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Balancing Tools

Balancing Tools. Recall in Balancing. If mass is conserved and atoms can not be created or destroyed in a chemical reaction. Our equations should show the same number of each kind of atom on both sides of the equation. The equation must balance. Recall Balancing Rules.

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Balancing Tools

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  1. Balancing Tools

  2. Recall in Balancing • If mass is conserved and atoms can not be created or destroyed in a chemical reaction. • Our equations should show the same number of each kind of atom on both sides of the equation. • The equation must balance.

  3. Recall Balancing Rules • Always show the correct chemical formulae of all substances involved in the reaction. You are not allowed to balance an equation by changing a formula! • Adjust the numbers of each kind of atom by writing numbers in front of the formulae of the compounds and elements. These numbers are known as coefficients.

  4. Diatomic Gas EquationsTool #1 • On group of equations that can be troublesome are those involving diatomic gasses. • A diatomic gas is any gas that tends to bond with itself when isolated. • Examples are H2, N2, O2, Cl2 and F2 • These gases are hard to balance because they make it difficult to get ODD numbers.

  5. Let us See • H2 + O2 =>H2O • The H’s balance but the O’s do not. • In cases where we are dealing with diatomic atoms we can temporarily use a fraction to get the desired result. • H2 + ½ O2 =>H2O This gives 1 O on the right and left. • 2(H2 + ½ O2 =>H2O) Multiply by 2 to cancel the fraction. • 2H2 + O2 =>2H2O BALANCED.

  6. Here is How • Check to see if there is a diatomic in the equation. • Yes. • Balance every part of the equation except the diatomic atoms. Leave them till the end. • If the number from the diatomic is an odd number use a fraction with base 2 to temporarily balance the equation. Ex. 1 , 3 , 5 , 7 , etc… 2 2 2 2 • Multiply through by 2 to eliminate the fraction.

  7. Try These • Al + H3PO4 => H2 + AlPO4 • Al + H3PO4 => 3/2 H2 + AlPO4 • 2Al + 2H3PO4 => 3H2 + 2AlPO4 • P + O2 => PO5 • P + 5/2O2 => PO5 • 2P + 5O2 => 2PO5 • Al + O2 => Al2O3 • 2Al + 3/2 O2 => Al2O3 • 2(2Al + 3/2O2 => Al2O3) • 4Al + 3O2 => 2Al2O3

  8. Radical Balancing MethodTool #2 • If the equation you are balancing contains radicals and the radicals remain in tact from reactant to product (not changed at all) you may treat them as a single atom. • Recall that radicals sometimes have brackets. This makes it easier to find a radical in the equation and check to see if it changed.

  9. Let Us Try • KI + Pb(NO3)2 => PbI2 + KNO3 • 2KI + Pb(NO3)2 => PbI2 + 2KNO3 • Al + H2SO4 => Al2(SO4)3 + H2 • 2Al + 3H2SO4 => Al2(SO4)3 + H2 • 2Al + 3H2SO4 => Al2(SO4)3 + 3H2 • Cu(NO3)2 + NH4OH => Cu(OH)2 + NH4NO3 • Cu(NO3)2 + NH4OH => Cu(OH)2 + 2NH4NO3 • Cu(NO3)2 + 2NH4OH => Cu(OH)2 + 2NH4NO3

  10. You Try • Balancing Equations #2 (1 – 10) • Balancing Equations #3 (1 – 10)

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