REVIEW AND RETEACHING FORMATIVE ASSESSMENT #2

QUESTION #1 (PS 1.6) Mixtures are combinations of matter that are physically combined. Mixtures can be separated by physical means such as: FilteringUsing a magnet EvaporatingStraining Sorting Examples of mixtures are: Sand on a beach Trail mix Kool Aid or Lemonade

QUESTIONS #2-3 (PS ) In a physical change, you have the same substance before and after the change occurs. Examples: Water freeing, melting, evaporating Crushing chalk Breaking glass Physical changes are often, but not always, reversible by physical means

QUESTIONS #2-3 (PS ) In a chemical change, something new, with new properties, is produced: Indicators of a chemical change include: Change of heat, light, or temperature Formation of a new type of solid Formation of a new type of gas Change of color or odor Example of a chemical change: Mixing baking soda and vinegar to get carbon dioxide gas. Chemical changes are sometimes reversible, but it is often a difficult or impractical process. Most changes that occur in nature have both physical and chemical properties.

QUESTION #4 (PS 1.9) The law of conservation of mass states that matter cannot be created or destroyed. Therefore, the mass of substances before a reaction will equal the mass of the substance after a reaction. Even if some of the product of a reaction escapes and cannot be measured (for example, in an open system), conservation of mass still applies. 5 g 10 g 15 g 5 g 3 g 12 g10 g

QUESTION #5 (PS 2.2) In an open system, mass and energy can enter and exit the system. Most systems on Earth are open systems. Example: An ecosystem. A closed system, does not allow matter or energy to enter or exit the system. It is difficult to identify real-life examples of closed systems. Example: A sealed tin can of baked beans.