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Types of Reactions and Balancing Equations. Review Notes Part 1. Subscripts and Coefficients Give Different Information. Subscripts tell the number of atoms of each element in a molecule. Subscripts and Coefficients Give Different Information.
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Types of Reactions and Balancing Equations Review Notes Part 1
Subscripts and Coefficients Give Different Information • Subscripts tell the number of atoms of each element in a molecule
Subscripts and Coefficients Give Different Information • Subscripts tell the number of atoms of each element in a molecule • Coefficients tell the number of molecules
Balancing Equations Balancing, Writing, and Naming Equations
Balancing Equations • Law of Conservation of Matter: • In a chemical reaction, matter can be neither created nor destroyed. • In a chemical reaction, the amount of reactants equal the amount of products.
Balancing Equations • Paraphrase: • Law of Conservation of Atoms: • The number of atoms of each type of element must be the same on each side of the equation.
Balancing Equations • Hydrogen + oxygen water • H2 + O2 H2O • Hydrogen and oxygen are diatomic elements. • Their subscripts cannot be changed. • The subscripts on water cannot be changed.
Balancing Equation • H2 + O2 H2O • Count the atoms on each side. • Reactant side: 2 atoms H and 2 atoms O • Product side: 2 atoms H and 1 atom O
Balancing Equations • H2 + O2 H2O • If the subscripts cannot be altered, how can the atoms be made equal? • Adjust the number of molecules by changing the coefficients.
Balancing Equations • H2 + O22H2O • Reactants: 2 atoms of H and 2 atoms of O • Products: 4 atoms of H and 2 atoms of O • H is no longer balanced!
Balancing Equations • 2H2 + O22H2O • Reactant side: 4 atoms of H and 2 atoms of O • Product side: 4 atoms of H and 2 atoms of O • It’s Balanced!
Balancing Equations • N2 + H2 NH3 • Nitrogen + hydrogen ammonia • Count atoms. • Reactants: 2 atoms N and 2 atoms H • Products: 1 atom N and 3 atoms of NH3
Balancing Equations • Nothing is balanced. • Balance the nitrogen first by placing a coefficient of 2 in front of the NH3. • N2 + H22NH3
Balancing Equations • Hydrogen is not balanced. • Place a 3 in front of H2. • Reactant side: 2 atoms N, 6 atoms H • Product side: 2 atoms N, 6 atoms H • N2 + 3H22NH3
Balancing Equations • This method of balancing equations is the inspection method. • The method is trial and error. • Practice.
Writing and Naming • Write each formula independently. • Ignore the rest of the equation. • Balance the equation after writing the formulas. • Ni + HCl NiCl2 + H2 • Ni + 2HCl NiCl2 + H2
Cu + H2SO4 • CuSO4 + H2O + SO2 • Balance the formula equation.
Cu + 2H2SO4 • CuSO4 + 2H2O + SO2