getting mass chemistry

Question

What mass of chlorophyll a, C₅₅H₇₂O₅N₄Mg (molar mass = 893.509 g/mol), would have the same number of oxygen atoms as that of 13.0 g of CO₂ (molar mass = 44.009 g/mol)?

Select one:

a.

52.8 g

b.

106 g

c.

231 g

d.

146 g

Answer 1

First, we'll find the number of oxygen atoms in 13.0 g of CO₂.

13.0 g CO₂ x 1 mol CO₂ / 44.009 g x 6.02x10²³ molecules CO₂ / mol x 2 atoms O / mol = 3.56x10²³ atoms of oxygen

Each molecule of chlorophyll contains 5 atoms of oxygen. Using this information, we can find the mass of chlorophyll that will contain the desired number of oxygen atoms.

3.56x10²³ atoms of O x 1 molecule chlorophyll / 5 atoms of O x 1 mol cholo / 6.02x10²³ molecules x 893.509 g/mol = 106 g chlorophyll