Chapter 2: The Chemistry of Life

Choose the six most abundant (by weight) elements that account for 98.5% of the body weight.

Phosphorus Carbon Hydrogen Nitrogen Oxygen Calcium

What term refers to a covalent bond in which the electrons are not equally shared?

Polar

What term is used to describe reactions that can proceed in either direction?

Reversible

___ radiation is a general term for radiation capable of converting atoms to ions or free radicals.

Ultraviolet, UV, Ionizing, x-ray, xray, gamma, ionization

___ electrons are the electrons found in the outermost shell of the electron cloud.

Valence

Which of the following best describes very weak, brief attractions between neutral atoms?

Van der Waals forces

Which type of bond listed below is the weakest?

Van der Waals forces

A(n) ___ is a chemical mixture containing particles that are too large to pass through most selectively permeable membranes, but small enough to remain evenly dispersed through the solvent.

colloid

Weight per volume, percentages, and molarity are different measures of ___.

concentration

A(n) ___ dissociates in water and produces a solution that can conduct electricity.

electrolyte, salt, electrolytes

A compound that dissociates in water, producing a solution that conducts electricity, is known as a(n) ___.

electrolyte, salt, ionic

The subatomic particle with a negative charge is a(n) ___.

electron

Which subatomic particle has a negative charge?

electron

In a solution, the solute can be a ______.

gas, solid, or liquid

Water molecules are weakly attracted to each other through ______ bonds.

hydrogen

To a certain point, increasing the concentration of reactants in a solution will ______ the rate of the reaction.

increase

When a sodium atom loses an electron, it becomes a sodium ______.

ion

A chemical bond that involves the attraction of a cation to an anion is called a(n) ___ bond.

ionic

The sodium ion (Na+) and the chloride ion (Cl-) are attracted to each other and form a(n) ______ bond.

ionic

High-energy radiation that can cause damage to human tissues by removing electrons from other atoms and destroying molecules is called ___ radiation.

ionizing/nuclear

Molecules with the same molecular formula but different arrangements of their atoms are known as ___.

isomers

Atoms of the same element that differ only in the number of neutrons are known as ___.

isotopes

The energy of motion is what type of energy?

kinetic

___ energy is energy that is actively doing work.

kinetic

A(n) ___ consists of substances that are physically blended but not chemically bound.

mixture, colloid, solution, suspension

The measure of chemical concentration, expressed as moles of solute per liter of solution, is known as ___.

molarity

The number of molecules of a chemical that is equal to its molecular weight in grams, is a(n) ___.

mole

Adding together the atomic weights of all atoms in a molecule gives a value known as its ___ weight.

molecular

A(n) is composed of two or more atoms that are held together by chemical bonds.

molecule, compound

Which term refers to the time required for 50% of a radioactive element to be cleared from the body?

Biological half-life

Solvency, cohesion, adhesion, hydrogen bonding, chemical reactivity, and thermal stability are all important properties of ___ and account for its ability to support life.

water

Hydrophilic substances are soluble in ___.

water, H20

Most biological colloids are composed of ___ dissolved in water.

protein

The process of energy being released from the decay of unstable radioisotopes is called ___.

radioactivity, radiation, radioactive

In general, a process that involves the formation or breakdown of molecules is called a chemical ___.

reaction

Consider the following scenario: Two reactants, A and B, combine to form product C. Under the correct conditions, C can degrade back to A and B. When considered altogether, the entire scenario is an example of a(n) ___ chemical reaction.

reversible, equilibrium

Which of the following is a definition of energy?

the capacity to do work

What does the breakdown of unstable atomic isotopes generate?

Radioactivity

___ energy is the potential energy stored in bonds of molecules.

Chemical, Bond

Which would require more calories?

Raising the temperature of 1 gram of water 1 degree Celsius

Substances that resist changes in pH are known as ___.

buffer

Salt on a watermelon is an example of a ______.

mixture

A cation has a net ___charge.

positive, +1, +

Which term means the study of the molecules and chemical reactions that occur in living cells?

Biochemistry

One millimole of NaCl is dissolved in a liter of water. What is the concentration of Na+ in the solution?

