Changes In Matter Study Guide 1 PDF

Changes in Matter  Focus Question How does a substance change when it burns?  New Vocabulary physical change phase change chemical change law of conservation of mass  Physical Changes A change that alters a substance without changing its composition is k...

Changes in Matter  Focus Question How does a substance change when it burns?  New Vocabulary physical change phase change chemical change law of conservation of mass  Physical Changes A change that alters a substance without changing its composition is known as a physical change. As temperature and pressure change, most substances undergo a phase change, a transition of matter from one state to another. Boiling, freezing, melting, vaporizing, and condensing all describe phase changes.  Chemical Changes A process that involves one or more substances changing into new substances is called a chemical change. Decomposing, rusting, exploding, burning, and oxidizing all describe chemical changes. A chemical change is commonly referred to as a chemical reaction.  Chemical Changes A chemical reaction always produces a change in properties. The observation that the product has different properties (for example, smell, color, magnetism) than the reactants is evidence that a chemical reaction has taken place.  Conservation of Mass The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; it is conserved. The mass of the reactants equals the mass of the products. massreactants = massproducts  Kinetic Theory of Matter The kinetic theory of matter is a scientific model that explains the behavior of matter in terms of the motion of its constituent particles, such as atoms and molecules. It is based on several key assumptions: Matter is composed of tiny particles. These particles are too small to be seen with the naked eye. The particles are in constant motion. They are moving in all directions, even in solids. The particles are colliding with each other and with the walls of their container. These collisions cause the pressure exerted by the gas. The average kinetic energy of the particles is proportional to the temperature of the matter. This means that the faster the particles are moving, the higher the temperature of the matter. Heating Curve Cooling Curve  Quiz 1. Which term refers to a physical change? A decompose B explode C melt CORRECT D tarnish  Quiz 2. Which term refers to a chemical change? A boil C rust CORRECT B freeze D vaporize  Quiz 3. Which observation is not evidence that a chemical reaction might have occurred? A There is an odor change. B A solid is no longer magnetic. C A solid melts. CORRECT D A solid changes color.