BIOLOGY CHAP 2
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Created by:
ngkristal Plus on May 9, 2012
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Terms | Definitions |
|---|---|
 CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: What do chemicals make up? | the bodies of organisms AND physical environment. |
| CHAP 2: Life's chemistry is tied to water because... | -Life first evolved in water. -All living organisms require water. -Majority of bodies are composed of water |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Matter = | = anything that occupies space and has mass (weight). -Living organisms are composed it |
| CHAP 2: Difference between Mass and Weight | _____= the quantity of matter contained in a body _____= the force by which the body is pulled to the earth's center |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Element = | =substance that cannot be broken down to other substances. -Makes up matter -92 elements in nature—only a few exist in a pure state. |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: What are the 4 Major Elements that make up 96.3% (specifically for humans) of weight of most living organisms | Oxygen= 65 % Carbon =18.5% Hydrogen = 9.5% Nitrogen =3.3 % |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Compound | = substance consisting of two or more different elements in a fixed ratio. -more common than pure elements. |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Emergent properties = | =Compound that has characteristics different from those its elements |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Atom = | = smallest unit of matter that still retains the properties of an element. -Each element consists of one kind of ___ |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Three subatomic particles in atoms are relevant to properties of elements. | Protons are positively charged. Electrons are negatively charged. Neutrons are electrically neutral. |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Regardless, what subatomic participle always remain the same? | Protons always remain the same |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: What is the location of subatomic participles in atoms? | -Neutrons and protons are packed into an atom's nucleus. -Electrons orbit the nucleus. -Negative charge of electrons and the positive charge of protons keep electrons near the nucleus. |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Atomic Number? | Number of protons, -In a non-charged electron, it is the same number of electrons |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Mass Number and Atomic Mass= | = Sum of the number of protons and neutrons in the nucleus of atom. = Mass of atom -Approximately equal to its mass number |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: What is trace element? | = Element that is essential for life but required in extremely minute amounts |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Although all atoms of an element have the same atomic number, some differ in what? | Some differ in mass number, however______. |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Isotopes = | -the same number of protons, -but different numbers of neutrons. |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Radioactive Isotopes = | = Nucleus decays spontaneously, giving off particles and energy. |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: What do cells that are not distinguishable between isotopes of the same element contribute to? | = Radioactive compounds in metabolic processes can act as tracers through instruments |
| CHAP 2; ELEMENTS, ATOMS & COMPOUNDS: Radioactive tracers are used often in medical diagnosis, however what are the negative side effects in radioactive isotopes? | Uncontrolled exposure can cause damage to some molecules in a living cell, especially DNA. Chemical bonds are broken by the emitted energy, -Causes abnormal bonds to form. |
| CHAP 2; CHEMICAL BONDS: Which subatomic particle is only involved in chemical activity? | Electrons |
| CHAP 2; CHEMICAL BONDS: Electron Shells = | Electrons level representing the distance of an electron from nucleus of atom |
| CHAP 2; CHEMICAL BONDS: What happens when the further an electron is from positively charged atom? | = greater energy |
| CHAP 2; CHEMICAL BONDS: What is the number of electron shells surrounding nucleus? | atom may have one, two, or three |
| CHAP 2; CHEMICAL BONDS: What does the number of electrons in the outermost shell determine? | -number the chemical properties of the atom. |
| CHAP 2; CHEMICAL BONDS: What do atoms with incomplete outer shells tend to do? How? What do they lead to? | -react so that both atoms end up with completed outer shells. -atoms may react with each other by sharing, donating, or receiving electrons. -interactions usually result in atoms staying close together, held by chemical bonds |
| CHAP 2; CHEMICAL BONDS: Chemical bonds = | = Attraction between 2 atoms resulting from a sharing of outer-shell electron or the presence of opposite charges on the atom -Completes outer electron shell |
| CHAP 2; CHEMICAL BONDS: Covalent bond = | The strongest kind of chemical bond in which two atoms share one or more pairs of outer-shell electrons |
| CHAP 2; CHEMICAL BONDS: Molecule= | Formed by two of more atoms held together by covalent bonds |
| CHAP 2; CHEMICAL BONDS: What do atoms in a covalently bonded molecule compete for? What is the thing that determines the outcome? Definition of it? | Shared electrons is what _________ ___________ for, which is determined by... Electronegativity = Attraction of a given atoms of a covalent bond -More electronegative atoms pull harder towards nucleus |
