Summary

These notes cover the properties of matter, including physical and chemical properties. The document then explains various types of matter and the different phases of matter, including solid, liquid, and gas. Useful for revision.

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SCIENCE 3RD UNIT EXAM NOTES CHAPTER 10 squishing. These actions may result in irreversible changes. LESSON 1: THE PROPERTIES OF...

SCIENCE 3RD UNIT EXAM NOTES CHAPTER 10 squishing. These actions may result in irreversible changes. LESSON 1: THE PROPERTIES OF CHEMICAL PROPERTIES OF MATTER MATTER A chemical change involves chemical reactions that The fundamental building blocks of matter are atoms and result in the formation of new substances or products. A molecules. chemical property is the ability of a substance to undergo chemical changes to become a different kind of matter. An element is a pure substance that is made up of only one kind of atom, whereas a compound is a combination Chemical changes involve giving off energy through an of two or more elements. Water is also considered as exothermic process where heat is released from a molecule as it is formed by two or more atoms. substance such as in combustion reaction. This process Not all molecules can be considered as compounds such results in making the surroundings hotter. as oxygen or 02. It is a molecule because it is composed E.g., Carbon in the charcoal combines with oxygen in the of two atoms of oxygen, but it is not a compound as it is air to become a new substance, carbon dioxide gas. made of oxygen alone. FLAMMABILITY Flammable substances that are usually in liquid and PROPERTIES OF MATTER gaseous form are those that can easily catch fire at A property is an observable characteristic that describes relatively low temperature. an The flammability of a substance is based on its flash object. point, which refers to the lowest temperature at which liquid can be ignited and mixed with the air near it. The PHYSICAL PROPERTIES OF MATTER lower the flash point of a substance, the easier it is to Physical properties are characteristics of matter that may ignite. be observed without changing the chemical composition of a substance. It can be either intensive or extensive. Volatility is the tendency of a liquid to vaporize. If a  Extensive properties are properties of matter flammable substance is volatile, then it would mix with air, that depend on the amount of matter. increasing it flammability. Volume, mass, size, weight, and length are extensive properties. REACTION WITH WATER  Intensive properties do not depend on the Another chemical property is the ability of iron to rust by amount of matter present. combining with oxygen in the air. Rusting is caused by Examples of these properties are melting point, the chemical reaction between the metal and the boiling point, density, and ability to conduct moisture in the air. energy such as heat and electricity. The orange-brown substance that we observe is called rust, which is a product of the reaction of the metal and INTENSIVE DESCRIPTION oxygen. PROPERTY OF LESSON 2: THE PHASES OF MATTER MATTER Color Pigment of a substance PHASES OF MATTER Odor Smell of a substance The water on the surface of Earth is constantly changing Luster How matter reflects light among three phases. Malleability How an object can be hammered into thin sheets The phrase five states of matter is a term to describe Ductility How matter can be stretched into thin everything that makes up the “stuff” in the universe. wires The different phases of matter behave in such a way that Hardness How matter can be stretched or dented their characteristics are physically affected by the motion Viscosity How liquids easily flow of the molecules and their intermolecular attractions. Texture Feel of a substance when touched Molecules are in constant motion because each of them Durability Ability to resist corrosion has its own kinetic energy. Brittleness Ability of an object to break apart Elasticity Ability to resume its shape  SOLID Temperature Amount of energy in a substance -It has a definite shape. Conductor Ability to allow heat or electricity to flow -It has a definite volume. of heat and into it -Its molecules are tightly packed. electricity -The particles vibrate about a fixed position. PHYSICAL CHANGE  LIQUID Physical changes are observable changes in the -It changes its shape depending on the container. appearance of matter while it does not change into a new -It has a definite volume. substance. These are changes caused by different -Its molecules are slightly loose. actions such as cutting, folding, grinding, bending, or -The particles move around one another. As the high temperature that forms plasma falls, the  GAS electrons will then begin to return to the atom, forming -It has no definite shape. back as a gas. This is called deionization. -It has no definite volume. -Its molecules can freely move. THE BOSE-EINSTEIN CONDENSATE -The particles move quickly in all directions. Is considered to be the exact opposite of plasma. It exists -Its molecules will spread out into the environment at extremely low temperatures or near absolute zero temperature.  PLASMA As the atoms start to cool down, they clump together that -It has no definite shape. they could no longer move, producing a condensate of a -It has no definite volume. gaseous superfluid. -Its molecules can freely move. -The particles move quickly in all directions with electron PHASE CHANGES charge. Phase change is a type of reversible physical change that -Energized gas that have lost their electrons makes the phase of matter change due to the absorption -Exists as fluid like that of a liquid and gas producing or the release of heat. electromagnetic forces When a substance changes its phase, its form volume, SOLID and particle motion may change as well. A solid is a phase of matter that has a definite volume THERE ARE GENERALLY SIX PHASE CHANGES and a distinct shape given a certain temperature. Ice is a THAT MATTER CAN UNDERGO: solid form of water, but it must have a temperature below 0°C to remain at this phase. MELTING The molecules in solid are closely packed together by Melting is a process by which a substance in the solid molecular forces. phase turns into the liquid phase. The kinetic energy of the molecules in a solid is so low FREEZING OR SOLIDIFICATION that the molecular attraction between the molecules is A substance in liquid phase may turn into solid by much stronger than the forces pulling them away. freezing it. This happens when a liquid