Definitions
the calculation of quantities of any substances involved in a chemical reaction from the quantities of the other chemicals involved
What is Stoichiometry?
The first step to solving a stoichiometry problem with an unbalanced equation and value of a reactant given to you.
What is balancing the equation?
__ CO2(g) + __ O2(g) --> __ CO2(g)
The unbalanced equation representing a chemical reaction is shown.
KEY: C = dark circle, O = clear circle
Draw a particle model that accurately represents the balanced chemical equation.
Answer on slide 7 in today's slides.
In chemistry, what do we call a representation showing equal amounts of moles on reactants and products side of an arrow.
What is a balanced [chemical reaction] equation?
Does writing "I used the example problems" on your shown work paper count for 0 points, 1/2 point, or 1 full point?
What is 0 points?
Ratios of coefficients in reactants and products from balanced chemical equations aka conversion factors.
What is mole ratio?
The step using the coefficients from a balanced chemical equation while calculating a stoichiometry problem.
What is converting moles of your given chemical into moles of your desired chemical using mole ratio?
*Image Required!* (slide 6 in today's slides)
Make any correct claim about the reactant mixture based on the information you were given involving the vocabulary "limiting reactant" and reasoning behind your choice related to "molar mass" or "mole ratio".
Answers may vary between Table Groups. (Individual groups still must match for points.)
A 4 mol sample of H2S(g) is combined with excess O2(g). The reaction goes to completion. How many moles of O2(g) react with the available H2S(g)?
Given balanced chemical equation:
2 H2S + 3 O2 --> 2 SO2 + 2 H2O
What is 6 moles of O2?
A 4 mol sample of H2S(g) is combined with excess O2(g). The reaction goes to completion. Calculate the theoretical yield of SO2 (in grams) from the reaction?
Given balanced chemical equation:
2 H2S + 3 O2 --> 2 SO2 + 2 H2O
What is 256 grams of SO2
Any other reactant that is left over (or extra) could be defined as existing in _______ supply.
What is excess?
The math step (e.g. divide, multiply, etc.) for converting grams of given chemical to moles of that same chemical while solving a stoichiometry equation.
What is calculating the molar mass of the chemical from the periodic table and dividing by that molar mass?
Please explain one way to find the limiting reactant in words or with math work, given '3 moles of Chemical A2T3 and 6 moles of Mg' in the following reaction.
A2T3 + 3 Mg --> 2 A + 3 MgT
What is (1) dividing the moles of each reactant by its coefficient in the balanced chemical equation to determine how many times the reaction could be completed with how much of each reactant is given. (2) Calculate theoretical yield of the same product (in moles or grams) from both given reactant values and compare product amounts. (3) Find the amount of each reactant needed to completely use up the other reactant. Disregard the scenario that requires more of a reactant than is actually present.
Interpret the following balanced equation in words.
2 P(s) + 3 Cl2(g) → 2 PCl3(l)
What is two atoms of phosphorus react with three molecules of Cl2 to produce two molecules of PCl3?
OR
What is two moles of phosphorus react with three moles of Cl2 to produce two moles of PCl3.
Balanced Equation: CH4 + 2 O2 --> CO2 + 2 H2O
If 48 g of CH4 is burned completely, how many moles of H2O are produced? Enter the number of moles to the nearest whole number.
What is 6 moles of H2O?
The reactant that is completely used up first in your given chemical equation.
What is the limiting reactant?
The unit your current value ALWAYS needs to be in to switch chemicals while solving a stoichiometry equation.
What is moles of the given chemical? (so you can switch to moles of desired chemical next)
*Image Required!* (slide 8 in today's slides)
Draw the correct number of molecules of each product and any excess reactants, given the amounts of reactants shown on the slide.
What is 2 CO2 molecules and 4 H2O molecules?
Balance the equation.
__ H3PO4 + __ KOH → __ K3PO4 + __ H2O
What is H3PO4 + 3 KOH → K3PO4 + 3 H2O ?
2 H2(g) + CO(g) --> CH3OH(l)
A 12 g sample of H2(g) is combined with a 28 g sample of CO(g), and the above reaction occurs.
If 20 g of CH3OH(l) is actually produced, the percent yield would be what (nearest whole number)?
Percent yield = 63%
A chemical reaction equation is not useful for stoichiometry calculations unless it is accurately __________.
What is balanced?
Given the equation below, calculate the number of H2 moles produced from the reaction of 0.450 mol HCl reacting with excess calcium. (Show work or no points)
HCl(aq) + Ca(s) → H2(g) + CaCl2(aq)
What is 0.450 mol H2?
Mole ratio of HCl to H2 = 1:1
After the reaction of 0.450 mol HF with 0.340 mol NaOH is complete, how much excess reactant remains? Use the given equation.
HF(aq) + NaOH(aq) → NaF(aq) + H2O(l)
What is .11 moles HF?
Balance the equation.
__ Al(s) + __ O2(g) → __ Al2O3(s)
What is 4 Al(s) + 3 O2(g) → 2 Al2O3(s) ?
Balanced Equation: CH4 + 2 O2 --> CO2 + 2 H2O
A 16 g sample of CH4(g) reacts with excess O2(g). Assuming that the reaction goes to completion, what is the total mass of CO2 and H2O produced? Write the number of grams to the nearest whole number.
Total product mass = 44 g CO2 + 36 g H2O = 80 grams total