Chemical Reactions and Equations (10/16-10/20)

http://www.mikeblaber.org/oldwine/chm1045/notes/Stoich/Equation/coeff.gif

Summary:

This week we learned about chemical reactions and how they are represented. Chemical equations show what happens when a chemical reaction takes place. In a chemical reaction, bonds between the atoms are broken and created to form new molecules. There are many chemical reactions in your everyday life. Some examples are when you are cooking, baking or even if a banana is rotting. There are many ways you can tell if a chemical reaction has taken place including:
  • Change in color (ex. If  an apple starts to become yellow on the inside)
  • precipitate formula (ex. If you mix ink in water)
  • Gas Formation
  • Odor/Smell (Ex. when you bake something, it might smell very good)
  • Temperature Change
  • Change in Acidity
In a chemical equation, there are a few important symbols and parts that you need to look out for. Subscripts are at the end of an element symbol and tell us how many atoms are in that element. The coefficient is the number before a molecule and tells us how many of that molecule there are. Sometimes in an equation, there is a parenthesis. Parenthesis group the atoms into bonds. When there is a parenthesis, you multiply the number of atoms in each of the elements that are in the parenthesis by the subscript that is after it. The main parts in a chemical equation are reactants and products. The reactants are used to form the product, which is the outcome of an experiment.

Some symbols that are used in chemical equations are the following:
  • + separates reactant a and b
  • → is used as a separation of the reactants and products, but also shows the direction of the chemical equation. The reactants "yield" the product.
The below symbols are used above the arrow, or "yields" sign:
  • (s) means that it is a solid state.
  • (aq) means that it is dissolved in water
  • (l) means that it is a liquid state
  • (g) means that it is a gaseous state

SP3: Planning and Carrying Out Investigations

This week, we conducted an experiment to see how chemical reactions occur and answer some questions about how the reactants and products are balanced, how the number of atoms in each element stays the same on each side of the equation. We controlled the amount of baking soda and vinegar and attempted to have the chemical reaction end up perfectly aligned, not overflowing or below. We collected our data in a table so that we could see how changing the different amounts of the reactants could change the products that we ended up with.

XCC: Systems and System Models

This week, I noticed and identified the system of a chemical reaction and how the chemical equation represents and shows what happens in a chemical reaction. Using a chemical equation as a model helps you visualize what happens in the reaction. The parts of a chemical equation are the reactants and the products. The system for counting the atoms are with coefficients, subscripts, and parenthesis. There are also symbols that help represent this system. The advantage of thinking of this as a system is that you can learn how to count the atoms in each element. Once you learn this method, you can learn how to balance the chemical equations. 

Multiplier

This week, I was a learner. I wanted to learn more about the topic and what chemical reactions are. I learned more about the topic by reading and completing the assignments that we did in class. Once I learned more about the topic, I talked to my group and classmates more about it and we shared what we all learned. We each learned more about the topic and then shared ideas and the knowledge so that we each understood the topic better. This has helped me understand and learn more about the topic that we are learning about in class.

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