1.Distinguish between the following
boiling and evaporation
gas and vapour
2.Explain the following
a.Can heat be classified as matter.
b.Which of the following does not sublime at all snow, camphor, dry ice, Mercury ,sodium?
c. State the characteristics of solid that make them rigid
d. State the characteristics of liquid that make them fluid
3.State the law of conservation of mass describe its experimental verification
4. What are the two factors responsible for interconversion of matter
5. Explain the following on basis of kinetic theory
Sublimation
Melting
Boiling
6.Give reason for the following
a.Light is not considered as matter
b. On heating a substance at its melting point the interparticle space increases
c. Naphthalene balls become smaller day by day
d. When iron is heated with Sulphur iron sulphide is formed the total mass of iron and sulphur is equal to the mass of iron sulphide
e. Why do solids and liquids have an open surface while gases do not
f. Name two substances which sublime at room temperature.
Answers
Answer:
1. Boiling - latent heat of evaporation is the heat energy required to change 1 kg of liquid to gas at atmospheric pressure at its boiling .
Evaporation - It is a surface phenomenon. Particles from the surface gain enough energy to overcome the force of attraction present in the liquid and change into vapour state.
Vapour - The water which is present in the gaseous form is called as vapour
2) a) Heat, light, and other forms of electromagnetic energy do not have measurable mass and can't be contained in a volume.
b) Mercury is a metal It do not sublime
c) We can observe that all these have a definite shape , distinct boundaries and fixed volumes, that is have negligible compressibility. Solid have a tendency to maintain their shape when subjected to outside force . Solid may break under force but it is difficult to change their shape so they are rigid
d) We observe that liquids have no fixed shape but have fixed volume. They take up the shape of the container in which they are kept. Liquid flow and change shape, So they are not required but can be called fluid.
3. Law of conservation of mass: It states that mass can neither be created nor be destroyed
4. Temperature and pressure are the two factors responsible for interconversion of matter.
6.a.Light do not occupy space, have no mass or volume, and therefore are not considered matter. Because matter is defined as anything which occupy space and have some mass.
6.b Because when a substance is heated the kinetic energy of the partilces(molecules/atoms) increases due to which they push each other farther than their mean position, therefore the distance between the particles(inter-molecular space) increases.
c. Naphthalene ball is a sublime substance which undergoes change of solid state directly to the gaseous state without going through liquid state . It goes continuous process where vapour not visible therefore naphthalene balls appears smaller day by day.
d. As we can see that both of them are combining and only one product is formed in the reaction. The mass of FeS formed is equal to the mass of Fe & S according to the "law of conservation of mass" which states that the total mass of reactants = total mass of products.
e. The particles of solids are very close to each other and force of attraction between the particles is very strong. ... Therefore, gases do not have definite shape, they diffuse easily into air and hence have no open surface area.
f. Dry ice and Camphor are the two substances which sublime at room temperature.