Introduction to Acids & Bases Phet

Introduction to Acids & Bases Phet

Name ______Date:______Period:______

Introduction to Acids & Bases – PhET

Go to the PhET simulation named “pH scale.” Take a few moments to play around with the simulation to see what the various buttons are.

https://phet.colorado.edu/en/simulation/ph-scale

Choose the “Macro” screen.

Part 1

1. Look at the scale to the left.

A. What does it measure? ______

B. Which numbers represent an acidic solution? ______

C. Which numbers represent a basic solution? ______

D. A solution that is neither acidic nor basic is called “neutral”. What is the pH of a neutral solution? ______

2. Look at the list of solutions. Choose four different solutions and list the pH and indicate if the solution is acid, basic, or neutral.

Solution / pH / Acidic/Basic/Neutral

Go to the “Micro” Screen

Part 2

  1. Check the box entitled “H3O+/OH- ratio.“ Red dots represent hydronium (hydrogen) ions while blue dots represent hydroxide ions. Adjust the pH slider up and down, observing how this changes the number of each type of ion.

(A) As you raise pH, which type of ion concentration increases?

(B) As you lower pH, which type of ion concentration increases?

(C) Based on your observations, what does a high (greater than 7) pH indicate?

(D) What does a low (lower than 7) pH indicate?

  1. Reset the simulation. Check the box entitled “Molecule Count.”

(A) From the drop down menu in the top right, select “vomit” (pH 2.0) and record the number of hydronium ions. ______

(B) Then, select “battery acid” (pH 1.0) and record the number of hydronium ions. ______

(C) Determine how many times more concentrated battery acid is than vomit. To do this, divide the number of hydronium ions in battery acid by the number of hydronium ions in vomit (use a calculator):

Battery acid is ____times more concentrated than vomit

  1. Reset the simulation. Check the box entitled “Molecule Count.”

(A) From the drop down menu, select “drain cleaner” (pH 13.0) and record the number of hydroxide ions. ______

(B) Then, select “hand soap” (pH 10.0) and record the number of hydroxide ions. ______

(C) Determine how many times more concentrated drain cleaner is than hand soap. In this case, you are dealing with basic solutions. Adjust your calculations accordingly.

Drain cleaner is ____times more concentrated than hand soap.

Part 3

  1. What happens to the pH of acidic solutions as you add water?
  1. What happens to the pH of basic solutions as you add water?
  1. In general, when we dilute and acid or a base, the pH always moves toward what pH value?
  1. Did an acid ever become a base or did a base ever become an acid? Why do you think so?
Top View