TOEFL IBT – Chemistry

Vocabulary is promordial in order to improve your TOEFL score. Remember, Preparation is the key to succeed !

This vocabulary will be useful if you ever take a chemistry course in school, for expanding your English vocabulary, or especially for any number of English language exams you may take. Here we will look at the most commonly used words in the field, along with their French translations.


how close a value is to the actual or true value

Polls are only as good as the accuracy of their audience.

la précision


a compound that, when dissolved in water, gives a pH of less than 7.0

The first step is to dissolve a fuel rod in acid.



a chemical element in its smallest form

The final step is to locate the atoms of other elements.


atomic number

the number representing an element which corresponds with the number of protons within the nucleus

The number of protons in an atom is called its atomic number.

le nombre atomique


a device used to measure the pressure in the atmosphere

I don’t think that’s a good barometer.

le baromètre

boiling point

the temperature at which a substance starts to boil

Their boiling points are high and their solubility in water is low.

le point d’ébullition


the attraction and repulsion between atoms and molecules

The atoms in ceramic materials are held together by a chemical bond.

la liaison


a chemical used to speed up or slow down a reaction

It will produce metallocene compounds, key ingredients of a catalyst.

le catalyseur

chemical reaction

the change of one or more substances into another or multiple substances

Fuel cells produced electricity through a chemical reaction between oxygen and hydrogen.

la réaction chimique


a reaction between an oxidant and fuel with heat and often light

After the engine warms up, the combustion is more efficient.

la combustion


a substance that is made up of two or more chemically bonded elements

Common salt is sodium chloride, the compound principally under indictment.

le composé


the phase change from gas to liquid

Condensation occurs on the metal frames because they too are cold.

la condensation


the amount of mass per unit volume

All flesh has the density of water, more or less.

la densité


a subatomic particle whose net charge is negative

But helium atoms have two electrons tightly bound to their nuclei.



an atom that is defined by its atomic number

It is the smallest atomic element in the DNA of information.



a system’s ability to do work

Mitochondria are parts of a cell that produce energy through respiration.



a protein that speeds up a reaction

The enzyme is not found in women free of the disorder.



phase transition from liquid to solid

Your physician can usually burn these off with liquid nitrogen freezing.

la congélation


a molecule that has gained or lost one or more electrons

The excited electron whizzes off, leaving a positively charged ion.



a unit of energy

The energy released is approximately 1200 to 1300 joules per gram.

le joule


a unit of measure for temperature based upon an absolute scale

Absolute temperatures are stated in units of kelvin in his honor.

le kelvin


the phase change from a solid to a liquid

A lot of it was steel, and steel was melting.



a chemically bonded number of atoms that are electrically neutral

Another project is a computation that would involve manipulating DNA molecules.

la molécule


a neutral unit or subatomic particle that has no net charge

Why is the neutron ever so slightly heavier than the proton?

le neutron


the center of an atom made up of neutrons and protons, with a net positive charge

In principle, you could detect a signal from a single nucleus.

le noyau

organic compound

compound that contains carbon

This chemical reaction is useful in the organic synthesis of organic compounds.

le composé biologique


the measure of acidity (or basicity) of a solution

Both compounds tend to raise the pH level of the water.



a positive unit or subatomic particle that has a positive charge

In the proton and the neutron, they always occur in triplets.

le proton


energy in the form of waves or subatomic particles when there is a change from high energy to low energy states

In some cases, radiation breaks down plastic and makes hydrogen gas.

la radiation


homogeneous mixture made up of multiple substances

Finally, the ore is extracted from another solution using electrolysis.

la solution


material with definite chemical composition

The hydrocarbons are cancer-causing substances found in cigarette smoke.

la substance


device that measures the average energy of a system

They have no thermometers, no timers, and no temperature controls.

le thermomètre


phase change from liquid to gas

This causes vaporization of surrounding material resulting in its rapid expansion.

la vaporisation


form of ionizing, electromagnetic radiation, between gamma and UV rays

X-ray astronomy has made impressive progress.

la radiographie

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