Experiment 6: Stoichiometry II: Reacting Mole Ratios – Student Version . placed in ice cold and hot water) Based on the demo, what is the relationship Part III. 1. What evidence do you have for a chemical change in each reaction? 2. Purpose: The purpose of this lab is to determine the mole ratio of the reactants sodium hypochlorite (NaClO) and sodium thiosulfate (Na 2 S 2 O 3) when. Theory. Stoichiometry is the measurement of quantitative relationships in chemical formulas and Mole of CaCl2: / = moles of CaCl2 are present.
Stoichiometry Video transcript We know what a chemical equation is and we've learned how to balance it. Now, we're ready to learn about stoichiometry.
And this is an ultra fancy word that often makes people think it's difficult. But it's really just the study or the calculation of the relationships between the different molecules in a reaction. This is the actual definition that Wikipedia gives, stoichiometry is the calculation of quantitative, or measurable, relationships of the reactants and the products. And you're going to see in chemistry, sometimes people use the word reagents.
For most of our purposes you can use the word reagents and reactants interchangeably. They're both the reactants in a reaction.
The reagents are sometimes for special types of reactions where you want to throw a reagent in and see if something happens.
And see if your belief about that substance is true or things like that. But for our purposes a reagent and reactant is the same thing.
- Mole relationships in chemical equations
So it's a relationship between the reactants and the products in a balanced chemical equation. So if we're given an unbalanced one, we know how to get to the balanced point. A balanced chemical equation.
So let's do some stoichiometry. Just so we get practice balancing equations, I'm always going to start with unbalanced equations. Let's say we have iron three oxide. Two iron atoms with three oxygen atoms. And it yields Al2 O3 plus iron.
Stoichiometry (video) | Khan Academy
So remember when we're doing stoichiometry first of all, we want to deal with balanced equations. A lot of stoichiometry problems will give you a balanced equation. But I think it's good practice to actually balance the equations ourselves.
So let's try to balance this one. We have two iron atoms here in this iron three oxide. How many iron atoms do we have on the right hand side? We only have one. So let's multiply this by 2 right here. All right, oxygen, we have three on this side. We have three oxygens on that side.
Aluminum, on the left hand side we only have one aluminum atom. On the right hand side we have two aluminum atoms. So we have to put a 2 here. Now lets convert to grams. We need to produce 0. There are two important pieces of information to take away from this lesson besides just knowing what a mole is. The first is always write down your units and make sure they cancel out to give you the units you are looking for.
Well done, So now we know what the mole is and why we need to know about it. Try some of these other problems to make sure you understand the calculations. And remember, always write down your units. If your units come out right, most likely your answer is correct. If you had difficulty understanding this problem, go to the mini lesson on stoichiometry. The stoichiometry mini-lesson goes into more detail on using the mole to figure out calculations using a balanced chemical reaction.
SWBAT balance chemical equations and model the law of conservation of mass. Count the number of atoms of each element: More balancing equations III. Paperclip bonding mini-lab IV. More balancing equations Homework: Week 13 Homework Lab Report: SWBAT model the law of conservation of mass and use mole ratios to relate moles of reactants and products in a reaction. Balance the following equation: Using mole ratios examples V.
Finish Paperclip mini lab p. How many moles of oxygen gas? How many moles of carbon dioxide gas? Mole ratio of oxygen to carbon dioxide. Mole ratio of carbon disulfide to oxygen.
Mole ratio of carbon dioxide to sulfur dioxide. Mole ratio of carbon disulfide to sulfur dioxide. Mole ratio of carbon dioxide to oxygen. Molecule ratio of iron to oxygen gas. Molecule ratio of oxygen gas to iron III oxide. Molecule ratio of iron III oxide to iron. Molecule ratio of oxygen gas to iron. How many molecules of iron? How many molecules of iron III oxide? SWBAT calculate mole relationships for chemical reactions.
Agenda Do now, homework solutions II. Mole relationships examples III. Finish Week 13 Homework: How many moles of oxygen gas react with 4 moles of solid iron?
How many moles of iron III oxide are produced by the reaction of 3 moles of oxygen gas?
Mole relationships in chemical equations
How many moles of solid iron are required to react with 3 moles of oxygen gas? How many molecules of iron III oxide are produced by the reaction of 4 molecules of solid iron? How many moles of O2 react with 8 moles of Fe? How many moles of Fe2O3 react with 2 moles of Fe?