is cooled to a It would cause the molecules to stay in their places even lower temperature called its freezing power. if they still have some energy, and their movement will be confined through vibrations only. VAPORIZATION Vaporization is the process by which a liquid turns into LIQUID gas. When a substance reaches its boiling point, it starts to change into the gaseous phase. A liquid is a phase of matter that has a definite volume, Evaporation occurs when the surface of water gains heat but it takes the shape of its container due to gravity. and changes into water vapor, which may start to occur The molecular forces in a liquid are weaker than those of at any temperature. a solid. The molecules in a liquid have enough kinetic energy to move fast to break out from their confined CONDENSATION structure so they can move loosely. Condensation is a process by which a gas turns into a liquid. This happens when water vapor comes in contact GAS with a cool surface. It looses heat and changes back into liquid water. The volume of a gas is dependent on its temperature and surrounding pressure. If affected by gravity, the gas will SUBLIMATION take the shape of the container. Sublimation is a process by which a solid turns into a A gas will fill its container. gas. Freeze-drying is a process in which food is frozen and placed in a very sealed and vacuum-packed The molecular forces in a gas are very weak because container. gaseous molecules are far apart from one another. The The moisture or water in the food sublimes, having a molecules in gases are more energetic and move rapidly. lesser effect on the food’s taste. Gas can easily be compressed than solids or liquids DEPOSITION because there is so much space between their Deposition occurs when a gas turns directly into a solid. molecules. PHASE DIAGRAMS PLASMA The phase diagram is a graphical representation that When gas particles gain energy through heating at very shows the different changes in the phase of a substance high temperature or when they absorb electrical energy, and the conditions of temperature and pressure. A typical plasma is formed. This happens through ionization. In phase diagram has pressure on the y-axis and this process, the atoms of an element break down, temperature on the x-axis. allowing the electrons to break free leaving a positively charged ion. The critical point of a substance is the temperature at and Plasma exists as fluidlike that of a liquid and gas above in which the vapor of the substance cannot be producing electromagnetic forces. liquefied. ERNEST RUTHERFORD THE HISTORY AND DEVELOPMENT OF THE ATOMIC -Former student of J.J. Thomson THEORY -Believed in plum pudding -Wanted to find out how big they are Atom is considered the smallest particle of matter. -Fired positively charged alpha particles at a piece of gold Atomic model is a representation of what an atom could foil, which can be made a few atoms thick. look based on observations and scientific evidence. -Gold foil experiment ATOMIC THEORY -Atoms mostly empty space and not filled with a positively  Democritus – realized that if you continued to charged material cut something, eventually you would end up with -Small positive charged center (nucleus) something that couldn’t be cut anymore, -Negatively charged particles around the nucleus. “atomos” meaning not able to divide.  Atoms – smallest particle that an element can NUCLEAR MODEL be divided & still be the same substance. All -Rutherford described that the atom consists of a dense matter is made of atoms. core called the nucleus with a positively charged particle  There are empty spaces between these inner known as proton, while the electrons surround the structures of matter. nucleus. He called this nuclear model of an atom. ARISTOTLE NIELS BOHR  Matter was made up of four natural elements. -Improved the idea of Rutherford by proposing that  The ratio of these four elements (Air, Fire, Water, electrons are not stationary as they move around the Earth) affects the properties of matter and can nucleus in fixed circular orbits known as energy levels. be also transformed into one another. -He called this new model the planetary model. JOHN DALTON JAMES CHADWICK  English physicist -In 1932, he discovered a third type of sub atomic particle,  Proposed the first atomic theory after conducting which he named the neutron. number of experiments about atoms -Neutrons help to reduce the repulsion between protons and stabilize the atom’s nucleus.  A NEW SYSTEM OF CHEMICAL PHILOSOPHY THE MODERN ATOMIC THEORY  Atoms as solid spheres which had four -Atomic number of an element is equivalent to the characteristics number of protons in its nucleus. -The number of protons is equal to the atomic number, DALTON’S ATOMIC THEORY and the number of electrons is equal to the number of 1. All elements are composed of submicroscopic protons which makes the atom electrically neutral. indivisible parts called atoms. 2. Atoms of the same element are identical, those MASS NUMBER of different atoms are different, -The mass number of an element is the combined 3. Atoms of different elements combine in whole number of protons and neutrons present in its nucleus. number ratios to form compounds. -An atoms can be considered unstable in one of two 4. Chemical reactions involve the rearrangement of ways. If it gains or loses an electron, it becomes atoms. No new atoms are created or destroyed. electrically charged and highly reactive. Such electrically charged atoms are known as ions. JJ THOMPSON -“Plum Pudding” or “Cookie Dough” model MODERN ATOMIC THEORY -Discovered the electron in 1897. -The modern atomic model represents atoms containing -Atoms were made from a positively charged substance a nucleus of protons and neutrons and a vague gradient with a negatively charged substance scattered about. or cloud surrounding it containing the electrons; this is sometimes referred to as the cloud model. The reason THOMPSON’S MODEL electrons are represented as a cloud is because of their -Found the electron behavior being probabilistic. >1 unit of negative charge >Mass 1/2000 of hydrogen atom >Later refined by Millikan to 1/1840 -Concluded that there must be a positive charge since atom was neutral -Atom was like plum pudding >A bunch of positive stuff, with electrons able to be removed JOSEPH JOHN THOMSON -Discover electrons from his observations in his cathode ray tube experiment. -Cathode ray tube – A glass tubing with two electrodes, namely, the anode (+) and the cathode (-).

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