Earth ScienceBell Work: Energy Structure of Life Space

Vers. 07/2020 © Kesler Science, LLC

Earth Science

Energy

Structure of Life

Space

Force and Motion

Ecosystems

Weather

Chemistry

Body Systems

Bell Work:

What are the two types of pure substances? What are the two types of mixtures? Give an example of each.

Vers. 07/2020 © Kesler Science, LLC

Acids and BasesPresented by Kesler Science

© Kesler Science, LLC

Acids and Bases

Essential Questions:

Reflect on the Essential Questions before you dive in…

1. If you were quizzed today, which questions would you know the answers to already?

2. Which questions would you need to learn more about to answer confidently?

1. What are the differences between acids and bases?

2. How are ions related to acids and bases?

3. How do you test for acids and bases using pH?

Type your answer here



Acids and Bases

• A solution that has an excess of H+ ions.

• From the Latin word acidus, which means “sharp” or “sour”

• Characteristics

• Taste sour

• React strongly with metals

• Dangerous and can burn your skin

• Turns blue litmus indicator red

• Increase H+ ion concentration in solution

Acids

Source: Kanesskong/CC BY-SA. wikipedia/commons/b/b3/Blue_and_Red_litmus_papers_in_acid_solution.jpg

Look at the characteristics and brainstorm examples of common acids.



Acids and Bases

• Acetic acid – vinegar

• Acetylsalicylic acid – aspirin

• Ascorbic acid – vitamin C

• Carbonic acid – soft drinks

• Citric acid – citrus fruits, artificial flavorings

• Hydrochloric acid – stomach acid

• Nitric acid – fertilizer, explosives

• Sulfuric Acid – car batteries

Acids Uses


Acids and Bases

• A solution that has an excess of OH- ions.

• Another word for base is alkali or alkaline

• Characteristics of bases

• Bitter taste

• Slippery feel

• Strong bases are very dangerous and can burn your skin.

• Turns red litmus indicator blue

• Increase OH- ion concentration in solution

Bases

Source: Kanesskong / CC BY-SA. wikipedia/commons/5/58/Blue_and_red_litmus_papers.jpg

Look at the characteristics and brainstorm examples of common bases.



Acids and Bases

• Ammonium hydroxide – glass cleaner

• Aluminum hydroxide – antacids, deodorants

• Magnesium hydroxide – laxatives, antacids

• Sodium bicarbonate – baking soda

• Sodium carbonate – dish detergent

• Sodium hydroxide – lye, oven and drain cleaner

• Sodium hypochlorite - bleach

Bases Uses


Acids and Bases

• There are many strong acids and bases in nature.

• Fruits contain citric acid.

• Some are dangerous and used as poisons by insects and animals.

• Many plants have acids and bases in their leaves, seeds, or even their sap.

Acids and Bases in Nature


Acids and Bases

• Our stomachs use hydrochloric acid to help digest foods, and also kills bacteria that causes us to get sick.

• Our muscles produce lactic acid when we exercise.

• Our pancreas releases a base into the small intestine to neutralize the acid.

Acids and Bases in BodiesProvide one example of an acid being beneficial to the human body.

Provide one example of a base being beneficial to the human body.



Think About It


Ashley has indigestion causing her stomach to be upset. You explained to her that indigestion occurs when the contents in the stomach are too acidic, and she would need to eat or drink something with a higher pH to neutralize the acid. Use the provided pH scale and provide a recommendation that could help with the indigestion. Be sure to explain your reasoning.

0 7 14

Soda

Orange Juice

Tap Water

Olives

Corn

Bottled Water

Green TeaType your answer here


Acids and Bases

• Chemist who came up with a way to define acids and bases in 1887

• Believed that acids were substances that produce hydrogen ions [H]+ in solution

• Bases were substances that produced hydroxide ions [OH]- in solution.

Svante Arrhenius


Acids and Bases

Sodium: Na Cation sodium [Na]+

Sodium loses 1 electron

Oxygen gains 2 electrons

Oxygen: O Anion oxygen:[O]2-

• Form when atoms lose or gain electrons to have full outer valence electron shells. (Octet rule)

• Remember electrons have a negative charge.

• Cations – lose electrons

+ charge

• Anions – gain electrons

- charge

Ions

Quick Action: INB


Acids and BasesBohr Model

# of valence

elections

Will give away (lose) valence elections

Will add (gain) extra elections

Study each element. Identify the number of valence electrons. Use (click and drag) the check marks below to identify which elements will gain electrons and which ones will lose electrons.

