Presentation on theme: "Chapter 6.3 Acids, Bases, and pH. What are acids? substances that give up (donate) hydrogen ions when you dissolve them in water. the donated hydrogen."— Presentation transcript:
What are acids? substances that give up (donate) hydrogen ions when you dissolve them in water. the donated hydrogen ions H+ become bonded to water molecules, turning into H 3 O + ions, called hydronium ions.
Indicators substances you add to see if something (another substance) is an acid or a base. pink (usually called red, but it really isn’t) turns blue when substance is a base blue litmus turns pink (“red”) when acid pH paper turns various colors, which indicate strength of acid or base
Other indicators Red Cabbage Juice - stinks, but makes really great colors that tell us whether substances are acids or bases.
Indicator If you miss the indicator lab planned for section 6.3, be sure you get the results from another student, or Mrs. Peterson.
pH scale 0-14 7 is neutral - not an acid, not a base distilled water is neutral below 7 is acidic lower the number, the stronger the acid above 7 is basic higher the number, the stronger the base
Neutralization reaction What do you do when you have some strong acid and don’t want it anymore? Pour it down the drain? Bad idea. Equally bad idea would be pouring a strong base down the drain. Both acids and bases can really do damage to materials.
Neutralization to the rescue! But if you add an acid and a base together, look what happens - HCl + NaOH ----> NaCl + H 2 O
Neutralization Now instead of two substances that could harm your plumbing pipes, HCl (hydrochloric acid) and NaOH, sodium hydroxide), you’ve combined them and they form harmless NaCl, a salt, and water.
Salt Note: NaCl is what we call salt in everyday life. But it’s just an example of what chemists call “salt”- in chemistry A SALT IS A COMPOUND FORMED WHEN YOU COMBINE AN ACID AND A BASE.
Salt Text definition: an ionic compound composed of cations bonded to anions. The anion comes from the acid (HCl gives up Cl - ) The cation comes from the base (NaOH gives up Na + ) Now the H from the acid and the OH from the base get together to form H-OH, or H 2 O
Neutralization You will not completely neutralize an acid and a base unless you have just the right amounts and just the right strengths. This makes sense. If you had a large amount of some really strong acid, obviously throwing a few Tums (antacid) into the acid isn’t going to help much!
Home safety DO NOT mix home cleaning products unless you know exactly what is in them. Mixing: Ammonia and bleach or Vinegar and bleach produce dangerous substances!