ACME ACADEMY

WEEKLY EVALUATION TEST

Subject: Science
Time Limit: 20 Mins
Max Marks: 20 Marks
Student Name:
Roll Number:
Class / Sec:
Date:

GENERAL INSTRUCTIONS:

  1. All questions are compulsory. Carefully read all instructions before starting.
  2. The question paper contains 20 questions.
  3. There is no negative marking for incorrect answers.
  4. Use of mobile phones, smartwatches, or calculators is strictly prohibited during the exam.
1. A mixture of sugar and water has a uniform composition throughout. What is the scientific term for such a mixture?
[1 Mark]
(A) Heterogeneous mixture
(B) Homogeneous mixture
(C) Suspension
(D) Colloid
2. Which of the following is an example of a suspension?
[1 Mark]
(A) Vinegar
(B) Soda water
(C) Muddy water
(D) Copper sulfate solution
3. What is the formula for calculating the mass by mass percentage of a solution?
[1 Mark]
(A) (Mass of solvent / Mass of solution) × 100
(B) (Mass of solute / Mass of solution) × 100
(C) (Volume of solute / Mass of solution) × 100
(D) (Mass of solute / Volume of solvent) × 100
4. If 10 g of salt is dissolved in 90 g of water, what is the total mass of the resulting solution?
[1 Mark]
(A) 80 g
(B) 90 g
(C) 100 g
(D) 110 g
5. A student prepares a saturated solution of a salt at 60°C. What will happen if this solution is allowed to cool down slowly to room temperature?
[1 Mark]
(A) The solvent will evaporate instantly.
(B) More of the salt will dissolve.
(C) The excess dissolved salt will separate out as solid crystals.
(D) The solution will turn into a colloid.
6. The process of forming pure solid particles arranged in a regular geometric pattern from a saturated solution is called:
[1 Mark]
(A) Distillation
(B) Sublimation
(C) Crystallization
(D) Centrifugation
7. Which physical property allows two miscible liquids like acetone and water to be separated using simple distillation?
[1 Mark]
(A) Difference in their densities
(B) Difference in their melting points
(C) Difference in their boiling points
(D) Difference in their particle sizes
8. In paper chromatography, what principle causes the different components of an ink spot to separate as the solvent moves up the paper?
[1 Mark]
(A) Differences in their boiling points.
(B) Differences in the sizes of the particles forming suspensions.
(C) Differences in how they interact with the solvent and the paper (solubility/mobility).
(D) Differences in their magnetic properties.
9. A separating funnel is commonly used in laboratories to separate which of the following mixtures?
[1 Mark]
(A) Two miscible liquids
(B) Two immiscible liquids (e.g., oil and water)
(C) A solid dissolved in a liquid
(D) Two sublimable solids
10. Camphor disappears when heated without melting into a liquid first. Which separation technique utilizes this specific property?
[1 Mark]
(A) Evaporation
(B) Centrifugation
(C) Sublimation
(D) Coagulation
11. Why is an alloy like brass considered a homogeneous mixture rather than a compound?
[1 Mark]
(A) Because the metals can be easily separated by physical filtration.
(B) Because it has a uniform composition but the components retain their individual properties and can vary in proportion.
(C) Because it is a liquid at room temperature.
(D) Because it is formed by a violent chemical reaction.
12. What process is commonly used in dairies to separate cream from milk by spinning the liquid at high speeds?
[1 Mark]
(A) Coagulation
(B) Distillation
(C) Centrifugation
(D) Chromatography
13. In municipal water treatment, powdered alum is added to muddy water. This causes fine suspended particles to clump together and settle. What is this process called?
[1 Mark]
(A) Sublimation
(B) Fractional distillation
(C) Coagulation
(D) Crystallization
14. Blood is structurally classified as a:
[1 Mark]
(A) True solution
(B) Colloid
(C) Pure compound
(D) Suspension that settles immediately
15. The scattering of a beam of light by colloidal particles, making the path of light visible, is known as:
[1 Mark]
(A) The Doppler Effect
(B) The Tyndall Effect
(C) The Raman Effect
(D) The Photoelectric Effect
16. Assertion (A): A beam of laser light passing through a true salt solution does not make its path visible. Reason (R): The particles in a true solution are smaller than 1 nm in diameter and cannot scatter light.
[1 Mark]
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
17. A perfume maker wants to separate multiple fragrance compounds from a flower extract. Which technique is most appropriate for isolating these colored or fragrant pigments?
[1 Mark]
(A) Sublimation
(B) Using a magnet
(C) Chromatography
(D) Centrifugation
18. If you have a mixture of iron filings, ammonium chloride, and sand, which is the correct sequence of separation?
[1 Mark]
(A) Sublimation → Magnetic separation → Dissolution & Filtration
(B) Magnetic separation → Sublimation → Dissolution & Filtration
(C) Dissolution & Filtration → Evaporation → Sublimation
(D) Distillation → Centrifugation → Sublimation
19. Petroleum is separated into fractions like petrol, diesel, and kerosene in a refinery. What specific technique is used since the boiling point differences between these fractions are small (less than 25°C)?
[1 Mark]
(A) Simple Distillation
(B) Fractional Distillation
(C) Centrifugation
(D) Sublimation
20. An emulsion is a specific type of colloid where:
[1 Mark]
(A) A solid is dispersed in a gas.
(B) A gas is dispersed in a liquid.
(C) Both the dispersed phase and the dispersion medium are liquids.
(D) A solid is dispersed in a solid.
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