Physical and Chemical changes
1) Substances pocess characteristics called properties by which they can be distinguished or identified. From the list of properties given below state which are physical and which are chemical.
a) Thermal conductivity.
b) liquification temperature.
c) Solidification point.
d) Action with indicators.
e) Reaction with dilute acid.
2) Listed below are certain characteristics of physical and chemical changes, identify the correct characteristics for the respective change.
a) loses its identity.
b) changes in form and state.
c) undergoes no change in its fundamental nature .
d) retains its identity.
e) undergoes a temporary change.
f) undergoing the change, changes in mass.
g) evolves or absorbs energy during the change.
h) undergoes change in certain physical properties only.
i) reverts back to original on removal of the change.
j) neither adds nor removes matter from itself.
k) forms at least one new product.
l) releases energy, which is required for completion of the change on reversal of the change.
3) In terms of the factors given below differentiate a physical change from a chemical change occuring in a substance.
a) composition
b) energy
c) mass
4) State whether the following are physical or chemical changes.
a) vaporization.
b) sublimation.
c) liquification
d) fermentation
e) dehydration
f) Putrefaction
g) Rain cycle
h) Carbon cycle.
i) Nitrogen cycle.
j) on magnetization.
k) on rusting.
l) an addition to Copper sulphate solution.
m) burning of a candle.
n) melting of paraffin wax.
o) ripening of a fruit.
p) drying fruit.
q) drying paint.
r) drying of white wash.
s) dissolution of copper sulphate in water .
t) dissolution of carbon dioxide in water.
u) dissolution of iron in dilute HCl
v) passage of current through an electric bulb.
w) passage of current through acidified water.
x) passage of current through copper metal.
z) digestion of food.
a') respiration animals.
b') heat on camphor.
c') heat on Potassium chloride.
d') souring of milk.
e') boiling of milk .
5) Give reasons for the following changes. The reasons should include characteristics such as composition, nature of its change, energy changes or changes in mass of the substance if any.
a) Addition of sodium chloride to water is considered a physical change , while addition of sodium to water a chemical.
b) magnetization of iron is deemed a physical change while addiction of iron to silver nitrate solution and rusting of iron are deemed chemical changes .
c) Heating a platinum wire in a non-luminous flame prior to performance of the flame test is considered a physical change, but heating an iron wire in a bunsen burner is a chemical change.
d) Action of heat on ammonium chloride results in formation of a basic gas and an acidic gas while action of heat on ammonium nitrite result in formation of steam and nitrogen, even then the former is deemed a physical change while the latter a chemical.
e) Heating zinc oxide in a hard glass test tube is a physical change but heating red lead in a test tube or burning of carbon in oxygen or air is deemed a chemical change.
f) Dissolution of sugar in water is physical change while burning of paper is a chemical change.
g) magnetization of iron is a physical change while rusting of iron is a chemical change.
h) Addition of zinc to dilute hydrochloric acid is a chemical change.
i) Change of State of matter is a physical change.
j) Burning and respiration are considered as chemical changes.
k) Photosynthesis is considered a photochemical reaction.
l) Energy released during respiration and burning differ.
6) Differentiation between physical and chemical properties. Classify the following properties as physical or chemical properties.
a) Solubility
b) odour
c) indicator test
d) electrical conductivity
e) dissolution in water
7) Select as Physical/changes
a) Ripening of a fruit
b) curdling of milk
c) melting of wax
d) the carbon cycle
e) separation of two liquids by distillation
f) melting of butter
g) formation of rain
h) boiling of liquid air
i) Composition of the molecules of the substance is altered.
j) change takes place in colour and solubility of substance only.
k) Energy required for completion of the change is released on reversing the change.
l) Matter undergoes changes, but the total mass is unaltered.
m) Change takes place in form or state only.
n) Oxidation of food substance in body cells.
o) Sublimation of iodine
p) Clotting of blood
q) Heat on zinc carbonate
r) Burning of magnesium
PHYSICAL AND CHEMICAL CHANGES - A
1) Substances possess characteristics called properties by which they can be distinguished or identified. From the list of properties given below state which are physical and which are chemical .
a) Rhermal conductivity.
b) Liquification temperature.
c) Solidification point.
d) Action with indicators.
e) Reaction with dilute acids .
