CHEMISTRY COMMUNITY

I'm not sure how everyone else's high school chemistry experience was, but my teacher didn't really cover the material in depth, so I was wondering - is there any other/more efficient strategy to balance chemical equations other than trial and error? And if not, is there at least a strategic starting point of which elements/compounds to try to balance first?

I don't know if this is an official efficient way, but I usually balance out the polyatomic ions/non-organic elements and then balance the organic ones.

I normally balance the metals first, then the nonmetals (except for H and O), then I balance Hydrogen and Oxygen.

It might also help to examine the full equation and start with the elemnts or molecules taht appear the least amount of times on each side and work your way up.

start with the element that exists only once on either side of the equation.

For example:
CO2 + CNO3 -->> N2 + CO2 + CO3

I know that's a weird equation that probably wouldn't exist in real life, but the element that exists only once will be easiest to track at the start and will make it easier to balance the others. In this case, it is N

Kehlin Hayes 4C wrote:It might also help to examine the full equation and start with the elemnts or molecules taht appear the least amount of times on each side and work your way up.

Yes I totally agree with this. One of the TA’s in the step up program recommended we balance equations this way and it’s actually been very helpful when dealing with more difficult equations!

Kehlin Hayes 4C wrote:It might also help to examine the full equation and start with the elemnts or molecules taht appear the least amount of times on each side and work your way up.

I agree that this is one of the easiest ways for me to balance equations. Professor Lavelle did also mention this method as his way of balancing. There are many strategies for solving these types of problems, but it isn't the hardest type of problem, just one that you need to check and rework multiple times.

I always begin with looking at the subscripts and then balancing the corresponding elements on the opposite side of the formula as I know it has to have at "least" that many as well

Something that really helps is staying organized. When I balance my equations, I list every atom that the equation has and how many of each atom there is. For example, if the equation you have to balance is N2 + O2 yields NO I will write down N and O in a vertical line. I will then put the number 2 (for the left side of the equation has 2 N atoms) on the left side of the N and 2 on the left side of the O. On the right side, I will write down a 1 for the N and a one for the O. Every time I put in a coefficient, I will mark the change, to keep track of how many atoms are on each side.

Also when you get those really annoying equations where nothing fits well you can put coefficients down as fractions to balance the equation and multiply everything later.

i start with the elements that are not carbon and then the rest before balancing hydrogen and oxygen

I balance the element that occurs the least in the equation. For example, if hydrogen occurs two times in the reaction and it is the least occurring element, I balance that first and then move on to the next element that occurs the least. If there's an odd number of moles of an element, you balance the element with a fraction and then multiply all the coefficients by the denominator of the fraction so that all the coefficients are whole numbers.

Is there ever a situation where a chemical equation can't be balanced?
Ex. 2HCl --> 3HCl