2 Step Stoichiometry

Step-by-Step Tutorial: 2 Step Stoichiometry

Problem 1: Finding Moles of LiOH

1. Given Information: The problem states that we need to find out how many moles of LiOH are required to react with 20 moles of CO2.
2. Identify Given Values: Circle or box the given value, which is 20 moles of CO2.
3. Determine the Starting Point: Since we are given moles, start at the "mole A" side on the mole island sheet.
4. Identify the Compound to Find: The problem asks for moles of LiOH, which means we need to end at "mole B" this time.
5. Mole Ratio Calculation: Use the mole ratio to convert from moles of CO2 to moles of LiOH. The coefficients from the balanced chemical equation will be used for this conversion.
6. Perform the Calculation: Calculate the number of moles of LiOH by multiplying the given moles of CO2 by the ratio of the coefficients.
7. Check Significant Figures: Ensure that the number of significant figures in the final answer matches the least number of significant figures in the given value.

Problem 2: Finding Moles of NH3

1. Given Information: Determine how many moles of NH3 are produced in a chemical reaction.
2. Identify Given Values: The problem provides 6 moles of H2.
3. Determine the Starting Point: Begin at the "mole A" side since we are given moles.
4. Identify the Compound to Find: We need to find moles of NH3, which means we end at "mole B" this time.
5. Mole Ratio Calculation: Use the mole ratio to convert from moles of H2 to moles of NH3 based on the coefficients in the balanced chemical equation.
6. Perform the Calculation: Multiply the given moles by the ratio of coefficients to find the moles of NH3.
7. Check Significant Figures: Verify that the final answer aligns with the least number of significant figures in the given value.

Problem 3: Finding Grams of C6H12O6

1. Given Information: Calculate the grams of C6H12O6 produced from 3.00 moles of H2O.
2. Identify Given Values: The problem provides 3.00 moles of H2O.
3. Determine the Starting Point: Start at the "mass A" side since we are given moles.
4. Identify the Compound to Find: We need to find the grams of C6H12O6, which is on the "mass B" side.
5. Multiple Conversion Steps: Convert from moles of H2O to moles of C6H12O6 and then from moles to grams using the molar mass of C6H12O6.
6. Calculate Molar Mass: Determine the molar mass of C6H12O6 by adding the atomic masses of carbon, hydrogen, and oxygen.
7. Perform the Calculation: Multiply and divide as per the conversion steps to find the grams of C6H12O6 produced.
8. Check Significant Figures: Confirm that the final answer matches the least number of significant figures in the given value.

Problem 4: Finding Moles of AgO

1. Given Information: Calculate the moles of AgO needed to produce 125 grams of O2.
2. Identify Given Values: The problem states 125 grams of O2.
3. Determine the Starting Point: Start at the "mass A" side since we are given grams.
4. Identify the Compound to Find: Find the moles of AgO, which is on the "mole B" side.
5. Conversion Steps: Convert from grams of O2 to moles of O2 using the molar mass, then from moles of O2 to moles of AgO using the mole ratio from the balanced chemical equation.
6. Calculate Molar Mass: Determine the molar mass of O2 to use in the conversion.
7. Perform the Calculation: Multiply and divide according to the conversion steps to find the moles of AgO needed.
8. Check Significant Figures: Ensure that the final answer aligns with the least number of significant figures in the given value.

By following these steps for each stoichiometry problem, you can successfully navigate two-step stoichiometry calculations involving mass and mole conversions in chemical reactions.