It is B. What I found is when water freezes it's entropy decrease. If water freezing that means the temperature is decreasing and that is B.
(4.0 moles of Na) x (6.02 x 10^23) / (1 mole) = 2.4 x 10^24 atoms of Na
There are 2.4 x 10^24 atoms of Na in 4.0 moles.
The molarity is 31.0 * x / 2, such that x is the molar mass of Ca₃(PO₄)₂
So you need to divide this number by avogadro's number, which tells us how many many moles the substance contains. Then multiply the number of moles you have by the molar mass of benzene, to find the amount of grams.
3.56×10^25 / <span>6.02x 10^23= 59.13 moles of the substance. </span><span>59.13 moles x 78.11g/mole= 4620 </span><span>4620 grams of Benzene</span><span>
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Answer: 
Explanation:
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.
The electrons are filled according to Afbau's rule in order of increasing energies where orbital with higher value of (n+l) has higher energy as compared to orbital having lower (n+l) value. Thus the electronic configuration for calcium with atomic number of 20 and hence containing 20 electrons is :
