Chemical Reactions Chemical Change • reorganization • original substances form new substances with different formulas • may or may not involve a change of state • symbols used to describe chemical reaction are known as a chemical equation • Chemical equations do not have equal signs (=) they have an arrow Chemical Equations • Must follow the Law of Conservation of Matter • atoms can neither be created or destroyed during a chemical reaction • What goes in must come out! Chemical Equations • Reactants = Products same number of atoms of each element on each side of the reaction arrow Equations must be balanced! • other symbols • (s)solid • (l)liquid • (g)gas • (aq)aqueous, dissolved inwater Balancing Chemical Equations • First check all ionic formulas to see if they are correct! Five steps to balancing equations 1. Count the number of atoms of each element (or polyatomic ion) on the reactant side and then on the product side. You may want to use a chart or table. 2. Determine which are out of balance – these need to be balanced 3.
Pick an element or polyatomic ion to start with… • Balance using coefficients. • Do not use coefficients of 1 • No changes may be made to the subscripts • use least common multiples 5. Check and recheck! • Practice balancing these equations • H2(g) + O2(g) > H2O • KCl + BaSO4 > K2SO4 + BaCl2 Types of Chemical Reactions • Combination /Direct Combinationsynthesis • 2Na(s) + Cl2(g) > 2 NaCl(s) Single Displacement • single substitution • anion always replaces anion • cation always replaces cation Mg + 2 HCl > MgCl2 + H2 • Complete the following Single Displacement (formula is correct) Al + CuSO4 Double Displacement • 2 substitutions • ion-exchange • MgSO4 + BaCl2 >BaSO4 + MgCl2 • Types of Chemical Reactions • Double Displacement • What are the expected products of MgSO4 + BaCl2 • Types of Chemical Reactions • KOH + MgCl ( • check formulas and complete) Decomposition • HgO > Hg + O2 (balance) • 2 HgO > 2 Hg + O2 • carbonic acid in lab activity Oxidation / Reduction • oxidize iron into rust 4Fe + 3O2 ( 2Fe2O3 Oxidation reactions • add O (or remove H) Reduction reactions • add H ( or remove O) Redox reaction • Combination of oxidation and reduction Practice • How many grams of diatomic oxygen (O2) are needed to make 4 moles of magnesium oxide (MgO) from magnesium ribbon (Mg)? • Hint balance equation and use coefficient as mole. Energy in a Chemical Reaction Endothermic • heat in • requires activation energy • A + B + 100kcal => C + D Exothermic • heat out • A + B => C + D + 100 kcal
Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.
You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.Read more
Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.Read more
Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.Read more
Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.Read more
By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.Read more