Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

10. Acids and Bases

The pH Scale

GOB Chemistry

10. Acids and Bases

The pH Scale

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2:12 minutes

Problem 39c

Textbook Question

Calculate the pH of each solution given the following:
c. [OH^-] = 1 × 10^-5 M

Verified step by step guidance

Step 1: Recall the relationship between pH, pOH, and the concentration of hydroxide ions ([OH⁻]). The formula to calculate pOH is:

pOH = - \log ({[OH]}_{-})

Step 2: Substitute the given [OH⁻] value (1 x 10⁻⁵ M) into the formula for pOH. This will give you the pOH of the solution.

Step 3: Use the relationship between pH and pOH, which is:

pH + pOH = 14

. Rearrange this equation to solve for pH:

pH = 14 - pOH

Step 4: Substitute the calculated pOH value from Step 2 into the equation for pH to determine the pH of the solution.

Step 5: Verify your result to ensure it makes sense. Since the [OH⁻] concentration is greater than 1 x 10⁻⁷ M, the solution is basic, and the pH should be greater than 7.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

pH Scale

The pH scale measures the acidity or basicity of a solution, ranging from 0 to 14. A pH of 7 is considered neutral, while values below 7 indicate acidity and values above 7 indicate alkalinity. The scale is logarithmic, meaning each whole number change represents a tenfold change in hydrogen ion concentration.

Hydroxide Ion Concentration

Hydroxide ions (OH⁻) are negatively charged ions that play a crucial role in determining the basicity of a solution. The concentration of hydroxide ions can be used to calculate the pOH of a solution, which is related to pH through the equation pH + pOH = 14. Understanding the concentration of OH⁻ is essential for calculating the corresponding pH.

Relationship Between pH and pOH

The relationship between pH and pOH is fundamental in acid-base chemistry. The pH is derived from the concentration of hydrogen ions (H⁺), while pOH is derived from hydroxide ions (OH⁻). The equation pH + pOH = 14 allows for the conversion between these two measures, enabling the calculation of pH when given the hydroxide ion concentration.

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