1 mEq/L

Hydrogen has an atomic weight of 1amu and oxygen has an atomic weight of 16amu. What is the molecular weight of water (H2O)?

18amu

A double covalent bond involves how many pair(s) of shared electrons?

2

If an atom has 2 electrons in its innermost shell and 3 electrons in its outmost shell, how many valence electrons does it have?

3

A neutral solution has a pH of ___.

7, seven, 7.0

Which of the following best describes a covalent bond?

A double covalent bond involves how many pair(s) of shared electrons?

Which of the following best describes what occurs in a decomposition reaction?

A molecule is broken down into smaller parts.

The pH of the stomach can be as low as 2. This pH is considered to be which of the following?

Acidic

What is an ion?

An atom that has gained or lost electrons

What is the term for an ion with a net negative charge (more electrons than protons)?

Anion

Which term refers to a negatively charged ion?

Anion

___ is the study of the molecules and chemical reactions that occur in living cells.

Biochemistry

Which of the following best describes what occurs in an exchange reaction?

Atoms are traded between molecules.

Which term refers to a chemical that binds protons in a solution and functions as a proton acceptor?

Base

A pH of 7.5 is considered to be which of the following?

Basic

A hydrogen bond is a weak attraction between a slightly ___ hydrogen atom of one molecule and a slightly ___ oxygen or nitrogen atom of another.

Blank 1: positive, electropositive, +, or Positive Blank 2: negative, electronegative, -, or Negative

Which of the following is an example of a suspension?

Blood cells in blood plasma

Solution A prevents solution C from changing its pH. Solution A is therefore a what?

Buffer

What type of ion has lost an electron and, consequently, has a net positive charge?

Cation

Which term refers to an attractive force caused by the sharing or transfer of electrons?

Chemical bond

Which term can apply to a molecule composed of two or more different elements?

Compound

Which type of bond is formed by the sharing of a pair of electrons between two atoms?

Covalent

A chemical reaction in which a larger molecule is broken down into smaller ones is which type of reaction?

Decomposition

Which of the following is most likely to decrease the rate of a chemical reaction?

Decrease temperature Decrease concentration of reactants

Which subatomic particle does not contribute significantly to the mass of an atom?

Electron

Which of the following best describes a polar covalent bond?

Electrons are shared unequally between two atoms.

Which term defines the simplest form of matter to have unique chemical properties?

Element

What term is used to describe a suspension of one liquid in another?

Emulsion

Which type of reaction occurs when two molecules trade atoms or groups of atoms?

Exchange

True or false: Free radicals have an even number of electrons.

False

Which is an example of an emulsion?

Fat in breast milk

Which term can be used to describe any potential energy available in a system to do work?

Free energy

Which type of particle has an unpaired electron, making it highly reactive and destructive to cells?

Free radical

Which of the following is an element?

Hydrogen

Which type of bond can be described as a weak attraction between a slightly positive region in one molecule and a slightly negative region in a different molecule?

Hydrogen

pH is a measurement of the concentration of what?

Hydrogen ions

Which term refers to polar molecules that dissolve in water?

Hydrophilic

What term can be used to describe any molecule that is non-polar and does not dissolve in water?

Hydrophobic

Where are protons of an atom located?

In the nucleus

Where is a neutron located?

In the nucleus of an atom

Which type of chemical bond involves the exchange of electrons?

Ionic

Glucose and fructose both have the chemical formula C6H12O6. Which term below describes the relationship between glucose and fructose?

Isomers

Which of the following statements about the molecular weight of a molecule are true?

It is equal to the sum of the atomic weights. It is measured in atomic mass units. It is useful for calculating concentrations.

Which law specifically states that reactions proceed from the side of the reaction with the greater quantity to the side with the lesser quantity?

Law of mass action

Which of the following is an example of a mineral?

Magnesium

Name the measure of concentration that takes into consideration the number of solute molecules.

Molarity

Which of the following are used to express concentration?

Molarity Percentages Weight per volume

Which of the terms below can be applied to glucose (C6H12O6)?

Molecule Compound

Which of the following would give you the molarity of a solution?

Moles/liter

What percentage of the body weight is made of oxygen?

