🚀 NEW: Self-Paced TEAS 7 Study Portal — 28 lessons, 16 tools, flashcards & practice tests Try Free Preview →

HESI A2 Chemistry Review: What to Expect and How to Pass

By Maria Santos, M.Ed. · Updated March 20, 2026

Chemistry lab equipment and periodic table for HESI A2 preparation
What chemistry concepts are on the HESI A2?

Expect questions on atomic structure, the periodic table, balancing chemical equations, and basic stoichiometry. Understanding polarity, states of matter, and acid-base pH scales is critical for passing this section.

Not every nursing school requires the HESI A2 Chemistry section — but if yours does, this guide covers exactly what's on it, how hard it really is, and the most efficient way to prepare, even if chemistry was never your strongest subject.

Is the HESI A2 Chemistry Section Hard?

The HESI A2 Chemistry section tests foundational, introductory-level chemistry — not advanced or organic chemistry. Most test-takers describe it as a "know it or you don't" section. If you took high school chemistry or a college general chemistry course, much of this will be review.

📋 From the Tutor's Desk:

Many HESI test-takers panic over the Chemistry section because they assume it will be full of complex stoichiometry math. In my experience reviewing HESI results, the vast majority of the chemistry section tests conceptual foundations: predicting bond types (ionic vs. covalent), understanding the properties of water, and basic periodic table trends (electronegativity). Don't get lost in complex math; focus on the behavior of atoms.

The section typically has 25 questions with a 25-minute time limit, giving you about one minute per question. Most are straightforward recall questions, not multi-step calculations.

💡 Tutor’s Tip: Chemistry is the section most students fear, but it's actually the most predictable. Learn: (1) atomic structure, (2) ionic vs. covalent bonds, (3) pH scale, and (4) balancing simple equations. These four topics cover 80% of the questions.

What Topics Are Covered?

1. Atomic Structure

You must understand the parts of an atom: protons (positive, in nucleus), neutrons (neutral, in nucleus), and electrons (negative, in electron shells). Know how to determine each from the periodic table using atomic number and mass number.

2. The Periodic Table

Understand how the table is organized: periods (rows) and groups (columns). Know the trends — electronegativity increases left to right, atomic radius increases top to bottom. Be able to identify metals, nonmetals, and metalloids.

3. Chemical Bonds

  • Ionic bonds: Transfer of electrons between a metal and nonmetal (e.g., NaCl)
  • Covalent bonds: Sharing of electrons between nonmetals (e.g., H₂O)
  • Hydrogen bonds: Weak bonds between molecules (important in water and DNA)

4. Chemical Reactions

Know the basic reaction types: synthesis (A + B → AB), decomposition (AB → A + B), single replacement, and double replacement. You should be able to balance simple chemical equations using the Law of Conservation of Mass.

5. Solutions and Concentrations

Understand solute (substance being dissolved), solvent (substance doing the dissolving), and solution (the mixture). Know what affects solubility: temperature, pressure, and the nature of the solute/solvent.

💡 Tutor’s Tip: Here's a trick for pH: anything below 7 is acidic (think 'A' for acid, 'A' comes before 'N' for neutral at 7). Stomach acid is pH 2, blood is about 7.4, bleach is pH 13. Memorize 5 common pH values and you'll nail these questions.

6. Acids, Bases, and pH

The pH scale runs from 0 (most acidic) to 14 (most basic), with 7 being neutral. Acids donate hydrogen ions (H⁺); bases accept them. Remember the scale is logarithmic — each whole number represents a tenfold difference.

7. States of Matter

Know the properties of solids, liquids, gases, and plasma. Understand phase transitions: melting, freezing, evaporation, condensation, sublimation, and deposition.

Study tip: Focus your time on atomic structure, bonds, and acids/bases first — these three areas account for the majority of chemistry questions on the HESI A2.

How to Study for HESI Chemistry Efficiently

  1. Don't over-study. This is introductory chemistry. If you find yourself studying reaction kinetics or stoichiometry calculations, you've gone too deep.
  2. Use flashcards for periodic table trends, bond types, and pH values of common substances.
  3. Practice with timed quizzes to get comfortable with the 1-minute-per-question pace.
  4. Watch YouTube videos on topics you're weakest in — visual explanations help chemistry concepts stick.

Find HESI A2 Prep Near You

Frequently Asked Questions

Does every nursing school require HESI Chemistry?
No. The HESI A2 is modular — each school selects which sections to require. Many programs only require Math, Reading, Vocabulary, Grammar, and Anatomy. Contact your school's admissions to confirm if Chemistry is required for your application.
How many questions are on the HESI A2 Chemistry section?
The Chemistry section typically has 25 questions with a 25-minute time limit. All questions are multiple choice.
Is HESI A2 Chemistry harder than college chemistry?
No. The HESI A2 tests introductory-level chemistry concepts — atomic structure, basic bonds, and the pH scale. It is significantly easier than a college general chemistry course. Most students who have taken high school chemistry can pass with focused review.
What score do I need to pass HESI Chemistry?
Most nursing programs require a score of 75% or higher on each required HESI section. Some competitive programs require 80%+. Check your specific school's requirements.
How long should I study for the HESI Chemistry section?
If you have some chemistry background, 1–2 weeks of focused review (30–60 minutes per day) is usually sufficient. If chemistry is completely new to you, plan for 3–4 weeks of study.