Is Matter Around Us Pure

Q. If a solution contains 20% sugar by weight, how many grams of sugar are in 200 grams of the solution?

Solution

Sugar in solution = 20% of 200g = 0.20 * 200 = 40g.

Correct Answer: B — 40g

Q. What is the boiling point of pure water at sea level?

Solution

The boiling point of pure water at sea level is 100°C.

Correct Answer: B — 100°C

Q. What is the mass of 50 mL of pure water, given that the density of water is 1 g/mL?

Solution

Mass = Volume × Density = 50 mL × 1 g/mL = 50g.

Correct Answer: B — 50g

Q. What is the percentage of salt in a solution that contains 5 grams of salt in 95 grams of water?

Solution

Percentage of salt = (5g / (5g + 95g)) * 100 = 5%.

Correct Answer: B — 10%

Q. Which of the following is a homogeneous mixture?

Solution

Air is a homogeneous mixture as its composition is uniform throughout.

Correct Answer: C — Air

Q. Which of the following is a pure substance?

Solution

Gold is a pure substance as it consists of only one type of atom.

Correct Answer: C — Gold

Q. Which of the following is an example of a colloid?

Solution

Milk is a colloid as it contains tiny particles suspended in liquid.

Correct Answer: C — Milk

Q. Which of the following is NOT a characteristic of a pure substance?

Solution

A pure substance has a fixed composition, while a mixture has a variable composition.

Correct Answer: C — Variable composition

Q. Which of the following methods can be used to separate a mixture of sand and salt?

Solution

Filtration can separate sand from saltwater, and evaporation can recover salt from the solution.

Correct Answer: D — Both Filtration and Evaporation

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