- Exam Overview and Structure
- Domain I: Scientific Inquiry and Processes (24%)
- Domain II: Matter and Energy (41%)
- Domain III: Chemical Reactions (23%)
- Domain IV: Science Learning, Instruction and Assessment (12%)
- How the 17 Competencies Map to the Test
- Scheduling Your Prep Around Domain Weight
- On-Screen Tools and Test-Day Format
- Frequently Asked Questions
- Domain II, Matter and Energy, is 41% of the TExES Chemistry 7-12 (240) exam - nearly half your score.
- The test has 100 selected-response questions over 4 hours 45 minutes of testing time, plus a 15-minute tutorial.
- Content is built from 17 competencies (001-017) grouped into four domains under a 2022 TEA framework.
- An on-screen periodic table, physical constants page, and scientific calculator are provided - no outside references.
Exam Overview and Structure
The TExES Chemistry 7-12 (240) exam is administered by Pearson on behalf of the Texas Education Agency and the State Board for Educator Certification, part of the Texas Educator Certification Examination Program. It's a computer-administered test made up of 100 selected-response items, and your full appointment window is five hours: 15 minutes for the tutorial and compliance agreement, followed by 4 hours 45 minutes of actual testing time. Some forms include unscored field-test questions mixed in with scored items, but your reported score reflects only the scored portion.
Scores are reported on a 100-300 scale, and you need a 240 to pass. If you want the full breakdown of what that scaled score actually means and how it's calculated, see our TExES Chemistry 7-12 Passing Score guide. For registration mechanics, fee details, and eligibility windows, the exam dates and scheduling guide and the requirements guide cover those specifics in depth.
Everything on the test traces back to a single content framework carrying a 2022 TEA copyright, organized into four domains built from 17 competencies. That structure - not generic "chemistry knowledge" - is what you're actually being tested against, and understanding its weighting is the single highest-leverage thing you can do before you start studying. This article breaks down each domain, what it covers, and how much of the exam it represents.
Domain I: Scientific Inquiry and Processes (24%)
Domain I covers competencies 001 through 004 and centers on how science is actually done and communicated in a classroom setting - not just chemistry content, but the methodology and safety practices around it. At roughly 24% of the exam, this domain is the second-largest content area, and it's easy to underestimate because it feels less "chemistry-specific" than the other domains.
Domain I Focus Areas
Candidates must demonstrate command of the scientific process as it applies to secondary chemistry instruction.
- Laboratory safety procedures, chemical storage, and hazard communication
- Designing and evaluating controlled experiments, including variables and experimental design
- Data collection, measurement, significant figures, and error analysis
- Scientific reasoning, use of models, and the nature of scientific knowledge
Because this domain blends process skills with foundational measurement concepts, it rewards candidates who can apply reasoning to unfamiliar lab scenarios rather than recall isolated facts. If you're trying to gauge how much this domain will affect your overall difficulty level, our difficulty guide discusses how inquiry-based items tend to feel compared to content-heavy items.
Domain II: Matter and Energy (41%)
Domain II is, by a wide margin, the dominant content area on the TExES Chemistry 7-12 (240) exam. Covering competencies 005 through 011, it accounts for 41% of the test - more than double the weight of Domain IV and larger than Domains I and III individually. If you only had time to master one domain, this is it.
Domain II Focus Areas
This domain spans the core physical chemistry content most candidates associate with "chemistry" itself.
- Characteristics and classification of matter (states, mixtures, pure substances)
- Atomic structure, electron configuration, and periodic trends
- Gas laws and kinetic molecular theory
- Chemical bonding - ionic, covalent, metallic, and intermolecular forces
- Chemical notation, formula writing, and stoichiometry calculations
- Solutions, concentration, and solubility principles
- Thermochemistry, including energy changes and calorimetry
Key Takeaway
Because Domain II alone represents 41% of the exam, it should anchor your entire study hierarchy - allocate more review sessions, more practice questions, and more calculation drills here than to any other domain.
Stoichiometry and gas law calculations in particular tend to require multi-step problem solving under time pressure, so fluency with dimensional analysis and unit conversions matters as much as conceptual recall. Our cheat sheet condenses the formulas and periodic trends most commonly tested in this domain into a single quick-reference page.
Chemical Reactions (23%)
Domain III, covering competencies 012 through 015, makes up 23% of the exam - nearly as large as Domain I. This domain picks up where Domain II's foundational matter-and-energy content leaves off, moving into reaction behavior and equilibrium.
Domain III Focus Areas
Expect items that test both conceptual understanding and applied calculation of reaction systems.
