List of Chemical Formulas
Common Name
Chemical Equation
Respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O
Combustion
Hydrocarbons (CxHy) + O2 → CO2 + H2O
Photosynthesis
6CO2 + 6H2O + sunlight → C6H12O6 + 6O2
Ocean acidification
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
Photochemical smog formation
NOx + VOCs + heat + sunlight → smog
Stratospheric ozone depletion
O3 + Cl → O2 + ClO
List of Mathematical Routines
Common Name
Mathematical Formula
Population
Area
Population density
70
Percent growth rate
Rule of 70
Births - Deaths
Number of people
Population growth rate as a percent
x 100
Final - Initial
Final time - Initial time
Rate of change
Final -Initial
Initial
Percent change
x 100
Net Primary Productivity (NPP)
Gross primary productivity (GPP) - Respiration
GPP = Rate of photosynthesis by plants
Gross Primary Productivity (GPP)
GPP can also be expressed as:
PP = Total solar energy captured by plants − Energy lost
G
due to respiration by plants
Fuel efficiency
Distance traveled
Unit of fuel consumed
The 10% Rule
T he 10% rule states that roughly only 10% of energy
transfers between trophic levels in a food chain, with the
rest being lost as heat.
Dimensional Analysis
uantity 1 x
Q
Conversion factor
Quantity 2
=Result
Half-Life
t ½=
ln(2)
λ
LD50
LD50=
Dose
Weight
T ips on how to use these formulas in APES exam
Here are some tips for effectively using the listed formulas on the AP Environmental Science exam:
1. Show All Work: Always show your work when performing calculations, even if they seem simple. This can help
you understand and review your process. Don't forget to include units in your calculations; they provide
important information.
2. Develop Math Sense: Make sure your answers actually make sense. If you calculate something, like a cost of $50
billion per gallon of water, it's likely incorrect. Trust your intuition while checking your answers.
3. Know Conversions: Be familiar with common conversion factors, such as the number of days in a year or hours in
a day. Additionally, remember key population figures, like the U.S. and world populations in scientific notation.
4. Master Metric Prefixes: Understand and convert metric prefixes, from tera to nano. This knowledge will help you
work with various units in scientific calculations.
5. Handle Negative Numbers: Be comfortable with negative numbers and understand how they affect calculations.
For instance, going from -8°C to +2°C represents a 10°C change.
6. Rates: Recognize the various ways to calculate rates, and understand that rates are about how something
changes over time. Also, remember that "per" means division, so miles per gallon is miles driven divided by one
gallon.
7. Use Dimensional Analysis: Use dimensional analysis (factor label) to perform conversions with units and
conversion factors. This method helps maintain the consistency of units in your calculations.
8. Calculate Percentage and Percent Change: Know how to calculate percentages and percent changes. Understand
that percentage is a measure of part divided by the whole, and percent change can be calculated using the given
formula.
9. Population Growth Rate and Density: Learn how to calculate population growth rates and population density.
These formulas are a necessity for environmental science calculations.
10. Rule of 70: Use the Rule of 70 to predict doubling times based on the annual growth rate. This is necessary for
understanding population dynamics.
11. Recognize Exponential Growth: Understand the formulas for exponential growth, which are important for
studying population trends.
12. Calculate Half-Life: Know how to calculate half-life for different elements and substances. The formula helps
estimate decay rates.
13. Calculate pH: Use the formula -log [H+] to find pH values. Remember that pH measures the concentration of
hydrogen ions and how each one-point change corresponds to a tenfold difference in concentration.
14. Units of Energy and Power: Familiarize yourself with units of energy and power, such as watts, calories, BTUs,
kilowatt hours, and efficiency.
15. AP Graphing Tips: When graphing, label each axis with units, use consistent scale increments, connect the data
points, interpolate, extrapolate, add a title and key, and practice creating graphs by hand.
0
