heat energy has the unit Joules.
Example Question #1 : High School Chemistry
Which of the following measurements contains 4 significant figures?
1. Any digit with a value 1-9 is always a significant figure
2. Any 0 between two digits 1-9 is always significant
3. If a number is greater than 1 and does not have a decimal point a 0 at the end is not significant because it is a tailing zero
4. If a number is less than 1 any 0 before a digit 1-9 is not significant because it is a leading zero
5. If there is a decimal point in any number, any 0 that follows a non-zero digit is always significant.
Thus, 
Example Question #2 : High School Chemistry
Which has the larger unit listed first?
Centigram and decigram
Kilojoule and megajoule
Picometer and millimeter
Decaliter and kiloliter
Microsecond and nanosecond
Microsecond and nanosecond
The following prefixes are ranked in order from largest to smallest with the power of 10 that the unit represents: peta (P) 
Example Question #4 : Using Si Units
The measurement of 
Units in the metric system can be converted using the correct factor of 10.
Example Question #1 : Using Si Units
A certain metal is weighed on a balance in a weighing boat. Before the metal is added, the mass of the weigh boat is recorded at 
What is the density of the metal?
Density is equal to the mass of the object divided by the volume.
The mass of the metal is figured out by taking the mass of the metal and the weighboat 
The volume of the water is calculated by the displacement of the water so take the final volume and subtract the initial volume.
The density of the metal is calculated by taking the mass divided by the volume.
Example Question #1 : Units
An object is measured to be 
You must use equalities and dimensional analysis to solve for the correct answer:
Each equality allows you to write a conversion factor 2 ways:
Example: 
To cancel out units if there is a unit on top it must be cancelled out by the same unit on the bottom.
To solve you must cancel out units until you get to the proper unit
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