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1610 Biology Ch. 2
Full Review
| Question | Answer |
|---|---|
| ________ are substances that cannot be broken down into simpler substances by ordinary chemical reaction. | Elements |
| What are the 4 elements that are responsible for more than 96% of the mass of most organisms? | oxygen, carbon, hydrogen, and nitrogen. |
| An ____ is defined as the smallest portion of an element that retains its chemical properties. | atom |
| The components of atoms are tiny particles of _______(anything that has mass and takes up space) known as subatomic particles. | matter |
| What are the three main subatomic particles? | electrons, protons, and neutrons. |
| An ______ is a particle that carries a unit of negative electric charge. | electron |
| A ________ is an uncharged particle. | neutron |
| A ________ proton carries a unit of positive charge. | proton |
| In an electrically __________ atom, the number of electrons is equal to the number of protons. | neutral |
| Clustered together, protons and neutrons compose the ________ ________. | atomic nucleus |
| The element ________ is required for cellular respiration; present in most organic compounds; component of water. | Oxygen |
| The element __________ forms the backbone of organic molecules; each __________ atom can form four bonds with other atoms. | Carbon |
| The element __________ is present in most organic compounds; component of water; ________ ion (+)is involved in some energy transfers. | Hydrogen |
| The element __________ is a component of proteins and nucleic acids; component of chlorophyll in plants. | Nitrogen |
| The element _________ is a structural component of bones and teeth; __________ ion 2+ is important in muscle contraction, conduction of nerve impulses, and blood clotting; associated with plant cell wall. | Calcium |
| The element ________ is a component of nucleic acids and of phospholipids in membranes; important in energy transfer reactions; structural component of bone. | Phosphorous |
| ____________ ion (+)is a principle positive ion (cation) in interstitial (tissue) fluid of animals; important in nerve function; affects muscle contraction; controls opening of stomata in plants. (Which Element?) | Potassium |
| The element _________ is a component of most proteins. | Sulfer |
| ______________ ion (+) is a principal positive ion (cation) in interstitial fluid of animals; important in fluid balance; essential for conduction of nerve impulses; important in photosynthesis of plants. (Which Element?) | Sodium |
| The element _____________ is needed in blood and other tissues of animals; activates many enzymes; component of chlorophyll in plants. | Magnesium |
| ___________ ion (-) is principal negative ion (anion) in interstitial (tissue) fluid of animals; important in water balance; essential for photosynthesis. (Which Element?) | Chlorine |
| The element ___________ is a component of hemoglobin in animals; activates certain enzymes. | Iron |
| Every element has a fixed number of protons in the atomic nucleus, known as the _________ ___________; which determines an atom's identity and defines the element. | atomic number |
| Protons plus neutrons determine the _______ ________ of an atom; which is a number that indicates approximately how much matter it contains compared with another atom. | atomic mass |
| Most elements consist of a mixture of atoms with different numbers of neutrons and thus different masses. Such atoms are called ________. | isotopes |
| The three isotopes of Hydrogen are: ________, ________, and ________. | Ordinary hydrogen, deuterium, and tritium. |
| A ___________ is an isotopes that was unstable and broke down, or decayed, to a more stable isotope (usually becoming a different element). | radioisotope |
| Radioactive decay can be detected by a method known as _____________, in which radiation causes the appearance of dark silver grains in photographic film. | autoradiography |
| Electrons move through characteristic regions of 3-D space called _________. | orbitals |
| Each orbital contains a maximum of __ electrons. | 2 |
| Electrons in orbitals with similar energies, said to be at the same principal energy level, make up an _________ ________. | electron shell |
| The most energetic electrons, known as _________ electrons, are said to occupy the _________ shell. | valence |
| ___________ electrons play a key role in chemical reactions. | valence |
| During ___________, light energy absorbed by chlorophyll molecules causes electrons to move to a higher energy level. | photosynthesis |
| _______ _________ are quite unreactive, because their valence shells are full; inc. Helium and Neon. | Noble Gases |
| A _______ __________ consist of atoms of two or more different elements combined in a fixed ratio. | chemical compound |
| Water and salt are _______ compounds. | chemical |
| Two or more atoms may become joined very strongly to form a stable particle called a ________. | molecule |
| A ________ _______ is a shorthand expression that describes the chemical composition of a substance. | chemical formula |
| In a ________ ________ (also known as an empirical formula), the subscripts give the smallest whole-number ratios for the atoms present in a compound: i.e., hydrrazine = NH2, indicating a 1:2 ratio of nitrogen to hydrogen. | simplest formula |
| In a ________ _________, the subscripts indicate the actual numbers of each type of atom per molecule; i.e., hydrazine = N2H2, which indicates that each molecule of hydrazine consists of two atoms of nitrogen and four atoms of hydrogen. | molecular formula |
| A ________ _________ shows not only the types and numbers of atoms in a molecule but also their arrangement; i.e., water = H-O-H. | structural formula |
