How do I calculate molarity of a solution?

Molarity (M) = Moles of solute / Volume of solution (L). Moles = Mass (g) / Molar mass (g/mol). For example, dissolving 58.44 g of NaCl (molar mass = 58.44 g/mol) in 1 L of water gives 1 M NaCl. For dilutions: C1V1 = C2V2.

How do you calculate pH of a solution?

pH = -log₁₀[H⁺], where [H⁺] is hydrogen ion concentration in mol/L. For strong acids: [H⁺] = molarity. For weak acids: [H⁺] = √(Ka × C), where Ka is the acid dissociation constant and C is the concentration. pH 7 is neutral, 7 is basic.

What is the ideal gas law formula?

The ideal gas law: PV = nRT, where P is pressure (Pa or atm), V is volume (m³ or L), n is moles of gas, R is the gas constant (8.314 J/mol·K or 0.0821 L·atm/mol·K), and T is temperature (Kelvin). For real gases, apply van der Waals corrections: (P + a/V²)(V - b) = nRT.

How do I calculate heat exchanger LMTD?

Log Mean Temperature Difference (LMTD) = (ΔT₁ - ΔT₂) / ln(ΔT₁/ΔT₂), where ΔT₁ and ΔT₂ are the temperature differences at each end of the exchanger. Heat duty Q = U × A × LMTD × F, where U is overall heat transfer coefficient (W/m²·K), A is heat transfer area (m²), and F is LMTD correction factor.

How do you calculate reaction conversion and yield?

Conversion X = (Moles reacted) / (Moles fed) × 100%. Yield Y = (Moles of desired product) / (Theoretical maximum moles) × 100%. Selectivity S = (Moles of desired product) / (Moles of reactant consumed) × 100%. For nth-order reactions: rate r = k × C^n, where k is rate constant and C is concentration.

🧪 Professional Grade

Chemical Engineering Calculator

Precision chemical engineering calculators — Molarity, pH, Dilution, Ideal Gas Law, Mass Balance & Heat of Reaction with professional PDF reports.

18Calculators

🧪Chemical

📄PDF Reports

Chemical Dosing Calculator Library

Chemical-specific dosing calculators for water-treatment, process and boiler applications — each pre-filled with realistic defaults (stock strength, specific gravity, target ppm).

About Our Chemical Engineering & Process Calculators

Chemical calculators on AI Calculator handle the daily math behind water treatment, process chemistry, and laboratory work. The bulk of this category is dedicated water-treatment dosing calculators — tools that convert a target residual or removal goal into a precise chemical feed rate (mg/L or kg/day) for the most common treatment chemicals: chlorine, alum, lime, polymer, caustic soda, RO antiscalant, calcium hypochlorite, hydrazine, phosphate, and chlorine dioxide. Plant operators and treatment engineers use these to set dosing-pump strokes, size day tanks, and verify chlorine demand against incoming water quality. Beyond dosing, the suite includes molarity, pH, and stoichiometric tools for general chemistry work. All tools default to SI but accept gpd/gpm/ppm freely, and every page exports a PDF report you can attach to a daily-log sheet.

Calculators in This Chemical Suite

Chemical Dosing Calculator — the master dosing tool: target dose (mg/L) × flow (m³/h or MGD) × (1/concentration) = feed rate. Handles both liquid and powder chemicals.
Chlorine Dosing Calculator — chlorine demand + residual target → chlorine dose. Critical for drinking-water disinfection per WHO/EPA.
Alum Dosing Calculator — aluminium-sulphate feed rate for coagulation in surface-water treatment.
Lime Dosing Calculator — CaO or Ca(OH)₂ for pH correction and softening; outputs mass and slurry feed rate.
Caustic Soda Dosing Calculator — NaOH for alkalinity and pH adjustment in industrial water and wastewater.
Polymer Dosing Calculator — cationic / anionic polymer flocculant for sludge dewatering and clarifier performance.
RO Antiscalant Dosing — antiscalant feed rate for reverse-osmosis membrane protection (typical 2–6 mg/L of feed).
Molarity Calculator — M = moles of solute / litres of solution; dilution C₁V₁ = C₂V₂.
pH Calculator — pH from [H+] and back; pOH conversion at 25 °C.

The Master Dosing Equation

Almost every chemical-dosing calculator on this site reduces to a single equation: Feed rate (kg/day) = Dose (mg/L) × Flow (ML/day) × (100 / % concentration). So if your raw-water flow is 50 ML/day, you want an alum dose of 30 mg/L, and your alum solution is 48% (typical liquid alum), the feed rate is 30 × 50 × (100/48) = 3,125 kg/day = about 130 kg/h. The dosing pump must be sized for this rate at its design stroke. The calculator automates this and lets you flip units freely (gpd to MGD, gpm to L/s, kg/d to lb/d).

Real-World Workflow Example

For a small drinking-water plant treating 5,000 m³/day of surface water: jar-test the raw water to find the optimum alum dose (typically 20–60 mg/L depending on turbidity); use the alum dosing calculator to convert that mg/L target into a kg/h feed rate; run the chlorine dosing calculator to set the post-filtration chlorine target (residual 0.5–1.0 mg/L at the far end of the distribution system, demand depending on raw-water organics); use the lime dosing calculator if final pH needs to be raised toward Langelier Saturation Index neutrality. The molarity and pH calculators help with reagent preparation in the lab.

Frequently Asked Questions

What concentrations should I use for the dosing calculators?
The calculators ask for the chemical’s purity or solution strength (e.g. 12% NaOCl for sodium hypochlorite, 48% Al₂(SO₄)₃ for liquid alum, 30% NaOH). The exact figure should come from your supplier’s certificate of analysis. Defaults are typical commercial concentrations.

Do these dosing tools account for chemical purity decay?
Sodium hypochlorite degrades over time (about 1–2% loss per week at 25 °C) — the calculator assumes the concentration you enter is the current strength, not the as-delivered strength. Re-test stored bulk solutions and update the input before each major run.

Can I use these for wastewater dosing too?
Yes — the math is identical for industrial wastewater treatment. Just enter the wastewater flow and the dose target from your jar test or treatment design.

What about safety overdosing margins?
The calculator outputs the calculated requirement. Most plants apply a +10% safety margin on the pump capacity to handle peak flow excursions and slight chemical-strength variation. Apply that margin to the pump sizing, not to the daily feed rate (overdosing residual chlorine wastes chemical and creates DBP issues).

Related calculator categories: Electrical engineering · Mechanical engineering · Civil & structural · Physics · Engineering formulas reference