Question 1
A current of 2.50 A passes through a solution of Cu²⁺ for 30.0 minutes. What mass of copper is deposited on the cathode? (Cu, 63.55 g/mol)
The AP Chemistry equations sheet, with a calculation drill
The equations and constants sheet and the periodic table are provided on both sections of the exam, in Bluebook and on paper. Knowing where each value is, and practicing with it, saves minutes on exam day. The drill below checks every answer step by step.
Stoichiometry, problem 1 of 8
Iron(III) oxide is reduced by carbon monoxide: Fe₂O₃(s) + 3CO(g) → 2Fe(s) + 3CO₂(g). What mass of iron, in grams, can be made from 50.0 g of Fe₂O₃?
| Gas constant | R = 8.314 J/(mol·K) = 0.08206 L·atm/(mol·K) |
|---|---|
| Avogadro's number | 6.022 × 10²³ per mol |
| Water at 25 °C | Kw = 1.0 × 10⁻¹⁴ |
| Faraday constant | 96,485 C per mole of electrons |
The constants on the sheet
- Planck's constant: h = 6.626 × 10⁻³⁴ J·s
- Speed of light: c = 2.998 × 10⁸ m/s
- Avogadro's number: 6.022 × 10²³ per mol
- Gas constant: R = 8.314 J/(mol·K) = 0.08206 L·atm/(mol·K)
- STP: 273.15 K and 1.0 atm, where one mole of an ideal gas occupies 22.4 L
- Kw = 1.0 × 10⁻¹⁴ at 25 °C
- Faraday constant: F = 96,485 coulombs per mole of electrons
Using it well
- Pick R by its units: 0.08206 with liters and atmospheres, 8.314 with joules.
- Convert to kelvins before any gas or thermodynamics calculation.
- Use Kw = [H₃O⁺][OH⁻] to move between pH and pOH, which add to 14 at 25 °C.
- Write the units through every step; they show when a value came from the wrong place.
Try 2 questions
Question 2
What is the energy of one photon of blue-green light with a wavelength of 486 nm?
Next step
Questions people ask
Do you get an equations sheet on the AP Chemistry exam?
Yes. The equations and constants sheet and the periodic table are provided for both sections, in Bluebook and as printed copies.
What is the value of R on the AP Chemistry equations sheet?
8.314 J/(mol·K), and 0.08206 L·atm/(mol·K) for calculations in liters and atmospheres.
Is Kw on the AP Chemistry equations sheet?
Yes: Kw = 1.0 × 10⁻¹⁴ at 25 °C.