Hint: half or more add extra electrons (gain) half or less give away electrons (lose)


Acids and Bases

Hydronium ion[H3O]+

Hydroxide ion[OH]-

H

H H

H

O

O

• Hydrogen ions [H]+ in water mixed with acidic compounds form hydronium ions [H3O]+

• Hydrogen ions [H]+ in water mixed with basic compounds form hydroxide ions [OH]-

Ions in Acids and Bases


Acids and Bases

What determines an acid or a base?

waterSulfuric acid Hydronium ion

Hydrogen sulfate ion

Ammonia water Hydroxide ion

Ammonium ion

Ions in Acids and Bases (cont.)

• A substance is determined to be acidic or basic by placing its molecules in an aqueous (water-based) solution.

• If it releases a hydrogen ion [H]+ when it breaks down, it is acidic.

• If it releases a hydroxide ion [OH]- when it breaks down, it is basic.

ACID

BASE


Acids and Bases

Acid Base

H+

H+

OH-H+

H+

H+

H+

H+H+

OH-

OH-OH-

OH-

OH-

OH- OH-

H+

pH stands for the Power of Hydrogen. It is the measure of H+ ions in a solution.

Look at the images to the left. describe the differences between the acid and base.

Make sure not to peak at the following slide.



Acids and BasesLo

w p

H H

igh

pH

H+

H+

OH-H+

H+

H+H+

H+H+

OH-

OH-OH-

OH-

OH-

OH- OH-

H+

• Power of hydrogen

• A measure of the number of H+ ions in a solution.

• Lots of H+ ions, the pH is very low

• Lots of OH- ions compared to the number of H+ ions, the pH is high

pH

Don’t Peek! Slide this over when you have answered on the previous slide.


Acids and Bases

• Used to measure strength of acids and bases in a solution

• Spans from 0 to 14

• Middle point (pH7) is neutral (neither acid nor base)

• Greater than 7 = base (14 strongest)

• Less than 7 = acid (0 strongest)

pH Scale

What is the pH of tomato juice?

Would tomato juice be classified as an acid or a base?

What can you conclude about the concentration of H+ ions in tomato juice?




Quick Action: INB


Acids and Bases

1 2 3 4 5 6 7 8 9 10 11 12 13 14

( +) ( -)Drag the following terms to their correct location on the pH scale.

Strong Acid

Weak Acid

Strong Base

Weak Base

Neutral

Quick Action: INB


Acids and Bases

1 2 3 4 5 6 7 8 9 10 11 12 13 14

( +) ( -)

Complete the pH scale using the images on the left.

water


Acids and Bases

• A special type of compound that changes color as the pH of a solution changes.

• Tells the pH of the solution

• There are several different types of indicators.

Indicators

Think About It


Red cabbage juice contains a natural pH indicator that changes colors depending on the acidity of the solution. More acidic substances are red and pink in color, while basic solutions turn green and yellow. Can you think of a situation where have you seen indicators used? If not, describe a situation in which the use of an indicator could be helpful.


Last Look Acids and BasesThis or That

Let’s see if you can crack the code. You will need to identify if each

statement is describing an acid or a base.

(Hint: Slide the word over to reveal a number. You will need the number

for the secret code.)

7 High concentration of H+ ions 0

9 High concentration of HO- ions 1

2 A pH higher than 7 5

3A substance that has a “slippery”

feel or bitter taste. 8

4This is found in our stomachs to help

digest food and kill bacteria7

SECRET CODE:

ACID


ACID

ACID

ACID

ACID

BASE

BASE

BASE

BASE

BASE

Last Look Acids and BasesEarth Science

Energy

Structure of Life

Space

Force and Motion

Ecosystems

Weather

Chemistry

Body Systems

VIDEO

http://studyjams.scholastic.com/studyjams/jams/science/matter/acids-and-bases.htm

Give your best answer to...

1. Explain the differences in acids and bases.

2. Relate ions to acids and bases.

3. Explain how to determine an acid using the pH scale.

Check for Understanding




Still have questions?

Which essential questions do you still need help to understand?


Give your best answer to...

1. Explain the differences in acids and bases.

2. Relate ions to acids and bases.

3. Explain how to determine an acid using the pH scale.

Check for Understanding

Classwork:

Ph Gizmo; Due next class along with the reading assigned last week

Documents

Earth ScienceBell Work: Energy Structure of Life Space