Answer to Question #267121 in General Chemistry for Elif

Question

a Amylum, commonly known as starch is a white powder with variable molecular formula due to the different number of repeating sugar units based on the plant that it is obtained from_ sample of amylum in the form of spherical beads was subjected t0 series of analyses to determine physicochemical properties in the quality control unit of a factory. From the results each bead is found to have a 4.5 mL volume and 1.47 glmL density_ 4 of the beads were placed in a reaction chamber combusted as a result; 43.1 g CO2 and 14.7 g HzO were obtained. If the molecular weight of the amylum is 972.84 glmol how many repeating units the starch molecule consist and what is the molecular formula of the starch? [Empirical Formula-CxHyOz' Repeating unit-n; Molecular Formula=( CxHyOz)"*n= CnxHnyOnz]

Answer 1

The molecular formula of amylum or starch (C6H10O5) calculate molecular mass of amylum is 162 and divide to molecular weight is given 972.84 g/ml by molecular mass of amylum is 162 then we get the 6 unit of starch molecule . The repeating unit is 6 the starch molecule consist and the molecular formula is (C6H10O5)6 .