Chemistry: The Process of Life

Question 1

Acid

Answer 1

Acids are molecules that can split apart in water and release hydrogen ions (H+). A common example is hydrochloric acid (HCl). When HCl is added to water, it splits apart into H+ and Cl–, increasing the number of hydrogen ions in the water/HCl solution.

A solution that contains more hydrogen ions than hydroxide ions is acidic, and the pH of the solution is less than 7. If a molecule releases hydrogen ions in water, it’s an acid. The more hydrogen ions it releases, the stronger the acid, and the lower the pH value.

Question 2

Adhesion

Answer 2

Adhesion may refer to the joining of two different substances due to attractive forces that hold them. For instance, cohesion causes water to form drops and adhesion keeps the water drops on the surfaces of leaves and flowers in place. The binding of a cell to another cell, or a cell to a surface, via specific cell adhesion molecules. Adhesion may also refer to the binding of a cell to another cell, such as a malarial protozoan cell (Plasmodium falciparum) binding to a liver cell via cell adhesion molecule called the circumsporozoite protein.

Question 3

Anion

Answer 3

A negatively-charged ion.

Question 4

Difference btw. an Anion and a Cation

Answer 4

Anion vs. Cation. Ions result from atoms or molecules that have gained or lost one or more valence electrons, giving them a positive or negative charge. Those with a negative charge are called anions and those with a positive charge are called cations.

Question 5

Aqueous solution

Answer 5

An aqueous solution is any solution in which water (H2O) is the solvent.

Question 6

Atom

Answer 6

An atom is the smallest unit of matter with unique chemical properties. Atoms are the chemical units of cell structure. They consist of a central nucleus with protons and neutrons and orbit(s) of electrons. A proton carries a +1 positive charge, while a neutron has no charge. Thus the nucleus has a net positive charge. Electrons carry a –1 negative charge and are consequently attracted to the positive nucleus. In general, the number of protons usually equals the number of electrons. Recall that atoms have unique (individual) chemical properties, and thus each type of atom is called a chemical element, or just element.

Clouds of electrons surround the nucleus. Electrons carry a negative charge but have no mass.

Atoms become ions when they gain or lose electrons. In other words, ions are essentially charged atoms. Positive (+) ions have more protons than electrons; negative (–) ions have more electrons than protons. Positive and negative charges attract one another, allowing atoms to form bonds.

Question 7

Atomic Mass

Answer 7

Atomic weight refers to the number of protons and neutrons in an atom, measured in daltons.

Also Known As: Atomic Weight

Question 8

Atomic number

Answer 8

Symbol Z in chemistry.

The number of protons in the nucleus of an atom and also its characteristic atomic number.

The atomic numbers of the known elements form a complete series (periodic table), from 1 (hydrogen) to 103 (lawrencium).

Question 9

Base

Answer 9

Bases are molecules that can split apart in water and release hydroxide ions (OH–). The most common example is sodium hydroxide (NaOH). When NaOH is added to water, it splits apart into Na+ and OH–.

A solution that contains more hydroxide ions than hydrogen ions is basic, and its pH is higher than 7. Bases dissociate (break apart) into hydroxide ions (OH–) and a positive ion. The hydroxide ions can combine with H+ to create water. Because the hydrogen ions are used, the number of hydrogen ions in the solution decreases, making the solution less acidic and therefore more basic. So, the more hydroxide ions a molecule releases (or the more hydrogen ions it takes in), the more basic it is.

Question 10

Buffer

Answer 10

Buffers keep solutions at a steady pH by combining with excess hydrogen (H+) or hydroxide (OH–) ions. Think of them as sponges for hydrogen and hydroxide ions. If a substance releases these ions into a buffered solution, the buffers will “soak up” the extra ions.

If something goes wrong with the buffer system and the pH drops too low, an organism can develop acidosis (meaning the blood becomes too acidic). If the reverse happens and the pH gets too high, an organism can develop alkalosis (meaning the blood becomes too basic).

Question 11

Calorie

Answer 11

Kilocalorie: a measure of heat energy that is equal to the amount of heat needed to raise the temperature of one kilogram of water by one degree Centigrade at one atmospheric pressure.

Calories are used to describe the energy producing potential of food. A one gram calorie is equal to 4.1840 joules. Joule (which is an SI unit) is now more preferred over calorie (which is nonSI unit) for measuring heat energy.

