Explore topic-wise InterviewSolutions in Current Affairs.

1. Take some hibiscus (china rose or mandara) petals. 

2. Take warm water into a beaker and place the petals in the beaker. 

3. Keep it until the water has completely turned into violet colour. 

4. Filter the solution with a strainer. 

5. Now hibiscus indicator is ready to test.

Test with indicator:

1. Take lemon juice, soda water, lime water, glucose solution, sugar solution, soap water etc. into test tubes.

2. Add sufficient amount of hibiscus indicator in each test tube. 

3. Observe the change in the colour of the substance and record in the table.

Conclusion : 

In acids and bases the hibiscus indicator changes its colour. Hence, it can used as an acid base indicator.

The correct answer is C) Clove oil.

1. Hibiscus is a natural indicator that changes its colour in acids and bases. 

2. It changes its colour from violet to pink in acids. 

3. It changes its colour from violet to green in bases. 

4. Thus it can be used to identify acids and bases.

A. At a given temperature, particles of steam are at higher kinetic energy than that of boiling water. Therefore, steam would produce more severe burns than boiling water.

B. During the change of state, the heat energy supplied to the substance is completely used to overcome the forces of attraction between the particles of the substance. So there is no change in the temperature of the substance during its change of state. The energy supplied at that time is called latent heat.

The correct answer is A) Hydrangea.

Among different components of the mixture, there are many substances that are harmful or not useful for us. To remove these harmful or unuseful components we need to separate them. 

Examples:

(a) Tea leaves are separated from the liquid with a strainer while preparing tea.
(b) Stone pieces from wheat, rice, or pulses are picked out by hand.

List of items that float on kerosene:

(i) Paper
(ii) Thermocol
(iii) Thin plastic sheet

List of items that float on an oil:

(i) Paper
(ii) Plastic sheet
(iii) Wax
(iv) Thermocol
(v) Wood

True

Viscosity is the property of resistance offered to the flow of a fluid (liquid or gas). It is informally referred to as “thickness”

Diffusion is the process of intermixing of two different states of matter on their own. Not all substances diffuse well, as it depends upon the chemical nature and viscosity of the diffusing liquids.

To prove: Diffusion becomes faster with the increase in temperature. 

Activity: 

i. Take a beaker A and beaker B. 

ii. Pour hot water in beaker A and cold water in beaker B.

iii. Now, put a drop of ink in beaker A and beaker B. 

Observations: 

We will observe that in beaker A, the ink spreads throughout the water faster than in the case of beaker B. 

Conclusion: Hence, this activity proves that diffusion becomes faster with increase in temperature.

A. The particles of liquid have the ability to flow. The particles are loosely packed and can move from one place to another. This property is called fluidity. Liquids have the ability to acquire the shape of the container in which it is kept in. This is possible because of the fluidity of liquids.

B. When alcohol or perfume is put on our palm, the particles of alcohol/perfume gain energy from our palm or surroundings and evaporate. This produces a cooling effect to the palm. The principle behind this is evaporative cooling. 

C. The rate of diffusion of a liquid in another liquid is affected by:

(1) Viscosity and chemical nature: 

Viscosity is the resistance offered to the low of liquids, or simply it is the thickness of the liquid. The rate of diffusion also depends upon the chemical nature of the liquids. 

(2) Temperature: 

An increase in temperature would increase the kinetic energy of the liquid particles which increases the rate of diffusion between them.

Both have mass and are in solid state.

(a) True

(b) True

(a) Baby (all others are non-living)

(b) Boat (all others are flowers)

(c) Sand (all others are metals)

(d) Sand (all others are soluble in water)

Hydrogen and nitrogen.

There are 1000 cm³ in 1L.

Experiment: 

i) In a glass filled with water, add 2 tablespoons of sugar and keep stirring until the sugar dissolves. 

ii) Gradually increase the amount of sugar added to the water and notice that it takes more time for the sugar to dissolve than it did when only 2 tablespoons of sugar were added. 

Explanation: The rate at which the sugar crystals dissolve in water is called the rate of diffusion. This rate was higher when the amount of sugar dissolved was less. As the amount or the density of sugar in the liquid increases the time taken for the sugar to dissolve also increases, i.e, the rate of diffusion decreases.

Hence, the rate of diffusion and density of liquid are inversely proportional to each other.

