OB: Compounds + Elements, the Law of Conservation of Matter We will discuss the conclusion for the penny lab, due Friday, Also take out HW #1

Review of yesterday: Elements are limited in number, pure, listed on the periodic table and, cannot be made simpler Compounds form when 2 or more elements chemically combine into a new pure substance, with unique properities, and a specific ratio of atoms to atoms Mixtures are just mixed up combinations of stuff, no ratios, no recipes, and can be physically separated. There are no new properties formed. Mixtures can be heterogeneous or homogeneous.

MATTER Pure substances all homogeneous Mixtures (heterogeneous or homogeneous) Elements examples: Mg, Ca, Fe Compounds examples: H 2 0, CO 2, NaCl Homogeneous examples: air, tap water, includes all solutions Heterogeneous concrete, soup, sugar + salt in a bowl sand + iron BB’s

The Law of Conservation of Matter Matter cannot be created or destroyed in any chemical reaction (or physical change) Iron + oxygen yields iron oxide Iron and oxygen are the __________________ Iron oxide is the ______________________ The mass of the _____________ equals the mass of the __________

223 g Iron + 96 g Oxygen ______ Iron Oxide 4 g hydrogen + X g oxygen 36 grams water

223 g Iron + 96 g Oxygen 319g Iron Oxide 223 g + 96 g = 319 g 4 g hydrogen + 32 g oxygen 36 grams water 4 g + X g = 36 g X = 32 g

8 g hydrogen + 64 g oxygen will form into ____ g water ____ g hydrogen + 28 g nitrogen 34 g ammonia (NH 3 )

8 g hydrogen + 64 g oxygen make how many g water? ______ 8 g + 64 g = 72 g ____ g hydrogen + 28 g nitrogen 34 g ammonia (NH 3 ) X g + 28 g = 34 g X = 6 g hydrogen

Home work #1 take out Then, Density by Displacement Lab Conclusion