| CHAP 2; CHEMICAL BONDS: Nonpolar Covalent Bonds = | = Substance in which electrons are shared equally between atoms of similar electronegativity -Displayed in molecules of only one element |
| CHAP 2; CHEMICAL BONDS: Polar Covalent Bonds =, and example using H20? | = Covalent bond between atoms that differ in more electronegativity. - The shared electrons are pulled closer to the more electroactivity atom -Making it slightly negative and the other slightly positive Ex: Oxygen attracts the shared electrons more strongly than hydrogen The oxygen atom has a slightly negative charge and the hydrogen atoms have a slightly positive charge |
| CHAP 2; CHEMICAL BONDS: Polar Molecule = | = Molecule containing polar covalent bonds and having an unequal distribution of charges |
| CHAP 2; CHEMICAL BONDS: Ion = | = Atom or molecule with an electrical charge resulting from gain or loss of electrons -When an electron is lost, a positive charge results. -When an electron is gained, a negative charge results |
| CHAP 2; CHEMICAL BONDS: Two ions with opposite charges attract each other, and this attraction results into Ionic Bond. Definition? | = Chemical bond resulting from the attraction between oppositely charged ions -One gives an extra electron, and the other receives it to complete valance shell. This makes both atoms happy. Ex: Salt - What is the cause of this? |
| CHAP 2; CHEMICAL BONDS: Explain how weak bonds are important using H20 | -Hydrogen has a weak bond, because it is partly positive due to the oxygen having more electronegativity. -This partial charge allows it to be attracted to regions of a nearby partially negative charged atom - Hence H20 molecules can hydrogen bond to as many as four partners |
| CHAP 2; CHEMICAL BONDS: Hydrogen Bond = | = Weak chemical bond formed when the partially positive hydrogen atom participating in polar covalent bond in one molecule is attracted to the partially negative atom participating in a polar covalent bond in another molecule (or in another region of the same molecule) |
| CHAP 2; CHEMICAL BONDS: What determines the way atom and molecule's chemically behaviour? | Structure (number and arrangement of its subatomic participles and so forth) determines____ |
| CHAP 2; CHEMICAL BONDS: Chemical Reaction = | = The making and breaking of chemical bonds, leading to changes in the composition of matter -Do not create or destroy matter. -Only rearrange matter. |
| CHAP 2; CHEMICAL BONDS: Reactants and Products = | = Starting material in chemical reaction =An ending material in chemical reaction The reactants (H and O2) are converted to H2O, the product. |
| CHAP 2; CHEMICAL BONDS: Photosynthesis = | = is a chemical reaction that is essential to life on Earth. -Carbon dioxide (from the air) reacts with water. -Sunlight powers the conversion to produce the products glucose and oxygen. |
| CHAP 2; WATER: Cohesion =, apply it to water | = The tendency of molecules of the same kind to stick together -Cohesion is much stronger for water than other liquids. -Most plants depend upon cohesion to help transport water and nutrients from their roots to their leaves. |
| CHAP 2; WATER: Adhesion = | =tendency of two kinds of molecules to stick together |
| CHAP 2; WATER: Cohesion is related to surface tension, which is ______, apply it to water | = a measure of how difficult it is to break the surface of a liquid. Hydrogen bonds give water high surface tension, making it behave as if it were coated with an invisible film. |
| CHAP 2; WATER: Because of hydrogen bonding, water has a greater ability to do what? | = Resist temperature change than other liquids. |
| CHAP 2; WATER: Temperature = | = Measures the intensity of heat. |
| CHAP 2; WATER: Heat =, relate it to hydrogen bonds | = Energy associated with movement of atoms and molecules in matter -Heat is released when hydrogen bonds form. -Heat must be absorbed to break hydrogen bonds. |
| CHAP 2; WATER: When a substance evaporates, the surface of the liquid that remains behind cools down, in the process of evaporative cooling, which is _______. Why does it occur? | = Process in which the surface of an object becomes cooler during evaporation -This cooling occurs because the molecules with the greatest energy leave the surface. |
| CHAP 2; WATER: Explain water, forms and hydrogen bonding | Water is less dense as a solid than a liquid because of hydrogen bonding. When water freezes, each molecule forms a stable hydrogen bond with its neighbors. As ice crystals form, the molecules are less densely packed than in liquid water. Because ice is less dense than water, it floats. |
| CHAP 2; WATER: Solution = , Solvent= , Solute=, *Aqueous solution = | = Liquid consisting of a uniform mixture of two or more substances. =Dissolving agent =Substance that is dissolved =One in which water is the solvent |
| CHAP 2; WATER: How is water as a solvent? How does it form aqueous solutions? | Water's versatility as a solvent results from the polarity of its molecules. Polar or charged solutes dissolve when water molecules surround them |
| CHAP 2; WATER: In aqueous solutions, what are ions called? Some contribute/ steal them. | Hydrogen ions (H+) Hydroxide ions (OH-) |
| CHAP 2; WATER: Acid=,Base = | = A compound that releases H+ to a solution = A compound that accepts H+ |
| CHAP 2; WATER: pH scale describes how acidic or basic a solution is | The pH scale ranges from 0 to 14, with zero the most acidic and 14 the most basic. Each pH unit represents a tenfold change in the concentration of H+. |
| CHAP 2; WATER: How can buffer is a substance that minimizes changes in pH? ex: blood | accept H+ when it is in excess and donate H+ when it is depleted. |
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