Download Chapter Two Review

Chapter Two Review
Section 2-1
 What is the basic unit of matter?
--atom
 What three particles make up an atom?
--proton, neutron, electron
 What particle(s) is/are located in the nucleus of an atom? -protons, neutrons
 Atomic number is the number of what?
--protons
 What does atomic mass mean?
--number of protons and neutrons
 The number of what particles determines the identity of an atom? --protons (atomic #)
 What is the charge of a proton, neutron, and electron?
-- +1, zero, -1
 What is a pure substance that consists entirely of one type of atom.
--element
 What is the name of a substance formed by the chemical combination of two or more elements in
definite proportions? --compound
 How is a covalent bond different than an ionic bond?
--covalent share electrons, ionic
transfer electrons (form ions) and the opposite charges attract
 A ______ is the smallest unit of most substances. Water is an example.
--molecule
 Where are electrons found? --outside of the nucleus of an atom in the electron cloud
 What are Van der Waals Forces?
--slight attractions that develop between oppositely charged
regions of nearby molecules
 Different isotopes of the same element vary in their number of what?
--neutrons
 What is an ion?
--a charged particle (it has either gained or lost electrons)
Section 2-2
 Why do we say water is neutral?
--10 protons balance out 10 electrons
 Why does ice float in water? What specific property of water is this due to?
--ice is less
dense than liquid water because of hydrogen bonding
 What term describes a molecule that has an uneven distribution of electrons creating areas of
slight negative and areas of slight positive charge?
--polar/polarity
 Water is polar. What area has the slight positive charge and what area has the slight negative
charge? Why?
--O (-) and H (+) because O has more protons and pulls the electrons in
closer to itself
 Because water is polar the areas of slight negative and slight positive charge on separate molecules
are attracted. This leads to ___________ between water molecules.
--hydrogen bonding
 Water’s ability to form _______ is responsible for many of its special properties.
--hydrogen bonds
 _________ is the attraction between molecules of the same substance.
--cohesion
 _________ is the attraction between molecules of different substances.
--adhesion
 A _______ is a material composed of two or more elements or compounds that are physically
mixed together but not chemically combined.
--mixture
 There are two types of mixtures. A ______ which has evenly distributed components, and a
______ which has nondissolved material suspended in it. --solution, suspension
 A solution is made up of a ______ which is dissolved and a ______ which does the dissolving.
--solute, solvent
 Pure water has a pH of ______ so we say it’s neutral.
--7
 pH is a measure of ______.
--concentration of H+ in solution
 A solution with a pH below 7 forms more or fewer H+ ions in solution than a solution with a pH
of 12. --more (remember: more H+ equals a lower number on the scale – it’s backwards!)
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A liter of a solution with a pH of four has _____ x more or less H+ ions than a solution with a pH
of 5.
--10x more
Two steps up or down the pH scale would form 100x more H+ ions in solution. --down
_______ contain higher concentrations of H+ ions in solution and register between 0 and 7 on the
pH scale.
--acids
Bases contain lower concentrations of H+ ions in solution and register between ____ and ____ on
the pH scale.
--7 and 14
__________ are weak acids or bases that can react with strong acids or bases to prevent sudden,
sharp changes in pH.
--buffers
__________ are responsible for keeping the pH of your body in the acceptable range of 6.5–7.5.
--buffers
Section 2-3
 What does organic mean? For example, what does organic chemistry study?
--organic = carbon containing
 What are the four classes of organic compounds? --carbohydrates, lipids, nucleic acids, and
proteins
 What class of organic compounds serve as main source of energy for living things?
--carbohydrates
 The class that includes oils, and waxes and makes up membranes and waterproof coverings. --fats
 The class that stores hereditary information.
--nucleic acids
 The class that is made up of polymers of amino acids.
--proteins
 The class that are “the doers of cells” meaning that they carry out all cellular processes.
--proteins
 The class that includes monosaccharides and polysaccharides.
--carbohydrates
Section 2-4
 What is a chemical reaction?
--process that changes one set of chemicals into another
 In a chemical reaction _______ are transformed into _______.
--reactants, products
 Chemical reactions always involve changes in chemical ________.
--bonds
 Give one example of a biological chemical reaction.
--photosynthesis, respiration, CO2 →
carbonic acid in the blood, carbonic acid → CO2 in the lungs, the breakdown of hydrogen
peroxide in the liver catalyzed by catalase, etc.
 Chemical reactions can _______ or _______ energy.
--release or absorb
 The energy needed to get a reaction started is referred to as what?
--activation energy
 How are catalysts and enzymes related?
--catalysts speed up chemical reactions; enzymes are
proteins that act as biological catalysts to speed up chemical reactions in cells
 The reactants of an enzyme catalyzed reaction are called what?
--substrates
 Why are enzymes and substrates often compared to a lock and key?
--they fit together
perfectly. A particular enzyme will only catalyze a certain reaction
 What is catalase?
--an enzyme in the liver that helps break down hydrogen peroxide into
water and oxygen
 How does an enzyme speed up a reaction?
--by lowering the activation energy
 Chemical reactions that _________ energy often occur spontaneously.
--release
 Chemical reactions that absorb energy need what to occur?
--an energy source