1. Unit 4 Review

2. 1. Define Compound A substance made by chemically combining two or more elements.

3. 2. How many elements make up each of these compounds? How many atoms of each elements are in one molecule of the compound? # of Element s 3542 # of Atoms 2418305

4. 3. List chemical reactions that can take place during the production of a new substance. Change in color Change in temperature Production of a gas Precipitate

5. 4. Chemical change or Physical Change C Iron rustingP Grinding something into powder C Leaves change color in the Fall P Sanding wood C Water separates into hydrogen and oxygen P Dry ice goes from a solid to a gas form of CO 2 P Ice meltingP Breaking glass P Sugar cube dissolving in water P Breath condensing on a cold window P Paper tearingP Mixing flour, salt, and sugar

6. 5. A new compound has just been made. Its formula is : COFeHNCoBNa 8 Elements C- Carbon O- Oxygen Fe- Iron H- Hydrogen N- Nitrogen Co- Cobalt B- Boron Na- Sodium

7. 6. List the characteristics of elements and compounds in the correct category. Pure substance Written using chemical symbol Found on the Periodic Table Can be broken down by chemical means Written using chemical formula New substance formed when two or more elements create a chemical reaction

8. 7. What should the following columns be titled? ABCD Penny turns dull over time Cutting paper into tiny pieces Dry ice disappears while sitting out Ingredients for cake batter are mixed together Trees produce oxygen Ice cream melting Water droplets form on a cold glass of soda Shredding cheese Piece of fruit turns brown after sitting out Dissolving sugar in tea A pencil is sharpened Mowing the grass A- Chemical Change B- Physical Change C- Physical Change D- Physical Change

9. 8. The table below is the recorded results of an experiment that produces a gas when specific amounts of a solid and liquid were mixed. Liquid (mL)Solid (g)Gas (g) 2550.8 50101.6 75152.4 10020X X= 3.2