C. Diffusion is not a phase change.
Metals like sodium, potassium, magnesium, etc. are extracted by electrolysis of their chlorides in molten state.
These metals are not extracted by reduction of their oxides with carbon because:
Carbon has less affinity for oxygen than these metals
Carbon is a weaker reducing agent than these metals
These metals easily form oxides with oxygen, their oxides are very stable. Affinity to the oxygen is one the greatest of all elements.
Reducing agent is element or compound who loose electrons in chemical reaction. Sodium, potassium, calcium and magnesium are very strong reducing agents because they easily loose one or two valence electrons.
Electrolysis is a chemical methode that uses electric currents for chemical reactions.
More about reducing agent: brainly.com/question/7484765
#SPJ4
The error caused will lower the number of moles when he did not do the second heating.This question is related to the empirical formula.
<h3>What is Empirical formula ?</h3>
A formula giving the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms.
The empirical formula is the simplest ratio of atoms in a given compound.
we know that heating is used to eliminate most of the water molecules which are attached to the compound in the question, it's given that the second heating was not performed by the students.
This means that there are still some water molecules attached to the compound. This will imply that higher mass will be calculated for the compound because the water molecules are also considered.
So now, if we look at the calculation for the number of moles of water in this, we can say that this will be lower than the actual amount.
This is because there are some unaccounted moles of water which are still attached to the compound and these will be accounted in the compound mass rather than the waters. Therefore, the number of moles will be lower.
Hence, The error caused will lower the number of moles when he did not do the second heating.
Learn more about Empirical formula here ;
https://brainly.in/question/32699671
#SPJ1
Answer:

Explanation:
Concentration: i is defined as the mole per litre.

mole=0.15
volume=400 ml=0.4 litre
