2.7

You probably know that the pH scale runs from....

0 to 14.

Acids are substances that have a pH less than _______

7

Bases have a pH greater than ______

7

Double replacement reaction:

AB + CD --> AD + CB You can see that the cations A+ and C+ switch places(double replacement), forming two new ionic compounds.

The general equation for a single replacement reaction is:

AB(aq) + C -> A + CB (aq) This says that compound AB, which is dissolved in water (aq, or aqueaous), and the element C react to form a new compound CB dissolved in water and the pure element A.

For example, if we stick with AgNO3, but this time react it with Kcl, we get:

AgNO3 +KCl -> AgCl + KNO3

Ionic salts dissolve readily in water, which causes the ionsto dissociate from one another. The result is a solution of_________ and ________ that can undergo a number of chemical reactions.

Anions and Cations.

Chemical reactions happen between:

Atoms, molecules, or compounds.

Molecules in solution or gaseous form are in ____________ motion

Constant

A chemical reaction is a process that?

Exchanges one bonding arrangement among atoms for a different bonding arrangement. For that to happen some bonds between atoms have to be broken and new bonds have to form.

As temperature increases molecules move ___________

Faster. So they are more likely to "bump into each other."

There are strong and weak bases. The stronger the base, the __________ the pH.

Higher.

If products are withdrawn from the reaction as they form, then the rate of product formation _____________

Increases.

Redox reaction

Involves a transfer of electrons between two chemical species. One of the species gains electrons from the other substance that gives up electrons. We have seen an example of this in a earlier section, when we discussed single displacement reactions. 2AgNO3 + Cu -> Cu(NO3) + 2Ag Now this examine this reaction more closely. AgNO3 is avaliable as a solid ionic salt. It is an ionic compound that dissolves readily in water. Dissolution means that the ions that make up the solid compound are pulled apart and coated with water molecules. We need to digress for a moment. Why would charged anions and cations be coated or surrounded by water, H20? This is because water, which is made of two hydrogen atoms covalently bonded to an oxygen atom, contains a partial charge.

Acid

Is a compound that has a tendency to transfer a proton to antoher molecule.

Base

Is a compound that has the tendency to accept a proton.

pH scale

Is a measure of the H+ concentration (written as [H+]) in a aqueous solution. Specifically, pH = -log [H+].

Molecule

Is any arrangement of two or more atoms bonded together. Water H20 is a molecule. Carbon Dioxide CO2. Ethanol CH3CH2OH. H2 and O2, are all molecules, most of these are compounds.

Compound

Is any molecule that contains two or more elements. So, H20, CO2, and C6H12O6 (glucose) are all compounds, but H2 and O2 (molecular hydrogen and molecular oxygen) are not.

A neutral atom contains an equal number of protons and electrons such an atom....

Is neutral because the positively charges of protons are balanced by the negative charges of the electrons.

Electronegativity

Is the tendency of an atom (or small group of atoms) to attract electrons.

pH scale is____________

Logarithmic scale. Meaning that every integer increase, say from 1 to 2 or 9 to 10, is a tenfol dincrease in [H+].

We divide acids into strong acids and weak acids. The stronger the acid, the ________ the pH.

Lower.

Equation is balanced

Meaning that there is the same number of each type of atom on both sides of the equation.

One type of bond is the ionic bond, which results when 2 atoms have a large electronegative difference between them, such as between

Metals and nonmetals.

A solution that is at pH 7 is a

Neutral solution.

Synthesis and decompostion reactions are essientially ________ reactions.

Opposing.

An example of a chemical reaction is the....

Precipitation of silver and formation of copper nitrate solution by combining silver nitrate and copper. We depict this reaction by writing a chemical equation.

Thus in general raising temperature increases the formation of ______

Products.

The substances on the right side of a equation are the ___________

Products. Things that are formed.

The substances on the left side of a chemical equation are the __________

Reactants. Things that you start with.

Oxidation-reduction reactions are an important and familar class of chemical reactions. Oftern abbreviated as redox reactions, these are the basis of:

Rust formation, combustion, and energy formation in our cells.

When the reaction is exothermic (where heat is a product), the reaction will ______ down or the reverse reaction will prevail.

Slow. Exothermic- involving release of heat.

All chemical reactions involve breaking and forming of bonds to create new substances. But there are many different ways that chemical reactions occur depending upon the reactants themselves, the concentrations (amount) of reactants, conditions such as.....

Such as temperature, pressure, and pH, and whether a catalyst.

Lets make and destroy water

Synthesis of water: 2H2 + O2 -> 2H20 Decomposition of water: 2H20 -> 2H2 + O2

Decomposition Reaction

That complex product is broken down into its constituent parts.

Enzymes are complex organic molecules that function as catalysts, molecules that.....

That increase the rate of a chemical reaction by lowering the activation energy, without themselves being permanently chemically altered in the process. Enzymes are absolutely essential for life, because without them, many of the reactions in our bodies either would never happen or would take far too long to support life.

Increasing the concentration of reactants increases the probability that reactants will come in contact with each other, therefore increasing the.....

The likelihood of breaking or creating a bond.

Single Replacement Reaction

The previous example, 2AgNO3 + Cu -> Cu(NO3)2+ 2Ag Is a single replacement reaction. In a manner of speaking, the silver and copper have switched places. The silver in the silver nitrate makes way for the copper, which bonds with the nitrate to form copper nitrate. So, copper has replaced silver in the compound, which is essence of a single replacement reaction: one element is substituted for another element in a compound.

For gaseous molecules, increasing the pressure drives molecules closer together, so by the same reasoning used with temperature, an increase in pressure will increase the number of interactions between reactant molecules and this increase the......

The rate of reaction.

Synthesis and decompositon reactions are fundamental to biochemistry. Organisms (like humans) consume food for two purposes.

They use it as energy source and as building blocks to make complex organic molecules. For example, humans consume proteins in our diet. Enzymes in our digestive system decompose (or break down) the proteins into various amino acids and other nitrogenous compounds, which are absorbed into our blood and carried to cells throughout our body. Inside our cells, these building blocks interact with different enzymes to synthesize the complete set of twenty amino acids. These amino acids are then used to build proteins inside our cells.

Chemical reactions occur when individual molecules get close enough to each other for their valence shell electrons to.....

To interact or to be drawn towards the nucleus of the nearby atom.

Synthesis reaction

Two different substances combine to form a more complex product.

If temperature rises, then the rate of an endothermic reaction )where heat is a reactant)

Will increase. Endothermic- involving absorption of heat.

If product concentration is increased, the reaction will....

Will slow down.

An ionic bond forms between an atom with low electronegativity (which readily gives up an electron) and an atom with.....

With high electronegativity (which accepts or takes the electron). The result is the formation of two ions held together by an ionic bond. For example, combining lithium (an alkali metal) and fluorine (a halogen) rapidly produces lithium fluoride. LiF is stable becasue the cation Li+ and the anion F- each have a full outer valence shell of electrons. Other ionic compounds includer familar salts, like NaCl (sodium chloride), KCl (potassium choloride), and NaHCO3 (sodium bicarbonate)