A student doubles the mass of an unknown compound used for an empirical-formula…
CHEMISTRY · Single correct · A Level · Chemistry · Amount of substance · Amount of substance
Problem
A student doubles the mass of an unknown compound used for an empirical-formula determination but follows the same analytical steps. Which of the following best explains why the calculated empirical formula will be unchanged?
(a) Because twice as many moles of each element are present, the subscripts in the empirical formula will double as well.
(b) Doubling the sample forces the individual element moles to approach whole numbers, eliminating rounding errors that would otherwise change the formula.
(c) Percent composition expresses constant mass ratios, so doubling the sample preserves the mole ratios of the elements.
(d) The molar masses of the constituent elements increase in direct proportion to the larger sample.