| The ________ _____ of a compound is the sum of the atomic masses of the component atoms of a single molecule; i.e., H20 is (hydrogen:2*1 amu) + (oxygen: 1*16 amu), or 18 amu. | molecular mass |
| The amount of an element or compound whose mass in grams is equivalent to its atomic or molecular mass is 1 ______. | mole |
| The very large number of units in a mole, 6.02 *10^23, is known as _______ _________. | Avagrado's number |
| One thousandth of a mole is a __________. | mmol or millimole |
| One millionth of a mole is a __________. | umol, or micromole |
| ____________ ____________ is when the rates of the forward and reverse reactions are equal in a chemical reaction. | dynamic equilibrium |
| Atoms can be held together by forces of attraction called ___________ ________. | chemical bonds |
| _______ ________ is the energy necessary to break a chemical bond. | bond energy |
| The two principal types of covalent bonds are ________ bonds and __________ bonds. | covalent; ionic |
| ____________ bonds involve the sharing of electrons between atoms in a way that results in each atom having a filled valence shell. | Covalent |
| A _________ consist of atoms joined together by covalent bonds. | molecule |
| Unlike atoms can be linked by covalent bonds to form molecules; the resulting compound is a __________ compound. | covalent |
| A simple way of representing the electrons in the valence shell of an atom is to use dots placed around the chemical symbol of the element. Such a representation is called the _________ structure. | Lewis |
| How many valence electrons does Oxygen have? | 6 |
| How many valence electrons does Carbon have? | 4 |
| How many valence electrons does Nitrogen have? | 5 |
| When one pair of electrons is shared between two atoms, it is called a ________ covalent bond. | single |
| When two pairs of electrons are shared between atoms, it is called a ________ covalent bond. | double |
| When three pairs of electrons are shared between atoms, it is called a ________ covalent bond. | triple |
| How many covalent bonds can Hydrogen form? | 1 |
| How many covalent bonds can Oxygen form? | 2 |
| How many covalent bonds can Carbon form? | 4 |
| How many covalent bonds can Nitrogen form? | 3 |
| How many covalent bonds can Phosphorous form? | 5 |
| How many covalent bonds can Sulfur form? | 2 |
| The function of a molecules in living cells are dictated largely by their _________ shapes. | geometric |
| When an atom forms covalent bonds with other atoms, the orbitals in the valence shell may become rearranged in a process known as _________ _________, therefore affecting the shape of the resulting molecule. | orbital hybridization |
| __________ is a measure of an atom's attraction for shared electrons in chemical bonds. | Electronegativity |
| Name 4 electronegative atoms that are sometimes called "electron greedy". | oxygen, nitrogen, fluorine, and chlorine. |
| When covalently bonded atoms have similiar electronegativities, the electrons are shared equally and the covalent bond is described as ___________. | nonpolar |
| The covalent bond of the hydrogen molecule is _________, as are the covalent bonds of molecular oxygen and methane. | nonpolar |
| A covalent bond between atoms that differ in electronegativity is called a __________ covalent bond. | polar |
| A _________ covalent bond has two dissimilar ends (or poles), one with a partial positive charge and the other with a partial negative charge. | polar |
| Each of the two covalent bonds in water are __________, because there is a partial positive charge at the hydrogen end of the bond and a partial negative charge at the oxygen end, where the "shared" electrons are more likely to be. | polar |
| A ________ molecule has one end with a partial positive charge and another end with a partial negative charge. | polar |
| A particle with one or more units of electrical charge is called an ______. | ion |
| An atom becomes an ________ if it gains or loses 1 or more electrons. | ion |
| Atoms with 1,2,or 3 valence electrons tend to lose electrons to other atoms and become positively charged ________. | cations |
| An atom is ________ charged when its nucleus contains more protons than the number of electrons orbiting around the nucleus. (positively or negatively) | positively |
| Positively charged ions are called _________. | cations |
| Atoms with 5,6, or 7 valence electrons tend to gain electrons from other atoms and become negatively charged _________. | anions. |
| An atom is ________ charged when its nucleus contains less protons than the number of electrons orbiting around the nucleus. (positively or negatively) | negatively |
| What are some of the interactions that cations and anions electrical charges are responsible for? | energy transformation, transmission of nerve impulses, muscle contraction, and many other biological processes. |
| A group of atom can become a ________ if it gains 1 or more electrons or loses 1 or more protons (unlike a single atom). | cation |
| An _______ ______ forms as a consequence of the attraction between the positive charge of a cation and the negative charge of an anion. | ionic bond |
| An ______ _________ is a substance consisting of anions and cations bonded by their opposite charges. | ionic compound |
| Compounds joined by _____ bonds have a tendency to dissociate into their individual ions when placed in water. | ionic |
| Why is water an excellent solvent? | Because of the polarity of water molecules. |
| Water as a liquid is capable of dissolving many substances, particularly those that are _______ or _________. | polar; ionic |
| A dissolved substance is referred to as a __________. | solute |
| A solution, each cation and anion of an ionic compound is surrounded by oppositely charged ends of the water molecules. This process is known as __________. | hydration |
