Question 1

What is VerChem?

Accepted Answer

VerChem is a free, professional-grade chemistry platform offering 8 chemistry calculators, 3 environmental engineering tools, an interactive periodic table with all 118 elements (NIST/IUPAC certified), and a database of 1,000+ compounds. Built for students, chemists, and engineers.

Question 2

Is VerChem free to use?

Accepted Answer

Yes! All VerChem features are completely free for AIVerID members. We follow a "Free First" strategy to make world-class chemistry tools accessible to everyone worldwide.

Question 3

How accurate is VerChem data?

Accepted Answer

VerChem uses NIST (National Institute of Standards and Technology) and IUPAC (International Union of Pure and Applied Chemistry) as authoritative data sources. All 118 elements have certified atomic masses and properties updated to 2021 standards.

Question 4

What calculators does VerChem offer?

Accepted Answer

VerChem offers 8 chemistry calculators: Molar Mass, Equation Balancer, Stoichiometry (8 modes), pH Calculator (7 modes), Gas Laws (9 modes including Van der Waals), Thermodynamics, Chemical Kinetics, and Electrochemistry. Plus 3 environmental tools: Water Quality, Air Quality, and Soil Quality.

Question 5

How do I calculate molar mass?

Accepted Answer

Enter a chemical formula (e.g., H2SO4, NaCl, C6H12O6) into the Molar Mass Calculator. It automatically calculates molecular weight by summing atomic masses × subscripts. For H2O: (2 × 1.008) + (1 × 15.999) = 18.015 g/mol. Uses NIST atomic masses.

Question 6

How do I balance a chemical equation?

Accepted Answer

Enter your unbalanced equation (e.g., H2 + O2 -> H2O) into the Equation Balancer. It uses algebraic matrix methods to find the smallest whole-number coefficients. The balanced result: 2H2 + O2 -> 2H2O. Works for redox, combustion, and synthesis reactions.

Question 7

What is the Ideal Gas Law formula?

Accepted Answer

The Ideal Gas Law is PV = nRT, where P = pressure, V = volume, n = moles of gas, R = gas constant (8.314 J/mol·K or 0.0821 L·atm/mol·K), and T = temperature in Kelvin. VerChem Gas Laws Calculator supports 9 modes including Combined Gas Law and Van der Waals equation.

Question 8

How do I calculate pH from concentration?

Accepted Answer

pH = -log[H+]. For a 0.01 M HCl solution: pH = -log(0.01) = 2. For bases, calculate pOH first, then pH = 14 - pOH. VerChem pH Calculator handles strong/weak acids and bases, buffer solutions, and shows visual pH scale.

Question 9

What is BOD and COD in water quality?

Accepted Answer

BOD (Biochemical Oxygen Demand) measures oxygen consumed by microorganisms decomposing organic matter over 5 days at 20°C. COD (Chemical Oxygen Demand) measures total oxygen needed to chemically oxidize all organic matter. BOD/COD ratio indicates biodegradability: <0.3 = non-biodegradable, 0.3-0.6 = moderately biodegradable, >0.6 = highly biodegradable.

Question 10

What are Thai water quality standards?

Accepted Answer

Thai PCD (Pollution Control Department) standards: Type ก (Industrial): BOD ≤20, COD ≤120, SS ≤50 mg/L. Type ข (Relaxed Industrial): BOD ≤60, COD ≤400, SS ≤150 mg/L. Type ค (Community): BOD ≤40, COD ≤200, SS ≤70 mg/L. VerChem Water Quality Calculator includes Thai standards compliance checker.

Question 11

How many elements are in the periodic table?

Accepted Answer

There are 118 confirmed elements. Elements 1-94 occur naturally (though some like Technetium and Promethium are extremely rare). Elements 95-118 are synthetic, created in laboratories. The latest additions (Nihonium, Moscovium, Tennessine, Oganesson) were confirmed by IUPAC in 2016.

Question 12

What are rare earth elements?

Accepted Answer

Rare earth elements include 17 elements: Scandium (Sc), Yttrium (Y), and the 15 Lanthanides (La-Lu: Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium). Despite the name, most are not rare but are difficult to separate from each other.

Question 13

What is a limiting reagent?

Accepted Answer

A limiting reagent is the reactant that is completely consumed first in a chemical reaction, determining the maximum amount of product that can be formed. VerChem Stoichiometry Calculator identifies the limiting reagent and calculates theoretical yield, actual yield, and percent yield.

Question 14

How do I convert moles to grams?

Accepted Answer

Mass (g) = Moles × Molar Mass (g/mol). For example, 2 moles of water: 2 mol × 18.015 g/mol = 36.03 g. To convert grams to moles, divide: Moles = Mass / Molar Mass.

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