Daily Science (Sept 18) List an example of a physical property and tell why it is a physical property List a chemical property and tell why it is a chemical property List two chemical changes and two physical changes What are the 4 ways to separate a mixture?

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Extensive and Intensive properties Extensive properties are dependent upon the amount Ex. Mass, volume Intensive properties are independent of the amount of substance. Ex. Density

States of Matter Solid- rigid, definite shape and volume. Particles move slowly in place. Liquid- constant volume, takes the shape of container. Particles can flow and slide past one another. Gas- no constant volume, takes shape of container. Particles move very fast.

Conservation of mass A law that states that matter can neither be created nor destroyed. Mass reactants = Mass products

Conservation of Mass Practice From a laboratory process designed to separate water into hydrogen and oxygen gas, a student collected 10 g of hydrogen and 79.4 grams of oxygen. How much water was originally involved in the process? (2H 2 O  2H 2 + O 2 ) A 10 g sample of magnesium reacts with oxygen to form 16.6 g of magnesium oxide. How many grams of oxygen reacted?

Organization of Matter

Law of Definite Proportions Says a compound is always composed of the same elements in the same proportion by mass. Mass of compound= mass of components of compound Can compare the ratio of component’s mass to compound. Called percent by mass

Percent by mass Percent by mass =(mass of element)/(mass of compound)x 100 Ex. A 78 g sample of an unknown compound contains 12.4 g of hydrogen. What is the percent by mass of hydrogen in the compound? Your Ex. A 28 g sample of water contains 2.8 g of hydrogen. How many grams of oxygen are present? Find the percent mass of each.

Law of Multiple Proportions When different compounds are formed by a combination of the same elements, different masses of one element combine with the same masses of the other elements in a ratio of small whole numbers. Ex. H 2 O and H 2 O 2 ; Both have hydrogen and oxygen but in different ratios. If we compare the ratio of oxygen we say there is a ratio of 2: 1 (2 O in hydrogen peroxide for every 1 O in water)