Question 12

Cation

Answer 12

A positively charged ion.

Question 13

Strong acid

Answer 13

An acid that releases all of its hydrogen ions in solution.

Hydrochloric acid (HCl) is an excellent example of a strong acid.

Question 14

Weak acid

Answer 14

An acid which does not completely ionize, or lose it’s hydrogen ions, in a solution.

Question 15

Chemical bond

Answer 15

Chemical bonds are what occur when two or more atoms bind together.

Some of these bonds are between atoms of the same type, resulting in a pure element. Other chemical bonds occur between atoms of different types and result in molecules.

Once formed, most of these bonds cannot be broken down, except by chemical means.

Each atom has what is called a “valence shell.” This is the outermost track its electrons can take around its nucleus, its outer orbit. The electrons in this orbit are called “valence electrons.” These electrons interact to form chemical bonds.

There are four primary types of chemical bonds: Ionic, Covalent, Metallic, and Hydrogen.

Question 16

Chemical equilibrium

Answer 16

The point at which the concentrations of reactants and products do not change with time. It appears as though the reaction has stopped but in fact the rates of the forward and reverse reactions are equal so reactants and products are being created at the same rate.

Question 17

Chemical reaction

Answer 17

A process in which one or more substances (reactants) are chemically changed into one or more new substances (products). Chemical changes may involve motionof electrons in the forming and breaking of chemical bonds.

Common chemical reactions are isomerization, syntheses, chemical decomposition, substitution, acid-base reactions, redox reactions, combustions, polymerization, ionization, hydrolysis, etc.

Question 18

Cohesion

Answer 18

This refers to the sticking together of alike molecules, such as water molecule being attracted to another water molecule.

Cohesion also causes water molecules to form drops.

Question 19

Compound

Answer 19

A substance consisting of atoms or ions of two or more elements that are chemically bonded together,

e.g. carbon dioxide, a substance consisting of carbon and two oxygen atoms.

Question 20

Covalent bond

Answer 20

Covalent bonds are formed when atoms share electrons in a covalent reaction.

When two oxygen atoms join together to form oxygen gas, they share two pairs of electrons with each other. Each shared pair of electrons is one covalent bond, so the two pairs of shared electrons in a molecule of oxygen gas have a double bond.

Covalent bonds are extremely important in biology because they hold together the backbones of all biological molecules.

Question 21

Dalton

Answer 21

A unit of mass equal to 1/12 the mass of a carbon-12 atom.

Also Known As: atomic mass unit, amu.

Question 22

Double bond

Answer 22

A double bond is a bond where two electron pairs are shared between two atoms.

Double bonds are drawn as two parallel lines in chemical structure diagrams.

Question 23

Electron

Answer 23

Clouds of electrons surround the nucleus.

Electrons carry a negative charge but have no mass.

Question 24

Electron shell

Answer 24

An electron shell is a set of atomic electrons grouped together by their quantum energy levels.

Question 25

Electronegativity

Answer 25

Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.

No electronegativity difference between two atoms leads to a pure non-polar covalent bond.

A small electronegativity difference leads to a polar covalent bond.

A large electronegativity difference leads to an ionic bond.

Question 26

Element

Answer 26

An element is a substance made of atoms that have the same number of protons. Think of them as “pure” substances all made of the same thing. All the known elements are organized into the periodic table of elements.

All matter is composed of elements. When you break down matter into its smallest components, you’re left with individual elements that themselves break down into atoms consisting of even smaller pieces called subatomic particles. And sometimes the number of those subatomic particles within a particular atom differs, creating isotopes.

Question 27

Evaporation

Answer 27

A change from liquid to vapor form.

Loss of volume of a liquid by conversion into vapor.

Question 28

Evaporative cooling

Answer 28

The cooling of a surface occurs when the liquid evaporates.

This is responsible for: moderating the earth’s climate, stabilizes temperature in aquatic ecosystems, prevents organisms from overheating.

Question 29

Heat

Answer 29

Energy transferred between two objects because of a temperature difference, the thermal motion of atoms and molecules.

For chemical systems the sign for heat flow into the system is positive, because this process increases the internal energy of the system. Heat flowing out of the system is defined to be negative, since this process decreases the internal energy of the system.

A form of energy that is transferred by a difference in temperature.

