ACIDS AND BASESEVERYDAY REACTIONS

WHAT ARE ACIDS?

• AN ACID IS A CHEMICAL THAT REACTS WITH A BASE TO PRODUCE A SALT AND WATER.

• SOME ACIDS ARE STRONG AND SOME ARE WEAK

• STRONG ACIDS CAN BE DANGEROUS IF NOT HANDLED CORRECTLY E.G. HYDROCHLORIC ACID

•WEAK ACIDS CAN BE SAFE ENOUGH TO EAT AND DRINK E.G. CITRIC ACID IN FRUIT

PROPERTIES OF ACIDS

•ALL ACIDS HAVE A SOUR TASTE

• THEY ARE HYDROGEN ION DONORS

• THEY ARE CORROSIVE

•REACT WITH A BASE TO NEUTRALISE IT

ACIDS AND METALS

•ACIDS CAN CORRODE METALS BREAKING THEM DOWN INTO HYDROGEN GASACID + METAL A SALT + HYDROGEN GAS

ACIDS AND CARBONATES

•WHEN THE BASE IS A CARBONATE THE REACTION BETWEEN IT AND AN ACID PRODUCES CARBON DIOXIDE AS WELL AS A SALT AND WATER

ACID + CARBONATE A SALT + WATER + CARBON DIOXIDE

WHAT IS A BASE?

•A BASE IS A CHEMICAL THAT REACTS WITH AN ACID TO PRODUCE A SALT PLUS WATER

•STRONG BASES CAN BURN LIKE STRONG ACIDS, BUT WE SAY STRONG BASES ARE CAUSTIC

PROPERTIES OF BASES

• THEY TASTE BITTER

• THEY ACCEPT HYDROGEN IONS

• THEY NEUTRALISE ACIDS PRODUCING A SALT AND WATER

• THEY FEEL SLIPPERY

ACID TEST

• TO TEST IF A SUBSTANCE IS AN ACID OR A BASE, YOU ARE BETTER OFF USING AN INDICATOR THAN TRYING TO TASTE IT TO SEE IF IT IS SOUR OR BITTER

• THERE ARE A VARIETY OF DIFFERENT INDICATORS TO USE TO TEST ACIDS AND BASES SUCH AS:

• LITMUS PAPER WHICH TURNS RED IN AN ACID AND BLUE IN A BASE

• PHENOLPHTHALEIN WHICH WILL BE BRIGHT PINK IN BASIC SOLUTIONS BUT COLOURLESS IN ACIDIC SOLUTIONS

MEASURING pH

• THE INDICATORS GIVE US A COLOUR TO TELL US WHETHER A SUBSTANCE IS AN ACID OR A BASE, BUT THE COLOUR CAN ALSO GIVE US MORE INFORMATION.

• THE COLOUR MAY ALSO INDICATE HOW STRONG OR WEAK THE ACID OR BASE IS

•BY USING THE pH SCALE WHERE NUMBERS HAVE BEEN ALLOCATED TO PARTICULAR COLOURS WE CAN DETERMINE THE STRENGTH OF THE ACID OR BASE WE ARE DEALING WITH

• THIS IS DONE USING UNIVERSAL INDICATOR

EXPLAINING ACIDS AND BASES•ACIDS HAVE SPECIAL PROPERTIES DUE TO HYDROGEN IONS H+

•WHEN A BASE DISSOLVES IN WATER IS FORMS HYDROXIDE IONS OH-

• THE STRENGTH OF AN ACID DEPENDS ON HOW EASILY IT CAN BREAK UP INTO H+ IONS, IF IT HAS A LOT OF IONS IT IS A STRONG ACID, IF IT HAS A FEW IT IS A WEAK ACID

• THE SAME GOES FOR A BASE; IF THE BASE CAN EASILY BREAK UP INTO OH- IONS THEN IT IS A STRONG BASE, AND IF IT CANNOT IT IS A WEAK BASE

NEUTRALISATION

•NEUTRALISATION IS THE REACTION WHERE AN ACID AND A BASE CANCEL EACH OTHER OUT TO FORM A SALT AND WATER

ACID + BASE A SALT + WATER

• EVERYDAY EXAMPLES OF THESE TYPES OF REACTIONS COULD BE USING ANTACIDS FOR INDIGESTION