Grade 10 science exam: SNC2D practice questions, strands and how the exam counts

Each daily paper has 8 original questions worth 25 to 35 marks. The biology paper fits SNC2D best; the chemistry paper fits in part; the physics paper only in its electromagnetic spectrum questions, because it has no mirrors or lenses. The strand sections below say what to skip in each. No paper covers climate change. The mixed Grade 10 Science (SNC2D) paper fits in its cell biology questions, but most of the rest is Grade 11 and 12 work.

How the Grade 10 science exam counts in 2026-27

In Grades 9 and 10, your final mark is now 65% classroom work, a 20% mandatory final evaluation, and 15% attendance and participation. In science, that 20% is a written exam, sat in your school board's exam period, so your board sets the date. These rules start in the 2026-27 school year and come from the Ministry of Education's Growing Success update, last changed October 14, 2026.

SNC2D still follows the 2008 science curriculum: only Grade 9 science was rewritten, in 2022. The prerequisite is Grade 9 science (SNC1W). SNC2D is in turn the prerequisite for Grade 11 biology (SBI3U), chemistry (SCH3U) and physics (SPH3U). Grade 10 also has an applied course, SNC2P, with different topics.

What's on the SNC2D exam: the strands

We wrote the practice questions below for this page. Try each one before you read the answer.

Grade 10 science biology: tissues, organs and systems

The daily Grade 10 Science: Biology paper fits this strand in its cell division, cell structure, circulatory system, nervous system, and enzymes and digestion questions. Skip its genetics, evolution, disease, ecology, photosynthesis, respiration and hormone questions.

1. Field of view. Under low power (40×) the field of view is 4.0 mm across. You switch to high power (400×) and count 8 cells across the field. About how wide is one cell? Answer: ten times the magnification gives one tenth of the field: 4.0 × 40 ÷ 400 = 0.40 mm, which is 400 µm. Each cell is about 400 ÷ 8 = 50 µm wide. The Magnification Calculator handles image size and real size.

2. Levels of organization. Put these in order from smallest to largest, and give an example of each from the digestive system: organ, cell, organ system, tissue. Answer: cell (a cell lining the stomach), tissue (epithelial tissue), organ (the stomach), organ system (the digestive system). Mitosis makes the new cells for growth and repair; specialization then makes them different.

Name the stage of mitosis in our Cell Biology course, then press Mark.

Grade 10 science chemistry: chemical reactions

The daily Grade 10 Science: Chemistry paper fits this strand in its bonding and structure, chemical tests, and occasional acids and pH questions. Its atomic structure questions are Grade 9 review. Skip moles, titration, organic chemistry, electrolysis, rates and equilibrium: those come in Grade 11 and 12.

3. Balance and classify. Aluminium burns in oxygen to make aluminium oxide. Write the balanced equation and name the type of reaction. Answer: Al₂O₃ has 3 oxygen atoms and O₂ has 2, so make 6 of each: 4Al + 3O₂ → 2Al₂O₃. Two substances join into one, so it is a synthesis reaction. Check both sides in the Equation Balancer.

4. Conservation of mass. Heating 10.0 g of calcium carbonate leaves 5.6 g of calcium oxide. What mass of carbon dioxide escaped? Answer: mass is conserved, so 10.0 − 5.6 = 4.4 g of carbon dioxide. In an open container the gas leaves, which is why the solid seems to lose mass.

5. Neutralization. Name the products when hydrochloric acid reacts with sodium hydroxide, and the type of reaction. Answer: HCl + NaOH → NaCl + H₂O: sodium chloride and water. An acid and a base make a salt and water, a neutralization, which is a double displacement. The mixture moves toward pH 7. Explore the scale with the pH Calculator.

Earth and space science: climate change

6. The greenhouse effect. Explain the difference between the natural and the anthropogenic greenhouse effect. Answer: sunlight warms Earth's surface, and the warm surface radiates infrared. Water vapour, carbon dioxide, methane and other greenhouse gases absorb part of that infrared and re-emit it, much of it back down, which keeps Earth warm enough for life: that is the natural greenhouse effect. Burning fossil fuels and clearing forests add more of these gases, so more heat is trapped and the climate warms: the anthropogenic (human-caused) greenhouse effect.

7. A feedback loop. Why does melting Arctic sea ice speed up warming? Answer: ice reflects much of the sunlight that hits it, while dark ocean water absorbs most of it. Less ice means more absorption, more warming and more melting: a positive feedback.

Grade 10 science physics: light and optics

From the daily Grade 10 Science: Physics paper, do the electromagnetic spectrum questions and skip the rest: SNC2D physics is light only. Practise mirrors, lenses and refraction with the questions here and the Ray Optics tool.

8. Index of refraction. Water has an index of refraction of 1.33. How fast does light travel in water? Answer: n = c ÷ v, so v = 3.00 × 10⁸ ÷ 1.33 = 2.26 × 10⁸ m/s. Light slows down entering water, so it bends toward the normal.

9. Converging lens. A 6.0 cm tall object stands 30 cm from a converging lens with a focal length of 10 cm. Find the image distance, its height and its characteristics. Answer: 1/d_i = 1/10 − 1/30 = 2/30, so d_i = 15 cm. Magnification = −d_i ÷ d_o = −0.50, so the image is 3.0 cm tall and real, inverted and smaller. The ray diagram below shows the same answer.

Use the daily papers as a practice exam

1. Start with the biology paper, which fits SNC2D best, and work to the suggested time, 30 to 40 minutes.
2. Skip the questions from other courses listed in each strand's section above.
3. Write the equation, the numbers with units, and the answer with its unit.
4. Mark it, note which strand each lost mark belongs to, and practise optics and climate change with the questions on this page.

Common Grade 10 science mistakes

• Changing subscripts to balance an equation. Only change the coefficients in front; subscripts change the substance.
• Forgetting the image is inverted. A real image from a single converging lens is always upside down, so the magnification is negative.
• Bending light the wrong way. Into a slower medium (higher n), light bends toward the normal.
• Confusing tissues and organs. A tissue is one type of cell working together; an organ is several tissues.
• Calling every greenhouse effect harmful. The natural greenhouse effect keeps Earth habitable; the problem is the extra, human-caused part.

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