Ch2 HW
Which of these statements reflects the relationship between elements, atoms, and chemical symbols? - Atoms are composed of elements. - Elements are composed of atoms. - All atoms have a unique chemical symbol
Elements are composed of atoms
Which of the following formulas indicates an acid? - CH4 - MgCl2 - H2SO4 - NaOH
H2SO4
Which of the following is an exchange reaction? - HCl+NaOH→NaCl+H2O - C6H12O6+C6H12O6→C12H24O12 - dehydration - hydrolysis
HCl+NaOH→NaCl+H2O
How do ions form ionic bonds? - Two atoms come together to share their electrons. - Ions of the same type are drawn together because they are attracted to their own kind. - Ions of opposite electrical charges are attracted to each other to balance the charges. - One atom swaps all of its negative electrons for all of the other atom's positive protons.
Ions of opposite electrical charges are attracted to each other to balance the charges.
Which statement best describes energy? - It exists in a solid, liquid, or gaseous state. - All living things are built of energy. - It has mass and occupies space. - It does not have mass or occupy space
It does not have mass or occupy space
Which of the following is true of polar covalent bonds? - They are rather weak bonds. - The electrons are shared unequally. - Electrons are shared equally. - The same number of electrons are gained by one atom as are lost by another.
The electrons are shared unequally.
What does the molecular formula CO2 mean? - The molecule contains no carbon atoms (C) but two atoms of oxygen (O). - The molecule contains one atom of carbon (C) and two atoms of oxygen (O). - The atom contains two molecules of carbon (C) and one molecule of oxygen (O). - The atom contains one molecule of carbon (C) and two molecules of oxygen (O).
The molecule contains one atom of carbon (C) and two atoms of oxygen (O).
What occurs when acid is added to a solution with a pH of 7? - The pH drops below 7. - The pH becomes neutral. - The pH rises to 10. - The pH becomes basic.
The pH drops below 7
Which of the following is not a result of hydrogen bonds? - An enzyme has a unique shape that allows it to bond only with specific molecules. - Two strands of DNA are linked together taking a shape similar to a ladder. - Some hair is straight, some wavy, and some very curly. - Two hydrogen atoms join together to form a molecule of hydrogen gas
Two hydrogen atoms join together to form a molecule of hydrogen gas
An atomic symbol is __________. - a one- or two-letter abbreviation for an atom - a one- or two-letter abbreviation for an element - a model of an atom
a one- or two-letter abbreviation for an element
Which of the following correctly ranks the types of chemical bonds, in order, from strongest to weakest? - hydrogen, ionic, covalent - ionic, hydrogen, covalent - covalent, ionic, hydrogen - hydrogen, covalent, ionic
covalent, ionic, hydrogen
Hydrolysis is an example of which type of reaction? - decomposition - exchange - dehydration synthesis - synthesis
decomposition
What type of chemical reaction is used by liver cells when synthesizing glycogen from glucose? - exchange reaction - decomposition reaction - dehydration synthesis - hydrolysis
dehydration synthesis
Which of these determines the chemical behavior of an atom? - number of neutrons - electrons in the valence shell - atomic mass - total number of electrons
electrons in the valence shell
Covalent bonds: - involve the sharing of one to three pairs of electrons. - involve the sharing of 8 pairs of electrons. - always result in slight electrical charges at different atoms. - always result in equal distribution of electrons between the atoms.
involve the sharing of one to three pairs of electrons.
Which subatomic particles contribute to an atom's mass number but not its atomic number? - protons - electrons - neutrons - None of them—atomic number and atomic mass number are essentially the same thing.
