The Problem: Students have trouble balancing charges in chemical compounds
The first MAJOR hurdle students come to in chemistry is when they have to start writing chemical formulas when given a chemical name. They seem to do better if you give them a chemical formula and have them write a name, but give them a name and they seem to have a harder time.
#1 Solution: Dive deep into subscripts and charges
I think it is because students are just really uncomfortable with subscripts at this point in their chemistry knowledge.
Draw it out for them using circles for the cations and anions. Explain that if you have to draw more than one circle for each cation or anion then you would use a subscript. Two cations would equal a 2 subscript, 3 cations would equal a 3 subscript etc.
When you start out explaining how to name compounds you probably use HCl or NaCl or something like that because they each have opposing charges of one and (1+) and (1-) equals zero, right?
The Problem: Students confuse subscripts and coefficients
In theory, I only help with the chemistry labs this semester. But, I or one of my tutors, teach a recitation for Gen. Chem 1 or Gen Chem 2 every other week. They have been learning how to balance chemical equations and it just wasn't clicking for them. So, at this week's recitation I explained the concept of having the same amount of each type of chemical on the left as you do on the right.
But, they kept making the same mistake. They were just slapping on 2's for coefficients where there should have been a subscript to balance the charge on the molecule.
Solution #1: Do they know how to properly balance charges on chemical compounds? If not, click here for the explanation and here for the worksheet on that topic.
Chemistry is hard. I mean really, it is one of those sciences you can't see without lots of expensive equipment. So, I began trying to make chemistry(and other sciences and math!) more real to my students.
Hi! I'm CoScine Creative. I have developed and run a tutoring center at a small college. I also teach some of their algebra and chemistry courses. And I will neither confirm nor deny pranking my students by pretending to be one.