- Types of chemical reactions and balancing equations
- Reaction rates and factors affecting kinetics
- Chemical equilibrium and Le Chatelier's principle
- Acid-base chemistry, pH, and titration calculations
- Oxidation-reduction reactions and electrochemistry
Because Domains II and III together represent 64% of the entire exam, chemistry content knowledge - not pedagogy - makes up nearly two-thirds of your score. Any study plan that treats content review as secondary to test-taking strategy is misallocating effort for this particular exam.
Domain IV: Science Learning, Instruction and Assessment (12%)
Domain IV, built from competencies 016 and 017, is the smallest domain at 12% of the exam. It shifts away from chemistry content itself and into pedagogy: how chemistry concepts are taught, assessed, and made accessible to secondary students.
Domain IV Focus Areas
This domain evaluates instructional judgment rather than raw chemistry recall.
- Selecting appropriate instructional strategies for chemistry concepts
- Designing formative and summative assessments aligned to learning objectives
- Addressing misconceptions and differentiating instruction
- Integrating safety and inquiry practices into classroom instruction
Because this domain is worth the least, many candidates deprioritize it - but with only 12 or so questions covering it, a handful of overlooked concepts can still move your scaled score. Treat it as a focused, efficient review area rather than an afterthought.
How the 17 Competencies Map to the Test
The four domains break down into 17 distinct competencies, and understanding the numbering helps you navigate the official framework and any practice materials that reference specific competency numbers.
| Domain | Competencies | Weight |
|---|---|---|
| I. Scientific Inquiry and Processes | 001-004 | 24% |
| II. Matter and Energy | 005-011 | 41% |
| III. Chemical Reactions | 012-015 | 23% |
| IV. Science Learning, Instruction and Assessment | 016-017 | 12% |
Notice that Domain II carries the most competencies (seven) and the highest weight, while Domain IV has only two competencies but still accounts for over a tenth of the test. If you're mapping out a broader certification timeline - including what happens after you pass - the certification overview and requirements guide walk through what's expected before and after this exam.
Scheduling Your Prep Around Domain Weight
Rather than dividing study time evenly across four domains, allocate weeks proportionally to exam weight. This isn't about generic study hacks - it's about matching your calendar to how the TExES Chemistry 7-12 (240) is actually scored.
Domain II: Matter and Energy
- Atomic structure, periodic trends, and bonding review
- Stoichiometry and gas law problem sets
- Thermochemistry and solution chemistry drills
Domain III: Chemical Reactions
- Balancing equations and reaction type identification
- Equilibrium, acid-base, and titration calculations
- Redox and electrochemistry basics
Domain I: Scientific Inquiry and Processes
- Lab safety and experimental design scenarios
- Measurement, error analysis, and data interpretation
Domain IV plus full review
- Instructional strategy and assessment design concepts
- Timed full-length practice test
- Targeted review of weakest competencies
For a more detailed week-by-week walkthrough with pacing benchmarks, see the full TExES Chemistry 7-12 Study Guide. You can also run through full-length timed practice on our practice test platform to get comfortable with the question format before test day.
On-Screen Tools and Test-Day Format
Because the exam is computer-administered through Pearson VUE, you won't bring outside reference materials. Instead, the testing system supplies an on-screen periodic table, a physical constants page, and an on-screen scientific calculator, all accessible during the testing window. This means memorizing constants isn't the priority - knowing how and when to apply them is.
The $116 exam fee is flat regardless of how many times you've tested previously, though additional service fees may apply depending on registration circumstances. Candidates get up to five attempts per certification exam, with a mandatory 30-day wait between attempts. Scores typically post about seven days after testing, at 10:00 p.m. Central on published score report dates. For a complete cost breakdown across the certification pathway, see the certification cost guide.
If you're still evaluating whether this credential fits your career plans, the ROI analysis and salary guide look at the bigger picture beyond the exam itself, while the jobs overview covers where this certification is typically required. You can also start building familiarity with the question style right now using practice questions modeled on the real exam format.
Frequently Asked Questions
Start with Domain II: Matter and Energy, since it accounts for 41% of the exam - the largest single content area by a significant margin over the other three domains.
The exam has 100 total selected-response questions. Applying the published weights, Domain II represents roughly 41 questions, Domain I about 24, Domain III about 23, and Domain IV about 12.
The domains are weighted by percentage of questions, not by stated difficulty. Domain II and Domain III together make up 64% of the test and involve the most multi-step calculations, which many candidates find more time-intensive than the process-focused items in Domain I and IV.
Domain IV, Science Learning, Instruction and Assessment, is built from competencies 016 and 017 and makes up 12% of the exam, the smallest of the four domains.
No. The testing system provides an on-screen periodic table, a physical constants page, and an on-screen scientific calculator during the exam, so no external tools are needed or permitted.