Regents Chemistry (High School): What is the pH scale?
Assessment: pH scale
(these are just questions based on the paragraphs we read on the slides)
9. A pH of 1 is how much more acidic than 5?
10,000 10^5 = 100,000 10^1 = 10 100,000 - 10 = 99,990 AROUND 10,000
7. Because the pH scale is exponential, it is always changing by a power of __ when you increase or decrease whole numbers.
10
2. On the pH scale, which number identifies a neutral substance?
7
5. What is another word for base?
Alkalinity.
1. On the pH scale, where can you find the most dangerous acids and base?
At the end of the scale, acids = 0-6 and bases = 14.
On the pH scale, where can you find the weaker bases?
By looking at the middle of the pH scale, which is around 7 (the green part of the scale).
3. Which is a basic substance, black coffee or eggs?
Eggs
10. A solution that is basic has more of which types of ions?
Hydroxide.
pH of 7
In the middle of the pH scale is the number 7. Substances that have a pH of this number are neutral. This means they are neither an acid nor a base. Pure water is an example of a neutral substance. Substances with this pH are completely fine to be consumed, in fact water is something we need to consume to live a healthy life.
Water has a pH of 7. What does this tell us about the substance?
It tells us that water is a neutral substance.
Neutralization
Like in the example above, neutralization is when an acid and a base work against one another. Some substances are formed when an acid and base react with one another. An example of this is salt. Salt can be formed when certain acids and based are mixed together. Salt is a neutral substance.
3. A pH of 4 compared to a 6?
More Hydrogen ions.
2. Water is considered to be?
Neutral.
pH of 0-6.9
On the left side of the scale, ranging from 0-6.9 are acidic solutions. Solutions that are the most acidic are located at the end. These substances can be reactive and very dangerous. One of the most acidic substances is battery acid. While battery acid is helpful to us by providing energy, it is important to understand that not all acids can be tasted or touched. You should never touch or taste an unknown substance. Hydrochloric acid is another example of a strong acid. While it is in our stomachs to help us digest food, it should not be touched with our bare hands when using it in a lab. Substances near this end of the scale can be identified by a dark red color. As the scale progresses to 7, the solutions become less acidic. The colors of the scale changes from orange, to yellow, to green. You will notice looking at the scale that as you move toward the center of the scale, you will come across acidic substances that you can eat or drink such as soda and lemons.
pH fo 7.1-14
On the right side of the scale are the basic solutions. Just like acids, strong basic solutions can be found toward the ends of the scale. Solutions with a pH of 14 are extremely dangerous. Liquid drain cleaner is an example of solution with a pH of 14. While it is useful to clear a clogged drain, it can be harmful if consumed or touched. Drain cleaner can irritate or burn your skin if touched. Substances with this pH are shown as the color purple. As you move toward the center of the scale the colors range from blue to green. Looking at the examples of bases, you will notice that most of them are used in cleaning. Unlike acids, many bases are not substances that we eat or drink. Milk of magnesia has a pH of 10. Milk of magnesia is an example of something people will drink. It is an antacid. People will drink this when they have an upset stomach. The antacid counteracts the acids in your stomach to make you feel better again. When an acid and a base work against one another, they cancel each other out or neutralize each other.
5. Which substance is more acidic, oranges or bananas?
Oranges
1. What does pH scale mean?
Power of Hydrogen.
Aqueous
Something was dissolved in water.
6. What would happen if you mixed coffee with toothpaste?
The coffee would stain your teeth even more and the toothpaste would not have a clean affect.
What does the dark red color tell you about substances on the pH scale?
The dark red color tells us that the substances on the scale are acids and can be very dangerous.
What is the pH scale?
The pH scale is a scale that is used to measure how acidic or basic a liquid is. The scale ranges from 0-14.
4. Why should you never taste or touch an unknown substance?
The unknown substance can be harmful to our bodies.
What is a ph scale?
To measure how acidic or basic a liquid is.
What is neutralization?
When an acid and a base work against one another.
6. a. A substance with a pH of 4 is considered? b. A substance with a pH of 9 is considered?
a. Acidic. b. Basic.
4. A pH of 1 is considered __ acidic than a pH of 4.
more
8. This means that a pit of 3 would have __ .
more Hydrogen ions (H +) than Hydroxide ions (OH -).
Edpuzzle Notes:
n/a