Question
Calculate the ratio of H+ ions to OH– ions at a pH = 7. Find the concentration of H+ ions to OH– ions listed in Table B of your Student Guide. Then divide the H+ concentration by the OH– concentration. Record this calculated ratio in Table A of your Student Guide.
Compare your approximated and calculated ratios of H+ ions to OH– ions at a pH = 7. Are they the same? Why or why not? Record your comparison in Table A.
What is the concentration of H+ ions at a pH = 7?
mol/L
What is the concentration of OH– ions at a pH = 7?
mol/L
What is the ratio of H+ ions to OH– ions at a pH = 7?
:1
Compare your approximated and calculated ratios of H+ ions to OH– ions at a pH = 7. Are they the same? Why or why not? Record your comparison in Table A.
What is the concentration of H+ ions at a pH = 7?
mol/L
What is the concentration of OH– ions at a pH = 7?
mol/L
What is the ratio of H+ ions to OH– ions at a pH = 7?
:1
Answers
GPT-4o mini
At a pH of 7, the solution is considered neutral, meaning the concentrations of hydrogen ions (H⁺) and hydroxide ions (OH⁻) are equal.
1. **Concentration of H⁺ ions at pH = 7:**
- The pH scale is logarithmic; specifically, pH is defined as:
\[ \text{pH} = -\log[H^+] \]
- At pH 7:
\[ 7 = -\log[H^+] \]
\[ [H^+] = 10^{-7} \text{ mol/L} \]
2. **Concentration of OH⁻ ions at pH = 7:**
- The relationship between H⁺ and OH⁻ concentrations in water at 25°C is given by:
\[ [H^+][OH^-] = 1.0 \times 10^{-14} \]
- If \([H^+] = 10^{-7}\) mol/L, then:
\[ [OH^-] = \frac{1.0 \times 10^{-14}}{10^{-7}} = 10^{-7} \text{ mol/L} \]
3. **Ratio of H⁺ ions to OH⁻ ions:**
- Since both concentrations are equal at a pH of 7:
\[ \text{Ratio} = \frac{[H^+]}{[OH^-]} = \frac{10^{-7}}{10^{-7}} = 1:1 \]
### Summary of the Calculated Values:
- Concentration of H⁺ ions at pH = 7: **10⁻⁷ mol/L**
- Concentration of OH⁻ ions at pH = 7: **10⁻⁷ mol/L**
- Ratio of H⁺ ions to OH⁻ ions at pH = 7: **1:1**
### Comparison of Approximated and Calculated Ratios:
Since both the approximated and calculated ratios of H⁺ ions to OH⁻ ions at pH = 7 are **1:1**, they are the same. This agreement occurs because, at neutral pH, the concentrations of H⁺ and OH⁻ ions are equal due to the self-ionization of water.
You can record these values and your observations in Table A of your Student Guide as follows:
| Attribute | Value |
|---------------------------------------|---------------------|
| Concentration of H⁺ ions (mol/L) | \(1.0 \times 10^{-7}\) |
| Concentration of OH⁻ ions (mol/L) | \(1.0 \times 10^{-7}\) |
| Ratio of H⁺ to OH⁻ ions | 1:1 |
| Comparison of ratios | Same (1:1) |
1. **Concentration of H⁺ ions at pH = 7:**
- The pH scale is logarithmic; specifically, pH is defined as:
\[ \text{pH} = -\log[H^+] \]
- At pH 7:
\[ 7 = -\log[H^+] \]
\[ [H^+] = 10^{-7} \text{ mol/L} \]
2. **Concentration of OH⁻ ions at pH = 7:**
- The relationship between H⁺ and OH⁻ concentrations in water at 25°C is given by:
\[ [H^+][OH^-] = 1.0 \times 10^{-14} \]
- If \([H^+] = 10^{-7}\) mol/L, then:
\[ [OH^-] = \frac{1.0 \times 10^{-14}}{10^{-7}} = 10^{-7} \text{ mol/L} \]
3. **Ratio of H⁺ ions to OH⁻ ions:**
- Since both concentrations are equal at a pH of 7:
\[ \text{Ratio} = \frac{[H^+]}{[OH^-]} = \frac{10^{-7}}{10^{-7}} = 1:1 \]
### Summary of the Calculated Values:
- Concentration of H⁺ ions at pH = 7: **10⁻⁷ mol/L**
- Concentration of OH⁻ ions at pH = 7: **10⁻⁷ mol/L**
- Ratio of H⁺ ions to OH⁻ ions at pH = 7: **1:1**
### Comparison of Approximated and Calculated Ratios:
Since both the approximated and calculated ratios of H⁺ ions to OH⁻ ions at pH = 7 are **1:1**, they are the same. This agreement occurs because, at neutral pH, the concentrations of H⁺ and OH⁻ ions are equal due to the self-ionization of water.
You can record these values and your observations in Table A of your Student Guide as follows:
| Attribute | Value |
|---------------------------------------|---------------------|
| Concentration of H⁺ ions (mol/L) | \(1.0 \times 10^{-7}\) |
| Concentration of OH⁻ ions (mol/L) | \(1.0 \times 10^{-7}\) |
| Ratio of H⁺ to OH⁻ ions | 1:1 |
| Comparison of ratios | Same (1:1) |