Which one of the following is a good conductor of electricity?
Diamond
Graphite
Silicon
Amorphous carbon
Doping of silicon with boron leads to
n-type semiconductor
p-type semiconductor
superconductor
insulator
The substance not likely to contain CaCO3 is
marble statue
calcined gypsum
sea shells
dolomite
B.
calcined gypsum
Gypsum is a very soft sulphate mineral composed of calcium sulphate dihydrate, with the chemical formula CaSO4.2H2O.
On heating, gypsum loses water and gives the hemihydrate (CaSO4.H2O) or the anhydrite.
The hemihydrate is known as calcined gypsum or plaster of paris.
The electronic configuration of an element C is 1s2, 2s2, 2p6. The formula of substance containing only C will be
C8
C4
C2
C
C14 is
a natural non-radioactive isotope
an artificial non-radioactive isotope
an artificial radioactive isotope
a natural radioactive isotope