Question 30

Heat of vaporization

Answer 30

The amount of heat one gram of a pure liquid must absorb to be converted from a liquid to a gas.

Question 31

Hydrogen bond

Answer 31

A type of chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond forms an electrostatic link with the more electreonegativeatom of a polar covalent bond in the same or another molecule.

A hydrogen bond is a weak type of chemical bond that is common in organisms. As the name suggests, this type of bond involves a hydrogen atom that is attracted to a strongly electronegative atom such as oxygen, fluorine, or nitrogen of a polar covalent bond in the same or another molecule. Nevertheless, the link between the hydrogen atom and an electronegative atom is a strong dipole-dipole attraction. However, this type of chemical attraction is weaker than other types of chemical bonds (such as covalent and ionic bonds).

Hydrogen bonds occur in inorganic molecules (e.g. water) and organic molecules (e.g. DNA and proteins). Hydrogen bonds in water accounts for the latter’s high boiling point. Hydrogen bonds are also the ones responsible for the secondary and tertiary structures of important biomolecules such as nucleic acids and proteins. DNA, for instance, has a double helical structure that is largely due to the hydrogen bonds between paired nitrogenous bases.

Question 32

Hydrogen ion

Answer 32

Strictly, the nucleus of a hydrogen atom separated from its accompanying electron.

The hydrogen nucleus is made up of a particle carrying a unit positive electric charge, called a proton. The isolated hydrogen ion, represented by the symbol H+, is therefore customarily used to represent aproton. Because the bare nucleus can readily combine with other particles (electrons, atoms, and molecules), the isolated hydrogen ion can exist only in a nearly particle-free space (high vacuum) and in the gaseous state.

Question 33

Hydrophilic

Answer 33

Having an affinity for water (loving water); capable of interacting with water through hydrogen bonding; hygroscopic.

Hydrophilic molecules typically have polar groups enabling them to readily absorb or dissolve in water as well as in other polar solvents.

Question 34

Hydrophobic

Answer 34

Lacking an affinity for water; insoluble in water; repelling water.

Of, or having hydrophobia (literally, the fear of or water).

Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general.

Question 35

Hydroxide ion

Answer 35

The anion OH having one oxygen and one hydrogen atom, i.e. OH-

Question 36

Ion

Answer 36

Atoms that possess a positive or negative charge due to the gain or loss of electrons.

Question 37

Ionic bond

Answer 37

Hold ions joined together by their opposite electrical charges.

Ionic reactions occur when atoms combine and lose or gain electrons.

When sodium (Na) and chlorine (Cl) combine, for example, sodium loses an electron to chlorine. Sodium becomes the positively charged sodium ion (Na+), and chlorine becomes the negatively charged chloride ion (Cl–). These two oppositely charged ions are attracted to each other, forming an ionic bond.

Question 38

Ionic compound

Answer 38

Two or more ions held next to each other by electrical attraction.

Question 39

Isotope

Answer 39

All atoms of an element have the same number of protons, but the number of neutrons can change. If the number of neutrons is different between two atoms of the same element, the atoms are called isotopes of the element.

For example, carbon-12 and carbon-14 are two isotopes of the element carbon. Atoms of carbon-12 have 6 protons and 6 neutrons. These carbon atoms have a mass number of 12 because their mass is equal to 12. Atoms of carbon-14 still have 6 protons (because all carbon atoms have 6 protons), but they have 8 neutrons, giving them a mass number of 14.

Question 40

Kilocalorie

Answer 40

A measure of heat energy that is equal to the amount of heat needed to raise the temperature of one kilogram of water by one degree Centigrade at one atmospheric pressure.

It is used in measurements of the heat production of chemical reactions, including those involved in biology.

Question 41

Kinetic energy

Answer 41

This is the energy of motion.

Light, heat, and moving objects all contain kinetic energy.

Examples of Kinetic Energy:

1. An airplane has a large amount of kinetic energy in flight due to its large mass and fast velocity.
2. A baseball thrown by a pitcher, although having a small mass, can have a large amount of kinetic energy due to its fast velocity.
3. A downhill skier traveling down a hill has a large amount of kinetic energy because of their mass and high velocity.
4. A golf ball sitting on a tee before it is struck has zero kinetic energy because its velocity is zero.
5. An asteroid falling to earth at incredible speeds has an enormous amount of kinetic energy.
6. A car traveling down the road has less kinetic energy than a semi-truck traveling at the same speed because the car’s mass is much less than the truck’s.
7. A river flowing at a certain speed possesses kinetic energy because the water has a certain mass and it also has velocity.
8. An insect flying has a small amount of kinetic energy because its mass and velocity are relatively small.

