NTSE Important Questions for CBSE Class 9 Science – Chapter 1| Matter In Our Surroundings

Matter in our surroundings provides an outline of the importance of matter based on their physical properties and chemical nature. This chapter helps students to understand the physical nature of matter. It talks about how matter is made up of particles, size and characteristics of particles, state of matter, and evaporation. The important questions provided herein are finely drafted by our Science Experts to further help the students in the NTSE preparation.

Science Important Questions:

Q1. When a teaspoon of solid sugar is dissolved in a glass of liquid water, what phase or phases are present after mixing-

(a) liquid only

(b) still solid and liquid

(c) solid only

(d) None of these

Ans: (a) liquid only

Sol: Liquid only and the mixture will be homogenous. This shows that particles of matter have space between them.

Q2. When heat is supplied to a solid substance at its melting point?

(a) The kinetic energy of the particles increases

(b) The kinetic energy of the particles decreases

(c) The kinetic energy of the particles remains constant

(d) None of these

Ans: (c) The kinetic energy of the particles remains constant

Sol: At melting point, ice at 0° C changes into the water at 0°C, the temperature remains constant and thus no change in kinetic energy takes place.

Q3. If gas is expanded at a constant temperature

(a) The pressure increases

(b) The kinetic energy of the molecules remains the same

(c) The kinetic energy of the molecules decreases

(d) The number of molecules of the gas increases

Ans: (b) The kinetic energy of the molecules remains the same

Sol: Kinetic energy depends on temperature only.

Q4. Liquids diffuse slowly as compared to gases because

(a) The molecules are held together by strong intermolecular forces.

(b) The molecules of liquids are heavy.

(c) Liquids have a definite shape.

(d) The molecules in liquids undergo a large number of collisions with the neighbouring molecules.

Ans: (a) The molecules are held together by strong intermolecular forces.

Sol:  The molecules are held together by strong intermolecular forces.
(a) Intermolecular forces are stronger in liquid than in gases and hence liquid diffuses (move less freely)

Q5. The substance which is known as dry ice:

(a) Potassium permanganate

(b) Copper sulphate

(c) Sulphur dioxide

(d) Solid carbon dioxide

Ans: (d) Solid carbon dioxide

Sol: (d) Solid carbon dioxide is known as dry ice

Other than these important questions, you must also go through the most probable questions available on NTSEGuru. Stay tuned to NTSEGuru.in for the important questions of Science Chapter 2 – Is Matter Around Us Pure.