General Chemistry Notes
General Chemistry Notes
General Chemistry Notes
Name _____________________________
Directions: Carefully read the following information. Look for the ** directions in italics** for prompts where you
can do some work. Use the information you have reviewed here to help answer questions in your Chemistry
Take-Home Test.
Chemistry is the study of atoms and the reactions they undergo to form compounds. Every biological system can be
reduced to the chemical level. Therefore, the study of biology must start at the chemical level. Metabolic processes like
photosynthesis and cellular respiration are composed of a series of chemical reactions which involve the combinations of
atoms to form new compounds. An understanding of these atoms and their chemical and physical properties will help in
the understanding of the chemical reactions that take place in living things.
Everything on earth is made of matter. Matter is anything that occupies space (volume) and has mass (weight).
The building blocks of matter are called atoms.
The Structure of an Atom:
An atom is made up of three basic particles.
1. Positively charged protons (p+)
2. Neutral neutrons (no)
3. Negatively charged electrons (e-)
neutrons (no)
protons (p+)
electrons (e-)
energy levels
The particles of the atoms have charges, yet atoms have a net charge of 0 (they are neutral). This is because the
number of positively charged protons is equal to the number of negatively charged electrons. The charges cancel each
other out.
Electrons orbit the nucleus in different energy levels. All of these energy levels make up an electron cloud. Although
the diagrams show electrons orbiting the nucleus in a circular fashion, this is not really accurate. The electrons in the
different levels are different distances from the nucleus, but instead of orbiting in a circular track, they occupy a
certain space at that distance. This will be explained in much more detail in honors Chemistry next year. Electrons in
the different levels possess varying amounts of energy. Electrons that are further from the nucleus have more energy
than those closer to the nucleus.
The different energy levels can hold different numbers of electrons:
Level 1 Can hold up to 2 electrons.
Level 2 Can hold up to 8 electrons.
Level 3 Can hold up to 18 electrons but it is composed of sublevels. The first sublevel holds up to 8 electrons.
Most important biological elements have fewer than 18 electrons so the first sublevel of the 3rd energy level will be
adequate for our studies.
The electron energy levels can be represented in a simple diagram. Hydrogen has 1 electron, oxygen has 8 electrons,
and sodium has 11electrons. Each can be efficiently illustrated as follows:
Hydrogen
1p ) 1
Oxygen
8p ) 2) 6)
Sodium
11p ) 2) 8) 1)
1
Oxygen, 65%
Oxygen 65%
Carbon 19%
Hydrogen 10%
Nitrogen 3%
Trace elements like Na, Ca, K, S, P, Cl, Fe, Mg
(Trace elements are essential for life but are needed
Only in small amounts.)
17
11
Cl
Na
12.0
35.45
14.0
22.98
1.0
carbon
chlorine
nitrogen
sodium
hydrogen
atomic mass
______
______
______
______
______
atomic no.
______
______
______
______
______
protons
______
______
______
______
______
neutron
______
______
______
______
______
electrons
______
______
______
______
______
Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons.
This will cause different isotopes of the same element to have different atomic masses. The number of protons in an
atom will define the element. An atom of carbon always contains 6 protons. Different isotopes of carbon will contain 6
protons but may contain 6, 8 or 10 neutrons. Since the number of electrons remains the same, the reactivity (the way they
combine with other atoms) is also the same for isotopes of the same element.
(Do not confuse isotopes with ions. Ions of the same element will have different numbers of electrons.)
Most elements have isotopes. Some examples are:
Carbon- 14 contains 6 protons and 8 neutrons
Carbon- 12 (most common isotope in nature) contains 6 protons and 6 neutrons
Oxygen-18 contains 8 protons and 10 neutrons
Oxygen-16 (common isotope in nature) contains 8 protons and 8 neutrons
Many isotopes are radioactive, which means they have an unstable nucleus which emits radiation, reducing the number of
protons or neutrons over time.
MOLECULES AND COMPOUNDS
A molecule is composed of two or more atoms bonded covalently (they share electrons to be stable).
Ex.
water H2O,
oxygen O2 ,
methane CH4 ,
hydrogen H2 ,
Ozone O3,
A molecular compound is a molecule composed of more than one type of atom. Some molecules are molecular
compounds. Some molecules, like diatomic (N2) are not considered a molecular compound because it only
contains N.