Question 42

Mass number

Answer 42

Mass Number = (Number of Protons) + (Number of Neutrons)

The mass number is a count of the number of particles in an atom’s nucleus. Remember that the nucleus is made up of protons and neutrons.

Question 43

Matter

Answer 43

Matter is the stuff of life — literally.

Every living thing is made of matter.

In order to grow, living things must get more matter to build new structures. When living things die, be they plants or animals, microbes such as bacteria and fungi digest the dead matter and recycle it so that other living things can use it again. In fact, pretty much all the matter on Earth has been here since the planet formed 4.5 billion years ago; it has just been recycled since then. So, the stuff that makes up your body may once have been part of Tyrannosaurus rex, a butterfly, or even a bacterium.

Invisible matter
What looks like nothing but is really something? Air! Earth’s atmosphere may seem like nothing, but it’s made of gases such as nitrogen, carbon dioxide, and oxygen. These gases interact with living things in many ways. Plants, for example, take in carbon dioxide to make food and then use that food to build their structures. It’s hard to believe, but the tallest tree in the redwood forest grows and grows from the result of invisible carbon dioxide gas being taken in and incorporated into the body of the tree. Obviously the redwood tree takes up space and has mass, but those invisible carbon dioxide molecules are matter too.

Matter takes up space. Space is measured in volume, and volume is measured in liters (L).

Matter has mass. Mass is the term for describing the amount of matter that a substance has. It’s measured in grams (g). Earth’s gravity pulls on your mass, so the more mass you have, the more you weigh.

Matter can take several forms. The most familiar forms of matter are solids, liquids, and gases. Solids have a definite shape and size, such as a person or a brick. Liquids have a definite volume. They can fill a container, but they take the shape of the container that they fill. Gases are easy to compress and expand to fill a container.

Question 44

The Difference btw. Mass and Weight

Answer 44

To understand the difference between mass and weight, compare your weight on Earth versus your weight on the Moon. No matter where you are, your body is made of the same amount of stuff, or matter. But the Moon is so much smaller than Earth that it has a lot less gravity to pull on your mass. So, your weight on the Moon would be just one-sixth of your weight on Earth, but your mass would remain the same.

Question 45

mole (mol)

Answer 45

A mole is simply a unit of measurement. Units are invented when existing units are inadequate. Chemical reactions often take place at levels where using grams wouldn’t make sense, yet using absolute numbers of atoms/molecules/ions would be confusing, too.

Like all units, a mole has to be based on something reproducible. A mole is the quantity of anything that has the same number of particles found in 12.000 grams of carbon-12.

That number of particles is Avogadro’s Number, which is roughly 6.02x10^23. A mole of carbon atoms is 6.02x10^23 carbon atoms. A mole of chemistry teachers is 6.02x10^23 chemistry teachers. It’s a lot easier to write the word ‘mole’ than to write ‘6.02x10^23’ anytime you want to refer to a large number of things! Basically, that’s why this particular unit was invented.

Question 46

Molecular formula

Answer 46

The molecular formula is an expression of the number and type of atoms that are present in a single molecule of a substance.

The molecular formula of glucose is: C6H12O6. One molecule of glucose contains 6 atoms of carbon, 12 atoms of hydrogen and 6 atoms of oxygen.

Question 47

Molecular mass

Answer 47

A number equal to the sum of the atomic masses of the atoms in a molecule. The molecular mass gives the mass of a molecule relative to that of the 12C atom, which is taken to have a mass of 12.

Examples: The molecular mass of C2H6 is approximately 30 or [(2 x 12) + (6 x 1)]. Therefore the molecule is about 2.5 times as heavy as the 12C atom or about the same mass as the NO atom with a molecular mass of 30 or (14+16).

Question 48

Molecule

Answer 48

Molecules are made of two or more atoms.

Question 49

Example of the Diffs. btw. Elements, molecules, and Compounds.

