Acid Base Chemistry Unit 5 Part 1 – Chapter 14

Warm-up (Jan 25) Notes, calculator, goggles OUT! If someone asked you to describe an acid, what would you say? Think of some words and examples Warm-up (Jan 25)

Demos PINK means base, colorless means acid Samples tested: Common attributes? NH3, NaOH, KOH, Mg(OH)2, HCl, HNO3, H2SO4, H3PO4 Also incorporate litmus and universal paper in? Other indicators? Demos

Arrhenius (1884): ONE Definition of Acids and Bases PROTON = H+ Arrhenius (1884): ONE Definition of Acids and Bases

Indicator – an inorganic chemical (dye) that reacts with acids or bases and produces certain color changes. Red Cabbage can be used to prepare an indicator! Common Indicators

Every pH unit is a 10-fold change in [H+] concentration Every pH unit is a 10-fold change in [H+] concentration! Which means that pH = 3 (vinegar) is not so dangerous, but pH = 1 is!

What is the pH scale?

What is the equation for [H+] according to the picture What is the equation for [H+] according to the picture? Now, rearrange the equation to solve for pH: pH = -log[H+] 10 ^ -pH = [H+] pH equations!

Calculate the pH of the following acids: 0.56 M HCl 0.05 M H2SO4 What is the [H+] (concentration) of a solution with a pH of: 2.8 10.5 Which one is more acidic? How do you know? P in pH = power of 10 Try some

Demo with universal indicator Milk of magnesia (Mg(OH)2) is meant to help with heartburn from acid reflux in the esophagus. Demo with universal indicator

HCl + NaOH  Svante Arrhenius Main father of H+ (acid) and OH- (base) theory: HCl + NaOH  H2SO4 + KOH  When acid and base meet in equimolar amounts = neutralization! What do we make? Svante Arrhenius

Acid-Base Calculations HCl + NaOH  ?? + ?? Think double-displacement! Acid + Base  Water + Salt Neutralization = point where moles of acid are equal to the moles of base Acid and Base “cancel” each other out Acid-Base Calculations

FLASHBACK TO Ksp! From your quiz: Ca(OH)2 (s)  Ca 2+ (aq) + 2OH- (aq) Which of the following will make calcium hydroxide more soluble? 50 mL H2O 50 mL 0.1 M Ca(NO3)2 50 mL 0.1 M HCl 50 mL 0.1 M NaOH FLASHBACK TO Ksp!

Acid/Base Neutralization a) Give the balanced chemical equation for the reaction of nitric acid (HNO3) with potassium hydroxide (KOH): b) If 250.0 mL of a 0.50 M solution of HNO3 was used, what volume of a 0.32 M KOH solution would be required to react perfectly? 390 mL Acid/Base Neutralization

Write the balanced chemical equation for the acid-base reaction between H2SO4 and NaOH How many moles of base do you need to neutralize one mole of acid? You try

Write the balanced chemical equation for the acid-base reaction between H2SO4 and NaOH Consider a 0.150 M solution of H2SO4. Calculate how many mL of that solution would be needed to neutralize 50.0 mL of 0.230 M NaOH 38.3 mL You try

Monoprotic Diprotic Triprotic --protic!

WS #1 Acid Base Read chapter 14.1-14.4 Homework Day 1

Intro to Titration (Lab 17) Lab and Class Wednesday – standardization of a base With a known amount of acid, what is the molarity of the base? Titrate to the endpoint (pH 7, indicated by LIGHT pink with phenolphthalein) Titration = adding a known amount of acid/base to an unknown amount of acid/base to neutralize! Intro to Titration (Lab 17)

Titration (Lab #17) A way to analyze an unknown acid or base Use an indicator to show when you reach the equivalence point (neutralization) Be analytical! Do good, controlled trials Titration (Lab #17)

LIGHT pink means…

Lab #17 work time! GOGGLES ALWAYS BE CAREFUL WITH ANALYTICAL BALANCE At LEAST 5 GOOD trials If bright/dark pink, don’t count it Pink solutions down the sink with lots of water Clean up everything well when done! Rinse buret with distilled water TWICE and store upside down by the goggles Waste NaOH in the waste beaker Wash glassware very well, take off sharpie Lab #17 work time!