Question

Green plants use light from the Sun to drive photosynthesis. Photosynthesis is a chemical reaction in which water (H2O) and carbon dioxide (CO2) chemically react to form the simple sugar glucose (C6H12O6) and oxygen gas (O2). What mass of oxygen gas is produced by the reaction of 5.2 g of water? Be sure to have the correct # of sig figs.

Answer 1

Answer : The mass of oxygen gas produced will be 4.45 grams

Explanation : Given,

Mass of water = 5.2 g

Molar mass of water = 18 g/mole

Molar mass of $O_2$ = 32 g/mole

The balanced chemical reaction will be,

$6CO_2+6H_2O\overset{sunlight}\rightarrow C_6H_{12}O_6+6O_2$

First we have to calculate the moles of water.

$\text{Moles of }H_2O=\frac{\text{Mass of }H_2O}{\text{Molar mass of }H_2O}$

$\text{Moles of }H_2O=\frac{2.5g}{18g/mole}=0.139mole$

Now we have to calculate the moles of oxygen.

From the balanced chemical reaction, we conclude that

As, 6 moles of water react to give 6 moles of oxygen gas

So, 0.139 moles of water react to give 0.139 moles of oxygen gas

Now we have to calculate the mass of oxygen gas.

$\text{Mass of }O_2=\text{Moles of }O_2\times \text{Molar mass of }O_2$

$\text{Mass of }O_2=0.139mole\times 32g/mole=4.45g$

Therefore, the mass of oxygen gas produced will be 4.45 grams