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 interactive tools: 3D Molecular Viewer, Lewis Structures, VSEPR Geometry, and a complete Periodic Table.

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

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 10

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 11

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 12

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.

Question 13

What is the difference between VerChem and asking AI like ChatGPT for chemistry calculations?

Accepted Answer

VerChem and AI chatbots serve different purposes. VerChem provides 100% accurate calculations every time using verified formulas and NIST/IUPAC certified data - the same result guaranteed on every calculation. AI chatbots like ChatGPT are excellent for explanations and learning concepts, but may occasionally make calculation errors (hallucination), give inconsistent results, or use outdated atomic masses. For critical calculations (lab work, exams, engineering), use VerChem. For understanding concepts and getting explanations, AI chatbots are great companions. Best practice: Use both together - VerChem for accurate calculations, AI for deeper understanding.

Question 14

Can AI chatbots replace chemistry calculators like VerChem?

Accepted Answer

No, they serve complementary roles. AI chatbots may: 1) Calculate atomic masses incorrectly (off by 1-2 decimal places), 2) Make errors in complex equation balancing, 3) Give different answers each time you ask, 4) Not know specialized standards like Thai PCD water quality limits. VerChem guarantees: 1) NIST-certified atomic masses for all 118 elements, 2) Deterministic results (same input = same output, always), 3) Calculation speed under 50ms, 4) Thai regulatory standards built-in. Use VerChem when accuracy matters, AI when you need explanations or learning support.

Environment	Range (ppm)	Category	Multiplicity	Examples
Cyclopropane, TMS	0.0–0.5	Shielded / Reference	varies	Cyclopropane (0.22); TMS (0.00); Metal hydrides
R-CH3 (alkyl methyl)	0.7–1.3	Alkyl	singlet, triplet, or doublet	Ethane CH3 (0.86); Propane CH3 (0.91); tert-Butyl (CH3)3 (0.90)
R-CH2-R (alkyl methylene)	1.2–1.8	Alkyl	multiplet	Cyclohexane (1.43); n-Hexane CH2 (1.28); Decalin CH2 (1.4-1.7)
R3-CH (alkyl methine)	1.4–1.7	Alkyl	multiplet	Isobutane CH (1.60); Isopentane CH (1.51); Adamantane CH (1.63)
Allylic (C=C-CH)	1.5–2.5	Unsaturated	varies	Propene CH3 (1.71); Cyclohexene allylic CH2 (1.97); 2-Methylpropene CH3 (1.78)
R-CO-CH (alpha to carbonyl)	1.9–2.5	Carbonyl-adjacent	varies	Acetone CH3 (2.17); Acetic acid CH3 (2.10); Acetaldehyde CH3 (2.20)
Ar-CH (benzylic)	2.1–2.6	Aromatic-adjacent	singlet or varies	Toluene CH3 (2.36); Ethylbenzene CH2 (2.64); Xylene CH3 (2.25)
C triple bond C-H (alkyne terminal)	2.1–3.0	Unsaturated	singlet or triplet	Acetylene (1.91); Propyne (1.80); Phenylacetylene (3.07)
N-H (amine, variable)	2.5–5.0	Exchangeable	broad singlet	Primary amine R-NH2 (0.5-3.0); Secondary amine R2-NH (2.0-4.0); Amide NH (6.0-9.0)
C-O-CH (alpha to oxygen, ethers)	3.2–3.8	Heteroatom-adjacent	varies	Diethyl ether OCH2 (3.47); THF OCH2 (3.75); Anisole OCH3 (3.77)
N-CH (alpha to nitrogen)	3.3–4.0	Heteroatom-adjacent	varies	Trimethylamine NCH3 (2.12); Pyridine alpha-CH (8.50); Piperidine NCH2 (2.36)
O-CH3 (methoxy)	3.5–3.9	Heteroatom-adjacent	singlet	Methanol OCH3 (3.49); Methyl acetate OCH3 (3.67); Anisole OCH3 (3.77)
R-OH (alcohol, variable)	3.5–4.5	Exchangeable	broad singlet	Methanol OH (3.40); Ethanol OH (2.61); Phenol OH (4.0-7.0)
O-CH2 (esters, carboxylic acids)	3.7–4.8	Heteroatom-adjacent	varies	Ethyl acetate OCH2 (4.12); Benzyl alcohol OCH2 (4.56); Glycol HOCH2 (3.76)
=CH2, =CHR (vinyl/vinylidene)	4.5–6.5	Unsaturated	doublet, triplet, or multiplet	Ethylene (5.25); Styrene vinyl (5.10-5.75); Cyclohexene (5.59)
O-CH-O (acetal)	5.0–5.5	Heteroatom-adjacent	singlet or doublet	Dimethyl acetal (4.47); Glucose anomeric H (4.6-5.4); 1,3-Dioxolane (4.75)
Ar-H (aromatic)	6.0–8.5	Aromatic	singlet, doublet, triplet, or multiplet	Benzene (7.36); Toluene ArH (7.17); Naphthalene (7.4-7.9)
CHO (aldehyde)	8.0–10.0	Carbonyl	singlet or doublet	Formaldehyde (9.60); Acetaldehyde CHO (9.80); Benzaldehyde CHO (9.99)
COOH (carboxylic acid)	9.0–11.0	Exchangeable	broad singlet	Acetic acid COOH (11.42); Benzoic acid COOH (12.0); Formic acid COOH (8.08)
Chelated OH, enol	10.0–13.0	Exchangeable	singlet	Acetylacetone enol OH (11.5); 2-Hydroxybenzaldehyde OH (11.0); Dimedone enol (11.2)