To show that the rate of diffusion of liquids decreases with increase in density of the liquids:

Activity: 

i. Take two beakers and pour some water in them. 

ii. Pour some honey in first beaker and pour small drops of ink in another beaker. 

iii. Leave both the beakers untouched for a while. 

Observations: We will observe that the ink whose density is low gets mixed easily and spreads throughout the water. On the other hand, honey whose density is high does not get mixed and takes more time to dissolve. 

Conclusion: We conclude that rate of diffusion of liquids decreases with increase in density of the liquids.

The energy possessed by moving objects is known as kinetic energy. It depends on the mass of the object and also the velocity or speed at which the object is moving. 

The unit of kinetic energy is Joules.

(a) Diffusion is the mixing of a substance with another substance due to the motion of its particles. The smell of perfume spreads over a whole room is an example for diffusion. 

(b) Gases diffuse fast because of the large space between the particles in gases and high kinetic energy. 

(c) Carbon dioxide and oxygen are the two gases in air which dissolves in water by diffusion. Carbon dioxide is important for aquatic plants for the photosynthesis. Oxygen is used by aquatic animals for breathing.

Correct answer is (d) Sawdust

Correct answer is (d) Sand

Density is the degree of compactness of the particles. It is also defined as the mass per unit volume of a material.

Water looses its temperature through small pores present in the pot. Hence in an earthen pot (matka) become cool during summer.

An earthen pot contains tiny holes. The particles present in the water surface acquire energy from the surroundings and get converted into vapour (The process involved is evaporation). The vapours escape through these tiny holes producing a cooling effect to the water inside the pot.

Sugar and salt are both solids. They take the shape of their respective jars as the individual crystals of each are small and many of these small sugar or salt crystals can fill up the empty spaces of a container.

The density of solids is higher than that of liquids because the particles are more compactly arranged in a solid with very less intermolecular spaces between them. In liquids, these intermolecular spaces are more and hence they are less dense.

The correct option is (d) because as we know that kinetic energy of the gases is maximum, liquid is intermediate and solids is minimum. Hence, the order is: 

Hydrogen (gas) > honey (solid but has high density than water) > water

1. Rigidity: The condition which do not alters the shape of solids.

2. Compressibility: Compressing particles of gases is called compressiblity.

3. Filling a gas container: In the laboratory, after the preparation of gases, they are collected in gas jar. This is called filling a gas container.

4. Fludity: Fluidity means flowing of liquids freely.

5. Shape: Things are in which form is called shape.

6. Kinetic energy: The energy possessed by moving body is called kinetic energy.

7. Density: Density is the mass per unit

Density = \(\frac{Mass}{Volume}\)

Particles start vibrating in the solids because: 

i. On increasing the temperature of solids, the kinetic energy of the particles increases. 

ii. Due to the increase in kinetic energy, the particles start vibrating with greater speed.

(a) Gases have maximum movement of particles. 

(b) Solids have maximum interparticle attractions 

(c) Solids have minimum space between particles.

Difference between gas and vapour:

The increasing order of forces of attraction for the three states of matter (solid, liquid, gas) is as follows:

Gas>Liquid>Solid 

Here, water → liquid, air → gas, sugar → solid, oxygen → gas, salt →solid, oil → liquid, juice → liquid.

The option which obeys the above order is (C)

(a) LPG – Liquefied Petroleum Gas. 

(b) CNG – Compressed Natural Gas.

In liquids:

i. The force of attraction between the constituent particles is lesser. 

ii. The rate of diffusion of liquids are higher than that of solids. 

iii. Hence, the particles of liquid move freely. 

iv. They have greater space between each other as compared to the particles in the solid state. 

v. Due to large space in the liquid, their particles held together less firmly as compared to solids.

Yes, they have relation. Metals like K, Na, Ca, Mg and Al are so reactive. They exist in all forms whereas moderate reactive metals like Zn, Fe, Pb, etc. exist as oxides, sulphides and carbonates. The least reactive metals are found even in free state.

Metal sulphides and carbonates are converted to metal oxides in the process of extraction of metal from them because metals can be obtained easier in oxide form than its sulphide or carbonate form

i. lesser 

The temperature at which solid melts to become a liquid at the atmospheric pressure is called its melting point. Higher the melting point of a substance, more easily the substance gets converted into a liquid which has less force of attraction between its particles. 

ii. vapour 

Boiling is a bulk phenomenon. Particles from the bulk of the liquid gain enough energy to change into the vapour state. 

iii. Sublimation 

Naphthalene undergoes the process of sublimation. Sublimation is a change of state directly from solid to gas without changing to liquid state or vice versa.

