Class 6 Science Chapter 3 Question Answers - Separation of Substances

Short Answer Questions

Q1: What is a pure substance?
Ans: A pure substance is made of only one type of substance.

Q2: Give an example of a mixture.
Ans: A salad made of cucumber, tomato, carrot, and sprouted mung is a mixture.

Q3: do we use handpicking in our daily life?
Ans: We use handpicking to remove unwanted materials, like small stones, from food grains.

Q4: Explain the process of sieving.
Ans: Sieving is a method to separate solid substances based on their size. For example, we use sieving to remove larger particles and insects from rice flour by passing it through a sieve.

Q5: What is the purpose of winnowing?
Ans: is used to separate lighter substances, such as chaff, from heavier grains. It relies on the wind to blow away the lighter parts, leaving the heavier grains behind.

Long Answer Questions

Q1: Describe the process of separating solid particles from a mixture using sedimentation and decantation.
Ans: Sedimentation is when undissolved solid particles settle at the bottom of a mixture over time due to gravity. Decantation involves carefully pouring off the liquid without disturbing the settled solids. It is an effective way to separate solids from liquids.

Q2: Explain the concept of a saturated solution. How does temperature affect solubility?
Ans: A saturated solution is one in which no more solute can dissolve in the solvent at a given temperature. Solubility, or the amount of solute that can dissolve in a solvent, increases with temperature. So, more solute can dissolve in a warm solution than in a cold one.

Q3: How do we separate immiscible liquids, and can you provide an example of such liquids?
Ans: Immiscible liquids, like cooking oil and water, can be separated by using decantation. For example, if you mix oil and water, they form two separate layers, and you can carefully pour off one of them to separate them.

Q4: Describe the steps to obtain salt from a mixture of salt, sand, and water.
Ans: First, use filtration to separate sand from the mixture. Then, heat the remaining liquid to evaporate the water, leaving the salt behind.

Q5: Explain how loading helps in separating extremely small insoluble particles in a liquid.
Ans: Loading is a method used to separate tiny, suspended solid particles in a liquid. By adding a substance like alum to the liquid, it causes the particles to become heavy and settle quickly. This facilitates their separation from the liquid.