Coal Petroleum and Combustion (Class 8)

What this worksheet covers

This is an eighteen-question practice worksheet on coal, petroleum, combustion and flame for Class 8, written to the pattern of the SOF National Science Olympiad (NSO). It carries 24 marks and is designed to be attempted in 45 minutes, split across three sections — Scientific Reasoning, Applying What You Know and Achievers Section. Every question is multiple choice with exactly one correct option, and every one comes with a fully worked solution rather than just an answer key — so a child who gets one wrong can see where the reasoning went astray instead of only learning that it did.

Skills your child practises

• Applied problem-solving on coal, petroleum, combustion and flame at Class 8 level
• Working accurately against a time limit, as the real paper demands
• Scientific Reasoning questions in the olympiad format
• Applying What You Know questions in the olympiad format
• Achievers Section questions in the olympiad format
• Reading worked solutions to find the step that went wrong

How to use it

1. 1There are 18 questions in this worksheet. All questions are compulsory.
2. 2Each question has four options (A), (B), (C) and (D). Exactly one option is correct.
3. 3Questions 1–15 carry 1 mark each. Questions 16–18 (Achievers Section) carry 3 marks each.
4. 4There is no negative marking. Study every diagram and table carefully.

Sample questions from this worksheet

A preview of what's inside Coal Petroleum and Combustion (Class 8) — the PDF has the full set, and every question comes with a worked solution like these.

1. 1. Coal, petroleum and natural gas are called _______ fuels.

   • AFossilcorrect
   • BRenewable
   • CSynthetic
   • DNuclear
   Solution: Fossil fuels were formed from the remains of organisms buried millions of years ago. They are non-renewable, since they cannot be replaced within our lifetime.

2. 2. Why does a candle flame go out when a glass jar is placed over it?

   • AThe wax runs out
   • BThe jar cools the flame instantly
   • CThe oxygen inside the jar is used up, so combustion stopscorrect
   • DCarbon dioxide is used up
   Solution: Combustion needs oxygen. Once the jar is placed over the candle, the limited oxygen inside is used up and the flame goes out. The carbon dioxide produced also settles around the flame and helps smother it.

3. 3. Consider the following statements.(i) Fossil fuels are renewable resources.(ii) The innermost dark zone of a candle flame is the coolest.(iii) A good fuel should have a high calorific value and leave little residue.Which of the statements is/are correct?

   • A(i) and (ii) only
   • B(ii) and (iii) onlycorrect
   • C(i) and (iii) only
   • DAll three
   Solution: Statement (i) is false — fossil fuels took millions of years to form and cannot be replaced in our lifetime, so they are non-renewable. Statement (ii) is true; the dark zone is unburnt wax vapour with almost no combustion. Statement (iii) is true. Hence (ii) and (iii).