Solvent	Formula	\u00B9H (ppm)	\u00B9\u00B3C (ppm)	BP (\u00B0C)	Notes
Chloroform-d	CDCl3	7.26	77.16	61	Most commonly used NMR solvent. Residual CHCl3 appears at 7.26 ppm. 13C triplet centered at 77.16 ppm (1:1:1 from deuterium coupling). Good for non-polar to moderately polar compounds.
DMSO-d6	(CD3)2SO	2.50	39.52	189	Excellent for polar compounds and compounds with exchangeable protons. Residual DMSO appears as quintet at 2.50 ppm. 13C septet at 39.52 ppm. Hygroscopic, absorbs water (peak at ~3.33 ppm).
Deuterium oxide	D2O	4.79	—	101	Used for water-soluble compounds and to identify exchangeable protons (D2O shake). Residual HOD appears at 4.79 ppm. No useful 13C signal. pH-sensitive shift.
Methanol-d4	CD3OD	3.31	49.00	64	Good for moderately polar compounds. Residual CHD2OD appears as quintet at 3.31 ppm. 13C septet at 49.00 ppm. Exchanges with OH, NH protons.
Acetone-d6	(CD3)2CO	2.05	29.84	56	Good general-purpose solvent. Residual acetone appears as quintet at 2.05 ppm. 13C: methyl septet at 29.84 ppm, carbonyl at 206.26 ppm. Low viscosity gives sharp lines.
Benzene-d6	C6D6	7.16	128.06	80	Used when CDCl3 signals overlap with analyte aromatic signals. Residual C6D5H at 7.16 ppm. 13C triplet at 128.06 ppm. Useful for studying aromatic solvent-induced shifts (ASIS).
TMS (reference)	(CH3)4Si	0.00	0.00	27	Universal internal reference standard. All 12 protons are equivalent, giving a single sharp peak at 0.00 ppm by definition. Chemically inert, volatile, easily removed.

