Balancing Chemical Reactions Also Known As… How to become the baddest, craziest chemical assassin to walk the planet!

Types of Chemical Equations There are a few different ways to describe any chemical reaction. There are a few different ways to describe any chemical reaction. Let’s look at the chemical reaction that describes the decomposition (breaking apart) of water. Let’s look at the chemical reaction that describes the decomposition (breaking apart) of water. Word Equations – These equations use the names of the substances involved in the “reactants  products” format. Word Equations – These equations use the names of the substances involved in the “reactants  products” format. Water  Oxygen gas + Hydrogen gas Skeleton Equations – These use the chemical formulas of the substances in the “reactants  products” format. Skeleton Equations – These use the chemical formulas of the substances in the “reactants  products” format. H 2 O  O 2 + H 2 A closer look at the skeleton equation will reveal a problem…We have only one oxygen atom going into the reaction, but, there are two oxygen atoms coming out of the reaction. A closer look at the skeleton equation will reveal a problem…We have only one oxygen atom going into the reaction, but, there are two oxygen atoms coming out of the reaction.

The Law of Conservation of Mass The Law of Conservation of Mass states that the mass of the atoms making up the reactants will be the same as the mass of the atoms making up the products. The Law of Conservation of Mass states that the mass of the atoms making up the reactants will be the same as the mass of the atoms making up the products. Atoms can’t be created or destroyed so this law basically means… Atoms can’t be created or destroyed so this law basically means… “What goes in…must come out!” For instance, if a chemical reaction has five carbon atoms going in with the reactants – it must have five carbon atoms exiting the reaction as part of the products. For instance, if a chemical reaction has five carbon atoms going in with the reactants – it must have five carbon atoms exiting the reaction as part of the products. For this reason, we must “balance” all of our chemical equations, because, what goes in…must come out! For this reason, we must “balance” all of our chemical equations, because, what goes in…must come out!

Balancing Act To balance a chemical equation – you first need a word equation. Once you have that you can figure out the proper formulas of the substances involved. To balance a chemical equation – you first need a word equation. Once you have that you can figure out the proper formulas of the substances involved. A skeleton equation shows a chemical reaction by using just the formulas of the reactants and products. A yield arrow (  ) is also used to show the direction of the reaction. A skeleton equation shows a chemical reaction by using just the formulas of the reactants and products. A yield arrow (  ) is also used to show the direction of the reaction. Now balance the skeleton equation by counting atoms and placing the appropriate coefficients in front of the formulas that need adjusting. Now balance the skeleton equation by counting atoms and placing the appropriate coefficients in front of the formulas that need adjusting. Coefficients are the large numbers in front of a chemical formula – you can adjust these. The smaller numbers within the formula are subscripts – if you touch these, I know places they will never find your body! Coefficients are the large numbers in front of a chemical formula – you can adjust these. The smaller numbers within the formula are subscripts – if you touch these, I know places they will never find your body! If both sides have the same number and type of atoms, you have achieved the pinnacle of chemistry expressionism! You now have a balanced chemical equation. If both sides have the same number and type of atoms, you have achieved the pinnacle of chemistry expressionism! You now have a balanced chemical equation. All work in chemistry usually begins with a chemical equation that has the proper formulas and is balanced properly. All work in chemistry usually begins with a chemical equation that has the proper formulas and is balanced properly.

How To Pass Grade 10 Chemistry Did you use the proper formulas based on the word equation provided. Did you use the proper formulas based on the word equation provided. Did you add only coefficients? I will snap if you use subscripts! Did you add only coefficients? I will snap if you use subscripts! Did you go back and double check your balancing act? Did you go back and double check your balancing act?

Practice Equations Try to balance the following chemical equations. Remember, count one element at a time and think – what goes in, must come out!...or else! Try to balance the following chemical equations. Remember, count one element at a time and think – what goes in, must come out!...or else! 1. MgCl 2 + FeBr 3  MgBr 2 + FeCl 3 2. AlBr 3 + F 2  AlF 3 + Br 2 3. CH 4 +O 2  H 2 O + CO 2 4. NaOH + H 2 SO 4  Na 2 SO 4 + H 2 O 5. H 2 O + CO 2  H 2 CO 3 6. Mg(NO 3 ) 2 + NaOH  Mg(OH) 2 +NaNO 3 7. AlPO 4 + Mg(ClO 3 ) 2  Al(ClO 3 ) 3 + Mg 3 (PO 4 ) 2 8. C 3 H 8 + O 2  CO 2 + H 2 O ( already balanced )

One Last Reminder! You only add coefficients – the big numbers in front. I will completely lose it if you start throwing around those little subscripts like you are some sort of chemistry revolutionary! You only add coefficients – the big numbers in front. I will completely lose it if you start throwing around those little subscripts like you are some sort of chemistry revolutionary!

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