Accelerated Chemistry Blog #4

Balancing an Equation

We have discussed a lot of different topics recently in chemistry class.  The first of these, and the one we have used most frequently, is balancing chemical equations.  In order to perform this task, you need to add coefficients to the front of compounds or individual elements.  This ensures that there are an equal number of each particular element on both sides of the equation.  It was cool to learn that the amount of elements or compounds on either side of the equation can change so that it remains in balance.

The next topics we discussed were the five different types of chemical reactions.  The first of these is a synthesis, or combination reaction in which two separate reactants are combined into one product.  The second of these is decomposition.  In decomposition, one reactant is broken down into two or more products.  The third type is single replacement.  Here, an individual element replaces a similar element that is already part of a compound.  The fourth type of reaction is the double replacement.  In this type, two compounds interchange either their metal or nonmetal, creating two new compounds.  The final type of reaction is combustion.  Here, carbon dioxide and water are created through burning.  I didn't realize before this that there were this many ways to predict what the products of a chemical reaction will be.

The final topic we covered was the activity series.  Here we learned four special rules about chemical reactions and learned which metals and nonmetals were more active than others.  The first rule was that any element in the list that was given could displace any of the elements that were less active and from the same list.  The second rule stated that any of the metals above hydrogen on the list are able to displace hydrogen from the compounds HCl or H₂SO₄.  The third rule is that any metal above magnesium on the list are able to displace the hydrogen from a water molecule.  Finally, rule four states that all metals that are above silver on the list can combine with pure oxygen in a synthesis reaction.  These rules are essential in determining the products of chemical reactions.  There are a lot of hidden rules that need to be remembered.

   

We also did several activities while learning about chemical reactions and activity in class.  The first experiment we did was "Identifying Chemical Activity."  During this series of experiments, we discovered which compounds and specific elements created a chemical reaction when combined.  In addition, we found out the relative activity of these elements.  It found it really interesting that in this experiment, through combining elements and substances, we were able to discover on our own which elements are more active than others and that our results matched up with the activity series.  The other activity we did was one in which we were instructed to combine certain elements and compounds together and use experimental evidence to determine the products.  This was a great experience because even though we weren't given the products before before we started, our group was able find them by using different series of tests.