The purity of a solid sample can best be determined by its
boiling point
melting point
conductivity
solubility
Correct answer is B
The purity of a solid can be determined by measuring the melting point. A pure solid will have a single, sharp melting point.
The seperation of Nitrogen from oxygen using fractional distillation of air is possible because
nitrogen is less dense than oxygen
oxygen is more reactive than nitrogen
of the difference in their boiling points
they belong to the same period
Correct answer is C
The various gases vaporize as their boiling points are reached, then they are pumped away and separately re-liquefied for convenient storage.
The species with no electron in the 3d-orbital is
\(Zn^{2+}\)
\(Sc^{3+}\)
Cu
\(Mn\)
Correct answer is B
Scandium has electronic configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{1}4s^{2}\) hence, \(Sc^{3+}\) has configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\). Hence, no electron in the 3d-orbital.
The following glasswares are used to measure the volume of liquids EXCEPT
graduated beaker
pipette
test tube
burette
Correct answer is C
Test tubes are convenient containers for heating small amounts of liquids or solids with a Bunsen burner or alcohol burner.
Which of the following species determines the chemical properties of an atom?
Electron
Neutron
Nucleus
Proton
Correct answer is A
An element's chemical properties depend on its valence electrons.The chemical properties of elements depend on an element's electron configuration.