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Thus Far…. HW Questions: Reviewed: S.I, Measurement, Acc, Prec., Uncertainty, S.F Added Uncertainty Propagation: +/-: x/divide: Exponents: Added types of error (random/systematic) Avg Deviation: % Avg. Deviation: Std. Deviation:. Chemical Reactions.
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Thus Far… • HW Questions: • Reviewed: S.I, Measurement, Acc, Prec., Uncertainty, S.F • Added Uncertainty Propagation: • +/-: • x/divide: • Exponents: • Added types of error (random/systematic) • Avg Deviation: • % Avg. Deviation: • Std. Deviation:
Chemical Reactions Potassium metal reacts with chlorine gas Zn metal reacts with aqueous copper(II) sulfate Aqueous silver nitrate reacts with aqueous potassium chromate Mercury(II) oxide reacts when heated Butane (C4H10) reacts with oxygen Write and balance the equation and identify the reaction type for each of the following reactions:
Quick Review: (go..go..gadget brain) Precipitate: Electrolyte: What is a(n): What types of combines form electrolytes? What does strong/weak electrolyte mean? What does soluble mean? What does insoluble mean?
Chemical Reactions 2 major categories of inorganic chemical reactions: Double Replacement Oxidation - Reduction Precipitation Neutralization Synthesis Decomposition Single Replacement Combustion Precipitation – Driving Force is formation of Precipitate (Use solubility rules to determine) Ex: AgNO3 + K2CrO4 - Molecular -Complete ionic -Net ionic
Equation Types: Molecular Explicit about what the reactant solutions are and what products you obtain. Closely describes what you actually do in lab/industry. Why? Why..would you do this to us??? Complete Ionic The actual “picture of what really is “in there” Write aqueous solutions as their separate ions in their actual ratios. (Ratio as coefficients: from balancing compound AND equation) Net Ionic A summary. A predictable pattern. Cancel spectators ions (non-changing ions) and reduce ratio if possible.
Chemical Reactions You try: Write the molecular, complete ionic and net ionic equations for the reaction of aqueous aluminum sulfate with aqueous sodium hydroxide. Neutralization – Arrhenius acid with Arrhenius base (driving force is the formation of H2O) Ex: HCl + NaOH -Molecular -Complete ionic -Net ionic
Chemical Reactions Six Strong Acids: HClO4 H2SO4 HI HBr HCl HNO3 Six Strong Bases: LiOH NaOH KOH Ca(OH)2 Sr(OH)2 Ba(OH)2
Chemical Reactions Oxidation – Reduction (Redox) • The following is the rxn. for the formation of rust: • Fe(s) + O2(g) Fe2O3(s) • What is the oxidation number of iron? • What is the oxidation number of iron in Fe2O3? • What happened? • Because it involved reacting with O2, corrosion of a metal was originally called oxidation. • It was later found that similar reactions occurred without O2. • Now oxidation simply means that an element has LOST electrons.
Chemical Reactions • Look back at the reaction, what happened to the O2? • When an element GAINS electrons, we say that it has been reduced. • The oxidation number become less/lower. • A way to remember REDOX, is to think of a lion. • LEO goes GER In the following reaction, determine the oxidation state for each element and then determine what is reduced, oxidized; the oxidizing agent and the reducing agent: Zn + CuSO4→ ZnSO4 + Cu Now do the same for butane reacting with oxygen.
Convert 3.97 x 10-14 km/ps to miles per hour. (Hint 1 mile = 1609.34 m) • (Answer = About 88 mph) • A product is milled from a single solid block of metal. Find the mass of the cube shape block measuring .600 ± .002 m per side. The block is a lead alloy with a density of .666g/mm3 • If the raw block provider reports the uncertainty of their density to ± .4 %, find the mass with the calculated uncertainty
This and That • Extra Credit available (and I.B. hours???) for working the football concessions on Friday the 18th. (Two groups of 3 to 5, each group works one half of the game) • Quiz Reminder next time we meet. (Tuesday) • Quiz will start at bell • Handle your business • Do your HW • Check your answers/ Questions (Before/After School) • Be prepared (you know…like you used to be as chem. one students) • Return Labs • Grade Checks? • Mole day update (2 Weeks?)
Stoichiometry Let’s look at the butane reaction once more: 2C4H10 + 13O2 → 8CO2 + 10H2O What do the coefficients represent? Stoichiometry is the use of these ratios to determine quantitative relationships b/w the species in a rxn. 0.500 mol of butane would produce how many mol of CO2? If 5.00g of butane reacts with an excess of oxygen how many grams of CO2 could be produced?
Stoichiometry If 5.00g of butane reacts with an 10.0g of oxygen how many grams of CO2 could be produced? How many grams of the butane would be left when the reaction is complete? How many dm3? If 7.91g of the CO2 are collected, what is the percent yield? Just for fun: When 50.0g of silicon dioxide is heated with 50.0g of carbon, 32.2g of silicon carbide is produced. The other product formed is carbon monoxide. -What is the percent yield of the reaction? -How many dm3 of carbon monoxide gas are produced? -How much excess reagent is left over?