pH Year 11

pH

Ms Anderson's Chemistry Class

This is a self driven lesson, you are required to engage in all activities and take notes.

Learning Goals

• Explain how pH is determined

• Use a pH scale to compare solutions

Multiple Select

Warm Up

Which compounds are water soluble?

•  $KCl$  

•  $CH_3OH$  

•  $Hexane\ \left(C_6H_{14}\right)$  

•  $NaNO_3$  

•  $KBr$  

pH

• The quantitative measure of the acidity or basicity of aqueous or other liquid solutions.

• Translates the values of the concentration of the hydrogen ion—which ordinarily ranges between about 1 and 10⁻¹⁴ gram-equivalents per litre—into numbers between 0 and 14.

Acidic

• When dissolved in water, an acid releases hydrogen ions (H+) and the solution becomes acidic

• If a solution has a high concentration of H+ ions, then it is acidic, with a low pH number.

• Many of our foods are acidic - oranges, apples, tomato sauce.

• Acids taste sour and feel "squeaky" when you rub your fingers together.

Basic/Alkaline

• When a base is mixed with water, it releases hydroxide ions (OH‐)

• If a solution has a high concentration of OH‐ ions, then it is basic, and has a high pH number.

• Many of our cleaning products are basic - windex, soap and bleach.

• Bases taste bitter and feel slippery.

What Makes an Acid or Base Strong?

• Strong acids and bases ionise almost completely in water, contributing many ions.

• Weak acids and bases ionise incompletely, contributing a few ions.

Multiple Choice

Which solution is more acidic?

• a solution with a pH of 4

• a solution with a pH of 2

Open Ended

Identify where water is situated on the pH scale and explain why.

Activity

Within your book or computer create your own pH scale.

Research the pH of the following solutions and place them on your pH scale:

Bleach

Blood

Milk

Water

Coffee

Battery Acid

Tomato Juice

Baking Soda