Answer:
Since moles are just "some number of particles", and since one O2 molecule contains enough oxygen for two H2O molecules, you need 2.5 moles of O2 for 5 moles of H2O.
Answer:
By heating the solution
Explanation:
Physical changes and chemical changes are the two types of changes that a substance undergoes. Physical change does not alter the substance's chemical composition, hence, can be easily reversed. There is also no new product formed. This is contrary to the occurrences of a chemical change, which cannot be reversed after a new product has been formed.
A physical change is what occurs when Adrian's teacher dissolves some sugar in a beaker of water to form a sugar solution. This change does not involve any new product formation, hence, can be reversed. The sugar can be derived back from the solution by HEATING THE SOLUTION. The water (solvent) will evaporate and the sugar (solute) will precipitate.
Answer:
The first ionization energy for K is less than Ca because Ca has a larger effective nuclear charge.
Answer:
4
Explanation:
Avogadro’s number represent the number of the constituent particles which are present in one mole of the substance. It is named after scientist Amedeo Avogadro and is denoted by 
.
Also, it is the number of particles in exactly 12.000 g of isotope carbon 12.
Avogadro constant:-
Hence,
Mass of 
= 131.293+ n18.998 g
So,
molecules have a mass of 131.293+ n18.998 g
Also,
molecules have a mass of 
g
So,
molecules have a mass of 
g
Also, given mass = 0.172 g
Thus,
<u>Thus, value of n is 4.</u>
