Why do chemical reactions work so perfectly?

Pick your best answer in your pairs on a whiteboard, face down and secure.

Which one below is a REAL chemical reaction? NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

Write down your answer and place it face down on your desk.

This one doesn’t do anything. NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

This one is just a mixture. NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

gotta love salt water!

Why doesn’t this one make sense? NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

Why doesn’t this one make sense? NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

Where did this oxygen atom come from? NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O ?????

We can’t have 2 chlorines in the reactants and only 1 in the products! NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O ?????

Are the NUMBERS right in A? NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

What happened to the 3 reacting oxygen atoms in the beginning What happened to the 3 reacting oxygen atoms in the beginning? Now there’s only 1 in the product? NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

And where did this chlorine come from???? NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

That leaves us with only one! NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

Why is “C” the legit reaction? NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O

Why is “C” the legit reaction? NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O Reactants have the same atoms, but just are re-made into different molecular products.

CHEMICAL REACTIONS DON’T make matter out of thin air! impossible NaOH + H2O2  NaCl + H2O NaCl + H2O  H2O + NaCl NaOH + HCl  NaCl + H2O NaCl + HCl  HCl + H2O impossible

How many had that right? LET’S TRY A COUPLE MORE…

Which is a REAL CHEMICAL REACTION? ZnSO4 + Cu  CuSO4 2 Fe + 6 HCl  2 FeCl3 + 3 H2 Cl2 + 2 K(OH)  H2 + 2 KCl CaBr2 + AgO3  AgBr + 2 CaNO3

BOARDS FACE DOWN!

Why is A not a real reaction? What element are we missing in the product? ZnSO4 + Cu  CuSO4 2 Fe + 6 HCl  2 FeCl3 + 3 H2 Cl2 + 2 K(OH)  H2 + 2 KCl CaBr2 + AgO3  AgBr + 2 CaNO3

What happened to the zinc in the product? ZINC didn’t just disappear from this reaction! ZnSO4 + Cu  CuSO4 2 Fe + 6 HCl  2 FeCl3 + 3 H2 Cl2 + 2 K(OH)  H2 + 2 KCl CaBr2 + AgO3  AgBr + 2 CaNO3

In CHEMICAL REACTIONS, matter does NOT just DISAPPEAR! And wasn’t there an oxygen atom in the reactants here? Where did it go? ZnSO4 + Cu  CuSO4 2 Fe + 6 HCl  2 FeCl3 + 3 H2 Cl2 + 2 K(OH)  H2 + 2 KCl CaBr2 + AgO3  AgBr + 2 CaNO3 No O!!! In CHEMICAL REACTIONS, matter does NOT just DISAPPEAR!

Where did the nitrogen atom come from?? ZnSO4 + Cu  CuSO4 2 Fe + 6 HCl  2 FeCl3 + 3 H2 Cl2 + 2 K(OH)  H2 + 2 KCl CaBr2 + AgO3  AgBr + 2 CaNO3

The correct chemical reaction formula is B! ZnSO4 + Cu  CuSO4 2 Fe + 6 HCl  2 FeCl3 + 3 H2 Cl2 + 2 K(OH)  H2 + 2 KCl CaBr2 + AgO3  AgBr + 2 CaNO3

CHEMICAL REACTIONS DON’T MAKE MATTER OUT OF THIN AIR! Reactants have the same atoms, but just are re-made into different molecular products. CHEMICAL REACTIONS DON’T MAKE MATTER OUT OF THIN AIR! In CHEMICAL REACTIONS, matter does NOT just DISAPPEAR!

How many had that right? LET’S TRY ONE MORE…

Which ONE is a REAL chemical reaction? 2 C8H18 + 25 O2  18 H2O + 16 CO2 6 CO2 + 6 H2S  C6H12O6 + 6 H2O + 12 S C3N6H6O6 + O2  3 CO2 + 2 H2O + 2 N2 + H2 Ba(OH)2 + 6 H2O + 2 NH4Cl  2NH3 + 10H2O + BaCl2 When you are done, put your boards face down.

