NSCI 113 Stoichiometry
NSCI 113 Stoichiometry
NSCI 113 Stoichiometry
stoichiometry
a quantitative assessment of the relationships between the amounts of substances
consumed and produced by the reaction.
+
balanced equation
represents the identity and physical state of each
reactant and product in a chemical reaction.
the coefficients in the equation show the relative amounts of reactants that
combine and the relative amounts of products expected to form.
NSCI 113 Chemistry for Engineers
Mole-Mole Conversion
3 mol O2(g)
Moles of O2 = 10 mol Cu2S(s) x = 15.0 mol O2
2 mol Cu2S(s)
NSCI 113 Chemistry for Engineers
= 7.58 g Cl2
NSCI 113 Chemistry for Engineers
Mass-Mass Conversion
atomic Stoichiometric atomic
Mass ratio Mass
mass mass
conversion factor
Given: stoichiometric ratio
58.45 𝑔 𝑁𝑎𝐶𝑙 1 𝑚𝑜𝑙𝑒 𝑁𝑎𝐶𝑙
mass NaCl(s) = 12.5 g 1 𝑚𝑜𝑙𝑒 𝑁𝑎𝐶𝑙
= 58.45 𝑔 𝑁𝑎𝐶𝑙
2 mol Na(s) : 2 mol NaCl(s)
M.M. Na(s) = 23.00 𝑚𝑜𝑙
𝑔
23.00 𝑔 𝑁𝑎 1 𝑚𝑜𝑙𝑒 𝑁𝑎
M.M. NaCl(s) = 58.45 𝑚𝑜𝑙
𝑔
1 𝑚𝑜𝑙𝑒 𝑁𝑎
= 23.00 𝑔 𝑁𝑎
Mass-Mass Conversion
atomic Stoichiometric atomic
Mass ratio Mass
mass mass
5. The food we eat is degraded, or broken down, in our bodies to provide energy for growth
and function. A general overall equation for this very complex process represents the
degradation of glucose C6H12O6 (180.2 𝑚𝑜𝑙
𝑔
) to carbon dioxide CO2 (44.01 𝑚𝑜𝑙
𝑔
) and water H2O
(18 𝑚𝑜𝑙):
𝑔
If 856 g of C6H12O6 is consumed by a person over a certain period, what is the mass of
CO2 produced?
1 C6H12O6 + 6 O2 6 CO2 + 6 H2O
Mass-Mass Conversion
Mass atomic Mole Stoichiometric Mole atomic
mass ratio mass Mass
1 C6H12O6 + 6 O2 6 CO2 + 6 H2 O
If 856 g of C6H12O6 is consumed by a person over a certain period, what is the mass of
CO2 produced?
stoichiometric ratio conversion factor
mass C6H12O6 = 856 g 180.2 𝑔𝐶6 𝐻12 𝑂6 1 𝑚𝑜𝑙𝑒 𝐶6 𝐻12 𝑂6
1 mol C6H12O6 : 6 mol CO2 =
M.M. C6H12O6 = 180.2 𝑔
1 𝑚𝑜𝑙 𝐶6 𝐻12 𝑂6 180.2 𝑔 𝐶6 𝐻12 𝑂6
𝑚𝑜𝑙 1 mol C6H12O6 : 6 mol H2O
M.M. CO2 = 44.01 𝑔 44.01 𝑔 𝐶𝑂2 1 𝑚𝑜𝑙𝑒 𝐶𝑂2
𝑚𝑜𝑙 6 mol O2 : 6 mol H2O
1 𝑚𝑜𝑙𝑒𝐶𝑂2
= 44.01 𝑔𝐶𝑂2
M.M. H2O = 18.00 𝑚𝑜𝑙
𝑔
6 mol O2 : 6 mol CO2
Mass-Mass Conversion
Mass atomic Mole Stoichiometric Mole atomic
mass ratio mass Mass
Step 4: From the mole ratio, (in the balanced eq.) we see that 1 mol C6H12O6 is
to 6 mol CO2. Therefore, the number of moles of CO2 formed is
Mass-Mass Conversion
Mass atomic Mole Stoichiometric Mole atomic
mass ratio mass Mass
5. The food we eat is degraded, or broken down, in our bodies to provide energy for growth and
function. A general overall equation for this very complex process represents the degradation of
glucose C6H12O6 (180.2 𝑚𝑜𝑙
𝑔
) to carbon dioxide CO2 (44.01𝑚𝑜𝑙
𝑔
) and water H2O (18𝑚𝑜𝑙
𝑔
):
Other Solution:
Mass-Mass Conversion
Mass atomic Mole Stoichiometric Mole atomic
mass ratio mass Mass
6. Ethanol, used in alcoholic beverages, can be produced by the fermentation of sucrose, which is
found in sugar cane and other plants. What mass of ethanol, C2H5OH( 46.06 𝑚𝑜𝑙
𝑔
), would be
produced when 15 grams sucrose C12H22O11 (342.22 𝑚𝑜𝑙𝑔
) reacts by this process?