1. Solve Chemistry Math Problems
“When in doubt, go to moles.”

2. Use Dimensional Analysis
Analyze the labels
Change them with converting fractions
Do the “number math” last (after all the labels cross off so they are the same on both sides of your equation.)

3. 1: Identify your goal unit:
What label goes with the number you want to find?
Is it grams, moles, liters, joules, or some other unit?
Is it a combined unit, like moles/liter, or cal/(gram*Celsius)?

4. 2. Write the label
Write an = sign, and leave a space for the answer number on the far right side of your paper.
Then write the label you want with your answer.

5. 3. Choose a number to convert
Choose one of the numbers you’re given, based on its similarity to the goal unit. On the far left side of your paper, write that number as a two line, flat fraction.

6. 4. Convert units multiply by two line, flat fractions
Cross out any unit label you find on both the top line and the bottom line.
Continue adding converting fractions and crossing out labels.
The top must equal the bottom.
Memorize the common converting fractions.
When all the labels left before the equals sign match the labels after the equals sign, you’re almost finished.

7. 6. Multiply then divide
Multiply all the numbers across the top line of your two line fractions.
Then divide that answer by each of the numbers across the bottom.
Write the result before the goal label on the right.

8. Common converting fractions
Atomic mass, formula mass:
X grams = 1 mole
STP liters of any gas:
22.4 Liters = 1 mole
Avogadro’s Number:
6.02X1023 particles = 1 mole

9. Gas Equations Dalton’s Law of Partial Pressures:
P1 + P2 + P3 … = Ptotal
Combined Gas Law:
P1V1T2 = P2V2T1 (T must be Kelvin)
Ideal Gas Law:
PV = nRT

10. Solutions
Molarity = M
M = moles of solute / Liter of solution

11. Heat and Energy Specific Heat : changing temperature # calories/gramoC
Heat of fusion: melting or freezing
#Joules/mole
Heat of vaporization: boiling or condensing
# Joules/mole

12. Units Moles Grams Liters Energy: calories or Joules
Temperature: Kelvin, Celsius, Fahrenheit
Pressure: Atmospheres, Torr, mm Hg, KiloPascals
Particles (atoms, ions, electrons, molecules, formula units…)

13. Prefixes Use these as converting fractions, too. Mega = M = 106
Kilo = K = 103
centi = c = 10-2
milli = m = 10-3
micro = “mu” (Greek letter) = 10-6

14. Liters of A Liters of B Grams of A Moles of A Moles of B Grams of B
X Ratio
Liters of B
X Ratio X
22.4 1/
22.4 X
22.4 1/
22.4
Grams of A
Moles of A
Moles of B
Mole/Grams
Grams of B
X Ratio
Grams/Mole
X Ratio
Grams/Mole
Mole/Grams
1/6.02
1023
X6.02
1023
1/6.02
1023
X6.02
1023
Particles of A
X Ratio
Particles of B
X Ratio
Mole Map

15. Learn the system
Dimensional analysis is a procedure you can use to solve most problems.
It’s not just for chemistry.
You will be given many equations on the SOL test.
You still need to memorize some equations.

16. Good Luck!