C isn’t right…There are 6 nitrogen atoms in the reactants, but only 4 in the products! 2 C8H18 + 25 O2  18 H2O + 16 CO2 6 CO2 + 6 H2S  C6H12O6 + 6 H2O + 12 S C3N6H6O6 + O2  3 CO2 + 2 H2O + 2 N2 + H2 Ba(OH)2 + 6 H2O + 2 NH4Cl  2NH3 + 10H2O + BaCl2

What’s wrong with B? 2 C8H18 + 25 O2  18 H2O + 16 CO2 6 CO2 + 6 H2S  C6H12O6 + 6 H2O + 12 S C3N6H6O6 + O2  3 CO2 + 2 H2O + 2 N2 + H2 Ba(OH)2 + 6 H2O + 2 NH4Cl  2NH3 + 10H2O + BaCl2

Count up your sulfurs on both sides of the reaction… 2 C8H18 + 25 O2  18 H2O + 16 CO2 6 CO2 + 6 H2S  C6H12O6 + 6 H2O + 12 S C3N6H6O6 + O2  3 CO2 + 2 H2O + 2 N2 + H2 Ba(OH)2 + 6 H2O + 2 NH4Cl  2NH3 + 10H2O + BaCl2

6 S on the reactants, 12 S on the products. 2 C8H18 + 25 O2  18 H2O + 16 CO2 6 CO2 + 6 H2S  C6H12O6 + 6 H2O + 12 S C3N6H6O6 + O2  3 CO2 + 2 H2O + 2 N2 + H2 Ba(OH)2 + 6 H2O + 2 NH4Cl  2NH3 + 10H2O + BaCl2

CHEMICAL REACTIONS DON’T make matter out of thin air! Reactants have the same atoms, but just are re-made into different molecular products. CHEMICAL REACTIONS DON’T make matter out of thin air! In CHEMICAL REACTIONS, matter does NOT just DISAPPEAR!

Did you notice anything off about D? 2 C8H18 + 25 O2  18 H2O + 16 CO2 6 CO2 + 6 H2S  C6H12O6 + 6 H2O + 12 S C3N6H6O6 + O2  3 CO2 + 2 H2O + 2 N2 + H2 Ba(OH)2 + 6 H2O + 2 NH4Cl  2NH3 + 10H2O + BaCl2

We have only 22 hydrogens & 8 oxygens in the reactants, but 26 H & 10 O after. 2 C8H18 + 25 O2  18 H2O + 16 CO2 6 CO2 + 6 H2S  C6H12O6 + 6 H2O + 12 S C3N6H6O6 + O2  3 CO2 + 2 H2O + 2 N2 + H2 Ba(OH)2 + 6 H2O + 2 NH4Cl  2NH3 + 10H2O + BaCl2

The CORRECT chemical reaction is A. 2 C8H18 + 25 O2  18 H2O + 16 CO2 6 CO2 + 6 H2S  C6H12O6 + 6 H2O + 12 S C3N6H6O6 + O2  3 CO2 + 2 H2O + 2 N2 + H2 Ba(OH)2 + 6 H2O + 2 NH4Cl  2NH3 + 10H2O + BaCl2 WHO PICKED A?

Now they are ALL real. 2 C8H18 + 25 O2  18 H2O + 16 CO2 6 CO2 + 12 H2S  C6H12O6 + 6 H2O + 12 S C3N6H6O6 + O2  3 CO2 + 2 H2O + 3 N2 + H2 Ba(OH)2 + 8 H2O + 2 NH4Cl  2NH3 + 10H2O + BaCl2

COLLECT BOARDS AND MARKERS.

In chemical reactions, matter DOES NOT magically appear nor DISAPPEAR.

Remember our chemical reaction to rip apart the water molecule?

2 H2O  2 H2 + O2

Were we able to see the two gases coming apart from 2 water molecules? OXYGEN GAS (O2) like to react with other atoms! HYDROGEN GAS (H2) is MUCH MORE EXPLOSIVE gas! to form rust/corrosion to keep fires burning can explode on its own!

NEW SUBSTANCES are REFORMED from the SAME OLD ATOMS! 2 H2O  2 H2 + O2

NEW SUBSTANCES are REFORMED from the SAME OLD ATOMS! 2 H2O  2 H2 + O2 the LAW of CONSERVATION of MATTER (mass)

In CHEMICAL REACTION, MATTER is NOT CREATED, it is NOT DESTROYED. 2 H2O  2 H2 + O2 2 CH2 + 3 O2  2 CO2 + 2 H2O 6 CO2 + 6 H2O  C6H12O6 + 6 O2

In chemical reactions, MATTER is NOT CREATED, NOT DESTROYED. 2 H2O  2 H2 + O2 2 CH2 + 3 O2  2 CO2 + 2 H2O 6 CO2 + 6 H2O  C6H12O6 + 6 O2 The same atoms are just REARRANGED into NEW MOLECULES.

In chemical reactions, MATTER is NOT CREATED, NOT DESTROYED. the LAW of CONSERVATION of MATTER (mass) 2 H2O  2 H2 + O2 2 CH2 + 3 O2  2 CO2 + 2 H2O 6 CO2 + 6 H2O  C6H12O6 + 6 O2 The same atoms are just REARRANGED into NEW MOLECULES.

conservation of matter AND MASS