Answer:
A) Sample B has more calcium carbonate molecules
Explanation:
M = Molar mass of calcium carbonate = 100.0869 g/mol
= Avogadro's number = 
For the 4.12 g sample
Moles of a substance is given by

Number of molecules is given by

For the 19.37 g sample

Number of molecules is given by


So, sample B has more calcium carbonate molecules.
The ratio of the elements of carbon, oxygen, calcium atoms, ions, has to be same in both the samples otherwise the samples cannot be considered as calcium carbonate. Same is applicable for impurities. If there are impurites then the sample cannot be considered as calcium carbonate.
Answer: Flow rate is inversely proportional to viscosity.
Explanation: The relation is called Poiseuille's law, which describes the smooth flow of a fluid along a tube.
You're off to a good start, now find the mass of H2O and put it under I mol,
then multiply 1 mol over the mass of H2O by 215 grams
They cause most of their damage when they reach land