Chapter4 Solutions 100416082428 Phpapp01

8/7/2019 Chapter4 Solutions 100416082428 Phpapp01

http://slidepdf.com/reader/full/chapter4-solutions-100416082428-phpapp01 1/35

Chemical Interactions

Chapter 4: Solutions



Section 4.1

A Solution is a Type of Mixture



The parts of a solution are

mixed evenly.� A solution is a homogeneous

mixture: all portions have identicalproperties.

� The solute is the substance that isdissolved.

� The solvent dissolves the solute.



Page 112

� Solutes, solvents,and solutions canbe liquids, solids, or

gases.� The solute and

solvent can be in

the same or indifferent physicalstates.



Page 113

� A suspension is a mixture with largeparticles.

The particles do not dissolve.

The mixture is not a solution.



Solvent and solute

particles interact.� When a solid dissolves in a liquid, the solute breaks apart.

� Solute particles are surrounded bysolvent particles and are evenlydistributed in the solution.



Page 114



Page 114

� Ionic compounds break up intoindividual ions when they dissolve.

� When covalent compounds dissolve, the molecules separate from eachother, but covalent bonds remainintact and the individual molecules

remain whole.



Properties of solvents

change in solutions.� A solute changes the physical

properties of a solvent. The freezing point of a solution is

lower than the freezing point of the pure solvent.

The boiling point of a solution ishigher than the boiling point of the pure solvent.



Section 4.2

The Amount of

Solute That

DissolvesCan Vary.



A solution with a high

concentration contains alarge amount of solute.

� The concentration of a solution is theamount of solute dissolved in it at aparticular temperature.

� Solutions can be made more

concentrated by adding solute.� Solutions can be made more dilute by

adding more solvent.



Page 118

Degrees of Concentration

Low Solubility High Solubility



Page 118

� A saturated solution holds as much of a

given solute as it can at a given temperature.

If it holds more solute than normal, it

is supersaturated.�Very unstable

�Disturbing the solution could cause

excess solute to come out of thesolution as a precipitate.



Page 119



Page 119

� Every substance has a characteristic

solubility, the amount that will dissolvein a certain amount of a certain solventat a given temperature.



The solubility of a solute

can be changed.� Changes in temperature will change the solubility.



Page 121



Page 122

� The solubilityof liquid and

solid solutesare not usuallyaffected bychanges in

pressure.



Solubility depends on

molecular structure.� Solubility depends on changes of solute

particles.

� Molecules with regions of electricalcharge (polar molecules) and ionsdissolve in polar solvents such as water.

� Nonpolar molecules (oils) do not havecharged regions and do not dissolve inpolar solvents, but they dissolve innonpolar solvents.



Page 123



Section 4.3

Solutionscan be

Acidic, Basic, or

Neutral



Acids and bases have

distinct properties.� Acids:

A substance that can donate ahydrogen ion to another substancewhen the acid is dissolved in water.

�HCl is an acid and donates a H+ ionin a water solution.



Page 126

� Acids also:

Taste sour

React with carbonates to form CO2.

React with many metals.

Turn litmus red.

� Common acids: Milk, beer,

cheese,

sauerkraut,wine, vinegar,lemon juice



Page 126

� Bases:

A substance that can accept ahydrogen ion from anothersubstance.

In water, the base NaOH releasesa hydroxide ion, which can accepta hydrogen ion.



Page 126

� Bases also:

Taste bitter Feel slippery or

soapy

Turn litmusblue.

� Common bases:

Borax, milk of

magnesia,ammonia, ovencleaner,peroxide





The strength of acids and

bases can be measured.� Strong acids and bases break apart

completely into individual ions. No complete molecules of the acid or

base remain in the solution



Page 129

� Weak acids and bases don·t break

apart completely into ions. It contains both molecules of the

acid/base and its ions.



Page 128

� The acidity of a solution is measured on the pH scale.

Acids produce higher hydrogen ionconcentration and have a low pH ²

from 0 ² 7. Bases produce a low hydrogen ion

concentration and have a high pH ²

from 7 ² 14. Solutions of pH 7 are neutral.



Acids and bases neutralize

each other.� When an acid and base come into contact, they undergo a neutralization reaction.

The hydrogen ion from the acid and thehydroxide ion from the base combine toform water.

The negative ion from the acid and the

positive ion from the base combine to forma salt.

The products of a neutralization reaction ² water and salt ² are both neutral

substances.



Section 4.4

Metal Alloys are Solid

Mixtures



Humans have made alloys

for thousands of years.� Alloy: a solid mixture that has many of the characteristics of a solution.

In an alloy, a solid (usually a metal)solute is mixed with a solid metallicsolvent.

Made by melting the metal componentsand mixing them in the liquid state.

The physical properties of the alloy aredifferent from those of the solvent

metal.



Page 135

� Two types of alloys:

Substitutional alloy: atoms of onemetal are replaced by the other

metal (brass). Interstitial alloy: (Steel) Carbon

atoms occupy the gaps between

the iron atoms.



Page 135



Alloys have many uses in

everyday life.� Automotive - pistons, cylinder blocks and

liners, sliding bearings, wheels.

� Aerospace - actuators and gears,structural elements, bearings and wheels, gas turbines.

� Oil, gas and chemical - valves, pumps,

hydraulic and pneumatic systems.� Cookware - frying pans, saucepans, knifesharpeners.

� Medical - prostheses.

�P

rinting - anilox rolls.

Chapter4 Solutions 100416082428 Phpapp01

Documents