Featured contributor PhD Applied Physics; former research associate at a national metrology lab.

Dr. Helena Ortiz

Senior Reviewer, Science & Engineering

0 calculators 0 articles Member since Jun 2026

About

Helena is the senior technical reviewer for physics, chemistry, and unit-conversion calculators. She is the last pair of eyes on every formula — checking constants, units, and edge cases against primary sources and standards bodies.

She holds a PhD in Applied Physics and previously held a research post at a national metrology lab.

Areas of expertise

Physics Chemistry Unit conversion Measurement standards

Education & credentials

BSc Physics — Universidad Complutense de Madrid
PhD Applied Physics — Stanford University

Chemistry

Latent Heat of Vaporization Energy Calculator

Compute the energy Q required to vaporize a substance at its boiling point from the mass and the substance-specific late...

basic

11,754 3.9 1 min

Physics

Power Factor Correction Capacitor Calculator

Calculates the reactive power compensation needed and capacitance required to correct a lagging power factor to a target...

basic

9,983 4.0 1 min

Statistics

Hypergeometric Distribution Urn Model Calculator

Calculates the hypergeometric probability of drawing exactly k successes from a finite population without replacement.

basic

13,505 4.2 1 min

Chemistry

Avogadro's Law Volume-Mole Calculator

Apply Avogadro's law to a gas held at constant temperature and pressure: V₁ / n₁ = V₂ / n₂. Compute V₂ (or any other unk...

basic

9,813 5.0 1 min

Chemistry

Ideal Gas Density Calculator

Compute the density of an ideal gas from its molar mass, pressure, and temperature using ρ = P · M / (R · T), with P in...

basic

19,996 3.9 1 min

Physics / Mechanics

Circular Orbit Period from Radius and Central Mass Calculator

Calculates orbital period T = 2π√(r³/GM), orbital velocity v = √(GM/r), and centripetal acceleration for a circular orbi...

basic

11,751 4.7 1 min

Everyday Life

Solar Panel Daily Energy Output Calculator

Estimates daily solar energy output: kWh = panel_kWp × PSH × performance_ratio. For a 5 kWp system with 5 PSH and PR=0.7...

basic

4,188 3.9 1 min

Physics / Mechanics

Angular-Momentum Conservation: Final ω from I₁ω₁ = I₂ω₂ Calculator

When no external torque acts, angular momentum I·ω is conserved. Given an initial moment of inertia I₁ and angular veloc...

basic

14,762 4.5 1 min

Physics

Satellite Orbital Period Calculator

Compute the orbital period of a satellite in a circular orbit around a chosen body (Earth, Moon, Mars) from its altitude...

basic

10,537 4.2 1 min

Chemistry

Crystal-Field Stabilisation Energy (CFSE) in Octahedral Field Calculator

Compute the crystal-field stabilisation energy (CFSE) for a transition-metal complex in an octahedral field: CFSE = n(t₂...

basic

11,341 4.3 1 min

Health

Revised Cardiac Risk Index (RCRI) Score Calculator

Calculates the Lee Revised Cardiac Risk Index from 6 factors (high-risk surgery, ischaemic heart disease, CHF, cerebrova...

basic

7,063 3.9 1 min

Chemistry

Langmuir Adsorption Isotherm Fractional Coverage Calculator

Compute the fractional surface coverage θ of an adsorbate on a uniform surface as a function of partial pressure P and t...

basic

17,916 5.0 1 min

Showing 265 to 276 of 504 results

No articles published yet.

Reviewed by Dr. Helena Ortiz

These calculators were technically reviewed by Dr. Helena Ortiz for accuracy.

Chemistry / Reactions

Equilibrium Constant Calculator

Compute the equilibrium constant K_c from the concentrations of two products (with stoichiometric coefficients 1) divide...

basic

5,060 4.0 1 min

Conversions / Length

Length Converter

Convert between meters, kilometers, miles, feet, inches, and yards.

Featured basic

4,965 4.2 1 min

Chemistry / Solutions

Combined Gas Law Calculator

Find the missing pressure, volume, or temperature using the combined gas law for a fixed amount of gas.

basic

5,360 4.2 1 min

Physics / Electricity

Capacitance Calculator

Compute the capacitance of a parallel-plate capacitor from plate area, plate separation, and the dielectric constant.

basic

12,524 4.1 1 min

Chemistry / Solutions

pOH Calculator

Compute pOH from hydroxide ion concentration and the matching pH at 25 °C.

basic

18,221 4.2 1 min

Ecology / Carbon Footprint

Carbon Footprint Calculator

Estimate your annual personal CO₂e footprint from home energy, driving, flying, and diet — with adjustable emission fact...

Featured basic

15,826 4.9 1 min

Calcify

Browse categories

Dr. Helena Ortiz

Latent Heat of Vaporization Energy Calculator

Power Factor Correction Capacitor Calculator

Hypergeometric Distribution Urn Model Calculator

Avogadro's Law Volume-Mole Calculator

Ideal Gas Density Calculator

Circular Orbit Period from Radius and Central Mass Calculator

Solar Panel Daily Energy Output Calculator

Angular-Momentum Conservation: Final ω from I₁ω₁ = I₂ω₂ Calculator

Satellite Orbital Period Calculator

Crystal-Field Stabilisation Energy (CFSE) in Octahedral Field Calculator

Revised Cardiac Risk Index (RCRI) Score Calculator

Langmuir Adsorption Isotherm Fractional Coverage Calculator

Reviewed by Dr. Helena Ortiz

Equilibrium Constant Calculator

Length Converter

Combined Gas Law Calculator

Capacitance Calculator

pOH Calculator

Carbon Footprint Calculator