Calculate the number of grams of oxygen required to convert 23.0 g of glucose to co2 and h2o.

Ok lets write this firstly in a chemical equation -> 

C6H12O6 + O2 -> H2O + CO2

Ok balance the equation.

C6H12O6 +6O2 -> 6H2O + 6CO2

Now both sides are balanced.

To see how many grams of oxygen are required to convert 23g of glucose we need to work in ratios and to work with ratios we need moles.

To convert moles divide by R.M.M (Relative Molecular Mass) of Glucose

6 C - 6 * 12 
12 H - 12 *1 
6 O - 6 * 16

      R.M.M = 180

23g / 180 = 0.127 moles of Glucose

C6H12O6 +6O2 -> 6H2O + 6CO2

The ratio between glucose and oxygen is 1:6 therefore for every glucose molecule we need 6 of oxygen.

0.127 moles * 6 = 0.762 moles of Oxygen

Now to find multiply by R.M.M. of O2 

2 O * 2 *16 = 32 

0.762 moles * 32 = 24.38 (rounded) grams of O2 required to convert Glucose to CO2 and H2O.

Hope this helps :D.

16- counting by fours