SG Chemistry 2A Week 1 blog

Chemistry 2 Week 1 blog

This week in SG Chemistry 2A we began to dive deeper in to the classifications of matter. Early in the week we learned the differences between atoms, elements, pure substances, mixtures and compounds. An atom is a single particle of an element, and the element is what categorizes and consist of only one type of atom.  When all the particles in a substance are identical, the substance is pure. If the substance contains different types of particles, it is a mixture. Both elements and compounds are defined as pure substances, only a compound contains two or more elements which are linked together by chemical bonds.  We also distinguished that mixtures can be separated by physical means while compounds can only be separated by a chemical reaction. This idea lead us to a demonstration where we watched Dr.Finnan separate water (H2O) into 2 units of Hydrogen and 1 unit of Oxygen (demonstrating the separation of compounds by breaking chemical bonds). We then did a worksheet that asked us about the means of mixture separation (as shown below). 

As we continued to learn about atoms and mixtures on our own, we also came together as a class to display what we've learned on white boards.  We first established some white board norms together, these included that we must always have a key to show which atoms represent which elements, always use more than one atom to represent an element, and that arrows represent movement. We demonstrated these rules in our display of Dr.Finnan's sugar in water and ethanol lab. In this lab he used three beakers each filled with a different substance, one with water, one with ethanol, and one with half water and half ethanol.  He then put one sugar cube in each beaker and we observed how the sugar dissolved.  The sugar dissolved in water, but not at all in ethanol, and only half way in the half-and-half beaker.  This was very interesting, I did not know that sugar didn't dissolve in ethanol. We then displayed our observation on white boards as tables, showing the before and afters of the sugar cubes. Below is my table's display: 

We also walked around the room with sticky notes and were able to give each other helpful tips and comments. This really allowed my table to see what we needed to improve on and also get some encouraging feedback.

We watched another video of a scientist performing lab demonstrations in which he was separating compounds and mixtures by both chemical and physical means. At the end of the video he came to the conclusion that if the same amount of gases are at the same temperature and pressure, then the number of particles must be the same. This is known as Avogadro's Hypothesis.

The Unit 4 Worksheet 2 that we worked on explored Avogadro's hypothesis more.  The worksheet contained problems in which we had to draw the combinations of elements. We also displayed our answers for this worksheet on white boards, and Avogadro's Hypothesis concluded our chemistry learning for the week.