Identify the mixture from the following.
Oxygen
Carbon dioxide
Hydrogen
Air
Sieving can be used only when the components of the mixture have :
different sizes
different melting points
different boiling points
different specific gravities
Which of the following mixtures will be the most difficult do separate ?
Iron fillings + sand
Sand + water
Saw dust + stones
Nitrogen + hydrogen
A few coloured glass pieces that are big in size are mixed with sugar . The easiest way to separate them is :
heat the mixture
add the mixture of water
handpick the glass pieces
handpick the sugar particles
A pure substance is made up of :
only one kind of molecules
two or more kinds of molecules
different types of molecules
none of the above
Winnowing is useful only when :
two solids have different melting points
two solids have different boiling points
two solids have different magnetic properties
two solids have different weights
Decantation is a :
process of transferring the clear liquid without disturbing the sediments
process of separating an insoluble solid from a liquid using filter paper
process of settling down heavier , insoluble particles from a mixture
process by which a solid changes directly into the vapour state
A coagulant is :
special chemical which helps small fine particles to settle down
which helps the substance to sublime
filtering agent
Alloys are the examples of mixtures of :
solid-in-gas
gas-in-solid
gas-in-gas
solid-in-solid
Pure substances possess :
variable melting points and boiling points
nonuniform composition
variable properties
fixed melting points and boiling points
