A piece of copper weighs 0.635 g. How many atoms of copper does it contain?
The number of carbon atoms present in a signature, if a signature written by carbon pencil weighs 1.2×10−3 g is:
Four grams of caustic soda contains :
(a) 6.02×1023atoms of it, (b) 4 g atom of sodium, (c) 6.02×1022 molecules
(d) 4 moles of NaOH.