Molecules and compounds are represented by chemical formulas: (ex. O2 C6H12O6, H3CO3,
The chemical formula tells you 1) the types of elements present in the molecule or compound
2) the number of atoms of each element in the compound.
N2 )
**Look at the following chemical formulas, and determine if they represent a molecule, a compound, or both.**
H 2O
O2
______
________
CH4
H2
________
O3
_______
_______
Subscripts and Coefficients-used to represent the number of molecules in a reaction and the number of atoms in a
molecule.
The number before the letters (the coefficient) in a chemical formula refers to the number of molecules. The number after
the letter (the subscript) refers to the number of that particular atom. To calculate the total number of a particular atom in
a compound, multiply the coefficient times the subscript. If there is no coefficient or subscript number it is considered to
be 1. In the first example in the chart below, there is no number before the glucose molecule - C6H12O6. - this means that
there is one molecule of glucose.
**Using the examples filled in for you, complete the information below:**
C6H12O6
2NH3
3H2O
3CO2
2PO4
Number of Molecules
Number of Atoms
C- 6
C- 3
H- 12
O- 6
O- 6
3
Oxygen______________
Hydrogen_____________
Nitrogen_____________
An easy way to remember the number of bonds these common atoms form HONC - 1234!**
Example of how a water molecule is formed from covalent bonding of hydrogen and oxygen:
NH3
O2
HOH
CH4
CO2
O=O
**Diagram how the following molecules are formed by covalent bonding. Show the energy levels in your drawing
(Methane and Oxygen have been done for you.) Circle each covalent bond in your diagram: Note: Oxygen forms a
double bond with other Oxygen atom. This means that they are sharing two pairs of electrons. There are also triple
bonds, where 3 pairs of electrons are shared. An example of this would be the molecule N2.**
H2
NH3
O2
CH4
N2
CO2
**In the box below draw the structural formulas for the following compounds. Make sure that the number of bonds
between the atoms are correct. Note that sometimes there is more than one way to diagram a structural formula from
a chemical formula. Remember HONC, 1234!**
CH2O
NHO
CNOH3
C2OH3N
2)8)1
Mg: 2)8)2
F:
2)7
O:
2)6
Ionic Bonds-are formed when two ions of opposite charge (one + and one -) are attracted to each other. There is
no sharing of electrons in an ionic bond, just the attraction of two atoms that have gained or lost electrons to one
another to become stable. In the process, they are of opposite charges and become attracted to each other.
In the diagram below, the lithium atom has 1 electron in its outer energy level and so will lose that electron in
order to become stable. This gives the Li ion a positive charge
Forming an ionic compound.
Ex. lithium and fluorine will combine to form lithium fluoride, and ionic compound.
Note: The opposite charges of the Li+ and the F+ cancel each other out so the compound formed,
lithium fluoride, is not charged it is neutral.
Diagram of a sodium ion and a chloride ion, forming the ionic compound, sodium chloride (NaCl):
**Diagram magnesium (Mg) ion and an oxygen ion, and show how they form the ionic compound Magnesium
oxide.**
**Diagram a magnesium (Mg) ion and a chloride (Cl) ion, and show how they form the ionic compound Magnesium
chloride.*
Note: You will need to use more than one chloride ion to form this ionic compound!
**Diagram a calcium (Ca) ion and an chloride (Cl) ion, and show how they form the ionic compound Calcium
chloride.*
You will have to decide how many of each ion is necessary to form this ionic compound!
**Diagram a potassium (K) ion and an chlorine ion, and show how they form the ionic compound Potassium
chloride.*
You will have to decide how many of each ion is necessary to form this ionic compound!
NOTE: The following material on Polar and Nonpolar covalent bonds will be discussed in greater
depth in class. You should still make an effort to learn the material and answer the questions
in the prompts. You will also have some questions on the multiple choice assessment on these
concepts.**
ANOTHER LOOK AT COVALENTLY BONDED MOLECULES
You will examine two kinds of covalent bonds: Polar Covalent bonds and Nonpolar Covalent bonds.
POLAR COVALENT BONDS
Polar means having two opposite ends, like the North and South Poles of the Earth. In the case of bonds it means
2 opposite charges.
A covalent bond between two atoms in which the electrons are NOT SHARED EQUALLY.
