Properties of Matter

Properties of Matter : Properties of Matter Chemistry Text Chapter 1

Properties of Matter : Properties of Matter Look around you. All the things you see are examples of matter. But what exactly is matter? Matter is defined as… anything that has mass and takes up space. Materials may differ in terms of the kind of matter they contain.

Classification of Matter : Classification of Matter

Substances : Substances Matter that has a uniform and definite composition is called a substance (pure substances) What are some examples of pure substances? A: any element or compound Mixtures are not substances as their compositions can vary (e.g. sugar water)

Physical properties : Physical properties All samples of a substances have identical physical properties. A physical property is a quality or condition of a substance that can be observed or measured without changing the substances composition. Physical properties include colour, solubility, odour, hardness, density, melting and boiling point.

Slide 6 : Chemists distinguish different substances from one another on the basis of their physical properties. Every substance has a unique set of physical properties. No two substances have exactly the same melting point, boiling point or density.

States of Matter : States of Matter The physical state of a substance is a physical property of that substance. What are the characteristics of solids, liquids and gases, and how do their shapes and volume differ?

Solid : Solid The particles in solids are packed tightly together in a fixed pattern. There are strong forces holding them together, so they can’t leave their positions. The only movements they can make are tiny vibrations back and forwards.

Liquid : Liquid The particles in liquids can move about and slide past each other. They are still close together but are not in a fixed pattern. The forces that hold them together are weaker than the forces in solids.

Gas : Gas The particles in a gas are far apart, and they move very quickly. There are almost no forces holding them together. They collide with each other and the walls of the containers, and bounce in all directions.

Physical Changes : Physical Changes What happens to a block of chocolate if you leave it in the sun? The solid chocolate turns to liquid chocolate. The chocolate is still chocolate but in a different state. When a physical change occurs, no new substance is formed.

Changing State : Changing State Particles gain energy and vibrate more Particles gain enough energy to break away and move around freely as a liquid. Solid

Physical change : Physical change In a physical change: No new substances are produced. The change is usually, fairly easy to reverse Boil, freeze, dissolve, melt, condense, break, split, crack, grind, cut, crush and bend usually signify a physical change.

Chemical Changes : Chemical Changes When you boil an egg, a chemical change takes place. At about 1000C the eggwhite & yolk undergo chemical changes which alter their chemical make-up. Whenever a new substances are formed a chemical reaction has taken place. Unlike the cooling the melted chocolate, which brings about another physical change, cooling the egg will not change it back to its raw state.

Chemical Changes : Chemical Changes In a chemical reaction, one or more substances change into new substances. Reactants and Products The ability of a substance to undergo a chemical reaction and form a new substance is called a chemical property.

Chemical Changes : Chemical Changes In a chemical change: New substance with new properties are produced. The change is often difficult to reverse. Burn, rot, rust, decompose, ferment, explode and corrode usually signify a chemical change.

Chemical changes : Chemical changes How do you know if the chemical change has occurred? During a chemical reaction you could possibly observe: Colour change Production of gas Production of heat Loss of heat Production of light Production of solid/precipitate.

Questions : Questions List three physical properties of a iron nail. Is every sample of matter a substance? Explain. Contrast the characteristics of the 3 states of matter.

Questions : Questions List three substances that you have experienced in at least two physical states. Provide two examples of physical changes and two examples of chemical changes. What happens to the mass of the reactants and products in a chemical reaction?

Questions : Questions Each day of your life you encounter some chemical changes that are helpful and some that are harmful. Think of 3 examples of each. For each example, list the indications that identified the change as chemical.