ACID,BASE AND SALTACID,BASE AND SALT

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IIN INDRIYATI IIN INDRIYATI

Biology Teacher of SMP 1 Biology Teacher of SMP 1 WonosariWonosari

A. Competence A. Competence Standard Standard : 5: 5. To understand the . To understand the characteristic characteristic of acid, base and salt of acid, base and salt B. Basic CompetenceB. Basic Competence : 5.1 To identify the : 5.1 To identify the characteristic of characteristic of

acid, base and salt by acid, base and salt by using using accurate tools and accurate tools and indicatorsindicators

Objective : Objective :

1. Student able to identify the characteristic of acid, 1. Student able to identify the characteristic of acid, base and base and

salt after do experimentsalt after do experiment

ACIDACID Acid is a substance that releases hydrogen Acid is a substance that releases hydrogen

ion ( Hion ( H++) when it’s dissolved in water and a ) when it’s dissolved in water and a negative ion will be formed according to the negative ion will be formed according to the following reaction :following reaction :

Acid HAcid H++ + negative ion + negative ion example :example : HCl H+ + Cl –HCl H+ + Cl – (Hydrochloric acid)(Hydrochloric acid) H2SO4 2H+ + SO42-H2SO4 2H+ + SO42- (Sulfuric acid)(Sulfuric acid)

Acid characteristicsAcid characteristics

There are corosive, meaning they can There are corosive, meaning they can destroy other materials including metal, destroy other materials including metal, marble, marble,

They have sour tasteThey have sour taste They can They can conduct electricityconduct electricity.. They can change blue litmus to red They can change blue litmus to red They have a They have a pH of less than 7pH of less than 7

Acids Affect Indicators, by Acids Affect Indicators, by changing their colorchanging their color

Blue litmus paper turns red in contact with an acid (and red paper stays

red).

Matters that contain acidMatters that contain acid

LemonLemon TomatoTomato VinegarVinegar ManggoManggo StarfruitStarfruit etcetc

Strong AcidsStrong Acids

Strong acids are very corrosive. They react Strong acids are very corrosive. They react with metals and can cause severe burns on with metals and can cause severe burns on the skin. They conduct electricity well.the skin. They conduct electricity well.

Strong acids:Strong acids:Hydrochloric HClHydrochloric HCl

Nitric HNONitric HNO33

Sulfuric HSulfuric H22SOSO44

Hydrobromic HBrHydrobromic HBr

Acids Acids have a have a

pH pH lessless

than 7than 7

Base Base Base is substance that releases hydroxide Base is substance that releases hydroxide ion (OH-) when it’s dissolved in water and ion (OH-) when it’s dissolved in water and positive ions are formed according to the positive ions are formed according to the following reactionfollowing reactionBase positive ion + OH-Base positive ion + OH-Example : NaOH Na+ + OH-Example : NaOH Na+ + OH-

Sodium hydroxideSodium hydroxide

NH4OH NH4+ + OH-NH4OH NH4+ + OH- Ammonium hydroxideAmmonium hydroxide

Base characteristicsBase characteristics

They caustic, meaning they can damage They caustic, meaning they can damage our skin or other materialsour skin or other materials

They feel smooth on our handThey feel smooth on our hand They have bitter tasteThey have bitter taste They can change red litmus to blueThey can change red litmus to blue

Bases Affect IndicatorsBases Affect Indicators

Red litmus paper turns blue in contact with a base (and blue paper stays blue).

Phenolphthalein turns purple in a base.

Bases Bases have a have a

pH pH greatergreater than 7than 7

Bases Neutralize AcidsBases Neutralize Acids

Milk of Magnesia contains magnesium hydroxide, Mg(OH)2, which neutralizes stomach acid, HCl.

2 HCl + Mg(OH)2

MgCl2 + 2 H2O

Magnesium salts can cause diarrhea (thus they are used as a laxative) and may also cause kidney stones.

Matters that contain baseMatters that contain base

SSoapoap DetergentDetergent ThootpasteThootpaste Baking sodaBaking soda Stomach medicineStomach medicine/ Antasid (obat perut)/ Antasid (obat perut) etcetc

Common BasesCommon Bases

Sodium hydroxide NaOHSodium hydroxide NaOH Calcium hydroxide Ca(OH)Calcium hydroxide Ca(OH)22

Magnesium hydroxide Mg(OH)Magnesium hydroxide Mg(OH)22

Ammonium hydroxide NHAmmonium hydroxide NH44OHOH

SALTSALT

Salt is formed by reaction between acid Salt is formed by reaction between acid and baseand base

The reaction between Acid and Base is The reaction between Acid and Base is called the neutralization reactioncalled the neutralization reaction

Acid + Base Salt + WaterAcid + Base Salt + WaterExample : NaClExample : NaClHCl (asam) + NaOH (basa) --------- NaCl HCl (asam) + NaOH (basa) --------- NaCl

(garam dapur) + H2O (air)(garam dapur) + H2O (air)

Measuring pHMeasuring pHWhy measure pH?Why measure pH?

Everyday solutionsEveryday solutions we use - everything we use - everything from swimming pools, from swimming pools, soil conditions for soil conditions for plants, medical plants, medical diagnosis, soaps and diagnosis, soaps and shampoos, etc.shampoos, etc.

Sometimes we can use Sometimes we can use indicatorsindicators, other times , other times we might need a we might need a pH pH metermeter

How to measure pH with wide-range paperHow to measure pH with wide-range paper

1. Moisten the pH indicator paper strip with a few drops of solution, by using a stirring rod.

2.Compare the color to the chart on the vial – then read the pH value.

Some of the Some of the many pH many pH

Indicators Indicators and theirand theirpH rangepH range

Acid – Base Indicators

Artificial indicators :- Lithmus paper- Universal indicator- Phenolphthalein- Red methil - Blue bromthymol

Natural indicators :- Hibiscus - Turmeric- Red cabbage- Mangosteen

SIFAT – SIFAT SENYAWA ASAM DAN BASA

Asam Basa

1, Rasa asam 1, Rasa pahit / getir

2, Korosif 2, Kaustik

3, Memerahkan lakmus biru 3, Membirukan lakmus merah

4, pH < 7 4, pH > 7

5, Tidak berwarna dengan indikator pp 5, Berwarna merah dengan indikator pp

6, Dapat menetralkan senyawa basa 6, Dapat menetralkan senyawa asam

Thank’s youThank’s you

See you next timeSee you next time Good byGood by