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Chemical Reactions Lesson 2. Warm-up IANB p41. #1. #2. Oxygen. 1. 2. 10. 4. 12. 4. 2. 8. Learning to Inventory the Atoms in the Equation. Reactants Products (produce) Reactants are the substances that combine or change. Products are the result of the reaction. 1 of 6.
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Warm-up IANB p41 #1 #2 Oxygen 1 2 10 4 12 4 2 8
Learning to Inventory the Atoms in the Equation Reactants Products (produce) • Reactants are the substances that combine or change. • Products are the result of the reaction.
1 of 6 Prove a ChemicalEquation is Balanced Remember: coefficients of 1 are not written out. • An equation must be balanced to be useful. • The equation below is not balanced. Can you see what is missing? 2 1 2 Na + Cl2 NaCl • There are no coefficients in the equation above. • Coefficients determine the amounts of reactant and product. • The amounts of reactant and product are correct when the coefficients make the equation balance.
2 of 6 Prove a Chemical Equation is Balanced • Prove the equation is balanced. 2Na + Cl2 2NaCl Na 2 2 Cl 2 2 This reaction is balanced because there are the same number and types of atoms on each side. This gives a total of two sodium atoms and two chlorine atoms on the product side. The Coefficient of 2 and the lack of subscripts, tells us there are 2 molecules of sodium chloride. Each molecule has 1 Na and 1 Cl. Third: Count the number of atoms of each type on the product side.You will consider both coefficients & subscripts The lack of a subscript and the coefficient of 2 on sodium, tells us that there are 2 Na atoms on the reactant side. The subscript of 2 and the lack of a coefficient on chlorine, tells us that there is one molecule of chlorine that contains 2 Cl atoms. Remember, a balanced chemical equation has the same type and number of atoms on both the reactant and product sides. Second: Count the number of atoms of each type on the reactant side.You will consider both coefficients & subscripts First: Identify the all of the different elements that are involved in this reaction.There are 2 types of atoms: Sodium & Chlorine We need to keep track of types and numbers of atoms on each side of the equation. So…Let’s get organized by creating a table Back
Complete the Atom inventory to prove the equation is balanced. MnO2 + 4HCl MnCl2 + Cl2 + 2H2O Mn 1 1 O 2 2 H 4 4 Cl 4 2 4 This reaction is balanced because there are the same number and types of atoms on each side. Chlorine shows up in two products MnCl2 & Cl2. Cl2 tells us there is 1 molecule of chlorine gas with 2 Cl atoms bonded together. There are a total of 4 chlorine atoms on the product side of the equation; 2 from the MnCl2 and 2 from the Cl2. MnCl2 tells us there is one molecule that has 1 manganese bonded to 2 chlorines.So, there is 1Mn atom and 2 Cl atoms. 2H2O tells us that there are two molecules each having one oxygen bonded to two hydrogens.So there are four hydrogen and two Oxygen Third: Count the number of atoms of each type on the product side.You will consider both coefficients & subscripts 4HCl tells us that there are four molecules each having one hydrogen bonded to one chlorine.So there are four hydrogen and four chlorine. MnO2 tells us that there is one molecule of this compound and it has one manganese bonded to two oxygens. Second: Count the number of atoms of each type on the reactant side.You will consider both coefficients & subscripts First: Identify the all of the different elements that are involved in this reaction.There are 4 types of atoms: Mn, O, H, & Cl We need to keep track of types and numbers of atoms on each side of the equation. So…Let’s get organized by creating a table Remember, a balanced chemical equation has the same type and number of atoms on both the reactant and product sides. Back
Prove a Chemical Equation is Balanced • Prove the following reaction is balanced. C6H12O6 + 6O2 6CO2 + 6H2O C 6 6 12 H 12 18 18 O Back Start
Use the Atom inventory to balance the equation. P4O10 + __HNO3 __HPO3 + __N2O5 4 4 2 = P 4 4 = 22 O 22 = 4 4 H = N 4 4 BALANCED! Back
Student Practice IANB p 40 & 42 • ONLINE TUTORIAL Website: http://www.chem.uiuc.edu/webFunChem/GenChemTutorials.htm • Also found by WHS website: CLICK ON • [Courses], [Science], [V. Ogle], [Resources], [Online Tutorials], [Fundamentals of Chemistry] • Part A: [Equations] • Part B: [Balancing Equations]