Unit 2 - Element Compound Mixture

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Solvent , Solute , Solution

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Unit 2 - Element Compound Mixture

Compound

A compound is formed when 2 or more different elements combined together by a chemical change to create a new substance. Compounds are pure substances that can be split into smaller substances. Examples: Water, Sugar, Salt, Carbon dioxide, Ammonia, Acids

Compounds Examples:  CO2  H2O  NaCl  NaOH  CaO A compound is formed when 2 or more different elements combined together by a chemical change to create a new substance. Compounds are pure substances. Compounds can be split into smaller substances.

Examples:  CO2  H2O  NaCl  NaOH  CaO

Element

Element is the simplest form of matter. Element is a pure substance, it cannot be broken into something smaller. Element is made of only one type of particles / atoms. All (and ONLY) the elements can be found in the periodic table.

Metal,Non-metal,Metalloid

Ex.Sliver,Helium,Silicon

Mixture

Tyndall Effect The Tyndall effect is the scattering of light as a light beam passes through a colloid. The tiny particles scatter and reflect light, making the beam visible. The amount of scattering depends on the frequency of the light and density of the particles. Blue light is scattered more strongly than red light by the Tyndall effect. The Tyndall effect was first described by 19th-century physicist John Tyndall.

Example: The visible beam of headlights in fog is caused by the Tyndall effect. The water droplets scatter the light, making the headlight beams visible

Mixtures A mixture is formed when 2 or more substances are mixed together by a physical method such as stirring, shaking, dissolving. No new substance is formed

Examples of mixtures: Blood – mixture of • red blood cells • white blood cells • platelets • plasma Can be separated in the lab by centrifuge. Air - Air is made of oxygen, nitrogen, carbon dioxide, inert gases etc. We can separate the oxygen from the air by our lungs, no chemical reaction, electricity or heat is needed. Sea water– mixture of water and salt Can be separated by evaporation of the water.

Concentration

The volume of liquid is measure in cm3 or mL or dm3

Concentration of solution is measured in g/dm3 or g/L

Ex - 10 gram of solute in 1000 cm3 of solution

RAdioactive Element

Uses of Alpha Radiation Used in smoke detectors. Radioactive element americium releases alpha radiation, which ionizes the air inside the detector. Smoke from a fire absorbs alpha radiation, changing the ionization and triggering the alarm. Uses of Beta Radiation Doctors may use radioactive chemicals called tracers for medical imaging, as these chemicals concentrate in different damaged or diseased parts of the body. Radiation detectors placed outside the body detect the radiation emitted and, with the aid of computers, build up an image of the inside of the body. Uses of Gamma Radiation Gamma radiation is used in the treatment of cancer, testing equipment and sterilising medical instruments.

Radioactivity was first discovered in 1896 by the French scientist Henri Becquerel , while working on phosphorescent (glow in the dark) materials. He wrapped a photographic plate in black paper and placed various phosphorescent minerals on it. All results were negative until he used uranium salts. Marie Curie isolated a new element polonium and separated a new element radium from barium.

Uses of radioactive elements 1) Determine the age of Fossils By analyzing the percentage of carbon-14 (radioactive element) in fossil we can know their age. 2) Producing Energy Nuclear fission releases huge amounts of heat that can be used to produce electricity. 3) Medical Uses Some radioactive elements are used to diagnose and treat cancer. 4) Atomic Bomb An atomic bomb gets its explosive force from the release of atomic energy from fission of Uranium. The first atomic bomb was successfully tested on July 16, 1945 First atomic bomb was used during WWII (World War 2) in Hiroshima, Japan (August 6, 1945)

Atom Structure

Protons and Neutrons are in the nucleus and cannot move. Only the electrons can move around in the shells . Protons are much bigger than the Electrons . The number of protons is usually equal to the number of electrons.

Ex - Sulfer,Neon,Rubidium,Iron,Magnesium,Fluorine

Solution

What is solution? Solution is a homogenous (uniform) mixture that is formed when a substance dissolves in another substance.

Example: Mix sugar in water. Solute = Sugar Solvent = Water Dissolve = Mix the sugar in the water Solution = The final mixture

Solute - solid / liquid / gas Solvent - liquid Solution - liquid (not pure) Dissolve - the process of mixing the solute in the solvent.