Quarter 3 Reflection Blog

The first activity this week was the Molecular Model Activity packet. We learned how chemical equations are written, and focused on having the same numbers of each kind of atoms on both sides of the equations. For example, If we started with 4 Hydrogen atoms and 2 Oxygen atoms on the left side (the reactants) then we had to have exactly 4 Hydrogen atoms and 2 Oxygen atoms on the right side with the products. When we started, I knew that the equations had to be balanced, but I never understood why.

Just like the molecular model activity, this picture shows
that there are 2 O2 molecules needed to form the products. 

Next we worked on balancing equations. Before we could do this, we had to remember how to write molecular formulas correctly based off of the name. In order to balance equations we could only add coefficients in front of each compound; we can't adjust the subscripts. Then after some practice we learned some hints to make balancing the more complex formulas easier. The first hint we learned was to always adjust the coefficients of a single species last. This means if you have a single element such as Mg or O2, balance that atom last. This way, when you add a coefficient you are only changing the number of that element and not adding more of any other element/molecule. The second hint was "sometimes the temporary use of a faction or decimal is useful." This helps especially when you only need half of one compound. Then after everything is balanced, multiple by 2 throughout the whole equation to end up with whole numbers. The last hint was to balance polyatomic ions as units if they are on both sides of the equation, such as PO3, SO3, or NH4. With all of these hints, they help to balance equations without having to physically see the molecules like the first activity we completed.

The last activity we did was our Reaction completion lab. We had to try to figure out what the products were in our reactions based off of observations and tests such as splint tests and litmus papers. 

These concepts make sense to me, especially after the different activities. I think the molecular model activity helped the most to understand why and how we balance equations. The different sides of the arrow should be equal because that's how the reactions occur in nature due to the Law of Conservation of Mass.