More than 50%

Which term applies to a solution with a pH of 7.0?

Neutral

Which is an uncharged particle found in the nucleus of an atom?

Neutron

The atomic mass of an element is approximately equal to the total number of which two subatomic particles?

Neutrons Protons

In a carbon dioxide molecule, electrons are shared equally among the atoms. What type of bond do they form?

Nonpolar covalent

Energy contained in an object due to its position or state is referred to as what type of energy?

Potential

Which term refers to energy in a system that is not being used to do work?

Potential

The energy that is stored in the bonds of a glucose molecule exemplifies which of the following?

Potential energy Chemical energy Free energy

How is chemical energy defined?

Potential energy stored in the bonds of molecules

The most common colloids in the body are mixtures of water and what other substance?

Protein

Which term refers to the positively charged particle that is found in the nucleus of an atom?

Proton

Which of the following best defines an acid?

Proton donor

Which are examples of electrolytes?

Salts Bases Acids

The particles of matter that are dissolved in a solution are known as what?

Solute

Which term defines a substance that consists of a solute dissolved in a more abundant substance called the solvent?

Solution

In a solution, the more abundant substance that dissolves another substance is known as what?

Solvent

Blood cells in the blood plasma is a biological example of which type of mixture?

Suspension

A chemical reaction in which two or more smaller molecules combine to form a larger molecule is what type of reaction?

Synthesis

Two amino acids are brought together to form a dipeptide. Which type of reaction is this?

Synthesis

Deuterium and tritium are isotopes of hydrogen. What is different about them?

They have different numbers of neutrons.

Which of the following terms refers specifically to an element that plays a physiological role in the body, but which accounts for less than 0.02% of the body weight?

Trace element

To move something, one is required to do work.

True

True or false: A chemical reaction is a process in which a covalent or ionic bond is broken or formed.

True

True or false: A molecule may be composed of one element or more than one element.

True

A base is a compound that acts as a proton ______.

acceptor

A proton (H+) donor, or a chemical that releases protons into solution, is a(n) ___.

acid

Solution A has a pH of 2. It is ______.

acidic

A(n) ___ is a chemical that neutralizes free radicals.

antioxidant

Glutathione binds to reactive oxygen (free radicals), neutralizing them. Therefore, glutathione is a(n) ___.

antioxidant

Solution B has a pH of 10. It is ______.

basic

Van der Waals forces are important in ______.

binding proteins to each other. protein folding. the association of lipid molecules within cell membranes.

A(n) ___ is the amount of energy required to raise 1 g of water by 1oC.

calorie or cal

Covalent, ionic, and hydrogen are examples of ___ bonds

chemical

A pure chemical substance that consists of one type of atom is called a(n) ___.

element

An input of ___ is required for a system to perform work.

energy, ATP

Reversible reactions exist in a state of chemical ___, in which the ratio of products to reactants is stable.

equilibrium

A reversible reaction continues as long as its products do not accumulate in the system. This is an example of the law of ___ action.

mass

Inorganic elements that are extracted from the soil by plants and passed up the food chain are known as ___.

minerals

Colloids are chemical mixtures that contain ______.

particles smaller than 100 nm suspended particles that scatter light

The abbreviation ___ is a measurement of acidity derived from the concentration of H+.

ph

The time required for one-half of a quantity of a radioactive element to decay to a stable isotope is the ___ half-life.

physical

Cesium-137 has a longer ______ half-life than a ______ half-life.

physical, biological

A(n) ___ is defined as a substance consisting of a solute mixed with a more abundant substance called the solvent.

solution

The ability of water to dissolve other chemicals is ______.

solvency

Saltwater is a solution of NaCl dissolved in water. In this example, NaCl is the solute and water is the ___.

solvent

The 12 elements that together account for 0.7% of the body weight, with each accounting for no more than 0.02%, are known as ___ elements.

trace

The concentration of an electrolyte in a body fluid is expressed as milliequivalents per liter. This is equal to the millimolar concentration of the electrolyte multiplied by the ___ of the ion.

valence, charge

Hydrophobic means that a substance is insoluble in ___.

water

Energy is the capacity to do ___.

work, activity