Listen NCERT Audio Books to boost your productivity and retention power by 2X.
Fill in the following blanks with suitable words:
(a) The best evidence that the particles of matter are constantly moving comes from the studies of………. and ……….
(b) The smell of perfume gradually spreads across a room due to ………….
(c) Solid, liquid and gas are the three………….. of matter.
(d) At room temperature, the forces of attraction between the particles of solid substances are………….. than those which exist in the gaseous state.
(e) The arrangement of particles is less ordered in the…………. State. However, there is no order in the………State.
(a) When an incense stick(agarbatti) is lighted in one corner of a room, its fragrance quickly spreads in the entire room. Name the process involved in this.
(b) A girl is cooking some food in the kitchen. The smell of food being cooked soon reaches her brother’s room. Explain how the smell could have reached her brother’s room.
(a) Compare the properties of solids, liquids and gases in tabular form.
(b) Give two reasons for saying that wood is a solid
During class, the students resemble molecules in a solid (because they are very close to one another)
While going from one classroom to another the students resemble molecules in a liquid (because they are a little more farther apart from one another)
And in the playground students resemble molecules in a gas (because they are very, very far apart from one another)
In which of the following conditions, the distance between the molecules of hydrogen gas would increase?
(i) increasing pressure on hydrogen contained in a closed container
(ii) some hydrogen gas leaking out of the container
(iii) increasing the volume of the container of hydrogen gas
(iv) adding more hydrogen gas to the container without increasing the volume of the container
When a gas jar containing colourless air is kept upside down over a gas jar full of brown-coloured bromine vapour, then after sometime, the brown colour of bromine vapour spreads into the upper gas jar making both the gas jars appear brown in colour. Which of the following conclusion obtained from these observations is incorrect?
Look at the diagram on the right side. Jar A contains are d-brown gas whereas Jar B contains a colourless gas. The two gas jars are separated by a glass plate placed between them
(a) What will happen when the glass plate between the two jars is pulled away?
(b) What name is given to the phenomenon which takes place?
(c) Name the brown gas which could be in jar A.
(d) Which is the colorless gas most likely to be present in jar B?
(e) Name one coloured solid and one colourless liquid which can show the same phenomenon.
Explain why, osmosis can be considered to be a special kind of diffusion. Classify the following into
(i) osmosis, and (ii) diffusion:
(a) swelling up of a raisin on keeping in water
(b) spreading of virus on sneezing
(c) earthworm dying on coming in contact with common salt
(d) shrinking of grapes kept in thick sugar syrup
(e) preserving of pickles in salt
(f) spreading of smell of cake being baked in the kitchen
(g) aquatic animals using oxygen dissolved in water during respiration
A student placed a gas jar containing air in the upside down position over a gas jar full of red-brown bromine vapours. He observed that the red brown colour spread upwards into the jar containing air. Based on this observation, the student concluded that it is only the bromine vapour which moves up and diffuses into air in the upper jar, the air from the upper jar does not move down by diffusion into the lower jar containing bromine vapours. Do you agree with this conclusion of the student? Give reason for your answer.
When extremely small particles X derived from the another of a flower were suspended in a liquid Y and observed through a microscope, it was found that the particles X were moving throughout the liquid Y in a very zig zag way. It was also observed that warmer the liquid Y, faster the particles X moved in its surface.
(a) What could particles X be?
(b) What do you think liquid Y is?
(c) What is the zig-zag movement of particles X?
(d) What is causing the zig-zag movement of particles X?
(e) Name the scientist who discovered this phenomenon.
(f) What does this experiment tell us about the nature of liquid Y?
When a beam of sunlight enters a room through a window, we can see tiny particles X suspended in a gas (or rather a mixture of gases) Y which are moving rapidly in a very haphazard manner.
(a) What could particles X be?
(b) Name the gas (or mixture of gases) Y.
(c) What is the phenomenon exhibited by particles X known as?
(d) What is causing the movement of particles X?
(e) What conclusion does the existence of this phenomenon give us about the nature of matter?
Fill in the following blanks with suitable words:
(a) Gases can be liquefied by applying ___ and lowering ___
(b) When steam condenses to form water, heat is ___
(c) Temp on Kelvin scale = Temp on Celsius scale + ___
(d) Scientists say that there are actually five states of matter: Solid, liquid, gas, ___ and ___
(e) The state of matter called ___ makes a fluorescent tube (or neon sign bulb) to glow.
There are four substances W, X, Y and Z. The substance W is a dark violet solid having diatomic molecules. A solution of W in alcohol is used as a common antiseptic C. The substance X is a white solid which is usually recovered from sea water on a large scale. The substance Y is a white solid which is insoluble in water and used in the form of small balls for the safe storage of woollen clothes. The substance Z is a yet another white solid which is used in making commonly used dry cells.
(a) Name (i) W (ii) X (iii) Y and (iv) Z.
(b) Out of W, X, Y and Z, which substance/substances can undergo sublimation?
(c) Which substances organic in nature?
(d) What is the name of substance C?
(e) Which substance belongs to the halogen family?
The substance X normally exists in a physical state which can flow easily but does not fill its vessel completely. It also turns anhydrous copper sulphate blue. When substance X is cooled excessively, it changes into a substance Y which has a fixed shape as well as a fixed volume. If, however, the substance X is heated strongly, it changes into a substance Z which has neither a fixed shape nor a fixed volume.
(a) Name the substances (i) X (ii) Y and (iii) Z.
(b) What is the process of conversion of X into Y known as?
(c) At which temperature X gets converted into Y?
(d) What is the process of conversion of X into Z known as?
(e) At which temperature X gets converted into Z?
The scientists now say that there are actually five states of matter A, B, C, D and E. The state A has a fixed volume but no fixed shape. The state B can be compressed very easily by applying pressure and state C has a fixed shape as well as a fixed volume. The state D is mixture of free electrons and ions whereas state E is named after an Indian scientist and a famous physicist.
(a) Name the physical states (i) A (ii) B (iii) C (iv) D, and (v) E.
(b) Name one substance belonging to state C which can directly change into vapours on heating. What is this process known as?
(c) Name one substance which normally belongs to state B but whose solid form changes directly into gaseous state.
(d) Name the most common substance belonging to state A.
(e) Which state of matter makes the sum and other stars to glow.
When water is cooled to a temperature x, it gets converted into ice at temperature x by a process called P. And when ice at temperature x is warmed, it gets reconverted into water at the same temperature x in a process called Q.
(a) What is the value of temperature x in Kelvin?
(b) What is the process P known as?
(c) What is the name of energy released during process P?
(d) What is the process Q known as?
(e) What is the name of energy absorbed during process Q?
When water is heated to a temperature x, it gets converted into steam at temperature x by a process called R. And when steam at temperature x is cooled, it gets reconverted in to water at the same temperature x by a process called S.
(a) How much is the value of x in Kelvin?
(b) What is the process R called?
(c) What is the name of the energy absorbed during the process R?
(d) What is process S known as?
(e) What is the name of energy released during the process S known as?