The electrons involved in the bond spend more time hovering around the nucleus of one atom, giving it a
partial negative charge.
This results in the other atom having a partial positive charge.
The partial positive and negative charges are not as strong as the charges in ions but can affect the attraction
of the molecule or compound with other charged substances.
Polar
Covalent
Bond
Polar
Covalent
Bond
Water is an example of a polar molecule because electrons are more strongly attracted to the oxygen atom than to the two
hydrogen atoms. This is because the oxygen atom has more protons in the nucleus which are attracting the shared
electrons. This gives the oxygen a partial negative charge, and each of the two hydrogens a partial positive charge.
You should note that the charges in a polar molecule are not complete charges, like an ion; they are only partial charges
(indicated by the delta sign), because the atom that is more negative has not pulled an electron completely away from the
atom that is positively charged. Electrons are still considered shared in a polar covalent bond.
Because water molecules are polar, they tend to stick to each other. A positive side of one water molecule is attracted to
the negative side of another water molecule.
Notice the dotted lines between the water molecules in the diagram on the left. These dotted lines represent a special type
of bond called a hydrogen bond.
Hydrogen bond- is a bond between the hydrogen in a polar molecule and the oxygen or nitrogen in a polar molecule.
Bonds can be found between atoms in different polar molecules (as in between 2 water molecules) or between atoms in
the same polar molecule (DNA and proteins will be discussed in another chapter).
Because hydrogen bonds are much weaker than covalent or ionic bonds, they are constantly breaking and reforming.
For example, in a glass of water at any given time most of the water molecules are hydrogen-bound to each other. Even
so, they are constantly breaking and reforming in liquid water. The weak nature of these bonds is extremely important in
chemical reactions that occur within living things. They will be discussed throughout the year.
Other Polar Molecules
Some molecules have polar regions which make either part of or the entire molecule polar. An example of
a polar molecule is the sugar glucose. The structural formulas of glucose can be shown in a linear or ring form. Note
the locations of polar covalent bonds.
Notice all the -O-H or hydroxyl groups in the glucose molecule below. Because in each O-H bond the electrons are
more strongly attracted to oxygen atom (as in water), the oxygen has a slightly negative charge, and the hydrogen has a
slight positive charge. The bonds between the oxygen and hydrogen are polar covalent bonds. As in water, the oxygen
atoms are partially negative in charge and the hydrogen atoms bonded to the oxygen are partially positive in charge.
The presence of hydroxyl groups make glucose a polar molecule.
Polar
Covalent
Linear
Form
Bond
Polar
Covalent
Ring
Form
Hydroxyl
group
between
the
Bond
hydrogen
and
oxygen
of
a
hydroxyl
group.
**Draw
arrows to show the location of additional polar covalent bonds between the oxygen and hydrogen in the
Ionic Bond
No sharing
10
NOTE: The following material on Solutions will be discussed in greater depth in class.
You should still make an effort to learn the material and answer the questions in the prompts.**
SOLUTIONS
Solution- a mixture where one substance is evenly dissolved into another. A solution is composed of a solvent
and one or more solutes.
Solvent- the dissolving agent. The solvent is in higher concentration compared to the solute. The solvent in
most biological systems is water but it can also be oils, gasses and other substances.
Solute- The substance that is dissolved in the solvent.
If salt is mixed with water, salt is the solute and the water is the solvent.
Water- the Universal Solvent
In biological systems, water is the main solvent. It is found in the blood, the cytoplasm of a cell and in the tissue fluid
between cells. Materials dissolved in water can be transported to and from cells. The characteristics of water make it the
universal solvent in biological systems:
Water is polar. It has partial positive and negative charges. It is attracted to molecules with opposite
Charges. By sheer numbers, water molecules can surround charged particles like ions or polar molecules
and cause them to separate. This separation is called dissolving.
How an ionic compound and a covalent compound dissolve in water
1) When sodium chloride (salt) dissolves in water the sodium ions (Na+)
separate or dissociate from the chloride ions (Cl-). The ionic bonds in the salt crystal break as water surrounds
the individual ions Dissociation only takes place when an ionic compound dissolves in water.
2) When glucose dissolves in water the glucose molecule do not separate or dissociate. This is because the atoms in
glucose are joined by covalent bonds which usually do not separate in water. When glucose dissolves in water, the
molecules of glucose are separated from each other but the individual molecules remain intact
no covalent bonds are broken.
