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PhET Computer Simulation Activity: Acid-Base Solutions and pH Scale, Assignments of Chemistry

Lab on acid base solutions at cuny

Typology: Assignments

2020/2021

Uploaded on 12/17/2021

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PhET Computer Simulation Activity: Acid-Base Solutions and pH Scale
PhET Investigation of Acids-Bases
Name: Habiba Abdelafattah Elaaidy
Part A.
Introduction
1. Take a few minutes to play with the sim (http://phet.colorado.edu/en/simulation/acid-
base-solutions). Check out both the Introduction and Custom Solution tabs. Explore
what factors affect pH. List the factors you found that affect pH.
Investigating Concentration Changes
2. a. Create a strong acid solution in the “Custom Solution” tab.
b. Draw bar graphs for Initial and Equilibrium concentrations.
Hints: No calculator needed – try the ‘Equilibrium Concentration’ view.
Don’t forget to label your graphs!
Initial Concentrations Equilibrium Concentrations
c.
c. What equilibrium concentrations are affected by changing the initial concentration?
a.
H3O
3. a. Create a weak acid solution in the “Custom Solution” tab.
b. Draw bar graphs for Initial and Equilibrium concentrations.
Hints: No calculator needed – try the ‘Equilibrium Concentration’ view.
Don’t forget to label your graphs!
Initial Concentrations Equilibrium Concentrations
pf3
pf4
pf5

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PhET Investigation of Acids-Bases Name: Habiba Abdelafattah Elaaidy Part A. Introduction

  1. Take a few minutes to play with the sim (http://phet.colorado.edu/en/simulation/acid- base-solutions). Check out both the Introduction and Custom Solution tabs. Explore what factors affect pH. List the factors you found that affect pH. Investigating Concentration Changes
  2. a. Create a strong acid solution in the “Custom Solution” tab. b. Draw bar graphs for Initial and Equilibrium concentrations. Hints: No calculator needed – try the ‘Equilibrium Concentration’ view. Don’t forget to label your graphs! Initial Concentrations Equilibrium Concentrations c. c. What equilibrium concentrations are affected by changing the initial concentration? a. H 3 O
  3. a. Create a weak acid solution in the “Custom Solution” tab. b. Draw bar graphs for Initial and Equilibrium concentrations. Hints: No calculator needed – try the ‘Equilibrium Concentration’ view. Don’t forget to label your graphs! Initial Concentrations Equilibrium Concentrations

c. What equilibrium concentrations are affected by changing the initial concentration? H 3 O

  1. Are your results for the strong and weak acid in questions 2 and 3 consistent with the definition of strong and weak acids? Investigating the Effects of Acid Strength and Concentration
  2. a. What does the ‘strength’ slider (in the sim) effect? The amount of H 3 O and A- b. What does the term ‘strength’ mean? (In your own words) The concentration of H 3 O and A-^ compared to water
  3. How does strength affect the pH of acids? Makes it have a lower pH
  4. How does initial concentration affect the pH of acids? It dosnt (?)
  5. Is it possible for a solution of weak acid and a solution of strong acid to have the same pH? Design and carry out an experiment using the simulation to answer this question. What are your results? It is possible because Because strong and weak refer to their tendency to form H+ ions, not the concentration of those ions. pH is a measure of the concentration of hydrogen ions Strong and weak are descriptors used to

a. pH, [H 3 O+], [OH-], Product of [H 3 O+] & [OH-]

**2. Each row of the table will be for the 11 available substances.

  1. Using the pH Meter, measure and record the pHs of all 11 substances.** Questions
  2. What is the pH range for an acid? a. 0-
  3. What is the pH ranger for a base? a. 7-
  4. When is a solution is considered neutral? What pure substance has a pH of 7? a. pH 7 b. water
  5. What happens to the pH of the solution when more of the substance is added? a. If its the same substance it should stay the same.
  6. What happens to the pH of the solution when more of the substance is added? a. Becomes more neutral, as the solution gets more diluted.
  7. What does pH measure? (Research) a. pH is a measure of the relative amount of free hydrogen and hydroxyl ions in a solution.
  8. What basic equation is used to calculate the pH of a solution? (Research) a. pH = −log [H+] **Part III: Micro
  9. Switch over to the Micro Option of the simulation.
  10. Record the concentrations for the H 3 O+**^ and OH-^ ions for each solution in the data table. a. Use the following format : for 1.0 x10-7^ **type in 1.0 E-
  11. Calculate the product of the two ions ( [H 3 O+], x [OH-] ) and record in the table.** Questions
  12. What relationship exists between the concentration of the [H 3 O+], and [OH-]? a. More of H30 + ions in a solution means that solution has lower pH which implies it is an acidic solution. More of OH - ions means that solution has higher pH which implies that is a basic solution.
  13. Does adding water to a solution change the product of the two ions? a. Adding water to an acid or base reduces the concentration of ions in the solution.
  14. If the solution is acidic, which ion is found in greater concentration? a. OH- **Part IV: My Solution
  15. Check the ratio box.**

2. Slide the Red or Blue sliders up and down and observe what happens to the pH as well as the number of particles represented in the solution? Questions

  1. What happens to pH when the red slider increases (goes up)? a. Concentration of H 3 O+^ increases and therefore the solution becomes more acidic .
  2. What happens to the red particles (acid) when the red slider increases? a. They increase
  3. What happens to the blue particles (base) when the red slider increases? a. They deacrease `