Stoichiometry.  It has brought many General Chemistry students to tears.  Like so many students, I struggled with this concept when it was first introduced to me in my sophomore year of high school.  Through my learning experiences, I will hopefully help you understand the method behind the madness of this somewhat complex word.  Simply put, stoichiometry is a concept in Chemistry that describes the amounts of substances, either reactants or products, in a given reaction.   It’s based on the Law of Conservation of Mass….mass is neither created nor destroyed.  Using stoichiometry you can determine the amount of product produced during a chemical reaction using a coefficient ratio of reactant to product.  It sounds complicated, right?  It can be, but if you have read my other posts and have mastered balancing chemical equations, then you will easily see the direct correlation between balancing equations and stoichiometry.  In order to be successful at stoichiometry, you must have an average understanding of the fundamentals of balancing chemical equations.  So, if you have supreme confidence in your balancing capabilities, let’s get started with my tips on understanding STOICHIOMETRY!

1.)  Know the Terminology

If you’re going to succeed with the mathematical calculations involved in stoichiometry, make it a point to familiarize yourself with basic terminology and various phrases used to describe a chemical reaction.  Know chemical equation, mass of reactants, mass of products, molecular weight, molar mass, formula, mole, Avagadro’s number, coefficient, standard unit (mg, g, kg, ect.), conversion factor, yield, molecule, element, and atom. By understanding these terms you will optimize your knowledge of stoichiometric calculations.  Know the terminology the lecturer is using and stoichiometry will be more enjoyable.

2.)  Know Your Algebra Rules

ALGEBRA!  I had that years….I mean decades ago.  Who needs Algebra?  Every single General Chemistry student.  Algebra rules are the core of stoichiometric calculations.  Know the rules of exponentials, cross-canceling, cross-multiplying, parentheses, scientific notation, and most importantly significant figures.  This tip is fairly straight forward….familiarize and remind yourself of the forgotten Algebra rules.  Understanding, performing, and applying the mentioned mathematical operations will make stoichiometry a breeze!

3.)  Stay Organized

Performing any calculations requires a logical thought process.  But, when doing stoichiometry it is extremely important to keep your calculations organized in a step-by-step format.  Stoichiometric calculations usually require several step before arriving at a solution.  Write down each individual step in the calculation.  If 2+2=4 is a step, write it down.  Do not do multiple steps in your head and expect to remember them later.  Calculations, especially those involving chemical equations, can get very complex.  Staying organized and allowing yourself to see the visual logic of a given calculation will enable you to recognize any mistakes before arriving at an incorrect solution.  Take the extra couple minutes and go the extra mile….write down every step.

4.)  Units, Units, Units

UNITS.  DO NOT forget your units when trying to complete a stoichiometric calculation!  Forgetting units while solving a given equation will result in many hours of mind-boggling wrong answers.  Remembering units and staying organized compliment each other in stoichiometry.  A written step-by-step thought process allows you to include units for each and every number (where applicable) in a calculation.  This simple tip will make your entire Chemistry career SO MUCH easier.  One final word….UNITS!

Are you ready to tackle stoichiometry?  Follow my tried and true tips and stoichiometry will become easier as your General Chemistry course progresses.  Preparation and organization are vital in any Chemistry course, but are especially evident in stoichiometry.  

Try the given tips mentioned in this post….they worked for me!  If you have time, read my other posts covering the basics of a General Chemistry course.  Did you find this post helpful?  Let me know by leaving a comment.  Keep me updated on your Chemistry success.  Check back often because I’m always trying to simplify General Chemistry.  Thank you and take care!  GOOD LUCK!

Secrets to BALANCING chemical equations!

Ah….chemical equations and stoichiometry; the stuff dreams are made of….I mean nightmares!  Chemical equations and stoichiometry are the backbone of any General Chemistry course.  Successfully balancing chemical equations will enable you to better understand stoichiometry and thus, pass that Chemistry course.  But, how do you know which coefficients go where?  I learned from trial and error and through many failed methods.  Read on and let me share my tips for balancing chemical equations!

1.)  Know What the Equation Means

A chemical equation isn’t just random numbers and symbols put into a format to annoy students.  Each component of the equation represents part of a chemical reaction.  Periodic symbols represent the elements within the reaction; the coefficients represent the amount of element either reacting or being produced; that little arrow in the middle of the equation let’s you know that given reactants are yielding products.  Everything in a chemical equation means something.  Simply put….the reactants undergo a chemical reaction to produce products.

2.)  The Law of Conservation of Mass

Wait….what is the law of conservation of mass?  Basically, it’s a principle stating that mass is neither created nor destroyed.  That’s great, but how does this principle relate to balancing chemical equations?  If mass is neither created nor destroyed, than the mass of reactants in a chemical equation must equal the mass of products within that same equation.  Voila!  You’re welcome!  In order for a chemical equation to be balanced, it must have the same number of each element on both the reactant and product side of the equation.  The number of each element on the left-side of the arrow must equal the number of that same element on the right-side of the arrow.  

3.)  Don’t Change the Equation

I cannot stress this enough….do not change the equation.  Subscripts and superscripts included within an equation serve a purpose and should not be altered.  When balancing a chemical equation, pay attention to the small details.  Neglecting this one simple tip will make balancing equations an absolute nightmare.  The only numbers you can change in any chemical equation are the coefficients of reactants and products.  This tip sounds amateur, but many equations were never balanced because the initial chemical equation was not written correctly….I’m speaking from experience!  Hours of aggravation caused by writing the number 2 instead of 3.  Trust me….it will happen!

4.)  Leave Hydrogen and Oxygen Until Last

Is there a specific order in which to balance the atoms of elements within a chemical equation?  Not really….to each their own.  However, I have found that balancing the hydrogen and oxygen atoms last has resulted in the successful balancing of many chemical equations.  Take care of the big guys first and leave the little guys until last.  It sounds elementary, but it does work!

If you’ve had the patience to read through this entire post, success is on the horizon.  By applying these four tips, you will find that balancing chemical equations is definitely doable.  Take the knowledge you’ve learned from balancing chemical equations and apply it to stoichiometry.  You will find that you can’t do one without the other!  Understanding stoichiometry is reliant upon your ability to successfully balance equations.

Don’t forget, practice makes perfect!  Hit those textbooks and complete a few practice problems.  The more you practice, the easier it will be to identify the proper coefficients for any given chemical equation.  Again, I’m speaking from experience!

Did you find this post helpful?  Do you still have questions pertaining to balancing chemical equations?  Feel free to leave me a comment.  Take care and thank you for reading!  Good luck!