Answer 49

One way to sort out the differences between elements, molecules, and compounds is to think about making chocolate chip cookies. First, you need to mix the wet ingredients: butter, sugar, eggs, and vanilla. Consider each of those ingredients a separate element. You need two sticks of the element butter. When you combine butter plus butter, you get a molecule of butter. Before you add the element of eggs, you need to beat them. So, when you add egg plus egg in a little dish, you get a molecule of eggs. When all the wet ingredients are mixed together, the molecule of butter is combined with the molecule of eggs, and you get a compound called “wet.” Next, you need to mix together the dry ingredients: flour, salt, and baking soda. Think of each of those ingredients as a separate element. When all the dry ingredients are mixed together, you get a compound called “dry.” Only when the wet compound is mixed with the dry compound is the reaction sufficiently ready for the most important element: the chocolate chips.

When you start putting elements together, you get more complex forms of matter, such as molecules and compounds. Molecules are made of two or more atoms, and compounds are molecules that contain at least two different elements.

Question 50

Neutron

Answer 50

The neutron is the particle in the atomic nucleus with a mass = 1 and charge = 0.

Question 51

Nonpolar covalent bond

Answer 51

Nonpolar covalent bonds form when the electronegativity values are very similar.

Nonpolar covalent bonds are a type of bond that occurs when two atoms share a pair of electrons with each other. These shared electrons glue two or more atoms together to form a molecule. Like children who share toys, atoms involved in a nonpolar covalent bond equally share electrons.

An example of a nonpolar covalent bond is the bond between two hydrogen atoms because they equally share the electrons.

Nonpolar covalent bonds are very strong bonds requiring a large amount of energy to break the bond.

Nonpolar covalent bonds are extremely important in biology. They form the oxygen we breathe and help make up our living cells.

One kind of nonpolar covalent bond that is very important in biology is called a peptide bond. A peptide bond joins together chains of amino acids, which are involved in the construction of our DNA. Amino acids are comprised of several atoms like carbon, oxygen, nitrogen and hydrogen.

Question 52

Orbital

Answer 52

Electron cloud having an energy state described by given values of the n, ℓ, and mℓ quantum numbers. An orbital can contain two electrons with paired spins and is often associated with a specific region of an atom.

Examples: The electrons in the 2px orbital of an atom are generally found within a dumbbell-shaped cloud about the x-axis.

Question 53

pH

Answer 53

pH is the negative log of hydrogen ion concentration in a water-based solution.

pH is an abbreviation for “power of hydrogen” where “p” is short for the German word for power, potenz and H is the element symbol for hydrogen.

The H is capitalized because it is standard to capitalize element symbols.

Logarithmic Scale

The pH scale is a logarithmic scale that usually runs from 1 to 14. Each whole pH value below 7 (the pH of pure water) is ten times more acidic than the higher value and each whole pH value above 7 is ten times less acidic than the one below it. For example, a pH of 3 is ten times more acidic than a pH of 4 and 100 times (10 times 10) more acidic than a pH value of 5. So, a strong acid may have a pH of 1-2, while a strong base may have a pH of 13-14. A pH near 7 is considered to be neutral.

Question 54

Polar covalent bond

Answer 54

Have you ever seen two children play and one child acts like a bully toward the other child? The bully child seems to spend more time playing with the toy than the other child. They are not equally sharing the toys.

This unequal sharing also happens with a type of bond called polar covalent bonding. Polar covalent bondingis a type of chemical bond where a pair of electrons is unequally shared between two atoms. In a polar covalent bond, the electrons are not equally shared because one atom spends more time with the electrons than the other atom. In polar covalent bonds, one atom has a stronger pull than the other atom and attracts electrons. Remember how electrons carry a negative charge? Well, when electrons spend more time with one atom, it causes that atom to carry a partial negative charge. The atom that does not spend as much time with the electrons carries a partial positive charge. To remember a polar covalent bond, instead say ‘puller covalent,’ and remember one atom has more ‘pull’ on electrons than the other atom.

In a polar covalent bond, one atom spends more time with the electrons than the other.

Your life actually depends on polar covalent bonding. You drink water right? A water molecule, abbreviated as H2O, is an example of a polar covalent bond. The electrons are unequally shared, with the oxygen atom spending more time with electrons than the hydrogen atoms. Since electrons spend more time with the oxygen atom, it carries a partial negative charge.