2) Listed below are certain characteristics of physical and chemical changes, identify the correct characteristics for the respective change.
a) losers its identity.
b) changes in form and state.
c) undergoes no change in its fundamental nature.
d) retains its identity.
e) undergoes a temporary change.
f) undergoing the change, changes in mass.
g) evolves or absorbs energy during the change.
h) undergoes change in certain physical properties only.
i) reverts back to original on removal of the change.
j) neither adds nor removes matter from itself.
k) forms atleast one new product.
l) releases energy, which is required for completion of the change on reversal of the change.
3) State whether the following are physical or chemical changes.
a) Interconversation of matter
i) vaporization
ii) sublimation
iii) liquification
b) Fermentation
c) Dehydration
d) Putrefaction
e) Natural processess
i) Rain cycle
ii) Carbon cycle
iii) Nitrogen cycle
f) changes in iron
i) on a magnetisation
ii) on rusting
iii) on addition to copper sulphate solution.
g) Effect on hydrocarbons
i) burning of a candle.
ii) melting of paraffin wax.
h) Changes in a fruit
i) ripening of a fruit .
ii) drying of fruits .
i) Changes in a point
i) drying of a point.
ii) drying of white wash.
j) Dissolution of substances
i) dissolution of copper sulphate in water.
ii) dissolution of carbon dioxide in water.
iii) dissolution of iron in dilute HCL.
k) Passage of electricity
i) passage of current through an electric bulb.
ii) passage of current through acidified water.
iii) passage of current through copper metal
l) Bio-chemical processes
i) digestion of food.
ii) respiration in animals.
m) Thermal changes
i) heat on camphor
ii) heat on potassium chloride
n) Changes in milk
i) souring of milk.
ii) boiling of milk.
i) Combustion
i) burning of kerosene oil.
ii) burning of petroleum gas.
a) A body will sink_____ in pure water than in seawater.
b) An iron nail sinks in water but can float on _____.
c) Solids have ____density than liquids and liquids have ____density than gases.
d) The SI unit of density is_____
e) Mass = density x _____.
f) The density of an object remains____.
g) Density of water is ____.
h) Solids which are denser then a liquid_____ in that liquid.
i) Compared to liquid, gases are____ dense.
a) The type of the motion in which whole body displaced is called______.
b) Turning effect of force depends on___ and____.
c) In bicycle pedal force applied to the chain is ____then force applied at the pedal .
d) Sleepers below the rail track are used to _____weight and____ pressure on the ground.
e) The tip of the needle is made sharp to ____the pressure on it.
f) The gaseous envelope surrounding the earth is called ____.
g) in steering wheel the turning effect is maximum when forces are applied ____to the wheel.
h) The force acting ____to the surface is called thrust.
i) The tyres of vehicles designed to carry heavy load are____ as compared to those of cycles and bikes.
j) foundations of high rise buildings are made wide so that load is___ over a ___area.
k) 1 kgf= ____N(nearly ).
l) moment of force = ____ distance x distance of force from the point of turning.
m) in a door, handle is provided___ from the hinges.
n) pressure is the thrust acting on a surface of ____area.
o) the unit of pressure is ____
p) pressure increases on ____the depth.
a) SI unit of work is ____.
b) The energy possessed by a body by virtue of its position in a gravitational field is called its____
c) energy can neither be created nor destroyed but can only ____
d) As mass m and v² are always positive, therefore ____is always positive, i.e., cannot be negative.
e) When the pendulum oscillates it has____ at the extreme position and ____at the mean positions.
a) Glasses is optically____ than air.
b) Speed of light is____ in air.
c) When a Ray of light moves from glass into air it bends___ the normal.
d) Bending of light when it moves from one medium into another is called___ of light.
e) ____ mirror is used in solar farms.
f) Real image can be taken on____.
g) concave mirror has a _____focus.
h) A concave mirror is a ____mirror.
i) Splitting of light into its constituent colours is called___
j) light consists of ____colours.
a) Unit of loudness is______.
b) any sound above 85 dB can____.
c) sound is a form of ____which excites in our ears the ___ of hearing.
d) Pitch is a sensation which determines____ of sound.
e) ____ is a continuous sound especially of someone speaking, that does not change in pitch .
f) The number of vibrations made by the vibrating body in 1 second is called ___.
g) Wind instrument produce sound when____ is blown in them.
