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Grade 10 Academic Science - Chemistry Matter Matter is anything that has mass and volume. Matter exists in five states or phases: Solid Liquid Gas Plasma Bose-Einstein Condensation Phase describes a PHYSICAL state of matter. Matter “moves” from one phase to another by physical forces such as temperature and pressure. If energy is added (e.g., increased temperature) or taken away (e.g., freezing), a physical change is created. SOLID + e = LIQUID + e = GAS + e = PLASMA Any kind of matter can be classified as a mixture or a pure substance. Mixture - Matter that has two or more kinds of particles and thus may have different properties in different samples Pure substance – A substance that has the same properties in any sample you choose. There are two kinds of pure substances: elements and compounds. Element - A substance composed of atoms having an identical number of protons in each nucleus. Elements cannot be reduced to simpler substances by normal chemical means. Compound - A substance formed by chemical union of two or more elements or ingredients in definite proportion by weight. Chemical Change - A change in the chemical composition of a substance to produce a new material with new properties Physical Change - A physical change is any change NOT involving a change in the substance's chemical identity (e.g., liquid to solid is freezing; solid to gas is sublimation, liquid to gas is evaporation) Grade 10 Academic Science –Chemistry Physical and Chemical Properties Physical Property A characteristics that can be determined without altering the chemical composition of the material Boiling point Brittleness - Hard but easily broken or likely to break. Colour Crystal structure – The unique arrangement of atoms in a crystal Density - Mass divided by its volume. Density is related to how compressed the material is and the weight of its atoms or molecules per unit volume. Ductility - The quality or state of being flexible (e.g., bounce, elasticity, flexibility) Electrical conductivity Freezing point Hardness - Relative resistance of a metal or other material to denting, scratching, or bending Heat conductance – Ability or power to conduct or transmit heat Luster - Brightness of an object that shines with reflected light rather than producing its own Magnetic properties Malleability - Ability of a substance to be molded into different shapes Specific heat capacity Solubility - Measure of how much of a given substance will dissolve in a liquid Tensile strength - The resistance of a material to a force tending to tear it apart, measured as the maximum tension the material can withstand without tearing Chemical Property A property used to characterize materials in reactions that change their identity Electronegativity - The ability of an atom or molecule to attract electrons in the context of a chemical bond Oxidization – Describes the loss of an electron Flammability - The ability of a substance to burn in the presence of oxygen Ionization potential – Energy required to strip an atom of an electron. States of Matter SOLID - What is a solid? Some Properties Solids are usually hard because their molecules have been packed together. The closer your molecules are, the harder you are. Solids hold their own shape. A rock will always look like a rock unless something happens to it. Even when you grind up a solid into a powder, you will see little tiny pieces of that solid under a microscope. Liquids will move and fill up any container. Solids retain their shape. The atoms of a solid do not move too much. Atoms and molecules in liquids and gases bounce and float freely. The molecules of a solid do not. Solids can have pure elements (one) or a variety of compounds (more than one). More than one type of compound in a solid is a mixture. When a solid is made up of a pure substance and forms slowly, it can become a crystal. The atoms are arranged in a regular repeating pattern called a crystal lattice. A diamond is a crystal. LIQUID - What is a liquid? Some Properties Water is a liquid. Your blood is a liquid. Liquids are an in-between state of matter (i.e., they are found in between the solid and gas states). Liquids can made up of the many compounds. If you have a variety of materials in a liquid, it is called a solution. Liquid take the shape of their “container”. If you pour water in a cup, the water will fill up the bottom of the cup first and then fill the rest. Liquids are difficult to compress. To compress something, you apply force. When you compress something, you force the atoms closer together. The atoms of a liquid are already. Thus, liquids are hard to compress. Liquids have cohesive forces that hold the molecules of a liquid together. GAS – What is a gas? Some Properties Gases are random groups of atoms. In solids, atoms and molecules are compact and close together. Liquids have atoms a little more spread out. However, gases are really spread out and the atoms and molecules move constantly. Gases take the size and shape of their “container” filling all parts of the container equally. A vapor is a gas in a liquids form at room temperature (e.g., water (H2O), mercury (Hg)). Gases hold huge amounts of energy Gas molecules are spread out. With very little pressure compared to liquids and solids, gas molecules can be compressed. PLASMA Plasma is a low-density gas with a neutral charge (i.e., an equal number of positively and negatively charged particles). Plasma consists of a gas heated to sufficiently high temperatures that the atoms ionize. The properties of the gas are controlled by electromagnetic forces among constituent ions and electrons, which results in a different type of behavior. Plasma is capable of conducting electricity. Most of the universe is plasma, and the solar wind is hot plasma blowing from the sun. BOSE-EINSTEIN CONDENSATION Bose-Einstein Condensation in a gas is the newest new form of matter at the coldest temperatures in the universe. It is a gaseous, superfluid phase formed by atoms cooled to temperatures very near to absolute zero Grade 10 Science - Chemistry Understanding Matter, Physical Change and Chemical Change Laboratories Lab #1 Experimenting with States of Matter Materials Cornstarch Water Cup Stir stick Methods Place 15 mL of cornstarch in a cup. Add 30 mL of water and stir well. Place some of the mixture on a table. Touch it with your fingertips. Is it a liquid or a solid? Results When cornstarch and water are mixed, a thixotropic mixture was formed. It is a mixture that cannot consistently retain the properties of any one state of matter. Thus, the mixture that was formed was neither a liquid nor a solid. Lab #2 Experimenting with Physical Changes Materials Salt Water Cup Methods Place 30 mL salt in a cup. Add 30 mL of water. S tir until all of the salt is dissolved. Place the cup in a sunny window. After a few days, check on the cup. What was left in the cup? Results The cup should contain only salt. The water evaporated. Since a new substance was not formed, a physical change has taken place. Lab #3 Experimenting with Chemical Changes Materials 30 mL baking soda 60 mL vinegar 100 mL water Cup Popcorn kernels. Methods Mix the vinegar and water together in the cup Add the baking soda Immediately add 5 popcorn kernels Observe what happens for the next five minutes Results The popcorn kernels should rise and sink during the five minutes. The vinegar and baking soda combined to form a gas. This was shown by the bubbles that appeared on the kernels. When the kernels reached the surface of the liquid the bubbles popped, causing the kernel to fall to the bottom again. Thus, a chemical change has occurred because gas was given off. Lab #4 Experimenting with Chemical Changes 2 Materials steel wool Vinegar Cup Methods Place the steel wool in the bottom of a cup. Add 50 mL of vinegar. Wait for 15 minutes. What evidence is there that a chemical change has taken place? Results After approximately 20 minutes, rust starts forming at the sides of the cup where the steel wool was touching. Rusting is a process that cannot be reversed, and thus, a chemical change has taken place. For each experiment, 1. Record results and observations 2. Provide a discussion for your observations (e.g., why did it occur?) 3. Identify a PHYSICAL or CHEMICAL CHANGE NOTE: Experiment #2 will take a few days. Make sure you observe your cup in two days.