Search for an ACS practice exam and you get a pile of results that all promise the same thing. Some are useful. Some are blurry PDFs of who-knows-what. A few are worth paying for, and plenty are not. If your final is a few weeks out, you don’t have time to sort through all of it. Where can you find a good ACS practice exam, free or paid?
The best places to find an ACS practice exam are the official study materials from the ACS Exams Institute, your own professor, your textbook, and online ACS-style practice tests. The Institute sells printed study guides for general and organic chemistry, plus 50-item practice and tutorial exams. Your professor may have review sheets or sample questions for free, and that’s the first place to ask. Textbook problem sets are free but aren’t in the exam’s multiple-choice format. Online practice exams, including ours, are written in the ACS style and are good for full-length practice runs, but no legitimate source sells the real secure exam.
What Counts as a Good ACS Practice Exam?
A good one looks and feels like the real test, since the format is a big part of what makes the ACS exam hard. That means multiple choice, mixed topics from the whole course, and a time limit that pushes you a little. It should also come with answers you can learn from, not just a letter key.
My short checklist:
- It matches your course (Gen Chem 1, Gen Chem 2, full-year, or organic).
- It’s multiple choice, so you practice choosing, not just solving.
- It covers the whole semester in one sitting.
- It explains the answers, so a wrong answer teaches you something.
- It’s legal to use. More on that below.
No single source checks every box perfectly. That’s fine. Most students do best with two or three sources used for different jobs.
Option 1: Study Materials From the ACS Exams Institute
The ACS Exams Institute, the group that writes the standardized finals, sells its own prep materials. According to its student study materials page, there are printed official guides for general chemistry, organic chemistry, biochemistry and physical chemistry. The general chemistry book is called Preparing for Your ACS Examination in General Chemistry: The Official Guide. The organic guide is in its second edition.
The Institute also lists 50-item tutorial exams (with feedback) and 50-item practice exams. Purchases go through the Institute’s online store.
Pros: written by the same organization that writes the finals, so the question style is about as close as you’ll get. The books also explain the concepts behind each topic area.
Cons: they cost money, and a printed book can’t save your results or track your progress across attempts. A 50-item practice set is also shorter than many full-length finals, so you’ll want to practice your pacing somewhere else too.
My take: if your class uses the ACS final and you can afford one resource, the official guide for your subject is a solid choice. Check your campus library first. Some keep a copy on reserve.
Option 2: Your Professor (Free, and Often Overlooked)
Ask your professor. It costs nothing, and you’d be surprised how often it works. Many instructors who give the ACS final keep review packets, sample multiple-choice questions, or their own old exams written in a similar style. Some post them on the course site. Others only hand them out if someone asks.
Your professor can also tell you which form your class uses, how long you’ll get, and which topics carry the most weight. That information shapes everything else you do.
One thing your professor won’t give you is the actual exam. ACS exams are kept secure so they can be reused and fairly compared across schools. Asking for “last year’s ACS final” puts them in an awkward spot. Ask for review material instead.
Option 3: Free Textbook and Open-Source Problem Sets
Your textbook’s end-of-chapter problems are free and cover every topic. If you don’t have a textbook, OpenStax Chemistry 2e is a free, peer-reviewed gen chem text with problems for every chapter.
Pros: free, plentiful, and good for building skills one topic at a time.
Cons: most are free-response, not multiple choice, and they’re sorted by chapter. The real test mixes everything together and usually gives you four choices to pick from. That changes how you think. On a multiple-choice question, you can sometimes rule out two answers by estimating, which is a skill textbook problems don’t train.
Use textbook sets to fix weak topics. Don’t count them as an ACS practice exam.
Option 4: Online ACS-Style Practice Exams
Online practice tests are useful for one thing the other options do poorly: full-length, mixed-topic practice that grades itself. Set your own timer and it becomes a realistic dress rehearsal. Quality varies a lot, so look for three things. The questions should match your course. The format should be multiple choice and long enough to take in one timed sitting. And every question should come with a real explanation.
Be careful with any site that says it has “real” or “leaked” ACS questions. Legitimate prep companies write their own questions in the ACS style. They don’t have the secure exams, and none should claim to.
That’s how ours work. We built our ACS-style practice exams for Gen Chem 1, Gen Chem 2 and Org Chem 1 around the format of the ACS final, and each one has 70 questions, a video solution for every question, and saved results from every attempt so you can track progress across retakes. (ChemExams isn’t affiliated with the American Chemical Society, and the questions are our own.)
Are Free ACS Exam PDFs Safe to Use?
Approach them with suspicion. Some are legitimate review sheets a professor posted publicly. Others are mislabeled, decades old, or copies of secure exams that shouldn’t be circulating. Using one of those can land you in an academic integrity mess that’s far worse than a low final grade. If you can’t tell where a PDF came from, skip it.
Which ACS Practice Exam Option Is Best?
The right one comes down to what you need right now. Here’s a quick comparison.
| Source | Cost | Format match | Best for |
|---|---|---|---|
| ACS Exams Institute study guides | Paid (check library) | Very close | Learning the style and topics |
| Institute practice and tutorial exams | Paid | Very close, 50 items | Short official practice sets |
| Professor review material | Free | Varies | Knowing what your class emphasizes |
| Textbook or OpenStax problems | Free | Low (mostly free-response) | Fixing one weak topic at a time |
| Online ACS-style practice exams | Free to paid | Varies by provider | Full-length, mixed-topic runs with explanations |
A sensible combination for most students: get review material from your professor, patch weak topics with textbook problems, then take one or two timed practice exams to test your pacing.
Do You Need to Pay for an ACS Practice Exam?
Not necessarily. If your professor gives you solid review material and you have the discipline to time yourself with it, you can prepare well for free. Paying makes sense when you want something free sources don’t give you, such as the official guide’s close match to the question style, or a full-length practice test that explains each answer. Spend money to fill a specific gap, not because spending feels like progress.
How to Get the Most From a Practice Exam
A practice exam is only as good as the way you take it. Treat it like the real thing, or it will give you a falsely rosy picture.
- Time it. Use the same time limit your class will use. If you don’t know it yet, ask.
- Close the book. No notes, no phone, just the reference sheet and calculator you’ll have on test day.
- Answer everything. Make your best guess when stuck, the way you would on the real test.
- Review every miss. Write down why you missed it: didn’t know the concept, made a math slip, misread the question, or ran out of time. Each one needs a different fix.
- Review lucky guesses too. A right answer you guessed is still a gap.
Then go back and study the weak spots before taking another one. Taking practice test after practice test without fixing anything in between mostly measures the same gaps again.
For the bigger picture, including how to plan your weeks before the final, see our guide on how to study for the ACS exam.
Where to Start Tonight
So where can you find an ACS practice exam? Start free: email your professor and ask for review materials, and check whether your library has the official study guide. Fill topic gaps with textbook problems. When you’re ready to see how you hold up under time pressure, set a timer and take a full-length ACS-style practice test that explains every answer, like the ones in Option 4.
Skip anything that claims to be the real exam. It’s either not true or not something you want to be caught with. A good practice test should show you what you don’t know yet, with enough time left to fix it.