8.3 & 8.4 Acids and Bases For health reasons, swimming pools are regularly treated with chemicals. The effectiveness of these disinfectants depends on how acidic or basic the water is.

Properties of Acids and Bases Although taste is not a safe way to classify acids and bases, you probably are familiar with the ___________ taste of acids. sour Fruit juice and vinegar, for example, are both aqueous solutions of acids. Base Bases, on the other hand, taste __________. bitter

slippery soap sticky Bases have a __________ feel. Acid Like taste, feel is not a safe chemical test for bases, but you are familiar with the feel of _________, a base, on the skin. Acids may feel __________ slippery Acid soap Base sticky

Litmus Test and Other Color Changes Acids and bases cause certain colored dyes, called _________________ to change color. The most common of these dyes is ________. indicator litmus When mixed with an acid, litmus turns _______. red When added to a base, litmus turns ________. blue

Reactions with Metals metals corrode Another characteristic property of an acid is that it reacts with ________ that are more active than hydrogen. metals This property explains why acids __________ most metals. corrode Bases do ____ commonly react with metals. NOT

Submicroscopic Behavior of Acids The Swedish chemist, Svante _____________ discovered that acids produce ____________ ions when dissolved in water. Arrhenius hydronium A hydronium ion, ________, consists of a hydrogen ion attached to a water molecule. H3O+ H + O H H

When HCl dissolves in water, it produces hydronium ions by the reaction shown below. HCl is definitely an _________; it produces ________ when dissolved in water. acid H3O+ + - H H H H H Cl Cl O O +  + H

The reaction below also shows the ________________ of HCl ionization Which two substances below are ions? H3O+ Cl- - + H H H H H Cl Cl O O +  + H

Acidic Hydrogen Atoms In an acid, any hydrogen atom that can be transferred to water is called an acidic hydrogen. To help distinguish acids from other hydrogen-containing molecules, acidic hydrogens are written __________ in the formula. first

Submicroscopic Behavior of Bases The behavior of bases is also described at the molecular level by the interaction of the base with water. A base is a substance that produces _____________ ions, ______, when it dissolves in water. NH3(g) + H2O ↔ NH4+(aq) + OH-(aq) hydroxide OH- - O base H

The pH Scale pH is a mathematical scale in which the concentration of ____________ ions in a solution is expressed as a number from 0 to 14. hydronium pH = -log[H3O+] Since pH is determined by the _____________ log of hydronium ions, acids are found on the _____________ end of the scale negative lower

pH of 7 is _____________ pH less than 7 is _____________ pH greater than 7 is ________________ neutral acidic basic

The concentration and strength of an acid or base are two different things For example, adding _________ of a base to water will increase the ______________ of hydroxide ions, causing a ____________ pH value more concentration higher

For an acid or a base to be strong, the formation of ions must be _____________ These reactions are indicated by a _______ sided arrow complete single

An acid or a base is said to be weak, when they ionize or dissociate only ______________ in water These reactions are indicated by a _______ sided or ____________ arrow partially two double

Question 1 Is H2SO3 an acid or a base? How do you know? acid … H is first and releases hydronium ions when dissolved in water

Question 2 Identify differences between acids and bases using the table below Acid Base Taste? Touch? Litmus Dye? Reacts with metals? Ions produced? sour bitter sticky slippery red blue yes no hydronium hydroxide

Question 3 What is the difference between strong and weak acids/bases? Ionize completely (single arrow) Ionize partially (double arrow)