190 likes | 214 Views
Acids and Bases. Year 10. Acids are common Some are dangerous and can burn your skin Some are safe to eat and drink Stomach acid helps digest food. What are Acids?. explosion. Acids. Definition A group of compounds which behave similarly All have low pH Turn Litmus paper RED
E N D
Acids and Bases Year 10
Acids are common Some are dangerous and can burn your skin Some are safe to eat and drink Stomach acid helps digest food What are Acids? explosion
Acids • Definition • A group of compounds which behave similarly • All have low pH • Turn Litmus paper RED • All donate H+ ions in aqueous solution • Examples • Hydrochloric HCl • Sulfuric H2SO4 • Nitric HNO3 • Ethanoic CH3COOH
Acids • A dilute acid has lots of water and a small amount of acid • A concentrated acid has lots of acid and not much water so must be handled carefully • A strong acid releases lots of H+ • A weak acid releases fewer H+
What are Bases (Alkalis)? • In our home we often use bases to clean things. Eg Bleach and toothpaste • Some things are not acids or bases, we say that they are neutral. Eg Water
Bases • Definition • A family of compounds that behave similarly • Have a high pH • Turn litmus BLUE • All donate OH- • Examples • Ammonia NH3 • Sodium Hydroxide NaOH
Measuring acid strength? • To decide if something is an acid or a base we can use an indicator. • Litmus and Universal Indicator are examples of indicators. • They change colour depending on if they are in an acid or a base.
Working with Indicators • Red litmus turns BLUE in the presence of Bases • Blue litmus turns RED in the presence of acid • Acids and bases react together in a NEUTRALISATION reaction
Acid Reactions • Acid + Base Salt + Water • Acid + Metal Salt + Hydrogen • Acid + Carbonate Salt + Water + Carbon Dioxide • Hydrochloric acids (HCl) form CHLORIDE salts • Nitric acid (HNO3) forms NITRATE salts • Sulfuric acid (H2SO4) forms SULFATE salts
Acid Rain • Consider • Causes • natural • human • Effects • buildings • flora • fauna • health • Chemical equations • Prevention/Solution
Testing Gases • Hydrogen -
Testing Gases • Hydrogen - POP TEST • Explodes with a squeaky pop • Carbon Dioxide –
Testing Gases • Hydrogen - POP TEST • Explodes with a squeaky pop • Carbon Dioxide – Limewater goes cloudy • Oxygen –
Testing Gases • Hydrogen - POP TEST • Explodes with a squeaky pop • Carbon Dioxide – Limewater goes cloudy • Oxygen – Relights a glowing splint
Antacid Investigation • NZ facts 2007 • 70% population get heartburn /GERD • $9m on 1 brand! • 3rd most widely prescribed medicine • Which brand is the best?
Rates of Reaction • Factors increasing the rate of reaction • Surface area • Concentration • Temperature • Catalyst/Enzyme • Pressure
Metals/periodic table • , Element, compound, exo/endo