The correct answer is (c) Oxygen, water, sugar

LPG (Liquefied Petroleum Gas) and Oxygen Gas are the two gases which are supplied in compressed form in houses and hospitals.

True

Inter-molecular forces are present in all states of matter. They are the highest in solids and lowest in gases. Inter-molecular forces determine the structure of the substance.

Gas is the physical state of matter which can be easily compressed.

This law states that “The physical and chemical properties of elements are a periodic function of their atomic weights.”

Yes, the matter is made up of very small particles. Any bulk material is made up of millions of smaller particles. 

For eg, when sugar crystals are dissolved in water, the smaller particles dissociate from the crystal and dissolve in water.

Solving Class 9 Science MCQ Questions of Matter in Our Surroundings. These questions can be of extreme help as you will be aware of all the concepts. Practice the MCQ Question for Class 9 and cross-check your answers during preparation.

MCQ Questions for Class 9 Science with Answers are prepared as per the Latest Exam Pattern. Students can solve these Matter in Our Surroundings Multiple Choice Questions with Answers and assess their preparation level.

Practice MCQ Questions for class 9 Chapter-Wise

1. The mass per unit volume of a substance is:

(a) acceleration
(b) density
(c) velocity
(d) weight

2. What is dry ice?

(a) Solid carbon dioxide
(b) Nitrogen oxide
(c) Carbon mono oxide
(d) None of them

3. Which of the following state is responsible for the glow in the sun and stars?

(a) Solid
(b) Liquid
(c) Plasma
(d) Gas

4. Which of the following phenomenon takes place when we add a drop of Dettol into the water?

(a) osmosis
(b) diffusion
(c) sublimation
(d) none of them

5. Which one of the following sets of phenomena would increase on raising the temperature?

(a) Diffusion, evaporation, compression of gases
(b) Evaporation, compression of gases, solubility
(c) Evaporation, diffusion, expansion of gases
(d) Evaporation, solubility, diffusion, compression of gases

6. Seema visited a Natural Gas Compressing Unit and found that the gas can be liquefied under specific conditions of temperature and pressure. While sharing her experience with friends she got confused. Help her to identify the correct set of conditions

(a) Low temperature, low pressure
(b) High temperature, low pressure
(c) Low temperature, high pressure
(d) High temperature, high pressure

7. The property to flow is unique to fluids. Which one of the following statements is correct?

(a) Only gases behave like fluids
(b) Gases and solids behave like fluids
(c) Gases and liquids behave like fluids
(d) Only liquids are fluids

8. What is the matter?

(a) anything that has mass.
(b) anything that has volume.
(c) anything that has mass and volume.
(d) anything that has mass and volume and occupy space.

9. Every matter has its own……………… and………….

(a) Mass, volume
(b) Weight, mass
(c) Brittleness, tough
(d) Shape, shadow

10. ‘Panch Tatva’ of life.

(a) Air, god, water, mother, father
(b) Air, fire, earth, sky, water
(c) Air, god, water, soil, crop
(d) Air, god, water, yield, money

11. Matter is classified on the basis of………….

(a) Physical and chemical properties
(b) Physical and biological properties
(c) chemical properties
(d) Biological and characteristical properties.

12. During summer, water kept in an earthen pot becomes cool because of the phenomenon of

(a) diffusion
(b) transpiration
(c) osmosis
(d) evaporation

13. A few substances are arranged in the increasing order of ‘forces of attraction’ between their particles. Which one of the following represents a correct arrangement?

(a) Water, air, wind
(b) Air, sugar, oil
(c) Oxygen, water, sugar
(d) Salt, juice, air

14. On converting 25°C, 38°C and 66°C to kelvin scale, the correct sequence of temperature will be

(a) 298 K, 311 K and 339 K
(b) 298 K, 300 K and 338 K
(c) 273 K, 278 K and 543 K
(d) 298 K, 310 K and 338 K

15. Any colour which we detected by our eyes….

(a) Due to light
(b) Due to air
(c) Due to visible light
(d) Due to darkness

16. When Potassium paramagnet dissolve in water shows…………

(a) Red in colour
(b) Blue in colour
(c) Violet in colour
(d) Orange in colour

17. Choose the correct statement of the following

(a) Conversion of solid into vapours without passing through the liquid state is called sublimation.
(b) Conversion of vapours into solid without passing through the liquid state is called vaporisation.
(c) Conversion of vapours into solid without passing through the liquid state is called freezing.
(d) Conversion of solid into liquid is called sublimation.

