Some basic concept of chemistry

Q1: A pure substance which contains only one type of atom is called ————–.

• An element
• A compound
• A solid
• A liquid

Q2: The smallest particle that can take part in chemical reactions is ————–.

• Atom
• Molecule
• Both (a) and (b)
• None of these

Q3: Which of the following is a homogeneous mixture?

• Mixture of soil and water
• Sugar solution
• Mixture of sugar, salt and sand
• Iodised table salt

Q4: The significant figures in 0.00051 are ————–.

• 5
• 3
• 2
• 26

Q5: Formation of CO and CO₂ illustrates the law of ————–.

• Law of conservation of mass
• Law of Reciprocal proportion
• Law of Constant Proportion
• Law of Multiple Proportion

Q6: The number of significant figures in 6.02 × 10²³ is ————–.

• 23
• 3
• 4
• 26

Q7: The prefix 10¹⁸ is ————–.

• Giga
• Exa
• Kilo
• Mega

Q8: The mass of an atom of carbon is ————–.

• 1 g
• 1.99 × 10⁻²³ g
• 1/12 g
• 1.99 × 10²³ g

Q9: A measured temperature on Fahrenheit scale is 200℉. What will this reading be on the Celsius Scale?

• 40 ℃
• 94 ℃
• 93.3 ℃
• 30 ℃

Q10: Which of the following pairs of gases contains the same number of molecules?

• 16 g of O₂ and 14 g of N₂
• 6 g of O₂ and 22 g of CO₂
• 28 g of N₂ and 22 g of CO₂
• 32 g of CO₂ and 32 g of N₂