Unit 6: Acids, Bases & the pH Scale A World of Liquids With Interesting Properties!
What is an Acid? • A substance that has an increased number of dissolved Hydronium ions, (H3O+) • When a Hydrogen ion (H+) bonds with a water molecule (H2O) • Hydronium is simply a water molecule with an extra hydrogen atom making it an ion+ • Acid comes from a Latin term acere, which means “sour”
What are the Properties of Acids? • Sour taste • React with metals to produce hydrogen gas • Change color of an indicator • Change blue litmus paper to red • Conduct electricity
What is a Base? • A substance that has an increased number of dissolved Hydroxide ions (OH-) • A substance that has less than 49% of Hydronium dissolved in it
What are the Properties of a Base? • Bitter taste • Slippery feel to them • Does NOT react with metals • Change color of an indicator • Change red litmus paper blue • Conducts electricity
What is a Strong Acid? • A substance that has ALL of the Hydronium ions dissolved in water • Note - • Strong acids don’t always mean the most corrosive
What is a Weak Acid? • A substance that only has a few molecules of Hydronium dissolved in water • Note - • Can be very corrosive, but not always
What is a Strong Base? • A substance that has ALL of the Hydroxide ions dissolved in water • Used mostly as household cleaners
What is a Weak Base? • A substance that only has a few molecules of Hydroxide dissolved in water • Most common in detergents/soaps.
What is a Neutralization Reaction? • When the H+ ions of an acid react with the OH- ions of a base to form water, which is neutral • 2 substances form from this reaction • Salt and Water
What is the pH scale? • A scale showing the concentration of Hydronium ions dissolved in water. • Each number represents a power of 10 • pH2 is 100 times more acidic than pH4
What are pH Indicators? • A substance that changes color in the presences of either an acid or a base. • Examples • pH paper • Litmus papers • Bromthymol blue
What are Salts? • Not necessarily table salt • An ionic compound formed from the neutralization of an acid and a base • Used for many products in society