Matter, Energy, and Change Problem Set: pg 22-23 # 6-14, 16, 19 - 21

1. Matter, Energy, and Change Problem Set: pg 22-23 # 6-14, 16, 19 - 21

2. Chemistry is the study of matter and its transformations. • Why Study Chemistry? • learn fundamental physical models • gain technical perspective on current events • develop problem solving skills • appreciate life's little mysteries Most of the building materials, clothes, and medicines today are the result of chemistry

3. Branches of Chemistry • organic –the study of the structures, synthesis, and reactions of carbon- compounds • inorganic – the study of the properties and reactions of inorganic compounds • physical - dealing with the physical properties of chemical substances • biochemistry - study of the chemistry of living things • analytical - analysis of material samples to gain an understanding of their chemical composition and structure.

4. Matter • Matter – anything that has mass and occupies space • Inertia – the tendency of a body to stay at rest or to continue to move at the same velocity, unless acted on by an outside force. A tractor trailer has more inertia than a bicycle. A bowling ball has more inertia than a tennis ball • Mass and weight – used interchangeably, but there is a difference…  • Mass – a quantity of matter, mass is measured using a balance  • Weight - a measure of gravity's effect on something; use a scale to measure weight • Law of Conservation of Mass • Matter can neither be created nor destroyed in chemical or physical changes. • Example – sodium metal + chlorine gas ---> table salt, an edible crystal

5. Energy • Everything that you see or sense is either matter or the interactions of energy and matter. True or False? • Ex: a book – a chunk of matter – hold it up – potential energy – drop it – kinetic energy • Energy – the ability to cause change or the ability to do work. (two types) • Kinetic –the energy of motion • Ex. baseball in flight, car rolling down a street  • Potential – stored energy waiting to be released Ex: gasoline, water behind a dam • Law of conservation of energy – • Energy can change forms, but it cannot be created or destroyed by ordinary chemical or physical changes

6. Liquid Solid Gas

7. PLASMA • Plasma – A highly ionized gas. • The fourth state of matter (it does matter). • 99% of all matter in the universe is in a plasma state. • Lightning, neon lights and fire are natural examples of plasma on Earth. • Plasma tv’s? What are they all about? • Plasma in flat-panel display technology that ignites small pockets of gas to light phosphors. Each plasma panel contains thousands of tiny tubes filled with ionized gas that, when excited by electricity, glow in different colors and intensities to create an image. • Bose-Einstein Condensate (BEC) – The fifth state of matter. • Found at really cold temperatures (0K) Lab produced

8. Properties and Changes of Matter • Properties – characteristics that enable us to distinguish one kind of matter from another • describe materials by listing their properties • Chemical properties vs. physical properties • Measurement of a chemical propertyinvolves a chemical change. • Ex: determining the flammability of gasoline involves burning it, producing CO2 and H2O; wood burning, rusting iron, tarnishing silver, leaves changing colors, baking a cake • Measurement of a physical propertymay change the arrangement but not the structure of the molecules of a material. • Ex: density, color, boiling point, volume, temperature, and mass.

9. Intensive properties vs. extensive properties • Extensive properties change when sample size changes; intensive properties don't.

10. Chemical change vs. physical change • A chemical changeoccurs when a substance is converted into a different substance • Ex. chemical change: sodium metal + chlorine nonmetal --> table salt (crystal, white, edible) • Ex. physical change: cutting paper, chopping wood, freezing water • Signs of a chemical change • evolution of heat and light • production of a gas • formation of a precipitate • Color change (but only if another sign is present)

11. Energy and Changes in Matter - Chemical reactions involve energy • ExothermicEndothermic • releases energy absorbs energy • reactants --> products + heat reactants + heat ---> products • water(l) → ice(s) + heat ice(s) + heat → water(l)

12. Examples of exothermic processes • making ice cubes • formation of snow in clouds • condensation of rain from water vapor • a candle flame • mixing sodium sulfite and bleach • rusting iron • burning sugar • forming ion pairs • combining atoms to make a gas molecule • mixing strong acids and water • nuclear fission

13. Examples of endothermic processes • melting ice cubes • conversion of frost to water vapor • evaporation of water • forming a cation from an atom in the gas phase • baking bread • cooking an egg • producing sugar by photosynthesis • separating ion pairs • splitting a gas molecule apart • mixing water and ammonium nitrate • melting solid salts

14. Separate physically Separate chemically

15. Mixture - combination of two or more kinds of matter, but each retains its own physical properties • Heterogeneous - composition is not uniform where samples are different • Homogeneous - Uniform composition; every sample is the same

16. Suspension (heterogeneous mixture) • Solid in liquid • muddy water, granite • Solution (homogeneous mixture) • small particles that won’t scatter light • ex: air, salt water • Colloid (homogeneous mixture) • particles larger than molecules, scatter light • Shaving cream, starch water

17. Pure Substance - homogeneous sample of matter that always has the same composition • Compound - substance that can be decomposed into 2 or more substances by chemical change • Ex: NaCl, H2O, C6H12O6, CO2 • Element - substance that cannot be broken down by ordinary chemical change • Ex: Au, Cu, Ni, Na

18. Side note: the Law of Definite Compositionstates that when a compound breaks down, it always gives the same proportion of its constituent elements (Joseph Proust – 1799) • Ex – sugar (C6H12O6) always consists of 42.1% C, 6.5 % H, 51.4 % O

19. The periodic table compactly shows relationships between elements, and features are: • Periods are horizontal rows on the table. • Groups (or families) are columns on the table. • elements in the same group have similar chemical properties. • Blocks are regions on the table.

21. alkali metals(Group IA, first column ) • soft, extremely reactive metals • react with cold water to form hydrogen gas • form +1 ions • alkaline earth metals (Group IIA, second column): • soft, reactive metals • compounds are a major component of earth's crust • form +2 ions

22. halogens (Group VIIA, next-to-last column): • poisonous and extremely reactive nonmetals • fluorine and chlorine are yellow-green gases • bromine is a volatile red-brown liquid • iodine is a volatile blue black solid • all form -1 ions • noble gases(Group 0, last column) • all are monatomic gases • a. k. a. inert gases; almost completely unreactive

23. Transition metalsare the elements in the 3rd to 12th columns. • hard, dense metals • less reactive than Group IA and IIA • Rare earth metalsare the elements at the bottom of the table. • lanthanides (annex, top row) • actinides (annex, bottom row) • Main group elementsare all elements (except transition and rare earth). • group numbers end with "A"

25. Metals, nonmetals, and metalloids(semimetals) • lustrous • malleable: can be hammered into thin sheets • ductile: can be drawn into wire • conduct heat and electricity well