Most Important Questions on Chapter 1: Matter in Our Surroundings
Which of the following is matter? Chair, air, love, smell, hate, almonds, thought, cold, lemon water, smell of perfume.
Answer-The following substances are matter:
Chair
Air
Almonds
Lemon water.
A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?
Answer-The diver is able to easily cut through the water in the swimming pool because of the weak forces of
attraction between water molecules. It is this property of water that attributes to easy diving.
What are the characteristics of the particles of matter?
Answer-The characteristics of particles of matter are:
(a) Presence of intermolecular spaces between particles
(b) Particles are in constant motion
(c) They attract each other
For any substance, why does the temperature remain constant during the change of state?
Answer-It is due to the latent heat as the heat supplied to increase the temperature of the substance is used up to transform the state of matter of the substance, hence the temperature stays constant.
Suggest a method to liquefy atmospheric gases
Answer-It can be achieved by either increasing the pressure or decreasing the temperature which ultimately leads to the reduction of spaces between molecules.
Why does a desert cooler cool better on a hot dry day?
It is because the temperature is high and it is less humid on a hot dry day which enables better evaporation. High levels of this evaporation provide better cooling effects.
How does the water kept in an earthen pot (matka) become cool during summer?
Answer-An earthen pot is porous in nature. These tiny pores facilitate penetration of water and hence their evaporation from the pot surface. The process of evaporation requires energy which is contributed by water in the pot as a result of which water turns cooler.
Question-Why does our palm feel cold when we put on some acetone or petrol or perfume on it?
Answer-Acetone, petrol, and perfume are volatile substances that get evaporated when they come in contact
with air. Evaporation is facilitated as it uses energy from the palm hence leaving a cooling effect on our
palms.
What type of clothes should we wear in summer?
Answer-In summer, it is preferred to wear light-coloured cotton clothes because light colour reflects heat and cotton materials have pores that absorb sweat, facilitating their evaporation hence causing a cooling effect in the skin
Arrange the following in increasing order of forces of attraction between the particles – water, sugar, oxygen.
Answer-Oxygen (gas) < water (liquid) < sugar (solid)
What produces more severe burns, boiling water or steam?
Steam produces severe burns. It is because it is an exothermic reaction that releases a high amount of heat which it had consumed during vaporization.
matter in our surroundings notes & solution
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