Look at the diagrams on the next page, which show in more detail how salt and sugar dissolve in water.
Note: When sugar or salt dissolves in water, the crystals that you could easily see on your spoon seem to disappear. This
is because the water molecules surround the ions or sugar molecules as they are dissolving and separate them into single
units (ions or molecules) that are too small to be seen. A crystal of salt or sugar is composed of billions of molecules or
ions that are compressed together. Crystals can be seen but molecules or ions are too small to see.
11
12
Water Molecule
Hydrogen bond
Glucose
Molecule
Water Molecule
Covalent
bonds
Water Molecule
**Try thisit wont be graded for points, just for effort!--Use the points in the explanation of ionic dissociation to
describe the diagram above. The first statement has been done for you. It is the same as for the ionic compound!
Make sure to include the statements that are similar but change or exclude statements that are not the same. For
example, you will not include dissociation as a term to describe the formation of a covalent solution but you will use
the term dissolves.**
1) Water is polar. The oxygen has a partial negative charge and the hydrogen has a partial positive charge.
2) ________________________________________________________________________________________________
_________________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Note: Sometimes a covalently bound compound will dissociate in water, if it is extremely polar. An example of this is
when covalently bonded hydrochloric acid (HCl) dissociates in water, to generate H+ ions and Cl- ions. However, most of
the organic compounds we will be discussing this year, such as sugars, do not dissociate. They are instead surrounded
by water molecules and separated into single molecules.
13
The different sized beakers below contain the same number of solute particles dissolved in water.
14
NOTE: The following material on Dissociation of Water will be discussed in greater depth in class.
You should still make an effort to learn the material and answer the questions in the prompts.**
DISSOCIATION OF WATER
Water molecules themselves can break apart and form ions. However, this is a very rare occurrence. The majority of
molecules in any sample of water will be covalently bound together. It is only approximately 2 in a billion of water
molecules in any sample that will dissociate.
Water molecules are constantly in motion. Water molecules may dissociate as shown below. This process is also
reversible, and the H+ and OH- can recombine to form H2O. This is constantly changing, but at any given moment, you
would expect to find approximately 2 in a billion water molecules that have dissociated:
H 2O
H+ +
OH-
(Dissociated)
1. The water molecule contains one oxygen bonded to two hydrogen molecules. When it dissociates, the proton breaks
away, but the electron is left behind with the remaining OH. This single proton is also called a hydrogen ion (H+).
2. The molecule that remains after the hydrogen ion breaks away has an extra electron, and has a negative charge.
This ion is called the hydroxide ion (OH-). (Do not confuse the hydroxide ion with a hydroxyl group (-OH). The
hydroxyl group is an OH bonded to another molecule. It was defined previously on page 9.)
In pure water, the number of hydrogen ions would equal the number of hydroxide ions, resulting in a
neutral solution. For example, if a beaker of pure water has 50 H+ ions, it will have 50 OH- ions.
A more accurate way to explain what happens when water dissociates is that the free hydrogen ion (H+) is attracted to
another water molecule to form a hydronium ion. The oxygen in one molecule of water attracts the proton in another
molecule of water so strongly that it literally steals the proton away and becomes a hydronium ion. The electron
remains with the OH and produces a hydroxide ion.
Overall reaction:
H 2O
+
H 2O
Water + Water
H 3O +
OH-
15
The dissociation of water always results in a neutral solution because the number of positively charged hydronium ions
equals the number of negatively charged hydroxide ions. Pure water is a neutral solution.
Simplified Equation:
H2O
H+ ( H3O+)
OH-
8 H+ ( 8 H3 O+ )
8 OH-
16
NOTE: The following material on acids and bases will be discussed in greater depth in class.
You should still make an effort to learn the material and answer the questions in the prompts.**
ACIDS
If you were to dissolve some HCl (hydrochloric acid) into water, it would dissociate:
HCl H+
Cl-
This would increase the number of H+ (hydrogen ions or protons) in the solution. The H+ ion concentration
would then be greater than the OH- ion concentration.
The resulting solution is said to be an acidic solution.
Acid-a substance that increases the H + ion concentration of a solution. Since an acid is a substance that adds
H+ ions to a solution when it dissociates it is called a hydrogen ion donor. When acids add H+ ions to a solution,
the H+ are attracted to water molecules and form hydronium ions (H+ + H2O H3O+).
