The concept we are looking for here is electronegativity. This concept is a measure of how strong an atom or element can attract a pair, that is bonding, of electrons to itself.
Fluorine is the element or atom of the greatest electronegativity. Electronegativity would increase as we move left to right of the periodic table.
High temperature and pressure produce the highest rate of reaction. However, this must be balanced with the high cost of the energy needed to maintain these conditions. Catalysts increase the rate of reaction without affecting the yield. This can help create processes which work well even at lower temperatures.
I hope this helps you.
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.
In the first situation: the mechanism of covection is the main form of heat transfer when warm air from a heater moves around and upward.
In the case of the metal pan the mechanism of heat transfer is conduction.
In the case of sunburn the mechanism is radiation.
In the case of an ice cube melting in a hand, conduction is the most important mechanism.
