Biology 1001-chp.2 – Flashcards
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Copper has 29 protons, 34 neutrons, and 29 electrons. What is the atomic number of copper?
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29
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Which part of the atom participates in a chemical bond?
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electrons in the outer shell
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hat is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?
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6
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Which of these refers to atoms with the same atomic number but different atomic masses?
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These atoms are isotopes
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Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?
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10
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An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron have?
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5
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Why does sweat cool off the human body?
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Water has a high heat of vaporization.
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What name is given to the bond between water molecules?
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hydrogen
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Which basic property of a single water molecule accounts for all of its special features, including adhesion and cohesion, its ability to act as a solvent, and its high specific heat?
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the polarity of water
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The innermost electron shell of an atom can hold up to _____ electrons.
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2
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Which of these relationships is true of an uncharged atom?
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The number of protons is equal to the number of electrons.
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What determines the types of chemical reactions that an atom participates in?
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the number of electrons in the outermost electron shell
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Which of these effects results from the hydrogen bonding between water molecules and nothing else?
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water having surface tension
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Which of the following contributes the most toward the ability of water to form hydrogen bonds?
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the ability of oxygen to attract electrons more strongly than hydrogen
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What force holds a molecule of NaCl together in an ionic bond?
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magnetism
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Sugar is a covalently linked compound with many atoms. Water is able to dissolve sugar. What does this suggest about the atoms of sugar?
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Sugar must contain oxygen or nitrogen atoms.
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In which scenario below will the electrons have the highest energy?
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electrons in the outer shell of potassium
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What is the difference between molecules and compounds?
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Molecules may be made from the same type of atoms or different types of atoms. Compounds are molecules made from different types of atoms.
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In a neutral solution the concentration of _____.
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hydrogen ions is equal to the concentration of hydroxide ions
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What is specific heat?
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the energy necessary to change the temperature of a substance by 1oC
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Atoms with the same number of protons but with different electrical charges _____.
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are different ions
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In salt, what is the nature of the bond between sodium and chlorine?
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ionic
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An ionic bond involves _____.
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an attraction between ions of opposite charge
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Which of these is the correct equation for the dissociation of water? A. H2O + OH- H2O+ B. H2O + H2O H3O+ + OH- C. H2O + H2O+ H2O + OH- D. H2O H+ + OH- E. H+ H2O + H2O+
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B. H2O + H2O H3O+ + OH-
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What is the charge on a hydronium ion?
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1+
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What is the charge on a hydroxide ion?
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1-
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About _____ molecules in a glass of water are dissociated.
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1 in 500,000,000
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Consider a molecule formed entirely of carbon and hydrogen atoms bound together. What properties might this molecule have?
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The molecule would be hydrophobic
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What property of an atom determines which element it is?
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The number of protons
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Each water molecule is joined to _____ other water molecules by ____ bonds.
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four ... hydrogen
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The unequal sharing of electrons within a water molecule makes the water molecule _____.
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polar
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The tendency of an atom to pull electrons toward itself is referred to as its _____.
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electronegativity
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Which of these bonds is weakest?
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Hydrogen Bonds are weaker than covalent bonds because they do not involve sharing of electrons, and they are weaker than ionic bonds because they involve the attraction of partial (not full) opposite charges.
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Which of these atoms will be inert? A. magnesium (12 electrons) B. chlorine (17 electrons) C. neon (10 electrons) D. sodium (11 electrons) E. nitrogen (7 electrons)
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C. neon (10 electrons)
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How many covalent bonds can an atom usually make?
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An atom can make a number of covalent bonds equal to the number of electrons it needs to fill its outer shell.
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A(n) _____ refers to two or more atoms held together by covalent bonds.
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molecule
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What is the fundamental structural unit of all matter?
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the atom
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What is contained in the nucleus of the atom?
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protons and neutrons
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Why does ice float?
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The hydrogen bonds in solid water force the molecules farther apart than the same bonds in liquid water.
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Because the specific heat of land is less than the specific heat of water, which of the following should be true?
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Lakes should be warmer at night than the land around them.
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How are ionic and covalent bonds related?
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Ionic and covalent bonds both result in a full outer electron shell.
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Cancer is caused by mutating DNA. What exactly do cigarette smoke and radiation do that can cause cancer?
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Cigarette smoke and radiation both cause free radicals, which damage DNA, leading to mutation.
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What is a hydrogen bond?
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a weak bond between two partially charged atoms
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Coffee has a pH of 5.0. Stomach acid has a pH of 2.0. How does coffee compare to stomach acid?
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Stomach acid is 1,000 times more acidic than coffee
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In water, the chemicals HsPO4-, HPO42-, and HCO3- all act as buffers. In dry form, these chemicals are often ionically bound to another element. Which of the following is a good candidate for that element? -chlorine (Cl) -carbon (C) -hydrogen (H) -sodium (Na) -hydroxide (OH)
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sodium (Na)
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If electrons in water molecules were equally attracted to the hydrogen and oxygen atoms, how would this affect the bonds between them?
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The bond would become less polar.
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Which of the following lists of terms is in the correct order of size, going from smallest to largest? -proton, electron, nucleus, atom, molecule -electron, proton, nucleus, molecule, atom -nucleus, electron, proton, atom, molecule -electron, proton, nucleus, atom, molecule -molecule, atom, nucleus, proton, electron
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electron, proton, nucleus, atom, molecule
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Why are hydrophobic molecules such as fats and oils unable to dissolve in watery solutions?
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Water molecules form hydrogen bonds with each other, excluding the hydrophobic molecules.
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How do atoms respond when they absorb energy?
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Electrons move to a higher orbital
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How do the hydrogen bonds between water molecules compare to the covalent bonds within water molecules?
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The hydrogen bonds are more easily broken than the covalent bonds.
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How does water dissolve salt?
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The partial positive charges of the hydrogen atoms on water surround the negative charge of a chlorine ion.
