# Calculating Hydrogen Ion Concentration & PH by Yonderboy98

• Yonderboy98
In summary, the person is comfortable with the formal definition of pH and logarithms, but still has trouble with actual calculations. They ask for help on how to calculate hydrogen ion concentration for different pH values. The answer is that [H+] = 10-pH and pH = -log([H+]).
Yonderboy98
I know what the formal definition of ph is, and I am comfortable with logarithms, anti-logs, and the laws of exponents. Still, I get confused doing actual calculations and would greatly appreciate your input on the following:
Suppose something has a ph of 3.5-How do you calculate the hydrogen ion concentration?
Suppose something has a ph of 7.2- How do you calculate the hysdrogen ion concentration?
Suppose that something has a hydrogen ion concentration of 2.8 times ten to the minus 15-How do you calculate its ph?
Suppose that something has a hydrogen ion concentration of 3.6 times ten to the minus 9-How do you calculate its ph? Yonderboy98

[H+] = 10-pH
pH = -log([H+])

That's all.

's guide provides a helpful overview of calculating hydrogen ion concentration and pH. To answer your questions, we can use the following equations:

1) To calculate the hydrogen ion concentration from pH, we use the formula [H+] = 10^(-pH). In this case, for a pH of 3.5, the hydrogen ion concentration would be 10^(-3.5) = 3.16 x 10^(-4) moles per liter (mol/L).

2) For a pH of 7.2, the hydrogen ion concentration would be 10^(-7.2) = 6.31 x 10^(-8) mol/L.

3) To calculate pH from hydrogen ion concentration, we use the formula pH = -log[H+]. In this case, for a hydrogen ion concentration of 2.8 x 10^(-15) mol/L, the pH would be -log(2.8 x 10^(-15)) = 14.55.

4) Similarly, for a hydrogen ion concentration of 3.6 x 10^(-9) mol/L, the pH would be -log(3.6 x 10^(-9)) = 8.44.

It's important to note that pH is a logarithmic scale, meaning that each unit change in pH represents a 10-fold change in hydrogen ion concentration. This is why a lower pH indicates a higher concentration of hydrogen ions and a higher acidity. I hope this helps with your calculations!

## 1. What is the purpose of calculating hydrogen ion concentration and pH?

The purpose of calculating hydrogen ion concentration and pH is to determine the level of acidity or basicity of a solution. This information is important in various scientific fields such as chemistry, biology, and environmental science, as it can help in understanding and predicting chemical reactions, as well as identifying potential health and environmental hazards.

## 2. How do I calculate hydrogen ion concentration from pH?

To calculate hydrogen ion concentration from pH, you can use the formula [H+] = 10^(-pH). This means that the hydrogen ion concentration is equal to 10 raised to the power of negative pH. For example, if the pH is 3, the hydrogen ion concentration would be 10^(-3) = 0.001 mol/L.

## 3. What is the relationship between hydrogen ion concentration and pH?

Hydrogen ion concentration and pH are inversely related. This means that as the hydrogen ion concentration increases, the pH decreases, and vice versa. A lower pH indicates a higher concentration of hydrogen ions, making the solution more acidic. On the other hand, a higher pH indicates a lower concentration of hydrogen ions, making the solution more basic.

## 4. What is the pH scale and what does it measure?

The pH scale is a measure of the acidity or basicity of a solution. It ranges from 0 to 14, with 7 being neutral. A pH of less than 7 indicates acidity, while a pH greater than 7 indicates basicity. The scale is logarithmic, meaning that each unit change in pH represents a tenfold change in hydrogen ion concentration.

## 5. Can I use the pH scale to measure the concentration of other ions?

No, the pH scale is specifically used to measure the concentration of hydrogen ions in a solution. It cannot be used to measure the concentration of other ions, such as sodium or chloride. However, the pH of a solution can be affected by the concentration of other ions, as they can interact with hydrogen ions and change the overall acidity or basicity of the solution.

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