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Flashcards in unit 15 Deck (46)
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1

solutions

a homogeneous mixture in which the components are uniformly interminged

2

Properties of Water

Triatomic molecule
Contains covalent bonds
Polar molecule

3

Hydrogen Bonds

intermolecular attractions between water molecules
affects surface tension and vapor pressure
*strongest molecular force

4

surface tension

inward force that minimizes the area of a liquid
Water molecules at the surface cannot hydrogen bond with air therefore turns inward to form a skin

5

Surfactant

Interferes with hydrogen bonding therefore reduce surface tension
*causes water molecules to collapse
ex: soaps/detergents

6

Vapor pressure

pressure of the gas acting above the liquid in a sealed container
Water has low vapor pressure due to hydrogen bonds

7

solid state of water

density decreases as water change to a solid
Honeycomb

8

solvent

the substance present in the largest amount in a solution
*substance that does the dissolving

9

solute

the other substance(s) in a solution
*substance that is dissolved

10

solvations

positive and negative ions of an ionic solid become surrounded by solvent molecules

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polar solvents dissolve..

polar molecules and ionic compounds

12

Nonpolar solvents dissolve..

nonpolar solutes

13

Electrolytes

Substances that break up in water to produce ions
These ions can conduct electric currents

14

Suspensions

large particle size ( > 1000nm) particles will settle out
will not stay suspended indefinitely

15

Colloids

smaller particle size than suspensions but larger then solutions (1nm to 1000nm)

16

Solutions (homogeneous mixture) size

small particle size

17

Emulsion

Colloidal dispersion of a liquid in a liquid
Ex: egg yolk

18

solubility

the amount of a substance that dissolves in 100g of water at a given temperature to produce a saturated solution

19

"Like dissolved like"

polar molecules dissolve polar molecules
nonpolar molecules dissolve nonpolar molecules

20

saturated

when a solution contains the maximum amount of solute

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unsaturated

when a solvent can dissolve more solute

22

supersaturated

when the solution contains more solute than a saturated solute will hold at that temperature

23

concentrated

when a relatively large amount of solute is dissolved

24

dilute

when a relatively small amount of solute is dissolved

25

Factors Affecting the Rate of Dissolution

Surface Area (particle size)
Stirring (agitation)
Temperature

26

Molarity

the number of moles of solute per liters of solution

M = moles of solute
---------------------
liter of solution

27

3 Properties of Water

High surface tension
Low vapor pressure
High boiling point

28

Vapor Pressure of water

*Low vapor pressure
Hydrogen bonds must be broken before water changes from liquid to vapor state; so, the tendency of these molecules to escape is low and evaporation is slow

29

Boiling Point of water

*High boiling point
Hydrogen bonding is more extensive in water than in other substances, making it more difficult to disrupt the attractions between water molecules; so more heat is needed to break them apart

30

Water in the solid state structure

Structure of ice - regular open framework of water molecules in a hexagonal arrangement

31

Which substances dissolve the best in water?

Ionic and polar covalent componds

32

Aqueous Solution

water that contains dissolved substances

33

Nonelectrolyte

A compound that does not conduct an electric current in either an aqueous solution or the molten state

34

In a solution that contains a strong electrolyte...

All or nearly all of the solute exists as an ion

35

A weak electrolyte...

conducts an electric current poorly because only a fraction of the solute in the solution exists as an ion

36

Surface Tension of water

Water molecules within the body of the liquid form hydrogen bonds with other molecules that surround them on all sides. On the surface, an unbalanced attraction occurs so that the water molecules are only hydrogen bonded on the inside of the drop, causing an inward force.

37

miscible

homogeneous mixture when added together
If a substance is soluble in another substance

38

immiscible

not forming a homogeneous mixture when added together
If a substance is insoluble in another substance

39

How temperature affects the solubility of ..
solids, liquids, and gases

solids - varies directly
liquid - varies directly
gas - varies inversely

40

how pressure affects the solubility of solids, liquids, and gases

solids- little effect on solubility
liquids- little effect on solubility
gases- directly proportional

41

Dilution Formula

Moles of solute =
M1 * V1 = M2 * V2
M - molarity
V - Volume

42

Percent by Volume of solutions

Percent by volume = volume of solute / volume of solution
* 100%

43

Percent by mass

mass of solute/mass of solution
* 100%

44

Molality

moles of solute
---------------------
kg of solvent

45

Freezing point formula

freezing point = m * 1.86 degrees C/m * i

m = molarity

46

1 g =

.001 kg