Starch has the same empirical formula as cellulose and a...

Starch has the same empirical formula as cellulose and a molar mass of about $1.0 \times 10^{5} \mathrm{~g} / \mathrm{mol}$ (a) What are the mass percents of $\mathrm{C}, \mathrm{H},$ and $\mathrm{O}$ in starch? (b) How many $\mathrm{C}_{6} \mathrm{H}_{10} \mathrm{O}_{5}$ units are linked together in a starch molecule?

Starch has the same empirical formula as cellulose and a molar mass of about $1.0 \times 10^{5} \mathrm{~g} / \mathrm{mol}$
(a) What are the mass percents of $\mathrm{C}, \mathrm{H},$ and $\mathrm{O}$ in starch?
(b) How many $\mathrm{C}_{6} \mathrm{H}_{10} \mathrm{O}_{5}$ units are linked together in a starch molecule?

Key Concepts

Molar Mass

Molar mass is the mass of one mole of a substance and is calculated by summing the atomic masses of all atoms in the compound’s formula. It is fundamental for converting between the mass of a substance and the number of moles, as well as for determining the size of complex molecules when comparing to repeating units in polymers.

Degree of Polymerization

The degree of polymerization is a measure of how many repeating monomer units are linked together in a polymer chain. It is calculated by dividing the total molar mass of the polymer by the molar mass of a single repeating unit, providing insight into the molecular size and structure of polymers such as starch.

Empirical Formula

The empirical formula represents the simplest whole-number ratio of atoms in a compound. It is used to summarize the proportion of each element present, regardless of the compound's actual large molecular structure, and is particularly useful in comparing compounds like starch and cellulose that share identical empirical formulas.

Mass Percent Composition

Mass percent composition refers to the percentage by mass of each element in a compound derived from its formula. By calculating the mass contributed by each element in one formula unit and dividing by the total molar mass of the unit, one can determine the individual component contributions. This concept is key for analyzing the elemental make-up of compounds such as starch.

Transcript

Please give Ace some feedback