משואה כימית של שריפת פחם (תגובה עם חמצן) A chemical equation gives the chemical formulas of the reactants on the left of the arrow and the products on the right. Reactants Product O2 (g) CO2 (g) C(s)

הסמלים שבמשואה Symbols used in chemical equations show: the states of the reactants. the states of the products. the reaction conditions. TABLE 5.2

סיכום וחזרה מהי משואה כימית A chemical equation tells us what substances react (reactants) and what substances are formed (products).

משואה כימית היא מאוזנת In a balanced chemical reaction atoms are not gained or lost. the number of reactant atoms is equal to the number of product atoms.

דוגמא 2 למשואה כימית מאוזנת In a balanced chemical equation, the number of atoms in the reactants is equal to the number of atoms in the products for each element.

איזון משואה כימית +דוגמא 3 To balance a chemical equation, whole number coefficients are placed in front of the chemical formulas. coefficients in front of a molecule represent the multiple of that molecule needed in a balanced reaction. subscripts are never changed. Al + S  Al2S3 Not Balanced 2Al + 3S  Al2S3 Balanced 2 Al = 2 Al 3 S = 3 S

משואה של תגובה כימית –דוגמא 4

Checking a Balanced Equation בדיקת משואה מאוזנת Checking a Balanced Equation Reactants Products balanced Atoms C 1 Atoms H 4 Atoms O

1 תרגיל Learning Check State the number of atoms of each element on the reactant side and the product side for each of the following balanced equations. A. P4(s) + 6Br2(l)  4 PBr3(g) B. 2Al(s) + Fe2O3(s)  2Fe(s) + Al2O3(s)

Solution פתרון A. P4(s) + 6Br2(l)  4 PBr3(g) 4 P 4 P 12 Br 12 Br B. 2Al(s) + Fe2O3(s)  2Fe(s) + Al2O3(s) 2 Al 2 Al 2 Fe 2 Fe 3 O 3 O

Learning Check תרגיל 2 Determine if each equation is balanced or not. A. Na(s) + N2(g)  Na3N(s) B. C2H4(g) + H2O(l)  C2H5OH(l)

פתרון תרגיל 2 Solution Determine if each equation is balanced or not. A. Na(s) + N2(g)  Na3N(s) No. 2 N on reactant side, 1 N on product side. 1 Na on reactant side, 3 Na on product side. B. C2H4(g) + H2O(l)  C2H5OH(l) Yes. 2 C = 2 C 6 H = 6 H 1 O = 1 O דילוג על נושא שלבים באיזון משואות

תרגיל 3 Learning Check Check the balance of atoms in the following equation: 1. number of H atoms in products A. 2 B. 4 C. 8 2. number of O atoms in reactants 3. number of Fe atoms in reactants A. 1 B. 3 C. 4

פתרון תרגיל 3 Solution Check the balance of atoms in the following equation: 1. number of H atoms in products C. 8 (4H2O) 2. number of O atoms in reactants B. 4 (Fe3O4) 3. number of Fe atoms in reactants B. 3 (Fe3O4)