Ph And Poh Worksheet Answers

Understanding pH and pOH is crucial in chemistry, particularly in understanding the nature of acids and bases. The relationship between pH and pOH is inversely related; as the pH increases, the pOH decreases, and vice versa. Here’s a detailed explanation and examples to illustrate the concepts and solve problems related to pH and pOH.

Understanding pH and pOH

• pH is a measure of the concentration of hydrogen ions (H+) in a solution, indicating its acidity or alkalinity. A pH of 7 is neutral (neither acidic nor basic), below 7 is acidic, and above 7 is basic.
• pOH is a measure of the concentration of hydroxide ions (OH-) in a solution. It is used to express the basicity of a solution.

The relationship between pH and pOH is given by the equation:

[ \text{pH} + \text{pOH} = 14 ]

at room temperature (25°C or 298 K).

Calculating pH and pOH

To calculate pH and pOH, you need to know the concentration of hydrogen ions (H+) for pH or hydroxide ions (OH-) for pOH.

• The formula for pH is: [ \text{pH} = -\log[\text{H}^+] ]
• The formula for pOH is: [ \text{pOH} = -\log[\text{OH}^-] ]

Where ([\text{H}^+]) and ([\text{OH}^-]) are the concentrations of hydrogen ions and hydroxide ions, respectively, in moles per liter (M).

Worksheet Examples

1. Given pH, find pOH

If the pH of a solution is 4, find its pOH.

Solution: Using the equation ( \text{pH} + \text{pOH} = 14 )

[ 4 + \text{pOH} = 14 ] [ \text{pOH} = 14 - 4 = 10 ]

1. Given pOH, find pH

The pOH of a solution is 9. Calculate its pH.

Solution: Using the equation ( \text{pH} + \text{pOH} = 14 )

[ \text{pH} + 9 = 14 ] [ \text{pH} = 14 - 9 = 5 ]

1. Given [H+], find pH and pOH

The concentration of hydrogen ions in a solution is ( 1 \times 10^{-5} ) M. Find the pH and pOH of the solution.

Solution:

For pH: [ \text{pH} = -\log(1 \times 10^{-5}) ] [ \text{pH} = 5 ]

To find pOH, we use the relationship: ( \text{pH} + \text{pOH} = 14 )

[ 5 + \text{pOH} = 14 ] [ \text{pOH} = 14 - 5 = 9 ]

1. Given [OH-], find pH and pOH

The concentration of hydroxide ions in a solution is ( 1 \times 10^{-9} ) M. Find the pH and pOH of the solution.

Solution:

For pOH: [ \text{pOH} = -\log(1 \times 10^{-9}) ] [ \text{pOH} = 9 ]

To find pH, we use the relationship: ( \text{pH} + \text{pOH} = 14 )

[ \text{pH} + 9 = 14 ] [ \text{pH} = 14 - 9 = 5 ]

Important Notes

📝 Note: The values of pH and pOH can vary slightly with temperature, but for most purposes, especially in introductory chemistry, the relationship pH + pOH = 14 is used as a reliable approximation at room temperature.

Summary

Calculating pH and pOH involves understanding the concentration of hydrogen and hydroxide ions in a solution and applying the formulas for pH and pOH. The relationship between pH and pOH provides a quick method to find one if the other is known. These calculations are fundamental in understanding the nature of acids and bases and are widely applied in various fields of science and engineering.

FAQ

Related Terms:

• pH Practice Worksheet answers
• pH Worksheet pdf
• pH and pOH formulas
• pH Calculations PDF