Ch. 2 Basic Chemistry

Concepts of Matter and Energy

Matter Matter- anything that occupies space and has mass Matter can exist in a solid, liquid, and gaseous states. Matter can undergo a physical or chemical change.

Energy Energy- the ability to do work Kinetic energy- energy of motion Potential energy- inactive or stored energy Forms of Energy Description Chemical Energy Energy stored in the bonds of chemical substances Electrical Energy Energy that results from the movements of charged particles Mechanical Energy Energy directly involved in moving matter Radiant Energy Energy of the electromagnetic spectrum

Composition of Matter

Elements and Atoms Elements- any of the building blocks of matter Elements cannot be easily broken down into simpler substances. Periodic Table- a complete listing of the elements Atoms- smallest part of an element Each element is designated by an atomic symbol.

Atomic Structure Each atom is composed of three subatomic particles. Protons (p+) Neutrons (nº) Electrons (e-) Since all atoms are neutral, they must share the same number of protons and electrons. The atomic structure is accurately portrayed by the orbital model.

Identifying Elements Atoms of different elements are composed of different numbers of protons, neutrons, and electrons. Atomic Number- number of protons Atomic Mass- sum of all the protons and neutrons Atomic Weight- equal to its atomic mass

Identifying Elements Isotopes- contain the same number of electrons and protons, but different numbers of neutrons Radioisotopes- heavier isotopes that are highly unstable Radioactivity- the process of spontaneous radioactive decay, which involve the ejection of particles or electromagnetic energy Radioisotopes tend to decompose to become more stable.

Molecules and Compounds Molecules- the chemical combination of two or more atoms Compound- chemical combination of two or more elements Compounds always have properties different from the atoms that make them up.

Chemical Bonds and Chemical Reactions Chemical Reactions- process in which molecules are formed, changed, or broken down Chemical Bonds- energy relationships between atoms

Bond Formation Electron Shells- fixed regions of space around the nucleus, which are occupied by electrons Maximum number of electron shells known is 7. Shell 1 can hold up to 2 electrons, Shell 2 can hold up to 8 electrons, and Shell 3 can hold up 18 electrons. Valence shell- an atom’s outermost shell of electrons The atom is completely stable when the valence shell contains 8 electrons.

Types of Bonds Covalent Bonds Ionic Bonds Hydrogen Bonds

Covalent Bond Covalent bond- chemical bond formed by the sharing of electrons

Ionic Bond Ionic bonds- chemical bonds formed by the transfer of electrons Ions- electrically charged particles Anions- negatively charged particles Cations- positively charged particles Salts- ionic compound that dissociates into charged particles when dissolved in water

Hydrogen Bond Hydrogen bond- a weak bond formed when a hydrogen atom forms a bridge between two electron-hungry atoms Hydrogen bonds are important intermolecular bonds

Patterns of Chemical Reactions In Chemical reactions, the total number of atoms of bonds remain the same, but appear in different combinations. Synthesis Reaction- reaction in which two or more atoms or molecules combine to form a more complex molecule Decomposition Reaction- a reaction in which a molecule is broken down into smaller molecules, atoms, or ions Exchange Reaction- reaction that involves both synthesis and decomposition reactions

Factors that Influence the Rate of Chemical Reactions Atoms and molecules must collide forcefully for atoms and molecules to react chemically so that valence electrons interact. Factor Mechanism to increase the number of collisions ↑ Temperature ↑ Kinetic energy of molecules ↑ Concentration of Reacting Particles ↑ Number of reacting particles ↓ Particle Size Smaller particles have more kinetic energy and move faster. Presence of catalysts ↑ the amount of energy of molecules

Biochemistry: The Chemical Composition of Living Matter

Inorganic Compounds Inorganics Compounds- a compound that lacks carbon Examples of inorganic compounds include water, salts, and many acids and bases.