Environment	Range (ppm)	Category	Multiplicity	Examples
Cyclopropane, TMS	0.0–0.5	Shielded / Reference	varies	Cyclopropane (0.22); TMS (0.00); Metal hydrides
R-CH3 (alkyl methyl)	0.7–1.3	Alkyl	singlet, triplet, or doublet	Ethane CH3 (0.86); Propane CH3 (0.91); tert-Butyl (CH3)3 (0.90)
R-CH2-R (alkyl methylene)	1.2–1.8	Alkyl	multiplet	Cyclohexane (1.43); n-Hexane CH2 (1.28); Decalin CH2 (1.4-1.7)
R3-CH (alkyl methine)	1.4–1.7	Alkyl	multiplet	Isobutane CH (1.60); Isopentane CH (1.51); Adamantane CH (1.63)
Allylic (C=C-CH)	1.5–2.5	Unsaturated	varies	Propene CH3 (1.71); Cyclohexene allylic CH2 (1.97); 2-Methylpropene CH3 (1.78)
R-CO-CH (alpha to carbonyl)	1.9–2.5	Carbonyl-adjacent	varies	Acetone CH3 (2.17); Acetic acid CH3 (2.10); Acetaldehyde CH3 (2.20)
Ar-CH (benzylic)	2.1–2.6	Aromatic-adjacent	singlet or varies	Toluene CH3 (2.36); Ethylbenzene CH2 (2.64); Xylene CH3 (2.25)
C triple bond C-H (alkyne terminal)	2.1–3.0	Unsaturated	singlet or triplet	Acetylene (1.91); Propyne (1.80); Phenylacetylene (3.07)
N-H (amine, variable)	2.5–5.0	Exchangeable	broad singlet	Primary amine R-NH2 (0.5-3.0); Secondary amine R2-NH (2.0-4.0); Amide NH (6.0-9.0)
C-O-CH (alpha to oxygen, ethers)	3.2–3.8	Heteroatom-adjacent	varies	Diethyl ether OCH2 (3.47); THF OCH2 (3.75); Anisole OCH3 (3.77)
N-CH (alpha to nitrogen)	3.3–4.0	Heteroatom-adjacent	varies	Trimethylamine NCH3 (2.12); Pyridine alpha-CH (8.50); Piperidine NCH2 (2.36)
O-CH3 (methoxy)	3.5–3.9	Heteroatom-adjacent	singlet	Methanol OCH3 (3.49); Methyl acetate OCH3 (3.67); Anisole OCH3 (3.77)
R-OH (alcohol, variable)	3.5–4.5	Exchangeable	broad singlet	Methanol OH (3.40); Ethanol OH (2.61); Phenol OH (4.0-7.0)
O-CH2 (esters, carboxylic acids)	3.7–4.8	Heteroatom-adjacent	varies	Ethyl acetate OCH2 (4.12); Benzyl alcohol OCH2 (4.56); Glycol HOCH2 (3.76)
=CH2, =CHR (vinyl/vinylidene)	4.5–6.5	Unsaturated	doublet, triplet, or multiplet	Ethylene (5.25); Styrene vinyl (5.10-5.75); Cyclohexene (5.59)
O-CH-O (acetal)	5.0–5.5	Heteroatom-adjacent	singlet or doublet	Dimethyl acetal (4.47); Glucose anomeric H (4.6-5.4); 1,3-Dioxolane (4.75)
Ar-H (aromatic)	6.0–8.5	Aromatic	singlet, doublet, triplet, or multiplet	Benzene (7.36); Toluene ArH (7.17); Naphthalene (7.4-7.9)
CHO (aldehyde)	8.0–10.0	Carbonyl	singlet or doublet	Formaldehyde (9.60); Acetaldehyde CHO (9.80); Benzaldehyde CHO (9.99)
COOH (carboxylic acid)	9.0–11.0	Exchangeable	broad singlet	Acetic acid COOH (11.42); Benzoic acid COOH (12.0); Formic acid COOH (8.08)
Chelated OH, enol	10.0–13.0	Exchangeable	singlet	Acetylacetone enol OH (11.5); 2-Hydroxybenzaldehyde OH (11.0); Dimedone enol (11.2)

Solvent	Formula	\u00B9H (ppm)	\u00B9\u00B3C (ppm)	BP (\u00B0C)	Notes
Chloroform-d	CDCl3	7.26	77.16	61	Most commonly used NMR solvent. Residual CHCl3 appears at 7.26 ppm. 13C triplet centered at 77.16 ppm (1:1:1 from deuterium coupling). Good for non-polar to moderately polar compounds.
DMSO-d6	(CD3)2SO	2.50	39.52	189	Excellent for polar compounds and compounds with exchangeable protons. Residual DMSO appears as quintet at 2.50 ppm. 13C septet at 39.52 ppm. Hygroscopic, absorbs water (peak at ~3.33 ppm).
Deuterium oxide	D2O	4.79	—	101	Used for water-soluble compounds and to identify exchangeable protons (D2O shake). Residual HOD appears at 4.79 ppm. No useful 13C signal. pH-sensitive shift.
Methanol-d4	CD3OD	3.31	49.00	64	Good for moderately polar compounds. Residual CHD2OD appears as quintet at 3.31 ppm. 13C septet at 49.00 ppm. Exchanges with OH, NH protons.
Acetone-d6	(CD3)2CO	2.05	29.84	56	Good general-purpose solvent. Residual acetone appears as quintet at 2.05 ppm. 13C: methyl septet at 29.84 ppm, carbonyl at 206.26 ppm. Low viscosity gives sharp lines.
Benzene-d6	C6D6	7.16	128.06	80	Used when CDCl3 signals overlap with analyte aromatic signals. Residual C6D5H at 7.16 ppm. 13C triplet at 128.06 ppm. Useful for studying aromatic solvent-induced shifts (ASIS).
TMS (reference)	(CH3)4Si	0.00	0.00	27	Universal internal reference standard. All 12 protons are equivalent, giving a single sharp peak at 0.00 ppm by definition. Chemically inert, volatile, easily removed.

VerChem

NMR Chemical Shift Analyzer

¹H Chemical Shift Scale (ppm)

Chemical Shift Lookup

Environment Search

¹H Chemical Shift Reference Table

Common NMR Solvents

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