University:
Eastern Kentucky University
Course:
CHE 111 | General Chemistry
Academic year:

2022
Views:

392

Pages:

2
Author:

Ean Mason

Chemistry: SÕmore Chemistry Name________________ An introduction to Stoichiometry Hr____ Date__________ You have spent a lot of time studying the various types of reactions that can occur in chemistry. You have also become experts in balancing chemical equations. In this activity, you will be introduced to simple stoichiometry. Stoichiometry is the chemical term to describe calculations that allow us to find the amounts of chemicals involved in a given reaction. After you finish this worksheet, bring it to your teacher to check your answers, when finished you may make your SÕmore. In stoichiometry, you must always start with a balanced equation! We will use the following balanced recipe (equation): 2 Gc + 1 M + 4 Cp Where: Gc = graham cracker M = marshmallow 1 Sm Cp = chocolate pieces Sm = SÕmore 1. Notice that to make this recipe you have 7 pieces (reactant) to the left of the arrow and 1 piece (product) to the right. This is supposed to represent a balanced equation, so how can 7 = 1? Explain. 2. If each student is to make one SÕmore, and I have 20 students, how much of each ingredient will I need? Explain your logic Ð using a chemical equation. For questions 3 Ð 4a, b USE DIMENSIONAL ANALYSIS 3. If I have 20 graham crackers, how many marshmallows and chocolate pieces will I need to make SÕmores? How many SÕmores can I make? _______________ 4a. You decide to make a large batch of SÕmores. You have 85 chocolate pieces. How much of each other ingredient do you need? How many SÕmores can you make? Round to the nearest whole number! _______________ 4b. While getting out the ingredients for the above batch you find you have only 30 graham crackers. How does this effect the number of SÕmores you can make? _______________ 5. How many S/mores can you make from these combinations? 2 Gc + 1 M + 4 Cp = ________ Sm 4 Gc + 2 M + 8 Cp = ________ Sm 10 Gc + 5 M + 20 Cp = ________ Sm 6. Continue to figure the possible number of SÕmores. Use the spaces to the left of the equation to tell how much of each ingredient will be left over. ___________________ 2 Gc + 1 M + 5 Cp = ________ Sm ___________________ 3 Gc + 1 M + 4 Cp = ________ Sm ___________________ 5 Gc + 2 M + 9 Cp = ________ Sm 7. A reactant that is left over is said to be in excess and those that are used up limit the amount of product that can be made and are thus called limiting reactants. The maximum number of SÕmores you could make is called the theoretical yield. For example, if you had 17 graham crackers, 7 marshmallows, and 20 chocolate pieces, what would the theoretical yield be? Which reactants are in excess and which are all used up and thus limiting reactants? Theoretical Yield: Excess Reactants: Limiting Reactants: You are now ready to bring this sheet to your teacher for checking! After it is checked, go to a Bunsen burner and obtain a wooden splint and SÕmore ingredients. You can use a paper towel as a clean surface for your ingredients. Step 1) Break your graham cracker into 2 pieces and break your chocolate into 4 pieces. Put your chocolate onto 1 of your graham crackers. Step 2) Roast your marshmallow over the Bunsen burner Ð DO NOT MELT! Step 3) Quickly place the marshmallow onto the chocolate pieces and cover it with your second graham cracker. Wait for it to cool and enjoy the sweet taste of success in chemistry!