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Free online chemistry lesson for elementary school, middle school and high school.
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Science class




Mechanics lessons
Water on Earth
Changes of state in the nature: the water cycle
Water in human body
Test for water
Properties of water in different states
States of matter
States of matter and its changes
Boiling water
Water: freezing and melting
Changes of state: mass and volume
Molecules in different states of matter

Mixtures and solutions
Heterogeneous mixtures
Homogeneous mixtures
Vaporization of water
Dissolving a solid in water
Conservation of mass on dissolving
Miscibility in water

Mass and volume
Volume and its units
Measuring volume with a graduated cylinder
Mass and its units
Measuring the mass of a liquid
Mass of a liter of water

Air and atmosphere
Earth's atmosphere protect us
Threats to the Earth's atmosphere
Composition of air
Air and life
Atoms and molecules
Molecules in mixtures and pure substances
Molecules and states of matter
Composition of molecules
Constituents of the atoms
The electrical neutrality of the atom

Basics of combustion
The combustion of carbon
The combustion of butane
Atoms and chemical reactions
Chemical reactions
Chemical equations
Law of conservation of mass
Chemical synthesis

Most common metals

How to distinguish metals ?

Corrosion of metals

Electrical conductivity of solid materials

Electrons and free electrons

Electric current in metals
The conductivity of aqueous solutions
Aqueous solutions and ions
The direction of movement of ions
Formation of ions
Tests for ions
Acidic and basic solutions
pH of aqueous solutions
Ions in acidic and basic solutions
Dilution of acids and bases
Composition of hydrochloric acid
Chemical reaction between iron and hydrochloric acid

Electrochemical cells and chemical energy
Chemical reaction beteween a copper sulphate solution and zinc
Copper sulfate and zinc battery
Basics of electrochemical cell



Mass and volume

Mass of a liter of water


The mass of a liter of water can be determined using one of the described  methods for weighing a liquid.
The chosen container must have a capacity of 1 liter but it is also possible to use a smaller container and use the proportionality between mass and volume.

In order to obtain the best result, we should use a container with the most accurate indications of volume. Beakers, flasks and test tubes have graduations but their accuracy is lower than that of a volumetric flask.
There are different models of volumetric flask: 25, 50, 100, 500 mL and 1L.
 Models of 1 L remain quite rare but we may measure the mass of 500 mL of water and multiply the result by 2 to obtain the mass of 1  L (1000 mL) of water.

The measure gives finally this result:
A liter of pure water has a mass of 1 kg

This value is a characteristic of pure water: another pure substance or a mixture that contains water would have a different mass.
This value has a historical origin: a kilogram was defined as the mass of a liter of pure water in 1995.