Presentation on theme: "DO NOW Classify the following as either acid or base: Toothpaste Orange juice Bleach Grapefruit Vinegar dish soap Objective: 1)Define and describe general."— Presentation transcript:
DO NOW Classify the following as either acid or base: Toothpaste Orange juice Bleach Grapefruit Vinegar dish soap Objective: 1)Define and describe general properties of acids and bases. 2)Identify a neutralization reaction. KEY TERMS ACID INDICATORBASE NEUTRALIZATION SALT
Identifying Acids An acid is a compound that produces hydronium ions (H 3 O + ) when dissolved in water. Some general properties of acids include sour taste, reactivity with metals, and ability to produce color change in indicators.
Common Acids and their uses- pg 241 NameFormulaUse Acetic acidCH3COOHVinegar Carbonic acidH2CO3Carbonated Beverage Hydrochloric acidHClDigestive juices in stomach Nitric acidHNO3Fertilizer Phosphoric acidH3PO4Fertilizer Sulfuric acidH2SO4Car Batteries
General Properties of Acids Sour Taste ▫F▫Foods that taste sour usually contain acids ▫E▫Examples include lemons, limes, vinegar, and spoiled dairy products. ▫N▫Never test an acid by tasting Reactivity with Metals ▫R▫Reaction between an acid and a metal is a single- replacement reaction UUsing aluminum foil to cover tomatoes (spaghetti) will turn dark, may develop small holes Color Changes in Indicators ▫A▫An indicator is any substance that changes color in the presence of an acid or base. LLitmus paper BBlue litmus turns red in the presence of an acid DDrop an unknown solution on a blue litmus and it turns red= acid
Identifying Bases A base is a compound that produces hydroxide ions (OH-) when dissolved in water. Some general properties of bases include bitter taste, slippery feel, and ability to produce color changes in indicators. Do not react with metals- low reactivity with metals is not a general property because some bases have strong reactions with metals.
Common Bases and Their Uses- pg 242 NameFormulaUses Aluminum hydroxideAl(OH)3Deodorant, antacid Calcium hydroxideCa(OH)2Concrete, plaster Magnesium hydroxideMg(OH)2Antacid, laxative Sodium hydroxideNaOHDrain cleaner, soap production
General Properties of Bases Bitter Taste ▫Unsweetened chocolate and cough syrup without all the fruity flavoring Slippery Feel ▫Wet soap and many other cleaning products Color Change ▫Turn red litmus paper blue- will turn back to red with an acid ▫Phenolthalein (fee nol THAY leen) – another indicator. In a solution with a base, will turn red In solution with acid= colorless Flowers like hydrangeas contain natural indicator- tells if growing in acidic or basic soil Acidic soil= bluish-purple flowers Basic soil= pink
pH Scale Project As you know the pH scale ranges from 0 to 14 and it is an indication of whether a substance is an acid or a base. Your job is to create a pH scale that has 3 substances for each number on the pH scale. Things that I am looking for on the scale include the substance, a picture of it, and its actual pH. Below is an example. Notice that in parenthesis is the actual measured pH of the substance and there is a glass of tomato juice next to the word. Be creative with your scale (I do not want to see all of these on your scale). It can be vertical or horizontal.
Neutralization and Salts The reaction between an acid and a base is called neutralization. During neutralization, the negative ions in an acid combine with the positive ions in a base to form an ionic compound called a salt. At the same time the hydronium ions from the acid form with the hydroxide ions from the base to produce water.
Proton Donors and Acceptors Acids are called proton donors Bases are called proton acceptors Since water is neutral it can act as either a donor or an acceptor depending on what it reacts with
RECAP What is an acid? What are the properties? What is a base? What are the properties? What happens in a neutralization?
Objective: 1)define pH and relate it to hydronium ion concentration in a solution. 2)Define buffer and describe how a buffer can be prepared 3)Explain how electrolytes can be classified. Key Terms ▫pH Buffer Electrolyte DO NOW ▫Take out your homework
The pH Scale The pH of a solution is a measure of its hydronium concentration. The lower the pH value, the greater the H 3 O + ion concentration in solution is. The higher the pH value, the lower the H 3 O + ion concentration is.
Strong Acids When strong acids dissolve in water, they ionize almost completely. HCl is an example of a strong acid. After it dissolves, there are the same number of hydronium ions in the solution as there were molecules of HCl at the beginning.
Strong Bases Strong bases dissociate almost completely in water. ▫Dissociate- separation of ions in an ionic compound as the compound dissolves. Sodium hydroxide is an example of a strong base. ▫Dissociates into sodium and hydroxide ions.
Weak Acids Forms few hydronium ions in a solution Are closer to neutral on the pH scale
Weak Bases When dissolved in water, very little ionizes Equilibrium favors reactants.
Buffers A buffer is a solution that is resistant to large changes in pH. Prepared by mixing a weak acid and its salt or a weak base and its salt. A buffer can react with an acid and a base, therefore its pH remains relatively constant.
Electrolytes An electrolyte is a substance that ionizes or dissociates into ions when it dissolves in water. These solutions can conduct electric current. Electrolytes in sports drinks help restore the bodies balance of ions. Strong acids and bases are strong acids and bases are strong electrolytes because they disocciate or ionize almost completely in water.
RECAP What is the pH scale measuring? If the pH value is high, is the H 3 O + ion concentration high or low? What is a buffer? Why do athletes drink sports drinks with electrolytes in them? Objective: 1)define pH and relate it to hydronium ion concentration in a solution. 2)Define buffer and describe how a buffer can be prepared 3)Explain what electrolytes are and do