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
Law of Conservation of Mass and Balancing Chemical Equations Let’s Review Counting Atoms Copy the following chemical formulas in your notes and count the TOTAL number of atoms. 1. 2. 3. 4. 5. 4 K2SO4 (NH4)PO4 Ba(OH) 2 2 KNO4 2 Ca3(PO4) 2 ________ ________ ________ ________ ________ Father of Modern Chemistry 1743 - 1794 First Described the “Law of Conservation of Mass” Conservation of Mass Antoine Lavoisier found that the mass of the reactants and the products are equal, even when the states of matter change. HgO He started with: 10g of Mercury Oxide (HgO) Hg + O2 He ended up with: ...But what happened to the O2? and 9.3g Mercury… 10 g. = 0.7 + 9.3 g This is the Law of the Conservation of Mass It states that: “Matter is neither created or destroyed, it only changes form.” • These ‘changes’ include phase changes solid liquid gas • The amount that you started with will be equal to the amount you end with MASS REACTANTS = MASS PRODUCTS Lavoisier’s Chemical Equation: 2HgO 2 Hg + O2 Hg (mercury) can exist by itself...but, oxygen will need to bond with another oxygen to make O2 To balance the atoms we need to: Put the coefficient of 2 in front of reactant HgO. Put the coefficient of 2 in front the product Hg. This balances the equation! Easy, Right? Not that easy? Let’s try... BALANCING CHEMICAL EQUATIONS Four Steps to Balance Equations: 1. Set up your equation. Write the metals, nonmetals, oxygen, and hydrogen. 2. Count and then write the number of atoms you have on both sides. 3. Balance by changing the coefficients and recounting. 4. Start the process again if it still does not balance. Before we begin balancing, we will look at a couple of rules. 1.You can only change the coefficients, and NOT the subscripts. 2.The coefficients must be whole numbers. (Ex. – 1, 2, 3, 4…) CLASS PRACTICE Copy these in your notes. ____ H2 + ____ ____ Mg + ____ Na + O2 ____ ____ ____ HCl HCl H2O ____ ____ H2+ ____ MgCl2 NaCl + ____ H2 Let’s kick it Up a Notch!! Copy these in your notes __ KClO3 __KCl + __O2 __ Na + __ H20 __ NaOH + __ H2 __ S8 + __ O2 __SO3 Independent Practice 1. __Fe + __ O2 __Fe2 + __O3 2. __Cl2 + __Li __LiCl 3. __ ZnS + __ O2 __ZnO + __SO2 4. __ Cl2 + __ NaI __ NaCl + __ I2