Water The most abundant inorganic compound on the body. Properties that make water vital include: High Heat Capacity, Polarity/solvent properties, chemical reactivity, and cushioning.

Salts Salt is an ionic compound containing cations other than H+ and hydroxyl ions other than the Hydroxyl Ion OH- All salts are electrolytes since they are charged particles. Electrolytes- substances that conduct electrical currents in solutions

Acids and Bases Similarly to salts, acids and bases are electrolytes that can ionize, dissociate in water, and conduct an electric current. Neutralization reaction- a chemical reaction that occurs between an acid and a base pH- concentration of hydrogen ions Buffers- substances that stabilize the pH of a solution Acids Bases Sour taste Bitter taste Dissolve many metals Slippery Proton Donors (H+) Proton Acceptors pH < 7 pH > 7

Organic Compounds Organic compounds- carbon-containing compounds The most essential organic compounds in the body include: carbohydrates, lipids, proteins, and nucleic acids

Carbohydrates Carbohydrates- organic compounds that contain carbon, hydrogen, and oxygen. According to size carbohydrates can be classified as Monosaccharide- one sugar (simple sugars) Disaccharides- double sugars formed by dehydration synthesis Polysaccharides- long, branching chains of linked simple sugars Hydrolysis- process in which water is used to split a substance into smaller particles

Lipids Lipids- a vast and diverse group of organic compounds that contain carbon, hydrogen, and oxygen atoms The number of carbon and hydrogen atoms outnumber the number of oxygen atoms. The most abundant lipids in the body include triglycerides, phospholipids, and steroids.

Triglycerides Triglycerides- compounds composed of fatty acids and glycerol, also known as neutral fats The major source of stored energy in the body, commonly found in fat deposits. Protect and insulate the body organs. Fatty acids can be saturated or unsaturated (monounsaturated and polyunsaturated).

Phospholipids Phospholipids- a modified triglyceride containing phosphorus Phospholipids have two instead of three attached fatty acids. Participate in the transport of lipids in plasma and are commonly found in the cell membrane. Phospholipids are copious in the brain and nerve tissue where they help to form insulating white matter.

Steroids Steroids- flat molecules characterized by four interlocking rings, including certain hormones and cholesterol Steroids hormones are vital to maintain homeostasis Cholesterol- steroid found in animal fats and in most body tissues

Proteins Proteins- a complex organic compound that contains hydrogen, oxygen, carbon, nitrogen, and sometimes sulfur. Amino acids- building blocks of proteins Proteins can be classified as either fibrous or globular proteins.

Proteins Fibrous proteins- a strand like protein that appears most often in body structures and binds structures together to strengthen certain body tissues, also called structural proteins. Globular proteins- a mobile and spherical protein referred to as functional proteins that assist in biological processes, including hemoglobin enzymes and certain hormones. Active sites- particular collections of atoms

Enzymes Enzymes- functional proteins that act as biological catalysts Catalyst- substance that increases the rate of a chemical reaction without becoming a part of the product or being changed Enzymes can determine which reactions occur at certain times. Enzymes are named by the specific type of reaction they catalyze.

Nucleic Acids Nucleic acid- a class of organic molecule that provides the basic blueprint of life including DNA and RNA Nucleotides- the monomers of nucleic acids Each nucleotide consists of a nitrogen-containing base, a pentose sugar, and a phosphate group.

Nucleic Acids Deoxyribonucleic acid (DNA)- genetic material found within the cell nucleus DNA replicates itself before a cell divides and provides the instructions for building every protein in the body Ribonucleic acid (RNA)- carries out the order for protein synthesis issued by DNA and is located outside the nucleus

Adenosine Triphosphate (ATP) ATP- a modified nucleotide that consists of an adenine base, ribose sugar, and three phosphate groups attached by unique chemical bonds called high-energy phosphate bonds. ATP is a direct form of cellular energy that helps cell to perform their activities. Adenosine diphosphate (ADP) builds up as ATP is used to provide cellular energy.

The End