Question

If a plant makes 500g of glucose, how many grams of carbon dioxide did it take in? First, describe the steps you would take.

Answer 1

steps :

1. At very first convert the mass of glucose in moles.
2. Now by stoichiometry ,find the moles of carbon di oxide.
3. After finding the moles of carbon dioxide ,find the mass of carbon dioxide.

Now the balance chemical equation of preparation of glucose is

$6CO_2+6H_2O \Rightarrow C_6H_{12}O_6+6O_2$

Now the mass of glucose taken =500 gm

Moles of glucose=$\dfrac{mass}{molar mass}=\dfrac{500}{180}=2.78$ moles

Now by the stoichiometry :

1 mole of glucose require= 6 moles of carbon dioxide

2.78 moles glucose require= $6$$\times2.78$ moles of carbon dioxide

so moles of carbon dioxide =16.68 moles

now the mass of carbon dioxide =moles of carbon dioxide $\times$ molar mass

=$16.78\times44=738.32gm$

So our answer is , we have to take 738.32 gm oxygen in to prepare 500 gm of glucose.