Chemical Reactions
Link to Glencoe text: Chapter 9
Mission 1: Fundamentals
Mission Objectives. You should be able to...
1. Identify all the parts of a chemical equation.
2. Transform word equations into skeleton equations.
3. Balance chemical equations.
A chemical reaction is a chemical change where a substance or substances are changed at the molecular level into a new substance or substances. The Law of Conservation of Mass states that mass cannot be created or destroyed, so the mass of all of the reactant atoms equals the mass of the product atoms.
Mass(reactants) yields (arrow) mass(products)
Below is a model of a simple chemical equation. The atoms are the colored balls. Notice that the number of atoms is the same on both sides of the arrow, but they are arranged differently.
Image courtesy of onlinescience.com.
Mission 1: Fundamentals
Mission Objectives. You should be able to...
1. Identify all the parts of a chemical equation.
2. Transform word equations into skeleton equations.
3. Balance chemical equations.
A chemical reaction is a chemical change where a substance or substances are changed at the molecular level into a new substance or substances. The Law of Conservation of Mass states that mass cannot be created or destroyed, so the mass of all of the reactant atoms equals the mass of the product atoms.
Mass(reactants) yields (arrow) mass(products)
Below is a model of a simple chemical equation. The atoms are the colored balls. Notice that the number of atoms is the same on both sides of the arrow, but they are arranged differently.
Image courtesy of onlinescience.com.
I'm including a series of videos from Beals Science. He has some good lessons on how to set up, write and balance chemical equations. The first video is a good introduction in equation fundamentals. Watch up to 4:51, and be sure you take notes on what he says about the structure of an equation.
The second video in this series introduces the concept of the skeleton equation, where we turn words into symbols. He provides four examples and takes you step-by-step in the creation of the skeleton equations. You're expected to include these equations in your notes, because you'll need them for the next video. You must watch this entire video.
The third video in this series covers balancing chemical equations. Again, he uses four examples and walks you through the process using something he calls the "TREE Method," which I've never heard of, but that doesn't matter. The way he explains the process is legitimate. Again, you must watch the entire video.
There are some situations where reactions don't take place. In order to determine whether this happens, you need to look at an element's reactivity. The Activity Series of Metals is a tool to use when determining if a reaction will take place. Any element on the list can replace an element that is below it, but not above it.
Mission 2: The Five Families
Mission Objective. You should be able to...
1. Identify the five kinds of chemical reactions.
2. Design a lab to investigate single-replacement and double-replacement reactions.
Mission 2: The Five Families
Mission Objective. You should be able to...
1. Identify the five kinds of chemical reactions.
2. Design a lab to investigate single-replacement and double-replacement reactions.
So we will go back to all those practice problems you completed and classify each equation.
Now we're ready for some real chemistry!
Now we're ready for some real chemistry!
Now let's go backwards a bit. What is the difference between substances, mixtures, elements and compounds? Paul Anderson of Bozeman Science gives you an overview of matter. What is it, what does it do, where you can find it, all that information.
So what's the deal with all this stuff? It's so much, it's too big...why is distinguishing it so important? Why does it matter (get it?)? Well, take a look here and then we'll go here to find out why. And while we're at it, we shall bask in the glory that is the Periodic Table of Elements.
Now you know the basic three states of matter. Did you know they could change into one another? Take a look at this graphic and try to explain what you're seeing using water as your example. Which set of triangles represent endothermic changes (energy absorbed)? Which set of triangles represent exothermic changes (energy released)? Tyler DeWitt helps out.
So what's the deal with all this stuff? It's so much, it's too big...why is distinguishing it so important? Why does it matter (get it?)? Well, take a look here and then we'll go here to find out why. And while we're at it, we shall bask in the glory that is the Periodic Table of Elements.
Now you know the basic three states of matter. Did you know they could change into one another? Take a look at this graphic and try to explain what you're seeing using water as your example. Which set of triangles represent endothermic changes (energy absorbed)? Which set of triangles represent exothermic changes (energy released)? Tyler DeWitt helps out.
Mission 3: The Notorious B.I.G.
Mission Objectives. You should be able to...
1. Understand the nature of the mole aka Avogadro's Number
2. Calculate molar mass
3. Sove mole conversion problems
Because chemistry is partially the science of very small things (atoms, molecules), there needs to be something to properly represent this concept. We cannot see with our naked eye what happens at the molecular level with experiments, and in order to do the necessary calculations, we need a big number to represent the atoms and molecules.
Enter Avogadro's number, aka the mole.
Mission Objectives. You should be able to...
1. Understand the nature of the mole aka Avogadro's Number
2. Calculate molar mass
3. Sove mole conversion problems
Because chemistry is partially the science of very small things (atoms, molecules), there needs to be something to properly represent this concept. We cannot see with our naked eye what happens at the molecular level with experiments, and in order to do the necessary calculations, we need a big number to represent the atoms and molecules.
Enter Avogadro's number, aka the mole.
In order for this to be useful in class, we need to turn the very small things into an amount that we can see. One mole of any substance is equal to its molar mass, whether it is an element or a compound. The average atomic mass of an element on the periodic is the same thing as the molar mass of that element.
For example: Hydrogen's molar mass is 1.01g/mol. Oxygen's molar mass (rounded to nearest whole number) is 16.00g/mol. The molar mass of water (H2O) is 2.02 + 16.00 = 18.02 g/mol. So it is very important that you read the correct number on the periodic table and write your formulas correctly.
You have a handout where you will practice calculating molar mass for different compounds.
You have a handout where you will practice calculating molar mass for different compounds.
Let's Practice!!
Download and complete these practice problems.
1. Molar Mass 2. Mole Conversions (I) 3. Mole Conversions (II)
Download and complete these practice problems.
1. Molar Mass 2. Mole Conversions (I) 3. Mole Conversions (II)