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?

Properties of MatterPg. 27

Extensive and Intensive propertiesExtensive properties are dependent upon the

amountEx. Mass, volume

Intensive properties are independent of the amount of substance.Ex. Density

States of MatterSolid- 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 massA law that states that matter can neither be

created nor destroyed.Massreactants = Massproducts

Conservation of Mass PracticeFrom 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?

(2H2O 2H2 + O2)

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 ProportionsSays 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 massPercent 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 ProportionsWhen 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. H2O and H2O2; 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)