7950627b...
a6a11f18...
7d7faccc...
6d38f9a0...
9f5f0c19...
c9adf894...
8f7349b5...
Use balanced chemical equations to calculate reactant and product masses, and identify the limiting reagent in a reaction.
Information provided by balanced equations and the concept of stoichiometric coefficients.
The word stoichiometry comes from two Greek words: stoicheion (meaning element) and metron (meaning measure). It is the quantitative study of reactants and products in a chemical reaction.
A visual showing molecular ratios (e.g., 1 CH4 + 2 O2 -> 1 CO2 + 2 H2O) helps anchor the math to reality.
A clean scientific diagram showing the reaction of one methane molecule and two oxygen molecules forming one carbon diox…
Worked Problem 1.3 on calculating mass of water produced.
Problem. Calculate the amount of water (g) produced by the combustion of of methane ().
Faded calculation for finding the required amount of reactant.
According to the chemical equation for the combustion of methane, we have the balanced reaction: CH4(g) + 2O2(g) → CO2(g) + 2H2O(g). This shows that 1 mole of CO2(g) is obtained from 1 mole of CH4(g). To find how many moles of methane are required to produce 22 g of CO2(g), we first need the molar mass of CO2. The molar mass of CO2 is g/mol, which means 1 mole of CO2 weighs this amount. We can calculate the number of moles of CO2 by dividing the given mass (22 g) by this molar mass. Using the formula, 22 g CO2 × (1 mol CO2 / 44 g CO2) = mol CO2. Since the stoichiometric ratio of CH4 to CO2 is 1:1, it will require exactly moles of CH4(g) to produce this amount of carbon dioxide. This type of stoichiometric calculation is crucial for chemists and chemical engineers to determine exactly how much reactant is needed to reach a desired production target without wasting materials.
Definition of limiting reagent.
In many laboratory reactions, reactants are not mixed in the exact stoichiometric amounts required by the balanced equation. One reactant is usually present in excess.
Worked Problem 1.5 calculating ammonia yield and limiting reagent.
Problem. of and of are mixed to produce . Calculate the amount of formed and identify the limiting reagent in this situation.
Free response practice on identifying limiting reagents.
Dinitrogen and dihydrogen react to produce ammonia according to the following equation:
If of reacts with of :
State your final calculated masses and identify the excess reactant.
Show your step-by-step mole conversions and stoichiometric ratios.