So,
Formate has a resonating double bond.
In molecular orbital theory, the resonating electrons are actually delocalized and are shared between the two oxygens. So the carbon-oxygen bonds can be described as 1.5-bonds (option B). I'm not sure if option C is correct, however, because the likelihood of both delocalized electrons being in the area of one oxygen atom is less than 50%.<span />
The density is mass divided by volume
A substance that consist of two elements is one IN WHICH THE ELEMENTS ARE CHEMICALLY COMBINED IN A FIXED PROPORTION.
A compound is a substance that is made up of two or more elements which have undergone chemical reaction together and their individual properties have been lost during the reaction, thus a compound has properties that are different from those of its constituents elements. Compounds are usually combined in specific fixed ratio.<span />
(57.0 g B2O3 / (69.6202 g B2O3/mol) x (4mol BCI3 / 2 mol B2O3) = 1.64 mol BC13
(44.7 g C12) / (70.9064 g C12/mol) x (4mol BCI3 / 6mol C12) = 0.42027 mol BC13
(68.8 g C) / (12.01078 G C/mol) x (4mol BCI3 / 3 mol C) = 7.63 mol BCI3
C12 is the limiting reactant.
(0.42027 mol BCI3) X (117 . 170 g BCI3/mol) = 49.2 g BCI3 in theory.
NaOH → Na⁺ + Cl⁻ ________________________________________________