10/7/16 Today we will define and describe energy Warm Up: Describe the term energy in your own words

Chemistry Chapter 2 Energy and Matter

Energy Energy is the capacity to do work or produce heat.

Energy Kinetic Energy – Energy of Motion thermal mechanical Potential Energy – Stored Energy gravitational electrical chemical Radiant Energy – Light Energy

Measuring Energy Common unit – calorie (cal) calorie - the amount of energy needed to raise one gram of water one degree Celsius A Food calorie is actually a kilocalorie (Calorie)

Conservation of Energy Law of Conservation of Energy – Energy cannot be created nor destroyed. In any process, the amount of energy you start with is the same as the amount of energy you end with. This energy may have changed forms!!! Potential  Kinetic

Energy Crisis If energy is conserved, how can our planet be “running out of energy”? Natural resources are converted to other types of energy. We are running out of these natural resources. Coal, Petroleum, Natural Gas

Temperature A measure of kinetic (thermal) energy Hot vs. Cold What tool do we use to measure temperature?

Temperature Scales Fahrenheit vs. Celsius In science we use Celsius 0°C = freezing point of water at sea level 100°C = boiling point of water at sea level Units are different sizes

Temperature Scales What is 35°C in Fahrenheit?

Temperature Scales Celsius vs. Kelvin Kelvin is based on absolute zero. Zero on the Kelvin scale is Absolute zero. Absolute zero – the point at which all atomic motion stops. Units are the same size

K=°C + 273 Temperature Scales Celsius vs. Kelvin Kelvin is the SI unit for temperature! K does not use the word degree! It is 338 Kelvins outside K=°C + 273

K=°C + 273 260=°C +273 -13ºC = °C Temperature Scales If you measure the temperature to be 260K, what is the temperature in degrees Celsius? K=°C + 273 260=°C +273 -13ºC = °C

Homework Energy & Temperature Conversions Practice

10/10/16 Today I will determine whether a change is physical or chemical. Warm up – Your radio says it is 95 degrees out. What is this temperature in the other two scales?

Matter Matter is all “stuff” Matter – anything that has mass and volume

Properties Physical properties – characteristics that can be observed without changing the identity of the substance (looks) Color, shape, size, density, melting point, state Chemical properties - characteristics that cannot be observed without changing the identity of the substance (acts) Flammability, ability to rust, reactivity with air

States of Matter Solid – definite shape ; definite volume Tightly knit particles with very high relative density Liquid – no definite shape ; definite volume Particles starting to spread out; high density Gas – no definite shape ; no definite volume Particles very far apart; low density Plasma – inside sun and stars. Exist only at very high temperatures

States of Matter

Changes in Matter Physical Change – changes that do not alter the identity of a substance Tearing, cutting, painting, changes of state

Changes in Matter

Changes in state Changes in state occur due to the kinetic energy of molecules. Solid  Liquid – melting Liquid  Solid – solidification Liquid  Gas – vaporization Gas  Liquid – condensation Solid  Gas – sublimation Gas  Solid – deposition

Changes in state Adding heat or energy makes particles move faster and spread out ( s  l  g ) Removing heat or energy makes particles move slower and clump together ( g  l  s )

Changes in Matter Chemical Changes – changes that do alter the identity of a substance Rusting, burning, cooking

Conservation of Matter Matter, like energy, is conserved. Matter can neither be created nor destroyed! This will play a big role in what we learn this year!

Properties Both chemical and physical changes alter a substances physical properties so it can be difficult to tell the difference between them Can it be easily reversed? Most chemical processes cannot be…

Indicators of a chemical change There are several indicators that a chemical change has occurred. These indicators are not PROOF! 1. Heat or Light

Indicators of a Chemical Change Cont 2. Color Change 3. Gas Bubbles – Be careful not to mix up with boiling!

Indicators of a Chemical Change Cont 4. Precipitate – A solid that forms from combining two liquids

Homework 2-3 R&R

10/11/16 Today I will demonstrate chemical and physical changes in the lab

10/12/16 Objective – to explain and differentiate between elements and compounds. Warm Up – Tell if the following are chemical or physical changes: 1. crushing a can 2. burning a log 3. baking bread 4. dying hair

Pure Substances Pure Substance – a substance made up of only one type of material with a unique set of properties Two types Element Compound

Pure Substances Element – A substance that cannot be separated into simpler substances by a chemical (or physical) change. Smallest particle of matter. Each unit of an element is called an atom. Periodic Table of Elements!

Pure Substances Element – Periodic Table of Elements!

Pure Substances Element – Where do elements get their names? People – Einsteinium, Curium Places- Plutonium, Europium, Californium, Berkelium

Pure Substances Element – What about their Symbols? First letter capitalized Hydrogen (H), Oxygen (O) Two letters – one capital one lowercase Aluminum (Al), Chlorine (Cl) Latin or old words Sodium (Na) old word natrium Gold (Au) Latin aurum

Pure Substances Compounds– Two or more elements chemically combined Cannot be separated by physical means We call each individual combination of atoms a MOLECULE or a FORMULA UNIT !

Pure Substances Compounds– What do we call them? Many different ways to name compounds For now, If two element names are put together, you can assume it is a compound! Ex. Aluminum oxide, sodium chloride Also, some compounds use common names. Ex. Sugar, water, salt, methane, ammonia

Pure Substances Compounds have unique properties unrelated to the elements in the compound. Salt – sodium & chlorine (both toxic) Compounds will always have the same percent proportions. Water is always 11% hydrogen, 89% oxygen

Pure Substances Review Both Compounds and Elements are referred to as PURE SUBSTANCES. Pure substance – unique set of chemical and physical properties

Matter – anything that takes up space Pure Substance – made up of only one type of material Element – composed of one type of atom Compound– composed of one type of molecule Examples: Lead Oxygen Silver Examples: Water Sugar Lithium fluoride

Homework 2-4 R&R

10/13/16 Today I will explain and differentiate between mixtures. Warm Up – Tell if the following are an element or a compound: 1. iodine 2. potassium chloride 3. sugar 4. krypton

Mixtures A mixture is a blend of two or more Pure Substances which can be separated by physical means. Some mixture are easy to see, others look like a single material. Element (atoms) Compound (molecules) Mixture

Mixtures Two types of mixtures 1. Heterogeneous – has visibly different parts.

Mixtures a.k.a. - solutions Two types of mixtures 2. Homogeneous – looks the same throughout a.k.a. - solutions

Separating Mixtures Heterogeneous Manually separate Decanting – pouring off Filtration – separates solid from liquid

Separating Mixtures Homogeneous Crystallization (allowing to evaporate) Distillation – boiling point differences 2 liquids Fractional distillation – more than 2 liquids Chromatography– different flows

Matter – anything that takes up space Pure Substance – made up of only one type of material Mixture – made up of two or more types of materials Element – composed of one type of atom Compound– composed of one type of molecule Homogeneous – same throughout (AKA Solution) Heterogeneous – separate parts Examples: Lead Oxygen Silver Examples: Water Sugar Lithium fluoride Examples: Salt Water Air Metal Alloys Examples: Muddy Water Chex Mix Oil and Water

Homework 2-5 R&R

10/14,18/16 Today I will isolate a dye and determine if it is a pure substance or a mixture.

10/20/16 Today I will review chapter 2 Warm Up – Tell if the following are an element, a compound, a homogeneous mixture, or a heterogeneous mixture: 1. bromine 2. salt water 3. water 4. air 5. pepperoni pizza

10/21/16 Today I will review chapter 2 Warm Up – How might you separate a mixture of sand, iron bits and salt?