18. The boiling points of diethyl ether, acetone and n-butyl alcohol are 35°C, 56°C and 118°C respectively. Which one of the following correctly represents their boiling points in kelvin scale?

(a) 306 K, 329 K, 391 K
(b) 308 K, 329 K, 392 K
(c) 308 K, 329 K, 391 K
(d) 329 K, 392 K, 308 K

19. Which condition out of the following will increase the evaporation of water?

(a) Increase in temperature of water
(b) Decrease in temperature of water
(c) Less exposed surface area of water
(d) Adding common salt to water

20. The matter is made up of: 

(a) cell
(b) molecules
(c) particles
(d) gas

Answer:

1. Answer: (b) density

2. Answer: (a) Solid carbon dioxide

3. Answer: (c) Plasma

4. Answer: (b) diffusion

5. Answer: (c) Evaporation, diffusion and expansion of gases

Explanation: Particles of matter are continuously moving as they possess kinetic energy. When temperature is raised particles of matter intermix with each other which is called diffusion.

Evaporation means conversion of liquid state into vapour state. When we increase temperature molecules move and vibrate so quickly that they escape into the atmosphere in the form of vapours.

Increase in temperature causes the molecules to move faster, which results in expansion of gases.

6. Answer (c) Low temperature, high pressure

Explanation: To compress gas into liquid, low temperature and high pressure are required. Between the particles of gas there is a lot of space. On applying pressure, particles get closer and they start attracting each other to form a liquid. A lot of heat is generated when gas is compresses hence it is necessary to cool it. Cooling lowers the temperature of compressed gas and helps in liquefying it.

7. Answer: (c) Gases and liquids behave like fluids

Explanation: In gases and liquids intermolecular force of attraction between the particles is less and they facilitate flow of these states of matter.

8. Answer: (d) anything that has mass and volume and occupy space.

9. Answer: (a) Mass, volume

10. Answer: (b) Air, fire, earth, sky, water

11. Answer: (a) Physical and chemical properties

12. Answer: (d) evaporation

Explanation: Evaporation of water through pores of earthen pot reduces temperature of immediate surroundings. This makes the water cool after some time.

Movement of water through plants and evaporation through its aerial parts is called transpiration.

Diffusion is the movement of a substance from an area of higher concentration to an area of lower concentration

If molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, it is called osmosis.

13. Answer: (c) Oxygen, water, sugar

Explanation: The intermolecular force of attraction is less in gases than liquid and solid. Solids have higher intermolecular attraction compared to liquid. In the answer, oxygen is a gas which has lesser intermolecular attraction than water-a liquid and sugar- a crystalline solid.

14. Answer: (a) 298 K, 311 K and 339 K

Explanation: Add 273 to respective temperature to get the temperature in kelvin. 25°-298K, 38°-311K, 66°-339K.

15. Answer: (c) Due to visible light

16. Answer: (c) Violet in color

17. Answer: (a) Conversion of solid into vapours without passing through the liquid state is called sublimation.

Explanation: Sublimation is a process in which a solid is converted into vapours without passing through a liquid state.
Vaporisation is a phase transition from liquid to vapours.
Conversion of liquid to solid at substance’s freezing temperature is called as freezing.

18. Answer: (c) 308 K, 329 K, 391 K

Explanation: The temperature in Celsius can be converted into temperature in kelvin by adding 273 to the Celsius value. Boiling points of diethyl ether, acetone and n-butyl alcohol are 308 K, 329 K, and 391 K, respectively.

19. Answer: (a) Increase in temperature of water

Explanation: Increase in temperature of water increases the kinetic energy of the water which will make more particles to attain enough energy to convert into the vapour state. This is how an increase in temperature favours evaporation.

On the other hand, the exposed surface is also responsible for the evaporation. Higher the exposed surface, higher will be the evaporation.

When common salt is added to water then the surface is occupied by the solvent as well as non-volatile solute particles.

This makes the escaping tendency of solvent particles decrease and thus the evaporation of water decreases. Hence options (b), (c) and (d) will decrease the evaporation of water.

20. Answer: (c) particles

Click here to practice Matter in our surroundings MCQ Questions for Class 9 Science

The main basic difference between Mendeleev’s periodic table and modem periodic table is that first one is constructed on the basis of atomic weight and the later is constructed on the basis of atomic number.