Page 220 - Chemistry eBook

Finding the Mass in Equations
How to Find the Mass in Equations
LAW OF CONSERVATION OF MASS: The amount of mass you start out with is the amount you must have at the end. (Mass can never be created or destroyed, so mass must stay balanced before and after a chemical reaction.)
A + B ➞ C. (This means ‘A’ and ‘B’ combine to form ‘C’.)
If there are 10 grams of ‘A’ and 80 grams of ‘B’, what is the mass of C’?
Well, we know that both sides of an equation must be equal. The left side (A+B) is 90 grams (10+80). That means that the right side must be 90 grams too. Therefore, ‘C’=90.
Sometimes, they won’t give you the equation straight out, and you will have to figure out the equation based on the words.
Just don’t try to figure out my mass (weight)!
219 © UNIT 6: MATH IN CHEMISTRY