1. Amylose is a \"polysaccharide\" that plants use to store energy. It is made o

Question

1. Amylose is a "polysaccharide" that plants use to store energy. It is made of repeating subunits of C6H10O5.

a. A particular amylose molecule has 2113 of these subunits, what is its molecular formula? Express your answer as a chemical formula.

b. What is its molar mass? Express your answer to four significant figures and include the appropriate units.

c. What is the empirical formula for amylose? Express your answer as a chemical formula.

2. Imagine that all our balances displayed mass in units of ounces instead of grams.

Part A Would we still want to use the number , 6.022×1023, for Avogadro's number? Why or why not?

Yes, because the value of Avogadro's number is a universal constant.

Yes, because the number of particles in one mole does not depend on the mass of the particles.

No, because we would not be able to use carbon-12 to define the mole

No, because we would use the number of atoms in exactly 12 ounces of carbon-12 to define the mole.

Part B What number would we want to use instead? (A ounce is equal to 28.350 g.) Express your answer using four significant figures.

3 Hydrogen, a possible future fuel , can be obtained from other compounds such as ethanol. Ethanol can be made from the fermentation of crops such as corn. Part A How much hydrogen can be obtained from 5.0 kg of ethanol (C2H5OH)? Express your answer using two significant figures.

Explanation / Answer

3) The molar mass of C2H5OH = 2x12 + 5x1 + 16 + 1 = 46g.
There are 6 H's in the fomula so 6/46 of the mass of C2H5OH is H.
5.0kg x 6/46 = 0.652kg of H2 (since hydrogen gas is diatomic.)

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