Chapter 2 Matter and Change Chemistry pg 38

  • Slides: 25
Download presentation
Chapter 2 Matter and Change Chemistry pg. 38

Chapter 2 Matter and Change Chemistry pg. 38

2. 1 Properties of Matter • Properties used to describe matter are classified as:

2. 1 Properties of Matter • Properties used to describe matter are classified as: 1. Extensive – depends on the amount of matter in a sample ex. Mass, volume 2. Intensive – depends on the type of matter in a sample, not the amount ex. Color, hardness, boiling point

Substance • Matter that has a uniform and definite composition ex. Gold, copper (pure

Substance • Matter that has a uniform and definite composition ex. Gold, copper (pure substances) Every sample has identical intensive properties because every sample has the same composition

Physical Property • A quality or condition of a substance that can be observed

Physical Property • A quality or condition of a substance that can be observed or measured without changing the substance’s composition • Help chemists identify substances • Hardness • Color • Conductivity • Malleability (see Table 2. 1, Pg. 40)

Three states of matter • Solid-definite shape, volume, not easily compressed • Liquid-indefinite shape,

Three states of matter • Solid-definite shape, volume, not easily compressed • Liquid-indefinite shape, flows, definite volume, almost incompressible • Gas-indefinite shape, indefinite volume, easily compressed • http: //www. chem. purdue. edu/gchelp/liquids/ character. html

Physical Changes • Properties of a material change but the composition does not ex.

Physical Changes • Properties of a material change but the composition does not ex. Boil, freeze, melt, condense AND break, split, grind, cut, crush Physical changes can be REVERSIBLE or IRREVERSIBLE

2. 2 Mixtures • Physical blend of 2 or more components ex. Chicken noodle

2. 2 Mixtures • Physical blend of 2 or more components ex. Chicken noodle soup, air Mixtures can be classified as… HETEROGENOUS or HOMOGENOUS (based on distribution of components)

Matter can be Heterogeneous • The composition is not uniform throughout • More than

Matter can be Heterogeneous • The composition is not uniform throughout • More than one phase…so it’s a mixture -Phase – any region with a uniform set of properties that can be separated from each other by definite boundaries called interfaces

Matter can be Homogeneous • The composition is uniform throughout, evenly distributed • Only

Matter can be Homogeneous • The composition is uniform throughout, evenly distributed • Only one phase

Identify the following • Concrete _____________ • Vinegar______________ • Carbon dioxide___________ • Granite rock____________

Identify the following • Concrete _____________ • Vinegar______________ • Carbon dioxide___________ • Granite rock____________ • Milk________________

Separating mixtures • Distillation - a liquid is boiled to produce a vapor which

Separating mixtures • Distillation - a liquid is boiled to produce a vapor which is condensed into a liquid Other ways? distillation • How to perform simple distillation in the chemistry lab | Wonder How To

2. 3 Elements and Compounds • Substances classified as 1. _____- simplest form of

2. 3 Elements and Compounds • Substances classified as 1. _____- simplest form of matter that has a unique set of properties (O, H) 2. ______- substance that contains 2 or more elements chemically combined in a fixed proportion (C 6 H 12 O 6)

 • Compounds can be broken down by _______ means. • Elements cannot be

• Compounds can be broken down by _______ means. • Elements cannot be broken down • Chemical change produces matter with a different composition than the original matter Sugar Carbon + Water

Properties of Compounds • Generally, properties of compounds are different from their component elements

Properties of Compounds • Generally, properties of compounds are different from their component elements • Sodium - soft, gray metal, reacts with oxygen + • Chlorine - yellow-green poisonous gas Sodium chloride Reaction

Distinguishing Substances and Mixtures • If the composition of a material is fixed, the

Distinguishing Substances and Mixtures • If the composition of a material is fixed, the material is a substance examples? • If the composition of a material may vary, the material is a mixture examples?

Classifying Matter

Classifying Matter

 • Classify the following materials as an element, compound, or mixture. a. Table

• Classify the following materials as an element, compound, or mixture. a. Table salt b. Salt water c. Sodium

Symbols and Formulas • Chemical symbols O, C, Na, Ne elements • Chemical formulas

Symbols and Formulas • Chemical symbols O, C, Na, Ne elements • Chemical formulas CO 2 , H 2 O compounds

2. 4 Chemical Reactions • Chemical Property – the ability of a substance to

2. 4 Chemical Reactions • Chemical Property – the ability of a substance to undergo a specific chemical change (describes the way a substance may react to form other substances) examples? - can be observed only when a substance undergoes a chemical change

 • Fig. 2. 13 (pg. 53) Chemical reaction S + Fe *physical -

• Fig. 2. 13 (pg. 53) Chemical reaction S + Fe *physical - composition of matter never changes *chemical – composition of matter always changes Chemical change = chemical reaction Reactants Products

 • Chemical change = chemical reaction (one or more substances change into one

• Chemical change = chemical reaction (one or more substances change into one or more new substances) Reactants Products

Recognizing Chemical Changes 4 Ways: 1. Color change 2. Formation of precipitate 3. Production

Recognizing Chemical Changes 4 Ways: 1. Color change 2. Formation of precipitate 3. Production of gas 4. Transfer of energy

 • Precipitate an insoluble substance that forms in, and separates from, a solution

• Precipitate an insoluble substance that forms in, and separates from, a solution

Identify clues for chemical changes magnesium ribbon in flame Sodium iodide solution added to

Identify clues for chemical changes magnesium ribbon in flame Sodium iodide solution added to mercury(II) chloride solution

Law of Conservation of Mass • In any physical change or chemical reaction, mass

Law of Conservation of Mass • In any physical change or chemical reaction, mass is __conserved_______. mass of products = mass of reactants