| Water molecules interact with one another extensively through _________ bond formation. | hydrogen |
| A region with a temporary excess of electrons will have a weak _________ charge. | negative |
| A region with an electron deficit will have a weak __________ charge. | positive |
| The chemical reaction in which one or more electrons are transferred from one substance to another is called a ________ ____________. | redox reaction |
| Oxidation and _________ always occur together. | reduction |
| __________ is a chemical process in which an atom, ion, or molecule loses electrons. | Oxidation |
| _________ is a chemical process in which an atom, ion, or molecule gains electrons. | Reduction |
| Oxygen atom is very __________, able to remove electrons from other atoms. | electronegative |
| In a redox reaction, the _________ agent accepts 1 or more electrons and becomes reduced. | oxidizing |
| In a redox reaction, the ________ agent gives up 1 or more electrons and becomes oxidized. | reducing |
| The water molecules in liquid water and in ice associate by _________ bonds. | hydrogen |
| Water molecules have a strong tendency to stick to one another, a property known as _________. | cohesion |
| Water molecules display _________, the ability to stick to many other kinds of substances, most notably those with charged groups of atoms or molecules on their surfaces. | Adhesion |
| A combination of adhesive and cohesive forces accounts for __________ ________, which is the tendency of water to move in narrow tubes, even against gravity. | capillary action |
| Water has a high degree of ________ _________ because of the cohesion of its molecules, which have a greater attraction for one another than for molecules in the air. | surface tension |
| Substance that interact readily with water are _________. | hydrophilic |
| ____________ interactions occur between groups of nonpolar molecules. | hydrophobic |
| "Water fearing" substances are called ___________. | hydrophobic |
| __________ molecules are insoluble and tend to cluster together. | hydrophobic |
| What are some examples of hydrophobic substances? | fatty acids and cholesterol |
| Energy of motion is also called ________ energy. | kinetic |
| Raising the energy of substances involves adding heat energy to make its molecules move faster, that is, to increase the ____________ of the molecules. | Kinetic energy aka Energy of motion |
| The total amount of kinetic energy in a sample of a substance is called _______. | heat |
| The measure of average kinetic energy of particles is called ___________. | temperature |
| __________ bonds must be broken for water molecules to move more freely. | hydrogen |
| ________ __ __________ is the amount of energy required to change 1 g of a substance from a liquid phase to the vapor phase. | Heat of Vaporization |
| A _________ is the amount of heat energy required to raise the temperature of 1 g of water 1 degree Celsius. | calorie (cal) |
| The human body can dissipate excess heat as sweat evaporates from the skin and a leaf can keep cool in the bright sunlight as water evaporates from its surface because of __________ __________. | evaporative cooling |
| Water molecules have a tendency to ________, that is, to dissociate into hydrogen ions (H+) and hydroxide ions (OH-). | ionize |
| When a water molecule ionizes the H+ immediately combines with a negatively charged region of a water molecule, forming a ____________ (H30+). | hydronium ion |
| An ________ is a substance that dissociates in solution to yield hydrogen ions (H+) and anions. | acid |
| And acid is a _________ donor. | proton |
| Hydrogen ion, or H+, is nothing more than a ___________. | proton |
| Hydrochloric acid is a common ___________ acid. | inorganic |
| When a solution has an equal concentration of hydrogen ions and hydroxide ions it is said to be ___________. | neutral |
| A _______ is defined as a proton acceptor. | base |
| Most __________ are substances that dissociate to yield a hydroxide ion (OH-) and a cation when dissolved in water. | base |
| A _________ ion can act as a base by accepting a proton (H+) to form water. | hydroxide |
| The degree of a solutions acidity is generally expressed in terms of ___. | pH |
| ___ is defined as the negative logoritm (base 10) of the hydrogen ion concentration (expressed in moles per liter). | pH |
| A negative logorithm corresponds to a __________ pH value. | positive |
| Pure water is an example of a __________ solution. | neutral |
| Pure water has a pH of __. | 7 |
| A _________ solution has a hydrogen ion concentration that is higher than its hydroxide ion concentration. | acidic |
| A _______ solution has a pH value of less than 7. | acidic |
| A ________ solution has a hydrogen ion concentration that is lower than its hydroxide ion concentration. | basic |
| A __________ solution has a pH greater than 7. | basic |
| The pH of most types of plant and animal cells (and their environment) ordinarily ranges from around ___ to ___. | 7.2 to 7.4 |
| The pH of human blood is about __. | 7.4 |
| A ______ is a substance or combination of substances that resists changes in pH when an acid or base is added. | buffer |
| The most common buffering system in the blood of vertebrates is ________ ___________. | carbon dioxide |
| A ____ is a compound in which the hydrogen ion of an acid is replaced by some other cation. | salt |
| When a salt, an acid, or a base is dissolved in water, its dissociated ions can conduct an electric current; these substances are called __________. | electrolytes |
| What are the chieg cations that are important for many aspects of body function. | sodium, potassium calcium, and magnesium |
| What are some important anions for many aspects of body function. | chloride, bicarbonate, phosphate, and sulfate |
Created by:
Grace Perry