270 likes | 338 Views
Chapter 9. Acids & Bases. Acids. donate protons to water to form hydronium ions taste sour turn cabbage juice red turn litmus paper red neutralize bases. Bases. donate hydroxide groups accept protons taste bitter feel slimy
E N D
Chapter 9 Acids & Bases
Acids • donate protons to water to form hydronium ions • taste sour • turn cabbage juice red • turn litmus paper red • neutralize bases
Bases • donate hydroxide groups • accept protons • taste bitter • feel slimy • turn cabbage juice yellow, green or blue depending upon the solution concentration • turn litmus paper blue
Everyday Uses for Acids • digestion of food • clean metals • production of fertilizers • making explosives • carbonating beverages
What Makes a Compound an ACID? When dissolved in water, all acids share certain physical & chemical properties • sour taste • color change (litmus paper to red, phenolphthalein turns colorless) • corrode metals • all contain hydrogen • produce a positive hydrogen ion when dissolved in water (creates the hydronium ion H3O) • known as proton donors
Three Common & Strong Acids • HCl – hydrochloric acid • H2SO4 – sulfuric acid • HNO3 – nitric acid • strong acids ionize to a high decree in water many H+ ions • strong acids are good electrolytes
What is an Electrolyte? • a substance whose water solution conducts an electric current • Strong acids conduct electricity very well because they produce many ions in water • Weak acids do not conduct electricity as well
Everyday Uses for Bases • found in antacids (like Mylanta & Milk of Magnesia) to neutralize extra acids in the stomach • used to make soaps (lye) • used to make household cleaner (ammonium) • found in deodorants
What Makes a Compound a BASE? When dissolved in water, all bases share certain physical & chemical properties • bitter taste • color change (litmus paper to blue, phenolphthalein turns bright pink) • slippery to the touch • all contain hydroxide ion OH- • known as proton acceptors
Three Common & Strong Bases • KOH – potassium hydroxide • NaOH – sodium hydroxide • Ca(OH)2 – calcium hydroxide • strong bases readily dissolve in water to produce a high # of ions • strong bases are good electrolytes (good conductors of electricity)
Acids & Bases in Solution • Solutions can be acidic, basic, or neutral • the pH scale is used to determine the acidity of a solution • the pH of a solution is a measure of the hydronium ion (H3O+) concentration
pH • the pH scale is a series of #s from 0 – 14 0 – 6 = acidic 7 = neutral (like distilled water) 8 - 14 = basic • strong acids have low pH numbers while strong bases have high pH numbers
Formation of Salts • when acids react chemically with bases, they for a class of compounds called the salts • a salt forms from the positive ion of a base & the negative ion from an acid • this reaction, called neutralization, also produces water as a by-product • H+Cl- + Na+OH-→ H2O + NaCl • What kind of reaction is neutralization?
Precipitates • many of the salts created by the neutralization process do not dissolve in water • they crystallize out of the solution to form a precipitate