Chemistry What do you know?

What is Chemistry Study of matters interaction with matter and energy What is Matter? Anything that… Takes up space Has Mass Basic structure is the atom

What is Energy Energy is the ability to do work 2 main types Potential energy Stored, can be used later Think of examples Kinetic Energy in motion Think of examples

Elements Cannot be broken down into simpler components without drastic changes Nuclear reaction Currently about 118 known elements Group on periodic table Vertical columns = groups/families Horizontal rows = periods

What Does Periodic Table Tell You? Elemental symbol : Oxygen =O, Nitrogen=N, Iron = Fe Atomic Number: Number of protons How the table is ordered Average atomic mass Average of the masses of all known forms of the element

Cont. Metals on the left, nonmetals on the right Small elements on top, big on bottom Black letter = solid Red letter = gas Blue letter = liquid Hollow letter = ?

Common Elements 96% of all biomass is made up of C, N, O, H What are you made of? Oxygen = 65% Carbon = 18% Hydrogen = 10% Nitrogen = 3% Calcium = 1.5% Phosphorous = 1.2% Potassium = 0.2% Sulfur = 0.2% Chlorine = 0.2% Sodium = 0.1% Magnesium = 0.05% Iron, Cobalt, Zinc, Copper, Iodine <0.05%

Atoms Smallest particle that maintains properties of the elements Made of smaller particles Called subatomic particle Proton, Neutron, Electron

Nucleus Region of high mass and low volume (very dense) Contains protons Positive charge Mass of 1 atomic mass unit ( × kilograms) Contains Neutrons Neutral charge Mass of 1 atomic mass unit ( x kg )

Cont. Protons are represented by atomic number Difference between atomic number and mass is the number of neutrons

Electrons Found outside the nucleus Very small in relation to protons and neutrons Move very fast Create area of negative charge around the nucleus Think of a fan blade

Cont. Found in different energy levels High energy electrons are far away from nucleus Low energy electrons near the nucleus What happens when they move?

Drawing Atoms Write number of protons and neutrons in the center Write the number of electrons in energy levels around the outside

Isotopes All elements have several natural occurring forms These are called isotopes Protons and electrons are the same between isotopes of the same element Neutrons/mass are different

Examples of Isotopes

More Isotope Info Difference in physical and nuclear properties Density: water v. heavy water Decay rate: 12 C v. 14 C Nearly identical in chemical properties Based on electrons Why?

Ions Either positive or negative charge Ions are NOT atoms Atoms must have neutral charge What causes change in charge? What are the trends for metals/nonmetals How can you determine using periodic table?

Metal Ions Give up electrons Range from +1  +5 (very rare) Name does not change Magnesium atom, magnesium ion

Non Metal Ion Gain electrons Range from -1  -4 (very rare) Name changes Chlorine atom  chloride ion Suffix become “-ide”

Compounds 2 nd type of “pure” substance Element/atoms are also Any combination of 2 or more atoms Formed by chemical reactions 3 major categories We will focus on 2 of these

Ionic Compounds Most often between a metal and a nonmetal Held together by opposite charge Positive metal, negative nonmetal Completely dissociate in water Break into individual ions

Example of an Ionic

Covalent (Molecular) Compounds Between 2 nonmetals Held together by sharing electrons Neither nonmetal wants to give up any electrons 2 main categories Polar and nonpolar Diatomic between 2 of the same element

Example of Covalent

Energy Driving force behind chemical change What are the types? Potential: Think of examples Kinetic: Think of examples

Energy in biology Focus on specific types of energy in biology Thought of as free energy This is high quality energy Mainly chemical potential energy Heat is not free energy Mostly waist in biology

Energy and Matter Energy of a substance determines the state Solid, liquid, gas Solid=low energy Gas=high energy

States of matter Solid Defined volume, defined shape Liquid Defined volume, undefined shape Gas Undefined volume, undefined shape

Energy of Reactions All reactions either absorb or release energy CH 2 O + O 2  CO 2 + H 2 O + energy CO 2 + H 2 O + energy  CH 2 O + O 2 Complex reactants  simple products = release of energy Simple reactants  complex products = absorb energy

Endergonic These reactions absorb free energy Example is photosynthesis Called endothermic in chemistry Not focused on free energy Considers all forms of energy

Exergonic Release free energy Cellular respiration is an example Called exothermic in chemistry Often thought to release heat

Combination of Reactions All living things build up molecules, and later break them down Combination of these processes are metabolism Catabolism= Break down/ exergonic Anabolism= Build up/ endergonic

Getting reactions started All reactions need a “shove” to get started Called activation energy Living things need to lower this value to make reactions possible Lower using a catalyst/enzyme

Solutions Another name for Homogeneous mixture 2 or more different things mixed together All parts of the solution have identical chemical and physical properties

Parts of a solution Solvent What does the dissolving Solute What gets dissolved Salt water Salt is the solute, water is the solvent Like dissolves like!

Concentration Depends on a ratio between solute and solvent Less than max solute = unsaturated Max amount of solute = saturated Over max amount of solute = supersaturated(jello/rock candy)

Water is Universal Solvent Anytime water is solvent called aqueous solution Base solvent for all living things Why you need to drink water Body reactions only take place in solution No water = no reaction = no life

Acids and Bases Special category of aqueous solution When in solution they dissociate / ionize

Acids Release H+ ions (H3O+) Strength of acid measured on how much H= put into solution A lot = strong acid HCl, HBr, HI, H2SO4, HNO3, HClO3, HClO4 A little = weak acid All other acids (H2CO3, HF, Organic acids)

Bases Can be thought of in 2 ways 1.Release OH- ion in solution 1.NaOH  Na+ + OH- 2.Accept an H+ from an acid 1.NH 3 + H +  NH 4 +

Determining Strength High H+, Low OH- = acid High OH-, Low H+ = base Measure on pH scale (-log [H+]) Base range is from 0-14 Can be under 0 and over 14 in some cases pH<7 = acid pH>7 = base pH = 7 neutral (pure water only true neutral)

Buffers Living things must maintain homeostasis Must control pH Food/drink impact body pH Different parts have different pH Blood must be near 7.4 Use buffers to control fluctuation