1. The Math of Chemistry Test- Things to know!!!

2. Conversion of Celsius to Kelvin and what is Kelvin
K = ⁰C
Kelvin is an absolute scale, meaning it has no negative values. OK is the lowest temperature there can be. At this temperature there is no motion, even in molecules
What is 37 ⁰C in K?
310K
What is 373K in ⁰C?
100 ⁰C (water boiling)

3. Definition of accuracy and precision
Accuracy is how close you are to the accepted value, where as precision is how close you are to all of your other values
If the accepted value is 4 and you got 2, 3, 4 and 6, you are neither accurate or precise

4. What is and what constitutes a sig fig and what are the rules for calculations
The only time a zero is not significant is:
0.0001
1000
All non zero numbers are significant
+ and -, answer can’t have more decimal place than the least number of decimal in the starting values
* and /, answer can’t have more sig figs the least amount in starting values

5. Mass versus weight Mass is how much matter an object contains
Weight is how much gravity is acting on that mass
Weight changes depending on where you are, mass does not

6. Conversion to and expansion of scientific notation
Always one number in front of the decimal place
Exponent is how many time you had to move the decimal
Positive exponent for whole numbers
Negative for non whole number
6.02x1023 is 602,000,000,000,000,000,000,000
1.45x10-5 is

7. What density is, and how to calculate it, and use it to calculate mass or volume. What happens to objects and liquids when heated in regards to density
Density is a measure of mass per unit volume d=m/V
What is the volume of an object that has a density of 0.88g/mL and a mass of 4.0g?
4.5mL
Objects expand with heat and contract with cold.

8. Two ways to calculate volume
LxWxH
Volume displacement

9. Conversion between metric units and why we like to use it
K-kilo 1,000 1Kg=1,000g
d-deci g=10dg
c- centi g=100cg
m-milli g=1,000mg
The metric system uses powers of 10 to convert between units

10. What digit is estimated in a measurement
The last digit is always estimated in a measurement

11. Percent error calculations
% error = |theoretical - actual| x 100
theoretical
What is your % error if the accepted value is and you measured ?
8.55%

12. How to take an average
Add all values and divide by the number of values you added
Your number should be close to the original values
What is the average of 7.00, 5.00, 9.00, 8.00
7.25

13. Why was your graphical density in the density lab, for most of you, a more accurate value
The trendline was forced through zero. At zero mass you should have zero volume.

14. Using moles in calculations
1 mole is equal to 6.02x1023 anything
So 1 mole of pencils is…………
How many moles of trees do you have if you have a forest that has 8.42x1024 trees
14.0 trees
If you have 6.98 moles of water, how many molecules of water do you have?
4.20x1024 molecules of water