neutrons
What is the main type of lipid found in cellular membranes? - glycogen - triglycerides - glycerol - phospholipids
phospholipids
A molecule of water (H2O) is formed by what type of bond? - nonpolar covalent bonds - ionic covalent bonds - weak bonds - polar covalent bonds
polar covalent bonds
Formation of hydrogen bonds requires hydrogen atoms and what else? - ionic bonds - polar covalent bonds - water - oxygen
polar covalent bonds
In which category of organic molecules would you place compounds that catalyze chemical reactions? - lipids - nucleic acids - carbohydrates - proteins
proteins
Which type(s) of subatomic particles can be located within the nucleus of an atom? - protons and electrons - electrons only - protons and neutrons - neutrons only
protons and neutrons
In a chemical equation, what are the chemicals on the left side of the arrow called? - water - products - disaccharide - reactants
reactants
Which of these is an example of kinetic energy? - high-energy phosphate bonds in ATP - skeletal muscles contracting as a person lifts weights - glycogen within liver cells - battery in a flashlight with no bulb
skeletal muscles contracting as a person lifts weights
In our body, many salts dissociate into their ions. Which ions are essential for nerve impulses? - sodium and potassium - oxygen (O2) - calcium - iron
sodium and potassium
Which of the following are especially important for growth and repair processes? - hydrolysis - synthesis reactions - exchange reactions
synthesis reactions
When an ionic bond forms, which part(s) of the atoms are directly involved? - both the protons and the electrons - the neutrons - the outermost electrons - the protons
the outermost electrons
Calcium's atomic number is 20. It forms ions with 18 electrons. What is the electrical charge of a calcium ion? +1 -2 +2 -1
+2
An atom of oxygen has an atomic number of 8 and a mass number of 18. How many of each type of subatomic particle does it contain? - 8 protons, 8 neutrons, and 8 electrons - 8 protons, 8 electrons, and 10 neutrons - The atomic number and the mass number do not provide enough information to determine how many of each subatomic particle is present. - 26 total subatomic particles
8 protons, 8 electrons, and 10 neutrons
Why are salts referred to as electrolytes? - After salts dissolve in a solution, the resulting ions can conduct an electrical current. - Electrical currents are required for salts to dissolve in body fluids. - Salts are organic molecules that can conduct electrical current when dissolved in a solution. - Salts transfer electrons to water molecules as they dissolve in solution. These electrons carry an electrical current.
After salts dissolve in a solution, the resulting ions can conduct an electrical current
Which of these statements best describes an element? - An element is formed when two or more different atoms combine chemically. - An element is composed of three subatomic particles. - An element is formed when two atoms of the same kind are bonded together. - An element is composed of identical atoms
An element is composed of identical atoms
In a covalent bond, - An atom gains one or more electrons from another atom to gain stability. - An atom loses electrons to another to gain stability. - Adjacent atoms share a single electron. - Atoms share one or more pairs of electrons.
Atoms share one or more pairs of electrons
Which of these is a chemical symbol? - C - carb - carbon
C
What is the most accurate description of C6H12O6? - C6H12O6 is a molecule of an element. - C6H12O6 is an element. - C6H12O6 is an acid. - C6H12O6 is a compound.
C6H12O6 is a compound.
Atoms of oxygen have a total of 8 electrons. Are these atoms stable, and why or why not? - Yes, because the Octet Rule says stable atoms have 8 electrons. - No, because only atoms with 2 valence electrons are stable. - No, because the atoms have only 6 valence electrons, but need 8 for stability. - Yes, because oxygen is in the air we breathe and it doesn't hurt us
No, because the atoms have only 6 valence electrons, but need 8 for stability
Which of these is a polar covalent bond? Na--Cl C--H O--H O=O
O--H
Which of the following distinguishes hydrogen bonds from covalent bonds? - Only ionic bonds can form within molecules. - Only hydrogen bonds can form within molecules. - Only covalent bonds can form between molecules. - Only hydrogen bonds can form between molecules.
Only hydrogen bonds can form between molecules
Which of the following best describes dehydration synthesis? - Two smaller molecules separate and reorganize into two new molecules after a water molecule is added to them. - A large molecule is broken down, or splits, to produce salt and water. - Two smaller molecules join together after a water molecule is removed from between them. - Two smaller molecules join together after a water molecule is added to split them apart.
Two smaller molecules join together after a water molecule is removed from between them.
Carbon atoms have four valence electrons. Are they likely to react with other atoms, and why or why not? - No, because they do not have enough valence electrons. - Yes, because they can become more stable by doing so. - Yes, but only with other stable atoms. - No, because they have an even number of valence electrons so they are already stable.
Yes, because they can become more stable by doing so
What organic molecule provides an immediate source of chemical energy within all cells? - glycogen - triglyceride - glucose - adenosine triphosphate
adenosine triphosphate
What is an ion? - an atom that has lost one or more neutrons - an atom that has either gained or lost electron(s) - an atom that loses all of its protons - an atom that is sharing electrons with another atom
an atom that has either gained or lost electron(s)
What type of bond is formed when electrons are transferred from one atom to another? - an ionic bond - a nonpolar covalent bond - hydrogen bond - a polar covalent bond
an ionic bond
Which of the following is not produced through chemical bonding? - the heart - cells - atoms - adipose (fat) tissue
atoms
Which organic molecule or molecules are found in subcutaneous tissues and around organs, and are the major source of stored energy in the body? - cholesterol - glycogen - triglycerides - lipoproteins
triglycerides
Which nitrogen-containing base is found only in RNA? - thymine - uracil - cytosine - adenine
uracil
Which parts of atoms can interact (react) to form chemical bonds? - the nucleus of each atom - the orbitals - valence electrons - protons
valence electrons