Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Balancing Chemical Equations The general format for chemical equations is: a+ b c +d The reactants go on the left side of the equation (___ and ____ in this case). The + sign means ___________________________. The means ____________________. The products go on the right side of the equation (____ and ______ in this case). Lets work with the statement: “Hydrogen gas reacts with oxygen gas to form liquid water” Word Equation Skeleton Equation To balance equations numbers called coefficients are put before the formulas. This changes the number of molecules. Notes: You cannot add or change subscripts. You do not write coefficients of 1 (one). Balanced Equation Why Must We Balance Equations? 1) Remember the Law of Conservation of Mass states that the total mass of reactants is always equal to the total mass of the products. 2) Dalton’s Atomic Theory states that atoms can not be created or destroyed. Compounds are formed when atoms of different elements combine in fixed proportions. To go from a skeletal equation to a balanced equation, follow these steps: 1) Balance the equation by adding coefficients – Pick single elements that appear on each side first to balance – Remember leave O then H until the end 2) Go back and re-check that all atoms are equal on both sides – If you have any fraction coefficients clear them by multiplying. – Also, make sure you have the smallest possible coefficients by reducing the ENTIRE EQUATION. Example: Fe + H2O H2 + Fe2O3 2Fe + 3H2O 3H2 + Fe2O3 Example 1: Skeletal Equation: Skeletal Reactants Balanced Equation: Na + H2O NaOH + H2 Products Balanced Reactants Products ____ Na + ____ H2O ____ NaOH + ____ H2 Example 2: Skeletal Equation: Skeletal Reactants Balanced Equation: Cu + AgNO3 Cu(NO3)2 + Ag Products Balanced Reactants Products ____ Cu + ____ AgNO3 ____ Cu(NO3)2 + ____ Ag Example 3: Skeletal Equation: Skeletal Reactants Balanced Equation: Ca(NO3)2 + NaOH Ca(OH)2 + NaNO3 Products Balanced Reactants Products ____ Ca(NO3)2 + ____ NaOH ____ Ca(OH)2 + _____ NaNO3