.ph-calc-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 25px;
border: 1px solid #d1d5db;
border-radius: 12px;
background-color: #ffffff;
box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}
.ph-calc-header {
text-align: center;
margin-bottom: 25px;
}
.ph-calc-header h2 {
color: #1e40af;
margin-bottom: 10px;
}
.ph-calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
margin-bottom: 20px;
}
@media (max-width: 600px) {
.ph-calc-grid { grid-template-columns: 1fr; }
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
font-weight: 600;
margin-bottom: 5px;
color: #374151;
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #9ca3af;
border-radius: 6px;
box-sizing: border-box;
}
.calc-btn {
width: 100%;
background-color: #2563eb;
color: white;
padding: 12px;
border: none;
border-radius: 6px;
font-size: 16px;
font-weight: bold;
cursor: pointer;
transition: background-color 0.2s;
}
.calc-btn:hover {
background-color: #1d4ed8;
}
.reset-btn {
width: 100%;
background-color: #ef4444;
color: white;
padding: 12px;
border: none;
border-radius: 6px;
font-size: 16px;
font-weight: bold;
cursor: pointer;
margin-top: 10px;
}
.ph-results {
margin-top: 25px;
padding: 20px;
background-color: #f3f4f6;
border-radius: 8px;
display: none;
}
.ph-results h3 {
margin-top: 0;
color: #111827;
border-bottom: 2px solid #e5e7eb;
padding-bottom: 10px;
}
.result-item {
display: flex;
justify-content: space-between;
padding: 8px 0;
border-bottom: 1px solid #e5e7eb;
}
.result-item span:last-child {
font-weight: bold;
color: #1e40af;
}
.article-section {
margin-top: 40px;
line-height: 1.6;
color: #374151;
}
.article-section h2 { color: #1e40af; }
.formula-box {
background: #f8fafc;
padding: 15px;
border-left: 4px solid #2563eb;
margin: 15px 0;
font-family: 'Courier New', Courier, monospace;
}
pH
pOH
Hydrogen [H+] (mol/L)
Hydroxide [OH-] (mol/L)
Calculate All Values
Reset Worksheet
Calculation Results
pH:
pOH:
[H+] Concentration:
[OH-] Concentration:
Solution Nature:
Understanding pH and pOH Calculations
In chemistry, the acidity or basicity of an aqueous solution is measured using the pH and pOH scales. These scales are logarithmic representations of the molar concentration of hydrogen ions ([H⁺]) and hydroxide ions ([OH⁻]).
Core Formulas for the Worksheet
pH = -log10[H+]
How to Calculate Step-by-Step
To master your pH and pOH worksheet, follow these logic paths:
If you have pH: Subtract from 14 to get pOH. Use 10 to the power of negative pH to find [H+].If you have [H+]: Take the negative log (base 10) to find pH.If you have [OH-]: Find pOH first by taking the negative log, then subtract from 14 to find pH.
Interpretation of Results
Once you calculate the pH, you can determine the nature of the solution:
pH < 7: Acidic (High concentration of H+)pH = 7: Neutral (Pure water)pH > 7: Basic / Alkaline (High concentration of OH-)
Practical Examples
Example 1: A solution has a [H+] of 2.5 x 10⁻⁴ M. Find the pH.
Example 2: A solution has a pH of 11.2. Find the pOH.
function calculatePH() {
var ph = document.getElementById("inputPH").value;
var poh = document.getElementById("inputPOH").value;
var hStr = document.getElementById("inputH").value;
var ohStr = document.getElementById("inputOH").value;
var finalPH, finalPOH, finalH, finalOH;
var Kw = 1.0e-14;
if (ph !== "") {
finalPH = parseFloat(ph);
finalPOH = 14 – finalPH;
finalH = Math.pow(10, -finalPH);
finalOH = Kw / finalH;
} else if (poh !== "") {
finalPOH = parseFloat(poh);
finalPH = 14 – finalPOH;
finalH = Math.pow(10, -finalPH);
finalOH = Kw / finalH;
} else if (hStr !== "") {
finalH = parseFloat(hStr);
finalPH = -Math.log10(finalH);
finalPOH = 14 – finalPH;
finalOH = Kw / finalH;
} else if (ohStr !== "") {
finalOH = parseFloat(ohStr);
finalPOH = -Math.log10(finalOH);
finalPH = 14 – finalPOH;
finalH = Kw / finalOH;
} else {
alert("Please enter at least one value.");
return;
}
if (isNaN(finalPH)) {
alert("Invalid input detected. Please check your numbers.");
return;
}
displayResults(finalPH, finalPOH, finalH, finalOH);
}
function displayResults(ph, poh, h, oh) {
document.getElementById("resPH").innerText = ph.toFixed(4);
document.getElementById("resPOH").innerText = poh.toFixed(4);
document.getElementById("resH").innerText = h.toExponential(4) + " M";
document.getElementById("resOH").innerText = oh.toExponential(4) + " M";
var nature = "";
if (ph 7.05) nature = "Basic / Alkaline";
else nature = "Neutral";
document.getElementById("resNature").innerText = nature;
document.getElementById("phResults").style.display = "block";
}
function resetPH() {
document.getElementById("inputPH").value = "";
document.getElementById("inputPOH").value = "";
document.getElementById("inputH").value = "";
document.getElementById("inputOH").value = "";
document.getElementById("phResults").style.display = "none";
}