Therefore, acids increase the number of hydronium ions (H3O+) in a solution. The H+ also binds to OHforming H2O. This decreases the OH- concentration.
Note: Acids lower the pH of a solution because an increase hydrogen ions lowers pH. For example, if the pH
of a solution goes from 7 to 4 the hydrogen ion concentration has increased.
BASES
If you were to dissolve some NaOH (sodium hydroxide) into water, it would dissociate as follows:
NaOH Na+
OH-
This would increase the number of OH- (hydroxide ions) in the solution. The OH- ion concentration would be
greater than the H+ ion concentration. The resulting solution is said to be a basic or alkaline solution.
Base-a substance that decreases the H+ concentration (or the hydronium ion concentration-H3O+) of a solution.
A base can attract the extra proton on the hydronium ion which results in the production of a water molecule.
Because the hydronium ion (H3O+) concentration decreases we tend to say that the hydrogen ion
concentration has decreased. Bases are therefore called hydrogen ion acceptors.
Note: Many bases donate hydroxide ions which bind to (accept) hydrogen ions:
Example-Sodium Hydroxide (NaOH):
NaOH Na+
OH- + H3O+ ( H+ )
OH
2 H2O
Note: Not all bases release hydroxide ions but they can accept and bind to hydrogen ions:
Example-ammonia ( NH3) is a base.
NH3 + + H3O+ ( H+ ) NH4+ + H2O NH3 accepts a H+ ion and water is formed. This
reduces the concentration of H+ (H3O+) in the
solution.
17
Note: Bases raise the pH of a solution because a decrease in hydrogen ions raises pH. For example, if the pH
of a solution goes from 7 to 10 the hydrogen ion concentration has decreased
**Draw the ions you would find in each of the following solutions. You should draw 2 intact water molecules to
represent the majority of water in each beaker, and draw one hydronium ion and one hydroxide ion to represent
the water molecules that are dissociated. In addition, in beaker 1, draw what happens when one molecule of
HCL is added to form an acidic solution. In beaker 3, draw what happens when one molecule of NaOH is added
to form a basic solution.
___
Acid-HCL
Neutral Water
Base-NaOH
pH
Scale:
1
7
14
__________________________________________________________
neutral
more
acidic
(more
H+)
more
basic
(less
H+)
less
OH-
more
OH-
18
pH
Neutral
19
Difference in pH:
There is a significant difference in hydrogen ion concentration in a change of a single pH unit, such as between pH 3 and
pH 4. There is really a 10 fold difference between each unit. For example, the concentration of H+ ions is 10 times greater
in a pH of 3 versus a pH of 4; there would be 100 times more H+ ions in a pH of 2 versus a pH of 4.
To better understand why there is a 10X difference in H+ concentration between each pH unit, study the chart below:
pH 1
pH 2
pH 3
pH 4
pH 5
pH 6
pH 7
Note that as the pH goes up, the number of hydrogen ions (H+) gets smaller. For example, 0.1 is greater than 0.01, and
0.01 is greater than 0.001, etc.
These numbers are expressed in units called moles/liter. You will learn more about this concept in chemistry.
BUFFERS AND pH
The body uses substances called buffers to insure that the pH of body fluids does not fluctuate very much. Buffers
prevent large sudden changes in pH. Buffers work by accepting H+ ions from solution when they are in excess, and
donating H+ ions to the solution when they have been depleted. Even small pH changes can drastically alter body
function. Remember, each pH unit represents a tenfold difference, so a slight change in pH represents a large change in
the actual pH. If the blood becomes too acidic or too basic it could cause serious problems.
An example of a buffer system in the human body is the carbonic acid/ bicarbonate ion buffer system, which exists in
the blood, and helps keep the blood at a relatively neutral pH. The equation that follows explains how this system works
to either remove excess hydrogen ions if the body fluid becomes too acidic, or release hydrogen ions if the body fluid
becomes too basic. Note that this chemical reaction is reversible, which is to say it can go in both directions, depending on
the needs of the body. H2CO3 can be either a reactant or a product, depending upon which way the reaction is going.
Note: Not all bases release hydroxide ions, but all bases remove hydrogen ions from the solution by combining with
them in some fashion, thereby raising the pH.
The equation below shows how the blood buffer system works.
Response to a
rise in pH
H 2 CO 3
+
H donor
Hydrogen
(acid)
Carbonic acid
Response to a
drop in pH
HCO 3 H + acceptor
(base)
H+
ion
Bicarbonate ion
20
How does this buffer system respond to a rise in pH (fluid becomes basic)?
How does this buffer system respond to a drop in pH (fluid becomes acidic)?
Questions:
________1) If the pH in a system changes from 8 to 7, how will the buffer system react?
a. act as an acid and release H+ from carbonic acid forming more bicarbonate ions
b. act as a base and accept more H+ to bind with HCO3- forming more carbonic acid
c. it will not shift at all
_________2) If the pH in your blood rises from 7.4 to 7.9, which of the following will result? (Choose three answers)
a. more carbonic acid will be formed
b. the reaction will shift from left to right above
c. more bicarbonate ion will be formed
CHANGES IN MATTER
Properties of Matter
Examples of the physical properties of a substance-density, volume, mass, color, shape, viscosity, texture.
Physical change-a change in the physical properties of a substance. The molecular structure is not changed, no
bonds are broken but dissociation of ions may take place.
Examples of physical changes: evaporation, condensation, sublimation, freezing, dissociation of ions like that of
NaCl in water, dissolving of sugar, ripping paper, breaking glass, chocolate melting, sawing wood, crushing
chalk, rock weathering, dissolving of sugar in water.
Chemical change-a change where the chemical bonds break apart and the atoms rearrange to form new
substances that have new chemical and physical properties. Old bonds in the reactants are broken and new bonds
in the products form.
Examples of chemical changes: burning of wood, rusting, use of an antacid, production of glucose in
photosynthesis and the breakdown of glucose in cellular respiration, any reaction producing heat, cooking food,
digesting food, if there is a color change.
21
CHEMICAL REACTIONS
In chemical reactions, reactants (shown on the left side of the chemical equation) react, or undergo chemical
changes, to produce products, shown on the right side of the chemical equation.
Chemical reactions are shown by using chemical equations. A chemical reaction may involve more than one
reactant and may produce more than one product. The following equation is not balanced because there are two
atoms of oxygen on the reactant side of the equation and only one on the product side.
**Balance the equation by changing coefficients.**
Hydrogen
H2
(Reactants)
+
Oxygen
O2
(Product(s))
Water
H 2O
Balancing Equations:
In a chemical reaction, bonds in the reactants break and the atoms are rearranged. New bonds form to make new molecule
(product). At no time during the reaction are both reactants and products present at the same time! The reactants are
used to make the products.
Chemical reactions are said to be balanced. A balanced reaction can be identified by counting the numbers and types of
atoms in the reactants and products. If an equation is balanced, they will be equal. When balancing reactions, remember
that the numbers and types of atoms in the reactants must be equal to the numbers and types of atoms in the
product. You cannot change a subscript when balancing a reaction but you may change a coefficient.
**Review what you learned during 8th grade chemistry and balance the following reactions by changing the
coefficients of the molecules involved in the reaction.**
H 2S
____O2
____Al + _____ O2
____H2O2
H2SO4
____Al2O3
____ H2O +
O2
C6H12 O6 + _____ O2
C 3H 8
+ _____ O2
____ H3PO4
22
Energy:
Energy is an important concept in chemical reactions. In order to break apart the bonds of the existing reactants to
form products, energy must be added to the reaction, and absorbed by the reactants. For example, to break the
covalent bonds of a sugar molecule, heat would have to be added to help destabilize the bonds, and cause more molecular
collisions between individual sugar molecules. Both of these events would allow bonds to more easily break. Conversely,
when the new bonds form in the products, energy is released. This concept of energy released when new bonds form is
sometimes difficult to grasp, and will be discussed more in the next chapter on biochemistry.
23
NOTE: You may skip the following discussion on the Rate of Chemical Reactions. This material will be
covered in class. You are finished with the Chemistry notes packet. Use the material in this packet to
answer the questions on the Chemistry Take-Home Test.
RATES OF CHEMICAL REACTIONS
The rate or speed of chemical reactions depends upon how long it takes for the reactants to break apart, and the
products to form.
One factor that influences the rate of a chemical reaction is heat (temperature) of the environment:
Heat increase -
_______
Enzyme-
24