Astudent weights out 635.94 g na2co3 and dissolved it in 2.0 l water. what is the molarity of his solution?

You have to find out the number of moles of the substance.

I will use rounded numbers for the atomic weights because every periodic table is different.

2Ca = 2 * 40 =  80

1 C   = 1 * 12  =   12

3O = 3  * 16  =   48

Atomic Mass = 140

moles = given mass / molar mass

moles = 635.94 / 140

moles = 4.54

Now you need to find the concentration

C = moles / Volume in liters.

C = 4.54/ 2.0 L

C = 2.27 moles / L

Technically since the volume is only 2 significant digits, your answer should be 2.3 moles / L

If you do not have this as a choice, what are your choices.

answer: option (b) is the correct answer.

explanation:

a covalent bond is formed by sharing of electrons. whereas polarity arises due to difference in electronegativity of two atoms.

therefore, more is the electronegativity of an atom which combines with the titanium, more readily it will induce a partial positive and negative charge.

thus, out of the given options fluorine is most electronegative and has an incomplete octet. therefore, it will readily combine with titanium to share the electrons and complete its octet.