Honors chemistry practice test: free questions with worked answers

The daily Honors Chemistry paper has 8 original questions worth 25 to 35 marks. It covers moles, electron configuration and ionization energy, bonding and molecular shapes, intermolecular forces, enthalpy and Hess's law, kinetics, equilibrium, redox and periodic trends. It also has organic chemistry, such as alcohols and alkenes, which many honors courses leave out, so check with your teacher.

Free honors chemistry practice test: 6 questions

We wrote these questions for this page. Give yourself 30 minutes with a calculator and a periodic table. Use H = 1.0 and O = 16.

1. Write the electron configuration of iron (Z = 26) in full and in noble gas notation.
2. 6.0 g of hydrogen reacts with 32 g of oxygen: 2H₂ + O₂ → 2H₂O. Which is the limiting reactant, what mass of water forms, and how much of the other reactant is left?
3. A gas fills 2.0 L at 300 K and 1.0 atm. What volume does it fill at 400 K and 2.0 atm?
4. Use Hess's law: C + O₂ → CO₂ has ΔH = −394 kJ/mol, and CO + ½O₂ → CO₂ has ΔH = −283 kJ/mol. Find ΔH for C + ½O₂ → CO.
5. Predict the shape and approximate bond angle of NH₃ and of CO₂.
6. N₂ + 3H₂ ⇌ 2NH₃ is exothermic. Write its equilibrium constant expression, and say which way the equilibrium shifts if the pressure is raised or the temperature is raised.

Honors chemistry practice test answers

1. Iron is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶, or [Ar] 4s² 3d⁶. The 4s orbital fills before 3d, and the superscripts must add up to 26. Check with the Electron Configuration Calculator.

2. Oxygen is limiting; 36 g of water; 2.0 g of hydrogen left. 6.0 g of H₂ is 3.0 mol and 32 g of O₂ is 1.0 mol. The equation needs 2 mol of H₂ per mole of O₂, so 1.0 mol of O₂ uses only 2.0 mol of H₂: oxygen runs out first. It makes 2.0 mol of water, which is 36 g, and leaves 1.0 mol of H₂, which is 2.0 g. Compare moles using the ratio, not grams. The Stoichiometry Calculator checks it.

3. 1.3 L. Use the combined gas law, with temperatures in kelvin.

Doubling the pressure halves the volume, and the rise in temperature makes it grow again by a third. Check the direction of each factor before you multiply. The Gas Laws Calculator handles all the gas laws.

4. −111 kJ/mol. Keep the first equation and reverse the second, which flips its sign to +283. Adding them cancels the CO₂ and half the O₂, leaving C + ½O₂ → CO with ΔH = −394 + 283 = −111 kJ/mol. The Enthalpy Calculator works through Hess cycles.

5. Nitrogen in NH₃ is surrounded by 3 bonds and 1 lone pair, so the molecule is trigonal pyramidal, about 107°: the lone pair pushes the bonds a little closer than 109.5°. CO₂ has two double bonds and no lone pairs on carbon, so it is linear, 180°. Try a shape question from our Chemical Bonding course, then press Mark.

6. K = [NH₃]² ÷ ([N₂][H₂]³), with each concentration raised to its coefficient. Raising the pressure shifts the equilibrium right, toward fewer gas molecules (2 instead of 4). Raising the temperature shifts it left, the endothermic direction, and lowers K. See it happen in the Rates and Equilibrium simulator.

What an honors chemistry final usually covers

Your teacher writes the final, so the syllabus is the real guide. Most honors courses build on the matter and reactions ideas in the Next Generation Science Standards (NGSS) and go further into the math: moles and stoichiometry, gas laws, thermochemistry, equilibrium, and acids and bases. Many students take AP Chemistry next, where these topics come back at college level.

Use the daily paper as a short timed practice test

1. Open today's Honors Chemistry paper with a periodic table and work to the suggested time, 35 to 45 minutes.
2. Skip the organic chemistry questions if your course doesn't cover it.
3. Mark it with the mark scheme and note the topic behind each lost mark.
4. Revisit weak topics in the Chemical Bonding and Reaction Kinetics courses.

Common honors chemistry mistakes

• Finding the limiting reactant by comparing grams instead of moles.
• Using Celsius in gas laws: always convert to kelvin.
• Forgetting to flip the sign when you reverse an equation in Hess's law.
• Ignoring lone pairs when predicting molecular shape.
• Putting coefficients in front of concentrations in K instead of using them as powers.

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