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:
Permanent = false
Explanation:
All of the other choices are true
The ribosomes are the ones delivering the products of the endoplasmic reticulum
Answer:
true
Explanation:
Materials science is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering. It includes elements of applied physics and chemistry, as well as chemical, mechanical, civil and electrical engineering.
and we all know matter involve solid liquid or gas
Answer:
2.34 gms left
Explanation:
3 weeks = 21 days = 7 half lives
300 * (1/2)^7 = 2.34 gms