Many ways to classify compounds Are they ionic or covalent? A common method is to separate into ACIDS and BASES. INTRODUCTION. We see, use, and eat acids everyday Sour grapefruit Tart taste of carbonated drinks Tangy taste of salad dressing. acids.
Acidic juices are added to food to improve tasteand help absorb nutrients
Stomach acid helps us digest food
eggs and baking soda
pH Scale: a number scale for measuring how acidic or how basic a solution is
Acids: have a pH of less than 7 when dissolved in water
Bases: have a pH of more than 7 when dissolved in water
Neutral: has a pH of 7 (not an acid or a base)
neither acidic nor basic
to 7.5 (slightly basic)
1 unit of change represent a 10 times change in the degree of acidity/basicity
Q: What is the increase in acidity if the pH drops from 6 to 4?
A: A 2 unit drop is a 10² or 100 times increase in acidity!
IMPACT: Even a small increase in acidity harms coral reefs and organisms that require a specific pH level to survive (ex. organisms that use calcium to make their shells)
Many common acids and bases form colourless solutions (look like water)
pH Indicators: chemicals that change colour depending on the pH of the solution they’re placed in
So what are some common indicators you could use?
Contains many indicators that turn different colours depending on a solution’s pH
Uses a digital pH meter or pH computer probe to measure the electrical property of the solution, determining its pH
Can sometimes identify acids by their chemical formulas
Many compounds (HCl) take on acid properties after mixing with water
Ex.: HCl dissolved in water is written as HCl (aq), where (aq) means “aqueous” or “dissolved in water to make a solution
Ex.: Hydrogen carbonate carbonic acid
Ex.: Hydrogen sulphite sulphurous acid
release ions in solution.