Presentation on theme: "Exploring Acids and Bases What are the properties of acids and bases?"— Presentation transcript:
Exploring Acids and Bases What are the properties of acids and bases?
Think About It Lemon juice is an acid. Soap is a base. Water is neither an acid nor a base. Think about it. Use the word bank to describe each property. Taste word bank: bitter, none, sour Feel word bank: burns, slippery, wet
Think Back Zn + 2HCl ZnCl 2 + H 2 When a metal was added to an acid what gas was released? Zn + 2NaOH Is the same gas released? Did a reaction occur? Zn + 2HOH Is the same gas released? Did a reaction occur?
Analyze This SubstanceConductivityForms ions in water Acid6(H) + Base7(OH) _ Water0No ions Decide if the substance conducts electricity.
The pH Scale Acid / base strength is a measure of relative H 3 O + and OH - concentrations. Acidic solutions have concentrations of H 3 O + above 1 X 10 -7 Neutral solutions have H 3 O + concentrations equal to 1 X 10 -7 Basic solutions have H 3 O + concentrations less than 1 X 10 -7 A neutral solution has a pH of 7, acidic solutions have pH below 7, and basic solutions have pH above 7. Each division of the pH scale is an increase or decrease in concentration to a power of 10, which makes the scale a logarithmic scale
The pH increases as the acidic strength of these substances decreases from left to right. Did you know that lemon juice is more acidic than vinegar? That a soft drink is more acidic than orange juice or grapefruit juice?
The pH Scale Strong and Weak Acids and Bases Strong acids ionize completely in water Weak acids ionize only partially in water Strong bases ionize completely in water. Weak bases ionize only partially in water.
Lab Cautions Wear goggles while testing the chemicals. Do not taste the chemicals. Be careful not to spill the chemicals.
Litmus Test Dip a piece of blue litmus paper in the liquid labeled acid. Dip a piece of red litmus paper in the liquid labeled base. Dip a piece of red litmus paper in the liquid labeled water. Repeat using blue litmus paper. Write the results in the appropriate box of the table.
Carbonate Test Add a small amount of sodium bicarbonate to the liquid labeled acid. Add a small amount of sodium bicarbonate to the liquid labeled base. Add a small amount of sodium bicarbonate to the liquid labeled water. Was there a chemical reaction? Write the results in the appropriate box of the table.
Properties of Acids and Bases PropertyAcidWaterBase TastesourNonebitter FeelburnsWetslippery React with metalYesNo Conduct electricity YesNoYes Litmus ColorredNo Changeblue React with carbonate YesNo
Properties of Acids and Bases PropertyAcidWaterBase Taste Feel React with metal Conduct electricity Litmus Color React with carbonate
Properties of Acids and Bases The properties of acids are: Sour taste Change blue litmus paper to red. React with metals to release hydrogen gas. Neutralize bases, forming water and salts The properties of bases are: Bitter taste Bases turn red litmus paper blue. Feel slippery to the skin. Neutralize acids, forming water and salts.