Your syllabus says the final is “the ACS exam.” That tells you who wrote it, but not how long you’ll be sitting there. Is it 50 questions? 70? Do you get two hours or one? Before you plan your studying, you want the basic shape of the thing. So, how many questions are on the ACS exam, and how much time do you get?
A full-length ACS general chemistry final is often around 70 multiple-choice questions with roughly 110 minutes to finish, but that’s a common ballpark, not a rule. The exact count and time limit depend on the exam form your school uses, and organic finals are multiple choice too. Some lengths are published: the Institute’s practice exams are 50 items, and its 2025 Preparatory Chemistry exam is 50 items in 60 minutes. Your professor or testing center picks the form and sets the time limit. The only number that counts is the one on your syllabus, so check it or ask.
How Many Questions Are on the ACS Exam for Each Course?
It depends on the course and the form. There isn’t one “ACS exam.” There’s a family of them, and new versions come out over time. If you’re not sure which one your class uses, our article on the ACS chemistry exam covers what it is and why so many schools use it.
Here’s how it breaks down for the versions most students meet:
- General Chemistry, first term (Gen Chem 1): Given at the end of the first semester. Length depends on the form your school uses.
- General Chemistry, second term (Gen Chem 2): Covers the second-semester topics like kinetics, equilibrium, acids and bases, thermodynamics and electrochemistry. Length is usually similar to the first-term exam.
- General Chemistry, full year: Covers both semesters in one sitting.
- Organic Chemistry: There are full-year and single-semester versions. Length is commonly reported in the same general range as the gen chem finals.
Notice the hedging. That’s on purpose. The Institute’s public pages confirm counts for some exams and leave others unstated, so anyone giving you a single exact number for every school is guessing.
Counts the Exams Institute Does Publish
A few lengths are stated plainly on the ACS Exams Institute’s homepage. They’re useful as reference points, even if they aren’t your exact final.
| Exam | Published length |
|---|---|
| ACS practice exams | 50 items (analytical: 30) |
| ACS tutorial exams | 50 items, with feedback |
| Preparatory Chemistry 2025 | 50 items in 60 minutes |
| GOB 2025 Condensed | 60 items |
| Toledo Placement Exam (2026) | Three parts of 20 items each |
If your class uses one of these, you’re set. If not, your syllabus is the source.
How Long Is the ACS Exam?
Your school decides. The Institute writes the exam, but the instructor or testing center sets the clock and the room rules. Many classes give something close to two hours for a full-length final. Some give a full class period. Some give less.
The useful number is time per question. A little math helps here:
- If your form had 70 questions and 110 minutes, that would be about 94 seconds per question.
- 50 questions in 60 minutes works out to 72 seconds per question.
Either way, you have roughly a minute to a minute and a half. That’s enough for a conceptual question or a short calculation. It is not enough to re-derive a formula from scratch or stare at one hard problem for five minutes. Speed counts on this test, which is why practicing under a timer matters more than most students expect.
What Does the ACS Exam Format Look Like?
It’s multiple choice, usually with four answer choices (A through D), and you mark your answers on a bubble sheet or in a computer system, depending on the school. There’s no “show your work” section, so on most forms you either pick the right letter or you don’t.
The questions mix a few types:
- Short calculations (stoichiometry, gas laws, pH, equilibrium)
- Conceptual questions with no math at all (trends, bonding, which statement is true)
- Questions built around a diagram, graph, structure or table of data
The questions cover the whole course. A topic you finished in week three can show up right next to one from last Tuesday.
Is There a Penalty for Guessing?
Usually not. Most ACS exams are scored by the number of correct answers, so a wrong answer and a blank answer typically count the same: zero. (One exception to know about: the Institute notes that scoring on its General Chemistry First-Term 2025 exam can include partial credit, so check how your form is scored.) That means you should answer every question. Still, your instructor controls how the exam is graded for your course, so if you’re unsure, ask. One question in office hours beats a surprise on the grade sheet.
Do You Get a Calculator, Periodic Table and Scratch Paper?
Usually some version of all three, but the rules come from your school, not from a single national policy.
- Calculator: Many classes allow a basic scientific calculator and ban graphing or programmable ones. Some require a specific model. Check the syllabus, and bring a backup battery or a second calculator.
- Periodic table: A periodic table is usually provided with the exam materials, often along with a short list of constants and formulas, but your instructor sets the rules, so ask. It’s one reason you rarely need to memorize the periodic table box by box.
- Scratch paper: Some schools let you write in the test booklet. Others hand out scratch paper and collect it. Either way, you’ll have somewhere to work.
Because the provided reference sheet is limited, you still need to know the formulas your class expects you to memorize. Don’t assume the sheet will bail you out.
Why Does the Number Vary So Much?
Because the exams change and schools have options. The Institute releases new forms over time, and different schools adopt them on different schedules. A school might still use an older form while another switches to the newest one. Some instructors use a first-term exam, others a full-year exam. Some give the whole test, and a few give it as only part of a larger final.
So when a classmate at another college says their ACS exam had a certain number of questions, they’re probably right about their exam. That doesn’t mean it applies to yours.
How to Use This Information to Prepare
Knowing the format is only useful if it changes how you study. Three things follow from everything above:
- Practice timed. Set a timer for your real time-per-question pace and work a full set of problems without stopping.
- Practice multiple choice, not just homework. Homework lets you grind through a problem for twenty minutes. The final won’t.
- Practice the whole course at once. Mix topics so you get used to switching from gas laws to Lewis structures without warning.
If you want to see what a full-length ACS-style test feels like, set a timer and take one of our ACS-style practice exams in one sitting. Each one has 70 multiple-choice questions in the format of the ACS finals, with a video solution for every question. (ChemExams isn’t affiliated with the American Chemical Society, and the questions are our own.)
The Short Version: Count, Clock and Your Syllabus
The number of questions on the ACS exam comes down to the form your school picks. Expect a multiple-choice test whose length and time limit follow that choice. The Institute publishes some lengths, like its 50-item practice exams, and full-length finals are often described as longer, but your syllabus has the real number.
The exact count and time limit come from your school. Read the syllabus, ask your professor if it’s vague, and then practice at the pace the real test demands. Knowing the shape of the exam won’t answer a single question for you. It does keep the clock from being the thing that surprises you.