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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
Volumetric mass density
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


Acidic and basic solutions

Chemical reaction between iron and hydrochloric acid

The purpose is to study the chemical reaction between iron and hydrochloric acid.

We use:
- Iron powder (Iron powder is more reactive than compact iron )
- A hydrochloric acid solution.
- A test tube which allows a better observation.

Reaction between iron and hydrochloric acid:
reaction between iron and hydrochloric acid

We observe the formation of bubbles which indicate that a gas forms
To understand this chemical reaction we must identify the gaz, and analyze the composition of the aqueous solution in order to check a possible change.



Analysis of the gas:
The test for hydrogen gas is positive. This reaction therefore produces dihydrogen.

Analysis of the resulting solution:
- A measurement of pH shows that the latter increased: the solution is less acidic, hydrogen ions therefore have been consumed.
- The addition of silver nitrate leads to the formation of a white precipitate which indicates that the chloride ions are still in solution.
- The test for iron 
(II) ions is positive: Iron (II) ions (Fe 2+) have formed.

- The reactants are substances initially gathered: iron and hydrochloric acid.
- Products are substances that have formed: dihydrogen and iron (II) ions that form with chloride ions a solution of Iron(II) chloride

Simple word equation:

                                    iron + hydrochloric acid →  dihydrogen + Iron(II) chloride