3. (a) State the main postulate of the Kinetic theory of matter. (b) The freezing point of a substance is -37°c and its boiing point is 357 °C, Find its melting and condensation point. (c) A cuboidal piece of wood measures 5 cm by 6 cm by 8 cm and a mass of 50gm. Find the density of the wood in s,l, unit. (d) An empty R.D. bottle has a mass 20.5 gm., when filled with water its mass is 28.75 gm and 25.2 gm when filled with kerosene. Find the (i) volume of the bottle (ii) R.D. of kerosene (iii) density of kerosene in s.i. unit. (5+4+5+6)
Answers
Answer:
Ans 3)a) The kinetic molecular theory of matter states that: Matter is made up of particles that are constantly moving. ... There are attractive forces between atoms/molecules, and these become stronger as the particles move closer together. These attractive forces are called intermolecular forces.
b)The substance described in question is water and its state at room temperature is liquid. A substance is said to be a solid if its melting point is above room temperature under atmospheric pressure. A substance is said to be a liquid if its melting point is below room temperature and boiling point is above room temperature. A substance is said to be a gas if its boiling point is below room temperature under atmospheric pressure.
c)
d)Mass of empty bottle, mb = 25.25 g
When bottle is filled with water, the mass of bottle is, mbw = 55.75 g
Thus, mass of water, mw = 55.75 - 25.25 g = 30.5 g
When filled with alcohol, mass of the bottle is, mba = 45.50 g
Thus, mass of alcohol, ma = 45.50 - 25.25 = 20.25 g
Volume of bottle = volume occupied by water
We know,
density = mass/ volume
density of water = 1 g/cm3
mass of water = 30.5 g
Thus, volume of water, vw = mw / 1 = 30.5 cm3
Hence,
volume of bottle = 30.5 cm3
volume occupied by water = voulme occupied by alcohol = 30.5 cm3
R e l a t i v e space d e n s i t y space o f space a l c o h o l space equals fraction numerator d e n s i t y space o f space a l c o h o l over denominator d e n s i t y space o f space w a t e r end fraction equals fraction numerator begin display style bevelled fraction numerator m a s s space o f space a l c o h o l space over denominator v o l u m e space o f space a l c o h o l end fraction end style over denominator begin display style bevelled fraction numerator m a s s space o f space w a t e r over denominator v o l u m e space o f space w a t e r end fraction end style end fraction space equals space fraction numerator m a s s space o f space a l c o h o l over denominator m a s s space o f space w a t e r end fraction equals space m subscript a over m subscript w space... space left parenthesis because v subscript w equals space v subscript a right parenthesis equals space fraction numerator 20.25 over denominator 30.5 end fraction space equals space 0.663 space almost equal to space 0.7
density of alcohol = mass of alcohol/ volume of alcohol = 20.25/30.5 = 0.66 g/cm3 = 0.7 g/cm3
Explanation: