Glucose is partially oxidized during the glycolysis process into two pyruvate molecules. Then these pyruvate molecules get totally oxidized into CO2 during the citric acid cycle. This citric acid cycle occurs in the matrix of mitochondria.
During a single turn of the citric acid cycle, 2 molecules of carbon dioxide are released. Apart from two molecules of CO2, 3 molecules of NADH, 1 molecule of FADH2 and 1 molecule of ATP or GTP are also produced.
So if 2 molecules of CO2 are produced in one turn therefore in 5 turn 10 molecules of CO2 will be produced.
