pH and Water Lab Flashcards
What is the PH of a solution?
Measure of its Hydrogen ion (H+) concentraion
What is a neutral PH?
A solution with the same amount of H+ as pure water (PH 7) is neutral
Solutions with more H+ than water are given higher or lower PH values? What are they defined as?
They have lower PH values and they are defined as acidic.
Solutions with less Hydrogen ion (H+) concentration are given higher or lower PH values? What are they defined as?
Higher PH values. Defined as basic or alkaline.
What is the pH Scale?
0-14
0, 1, 2, 3, 6, 7, 8, 9, 14. What is the quality and what is a comparable substance?
0 is most acidic in quality. 1 is battery acid , 2 stomach acid, 3 vinegar, as comparable substances.
6 is least acidic, saliva comparable substance.
7 is neutral, pure water being a comparable substance.
8 is least basic, sea water being a comparable substance.
9, comparable substance intestinal fluids.
14 is most basic, comparable substance lye (Drano) drain cleaner.
The concentrations of hydroxyl ion (OH-) are equal to what substance? What are they decreased/increased of?
Concentrations of the hydroxyl ion (OH-) equal hydrogen ion concentration in pure water. They are decreased in acids and increased in bases.
What does a strong acid have a high and low concentration of?
A high concentration of H+ and a low concentration of OH-.
What does a strong base have a high and low concentration of?
A low concentration of H+ and a high concentration of OH-.
What do pH values represent in terms of changes?
They represent ten-fold changes in ion concentration.
Are water molecules polar or nonpolar?
Polar.
What does polar mean?
Slight electrochemical charges at each of their four poles, two negative charges on the oxygen atom, and a positive charge on each of the two hydrogen atoms.
How does a weak hydrogen bond get formed?
A positive charge on one water molecule forms a weak hydrogen bond with a negative charge on another water molecule. Each water molecule forms four hydrogen bonds with other water molecules.
What did we do in the lab regarding testing pH paper?
There were liquid solutions of a variety of household substances on the lab counter tops. We used strips of pH paper with forceps (tweezers) in the solution because the salt on our fingertips could have misconstrued the results of the pH, which produces incorrect results. We recorded these results and placed the used paper strips in the used pH paper container.
How did we do the buffer experiment?
We poured 10 ml of milk into a 30 ml beaker and 10 ml of tap water into another. We measured the pH of each using the same pH paper we had had used, and recorded the results. We added 5 drops of hydrochloric acid (HC1) to each beaker and stirred and measured their pH’s again. Concluding this experiment, we added 10 drops of a weak base called sodium hydroxide, NaOH to each beaker and stirred and measured the pH again.