Another example of a polar covalent bond is between a hydrogen and chlorine atoms. In this bond, the chlorine atom spends more time with the electrons than the hydrogen atom. Because of this unequal sharing of electrons, the chlorine atom carries a partial negative charge, and the hydrogen carries a partial positive charge.

Question 55

Polar molecule

Answer 55

A polar molecule is a molecule containing polar bonds where the sum of all the bond’s dipole moments is not zero.

Examples: Water is a polar molecule. Carbon dioxide is made up of polar bonds, but the dipole moments cancel each other out and therefore is not a polar molecule.

Question 56

How to Predict Bonding Type Using Electronegativity

Answer 56

You may be wondering: how do you know what type of bond will occur between atoms?

You can predict which type of bond will form by looking at the electronegativity of each atom involved in the bond. Electronegativityis how strongly an atom will attract electrons from another atom in a chemical bond. Some atoms have a higher electronegativity, while others have a lower electronegativity.

Electronegativity is like a tug of war game between two atoms. If you have one person on the side of the rope that is stronger than the other person, then that stronger person will tug harder pulling the other person in their direction. On the other hand, if you had two people of equal strength, then the rope would not shift in any one direction and stay in the same place.

Like tug of war, if you have a stronger atom with a higher electronegativity, then it will be able to tug electrons in their direction. Since the atoms have a different electronegativity, the electrons are unequally shared. On the other hand, if you have two atoms with the same strength, or the same electronegativity, then the electrons will not be tugged in any one direction and will stay in the middle of the two atoms. Since there is no tugging, electrons are equally shared between the two atoms.

Remember how the periodic table is a like a roadmap that can tell you the properties of each element? An additional trend the periodic table can tell you is the electronegativity of an element.

Before I describe the trend, first remember that hydrogen is considered a nonmetal and is moved to the far right with the other non-metals. The electronegativity trend I am about to describe excludes the noble gases and most transition metals. Remember, noble gases are located in the last column of the periodic table, and the transition metals are located in groups 3 through 12 on the periodic table. Now that you know the exclusions, the main trend is as you move from left to right, the electronegativity increases, and as you move from bottom to top, the electronegativity increases.

When two atoms have unequal levels of electronegativity, one atom will tug electrons from the other.

Using this trend, you can see the most electronegative elements are found on the top right such as oxygen, chlorine and fluorine. And the least electronegative elements are found in the bottom left such as francium, cesium, barium and radium.

Question 57

Potential energy

Answer 57

This is the energy that’s stored in something because of the way it’s arranged or structured. Energy in a battery, water behind a dam, and a stretched rubber band that’s about to be released are all examples of potential energy. Food and gasoline also contain potential energy called chemical potential energy (energy that’s stored in the bonds of molecules).

Question 58

Product

Answer 58

A product is a substance that is formed as the result of a chemical reaction.

Example: AgCl (s) is the product of the reaction Ag+ (aq) + Cl- (aq) → AgCl (s)

Question 59

Proton

Answer 59

A proton is a positively charge particle that resides within the atomic nucleus.

The number of protons in the atomic nucleus is what determines the atomic number of an element, as outlined in the periodic table of the elements.

The proton has charge +1, the exact opposite of the -1 charge contained by the electron. In mass, however, there is no contest, since the proton’s mass is approximately 1,836 times that of an electron.

Since the proton is in the atomic nucleus, it is a nucleon.

Question 60

Radioactive isotope

Answer 60

‘radioactive’, refers to a unique and unstable type of energy. If an isotope has an unstable nucleus that breaks down to emit radiation, then these are what we call radioactive isotopes, also known as radioisotopes.

Radioactive isotopes have an unstable nucleus that decays or emits excess energy or radiation until the nucleus becomes stable. They can be naturally occurring or artificial isotopes of an element.

Question 61

Reactant

Answer 61

Starting material in a chemical reaction.

Examples: H2 and O2 are reactants in the reaction H2(g) + 1/2 O2(g) → H2O(l).

Question 62

Salt

Answer 62

The crystallized product of evaporation, especially of sea water.

The neutral ionic compound formed by chemical combination of acid and base, or through neutralization.

Question 63

Single bond

Answer 63

A single bond is a chemical link between two atoms in which electrons are shared between them.

Examples: There is a single bond between the oxygen and each hydrogen in a water molecule (H2O). Each of the covalent bonds contains two electrons - one from a hydrogen atom and one from theoxygen atom. Both atoms share the electrons.