Answer to Question #83372 in General Chemistry for Jenn

Question

In the following combustion reaction of pentanol, first find out how many oxygen molecules would be used to completely react with 530 grams of pentyl alcohol (C5H11OH)? Then, if exactly 1.505 x 10<21 carbon dioxide molecules were formed in this reaction, calculate the grams of water formed during this reaction. C5H11OH+O2--->CO2+H20

Answer 1

1)balance the reaction

2C5H11OH+15O2--->10CO2+12H20

2) number of moles of pentyl alcohol (C5H11OH) = 530 grams / 88.15 g/mole = 6.012 moles;

From the reaction’s coefficients, number of moles of oxygen =

= (15 x 6.012) / 2 = 45.1 moles;

Number of oxygen molecules = moles x Na = 45.1 mole x 6.02x1023 molecules/mole= 2.7 x 1025 molecules

3) Number of moles of carbon dioxide CO2 = 1.505 x 1021 / 6.02x1023 = 0.0025 moles;

From the reaction’s coefficients, number of moles of water =

= (12 x 0.0025) / 10 =0.003 moles;

Therefore, mass of water formed during this reaction = 0.003 mole x 18 g/mole = 0.054 g.