How can we describe matter? Page 39 Extensive Properties – depend on the amount of matter in a sample Ex. Mass, Volume Intensive Properties – depends on the type of matter, not the amount Ex. Density, Boiling Point, Freezing Point

Identifying Substances Substance - matter that has a uniform and definite composition Physical Property – a property that can be observed without changing the substance’s composition Color, Luster, Malleability, Boiling/Melting/Freezing Point, Density, conductivity,

States of Matter and Phase Changes P. 41 Chapter 2: Matter and Change States of Matter and Phase Changes P. 41 Exothermic Exothermic P. 59 Q - 60-64 Exothermic

Is it a gas or a vapor? Vapor – the gaseous state of a substance that is generally a solid or gas at room temperature Question 40 - P. 58

Physical Change – a property of a substance that changes but the identity of the substance does not Ex. Melting, freezing, splitting, grinding Density of water (l) – 1.00 g/cm3 Density of water (s) - .92 g/cm3

Classifying Mixtures – a blend of two or more substances Heterogeneous Not uniform throughout Ex. Salad dressing, Sand, chocolate chip cookie dough Homogeneous Uniform throughout Solution – liquid or gas Coke, Sea water, gold jewelry, air P. 58 Q-44-46, P. 59 Q 66

Separating Mixtures Density Filtration – separates a solid from a liquid in a heterogeneous mixture Distillation – separates a homogenous mixture of water and another substance (Boiling Points) P. 58 Q - 47

Element Simplest form of matter that has a unique set of properties Ex. Carbon, Oxygen, Iron Compound A substance that contains 2 or more elements chemically combined in a fixed proportion Ex. Salt – NaCl, Glucose C6H12O6 Can be broken down into simpler substances by chemical means

Representing Elements and Compounds Element – first letter capital, second letter lower case K = Potassium Na = Sodium Aspirin – C8H9O2N Subscript – indicates the number of atoms, follows the element P. 58 Q - 50,52

Compounds - continued Cu(NO3)2 Multiply the subscripts inside and outside the parentheses to determine the number of atoms Subscript outside the parentheses only refers to the elements inside

Indicate the names of each element and the total number of atoms in each compound. MgCl2 Ca3(PO4)2 CrCO3 Ca(C2H3O2)

Breaking Down Compounds Chemical change –produces matter with a different composition than the original matter Heating – raw egg vs. fried egg Electricity – decomposes water into H2 and O2 gas.

Indicators of a Chemical Change color change production of a gas formation of a precipitate (solid) transfer of energy Production of light Change in Temperature Exothermic – release in heat, increase in temp. Endothermic – heat absorption, decrease in temp. multiple forms of evidence are needed P. 59 Q - 69-71

s = solid, l = liquid, g = gas, aq = aqueous Chemical Property – the ability of a substance to undergo a specific chemical change Ex. Reactivity with acids, flammability, decomposition Coefficients – state the number of individual atoms, compounds or molecules 4Fe(s) + 3O2(g)  2Fe2O3(s) rust State of matter – before and after the reaction s = solid, l = liquid, g = gas, aq = aqueous P. 59 Q - 67

Chemical and Physical Properties

Law of Conservation of Matter Mass is neither created nor destroyed in a chemical reaction it is conserved Mass reactants = Mass products Antoine Lavoisier (1743-1794)

Applying the Law of Conservation of Matter 4Fe (s) + 3O2 (g)  2Fe2O3 (s) 3.5 kg x kg 3.7 kg + = x = .2 kg

Sn (s) + 4HCl (aq)  SnCl4 (s) + 2H2 (g) When 5.0 g of tin reacts with hydrochloric acid, the mass of the products tin chloride and hydrogen totals 8.1 g. Sn (s) + 4HCl (aq)  SnCl4 (s) + 2H2 (g) How many grams of hydrochloric acid were used? How many atoms of hydrogen are present on the reactants side of the equation? Products? How many atoms of tin are present on the reactants side of the equation? Products? How many atoms of chlorine are present on the reactants side of the equation? Products? Identify the state of each reactant. Identify the state of each product. How many molecules of HCl are present? H2? P. 55 #34, P. 58 # 56 P. 61 #10-14