# According to the balanced equation, 6 moles of carbon dioxide will react with 6 moles of water to...

## Question:

According to the balanced equation, 6 moles of carbon dioxide will react with 6 moles of water to produce 1 mole of sugar and 6 moles of oxygen. What are the molar masses of the following compounds from the photosynthesis equation?

a. {eq}CO_2 {/eq}

b. {eq}H_2O {/eq}

c. {eq}C_6H_{12}O_6 {/eq}

d. {eq}O_2 {/eq}

## Molar Mass of a Chemical Species

A mole is the amount of a chemical substance that contains exactly {eq}6.022 \times 10^{23} \ {/eq} particles (atoms or molecules). If this number of particles is weighed, that mass is called the molar mass. More formally, the molar mass is the mass of exactly one mole of the substance. For elements, the analogous quantity is the atomic mass (because elements are made of atoms). To compute molar masses for compounds, we sum up the atomic masses of the constituent elements weighted by their quantity in the compound's molecular formula.

We are required to find the molar mass of all the reagents that are involved in the photosynthesis reaction. We need a periodic table to obtain the atomic masses of the elements found in these compounds. Then, we simply multiply the atomic mass of an element by the number of atoms of that element in the compound, and sum up these products for the entire compound, as shown below:

(a)

{eq}CO_2 : 12 + 2(16) = 44 \ g/mol {/eq}

(b)

{eq}H_2O : 2(1) + 16 = 18 \ g/mol {/eq}

(c)

{eq}C_6H_{12}O_6 : 6(12) + 12(1) + 6(16) = 180 \ g/mol {/eq}

(d)

{eq}O_2 : 2(16) = 32 \ g/mol {/eq}.

Though the SI unit for molar mass is kg/mol, it is more common to find them written in g/mol. We have followed this practice in the above calculations.