pH, Acidic and Basic Solutions

Acids Acids are substances that release positively charged hydrogen ions, H+, in the water. H+ will combine with water releasing a positively charged ion called hydronium (H3O)+ HYDRONIUM ions + charge - HYDROCHLORIC ACID HCl + H2O -----> (H3O)+ + Cl-

Bases Bases are substances that release negatively charged hydroxide ions, OH-, in the water. NaOH +H2O ---------> Na+ + OH- + H2O SODIUM HYDROXIDE H= and OH- is VERY IMPORTANT!!!!!!

Strengths of Acids and Bases The strength of an acid depends on how easily the acid will release H+ (hydrogen) ions when in water The strength of a base depends on how easily the base will release OH- (hydroxide) ions when in water

Indicators Indicators are compounds that react with acidic and basic solutions and produce certain colors, depending on the solution’s pH. Indicators help you determine the pH of a solution.

*Litmus paper is an indicator It shows if a substance is an acid or a base: Red litmus paper in a base solution turns blue Blue litmus paper in an acid turns red

3 *Universal Indicator Gives you more information than the Litmus paper because gives you the pH value of the substance

pH and pH Scale pH is a measure of how acidic or basic a solution is and depends on the concentration of hydronium and hydroxide ions. “pH stands for percentage hydrogen”

pH and pH Scale The pH scale ranges from 0 to 14. Acidic solutions have pH values below 7. A solution with a pH of 0 is very acidic. A solution with a pH of 7 is neutral. Basic solutions have pH values above 7.

Mini Lab 1: Litmus paper In groups. Each group has 2 substances ( vinegar and ammonia), 2 strips of red litmus paper and 2 strips of blue litmus paper. Dip one red strip and one blue inside each one of the substances and record your results on a table. VINEGAR, WATER, baking soda solution , milk of magnesia , ammonia

Mini Lab 1: Litmus paper Ammonia Soda Red color ? Blue Acid or Base? ? VINEGAR, WATER, baking soda solution , milk of magnesia , ammonia

Mini Lab: Write a paragraph explaining why you obtained such results and if the substances you tested are acids or bases . Explain what is the role of the paper you used during the experiment and why did it changed color. VINEGAR, WATER, baking soda solution , milk of magnesia , ammonia

Mini Lab 1: Litmus paper Ammonia Soda Red Turn blue Stay red Blue Stay blue Turn red Acid or Base? base acid VINEGAR, WATER, baking soda solution , milk of magnesia , ammonia

*Properties of Acidic Solutions -sour taste -can conduct electricity because it has ions -are corrosive, which means they break down -certain substances. Many acids can corrode fabric, skin, and paper. -react strongly with certain metals.

Uses of Acids Acetic Acid - vinegar and salad dressings Citric Acid in limes, lemons and oranges Ascorbic acid – vit C Sulfuric acid - fertilizers, steel, paints, and plastics. Acids – batteries

Properties of Basic Solutions Slippery Bitter taste Bases are corrosive. can conduct electricity ( have ions) Basic solutions are not as reactive with metals as acidic solutions are.

Uses of Bases soaps, ammonia, and many other cleaning products Chalk is basic Blood is basic

Neutralization *Neutralization is the chemical reaction of an acid with a base. Ex: NEW SUBSTANCES WILL FORM ACID AND BASE ARE NOT THERE ANYMORE, new substances will not release Hydrogen ion and hydroxide ion, new substances are neutral It is a chemical reaction because new substances are being formed ( salt and water)

*How does neutralization occur? Recall that every water molecule contains two hydrogen atoms and one oxygen atom. The reaction of a base and an acid results in water and a salt . Water has a neutral pH. It is called neutralization because the acid and the base are not there anymore……. HCl + NaOH  NaCl + H20 ( neutral) BOOK MAKES IT TOO COMPLICATED ….. NOTES ARE WHAT YOU SHOUL KNOW

Lab: Creating a pH scale