TCAP Review Lesson 17 Vocabulary Foldable (IX) ACIDS AND BASES TCAP Review Lesson 17 Vocabulary Foldable (IX)

ACID A substance that releases hydrogen ions (H+) in solution

ION An atom or group of atoms that has a positive or negative charge because it has lost or gained electrons

BASE A substance that releases hydroxide ions (OH-) in solution

pH SCALE Used to identify how acidic or basic a substance is

NEUTRAL When a liquid has a pH of 7

Acids and Bases Notes p. 21 TCAP Lesson 17

Acid A substance that releases hydrogen ions (H+) in solution, that is, when it is dissolved in water Acids can easily be recognized by their chemical formula Acids generally have formulas that start with H Examples: HCl (hydrochloric acid, found in the human stomach) and H2SO4 (sulfuric acid, found in car batteries

Acid Properties: taste sour, some are corrosive (nitric acid, sulfuric acid) pH < 7 Release H+ ions Turn blue litmus paper red React with certain metals to produce hydrogen gas

Base Substance that releases hydroxide ions (OH-) in solution Have chemical formulas that end in OH Examples: NaOH (sodium hydroxide or lye used in drain cleaners) Ca(OH)2 (calcium hydroxide, used fertilizer)

Base Properties: taste bitter, feel slippery pH > 7 Release OH- ions Turn red litmus paper blue

Properties of Both Acids and Bases Can cause burns if concentrated; must be handled with care Can conduct electricity when dissolved in water

pH Scale Used to identify how acidic and basic a substance is Numbered from 0 to 14 Less than 7 is an acid (lower pH stronger the acid) Higher than 7 is a base (higher pH stronger the base) When pH is 7, substance is considered neutral

Indicators Some substances that change color in the presence of an acid or a base These substances are called indicators because they can be used to indicate whether an unknown solution is an acid or a base Litmus paper is an example of an indicator

Acids and Bases HW p.20 TCAP Lesson 17 An unknown solution is tested using blue litmus paper. The blue litmus paper remains blue. What can be determined about the pH of the solution using this test? The pH is greater than 8 The pH is less than 7 The pH is greater than 5.5 The pH is 5.5 or less

Acids and Bases HW p.20 TCAP Lesson 17 2. Which of these substances is a base? a. vinegar b. lemon juice c. water d. liquid soap

Acids and Bases HW p.20 TCAP Lesson 17 3. An unknown substance is dissolved in water. The solution is corrosive, conducts electricity, and has a higher concentration of H+ ions than OH- ions. What kind of solution does this substance form? a. an acidic solution b. a basic solution c. a neutral solution d. There is no way to tell whether it is an acid or a base.

Acids and Bases HW p.20 TCAP Lesson 17 4. What is the MOST LIKELY pH of lemonade? a. 10 b. 8 c. 7 d. 4