UNIT 2 PHYSICAL & CHEMICAL PROPERTIES

Transcription

1 UNIT 2 PHYSICAL & CHEMICAL PROPERTIES

2 What Is Matter? How matter is made of Elements? What atoms make up? Theory Law and Hypothesis Physical and Chemical Changes Heterogenous and Homogenous Substances

3 WHAT IS CHEMISTRY? Chemistry is the study of the structure and composition of matter, the physical and chemical changes it undergoes, and the energy that is exchanged By understanding how matter interacts with itself we are able to make compounds that help benefit the world (medicine, fuels, clothes, soap, etc.)

4 WHAT IS MATTER? Matter- Anything that takes up space and has mass Everything is made up of matter (Rocks, Metals, Oils, Gases, Human Body) Matter can be found in 3 states (solid, liquid, & gas)

5 WHAT MATTER IS MADE OF? Matter is made up of Elements Element- is a substance that cannot be broken down to other substances by chemical reactions 92 naturally occurring elements Around 24 man made elements Each element is classified into one of 3 classes Metal, Nonmetal, Metalloid

6 ELEMENTS Elements are represented by symbols Carbon = C Oxygen = O Sodium = Na

7 ESSENTIAL ELEMENTS 25% of the natural elements are Essential Elements Essential Elements- Elements that are needed for basic everyday functions of life Around 96% of all the elements Humans use can be broken down into 4 Essential Elements (Carbon, Oxygen, Hydrogen, & Nitrogen)

8 NAME THESE ELEMENTS:

9 COMPOUNDS Compound- Consist of 2 or more different elements combined (chemically bonded) in a fixed ratio

10 ATOMS Atom- The smallest unit of matter that still retains the properties of an element Each element consist of a certain type of atom different from the atoms of any other element (every type of atom is different) Atoms make up all matter!

11 LAWS, THEORIES, & HYPOTHESES Law: tells us exactly what is going to happen, these are statements that have been proven correct through hundreds if not thousands of experiments Theory: attempts to explain why something happens not a proven law Hypothesis: educated guess on whats going to happen

12 LAWS Law of Conservation of matter/mass: Mass cannot be created or destroyed in ordinary chemical or physical processes Law of Conservation of Energy: Energy is cannot be created or destroyed in ordinary chemical or physical processes

13 ENERGY AND INERTIA Inertia: The tendency of a body in motions to resist change in either direction or velocity when acted on by another force Energy: the capacity to do work or transfer heat If it moves something, resist movement, heats up or cools down energy is involved

14 TYPES OF ENERGY Potential energy: this type of energy is the energy of position Gravitational Potential Energy Kinetic energy: the energy of motion Peeling out of tires (heat is exerted)

15 MASS VS WEIGHT Mass: The amount of matter present Does not change with position Weight: Measured by the amount of gravitational force on an object varies from position due to gravitation forces (think of a man on the moon)

16 HOMOGENEOUS & HETEROGENEOUS All matter can be classified into 2 categories- Homogeneous and Heterogeneous Homogeneous: one phase throughout or completely uniform Looks the same throughout (water) Heterogenous: matter made up of more then one phase Visible differences throughout (Chocolate Chip Cookie Dough)

17 CLASSIFY HOMOGENEOUS OR HETEROGENOUS : Bird Seed Silver Water Salsa Cherry Kool-Aid Heterogenous Homogenous Homogenous Heterogenous Homogenous

18 HOMOGENOUS SUBSTANCES Element (simplest unit matter can be broken down to) Compound (combination of elements) Solution: a uniform mix of 2 or more substance which are not chemically bonded therefore the components retain its original identity and properties

19 SOLUTIONS Solute Component which disappears whose phase is changed This only happens if both components are in the same physical state or the solute is in lesser quantity the the solvent Think of Salt in water Solvent Component which remains unchanged This only happens if both components are in the same phase or if the solvent is in greater quantity

20 EXAMPLE 2-2: Aluminum Chloride is a white crystal and alcohol is a clear liquid. When mixed, a clear liquid solution results. If 100 grams of aluminum chloride is mixed with 95 grams of alcohol, what is the Solvent? Alcohol Even though there was more aluminum chloride a clear liquid was formed. This bit of information gave you your answer. Alcohol retained its properties and remained unchanged so it s the solvent.

21 HETEROGENEOUS SUBSTANCES Always Mixtures but not uniform compositions there is more then one phase present in the mixture 95% of mixtures are Homogeneous

22 CLASSIFYING MATTER You must always have 2 words to classifying types of matter Homogenous or Heterogenous Element, Compound, Solutions, Mixture

23 REMINDERS Element-is a substance that cannot be broken down to other substances by chemical reaction Compounds consist of 2 or more different elements combined (chemically bonded) in a fixed ratio Solution- are uniform mix of 2 or more substances one of which is dissolved into the other Mixtures- any substance that has a uniform and unchanging composition that is considered to be pure.

24 CLASSIFY THE FOLLOWING SUBSTANCES Birdseed Cooking Oil Water (H2O) Silver Salsa Heterogenous Mixture Homogenous Solution Homogenous Compound Homogenous Element Heterogenous Mixture

25 PROPERTIES OF MATTER Physical Properties- describes the substance by itself Intensive properties- Properties that do not change with the amount of it (density, melting point, boiling point, color) Extensive properties- depends on the amount of matter present (mass, volume, length, heat) Chemical Properties- describe how a substance reacts to something else (does it burn?)

26 TYPES OF CHANGES IN MATTER Physical Change- matter will change its physical state but not composition often reversible Chemical Changes- A new substance is being formed these are typically not reversible

27 PHYSICAL CHANGES A physical change can have a compound or solution changing its physical characteristics without changing the chemical makeup of the compound or solution Ice melting changes solid to a liquid but its still H2O Melting, Vaporization, Condensation, Freezing, Sublimation (solid to vapor), deposition (vapor to a solid)

28 CHEMICAL CHANGES A new substance is being formed Think of burning, digestion, rusting Clues that can indicate a chemical change color change texture change Gas is produced mass change Precipitation is formed

29 SOLIDS, LIQUIDS, & GASES States of Matter depend on the freedom of movement of atoms in that state Solids have a definite shape and volume their atoms are tightly packed in together Liquids have a definite volume but not shapes the atoms have some freedom to move around Gases have neither a definite shape or volume this allows them to have freely flowing atoms

30 Matter makes up Everything Matter is made up of Elements Atoms make up elements and compounds Scientific Theories, Laws, and Hypothesizes The difference between mixtures and solutions are Heterogenous and Homogenous Substances Physical and Chemical Changes Difference between Solid, Liquids, and Gases

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