Asolution is prepared by adding 16 g of ch3oh (molar mass 32 g) to 90 g of h2o (molar mass 18 g). the mole fraction of ch3oh in this solution is closest to which of the following?
(a) 0.1
(b) 0.2
(c) 0.3
(d) 0.4
(e) 0.6

The mole fraction of CH3OH in this solution is closest to 0.1.

Explanation:

The mole fraction of CH3OH can be calculated by dividing the number of mole of CH3OH by the sum of all moles present in the solution. In our example, we have 16 g CH3OH and 90 g H2O. Let´s see how many mols of each constituent we have:

1 mol CH3OH = 32 g ⇒ 16 g CH3OH = 0.5 mol.

1 mol H2O = 18 g ⇒ 90 g H20 = 5 mol

Then, the mole fraction is:

X = mol CH3OH / (mol H2O + mol CH3OH)

X= 0.5 mol / (5 mol + 0.5 mol) ≅ 0.1

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms