Chemistry Unit 7

Question 1

What are the types of solutions?

Answer 1

Liquid-Liquid
Solid-Liquid
Liquid-Gas
Gas-Gas
Solid-Solid

Question 2

Example of liquid-liquid solution

Answer 2

ethanol and water – ALC

Question 3

Example of Liquid-Solid solution

Answer 3

water and salt – salt water

Question 4

Ex. Liquid - gas solution

Answer 4

co2 and water – fizzy water

Question 5

ex. of gas gas solution

Answer 5

n2 and o2 – air

Question 6

ex. of solid solid solution

Answer 6

alloys – bronze steel etc

Question 7

What does immiscible mean

Answer 7

parts of solution cant mix ( wont form a homogenous mixture together)

ex: oil and water

Question 8

What does miscible solution mean

Answer 8

The parts of a solution can be mixed in any proportion

Ex. Water and ethanol

Question 9

What does solubility mean

Answer 9

It is the ability of a solute to dissolve in a solvent to form a solution

Question 10

What are intramolecular forces

Answer 10

strong forces within molecules
Ex: covalent bonds

Question 11

What are intermolecular forces

Answer 11

forces between molecules

** due to dipoles

Question 12

Why is water a good solvent

Answer 12

because its a very polar substance

Question 13

How does water interact with other polar molcules?

Answer 13

by making h bonds or dipole dipole

Question 14

What are the most polar substances?

Answer 14

Ionic compounds

ex: NaCl –> Na+ and Cl-

Question 15

What happens to ionic compounds when they disolve

Answer 15

They DISSOCIATE into hydrated ions (aq)

Question 16

what represents the Dissociation of ionic compounds

Answer 16

Dissociation equation

Ex: NaCl(s) –> Na+(aq) + Cl-(aq)

Question 17

Do non polar molecules dissolve in polar solvents

Answer 17

NO – Like disolves like

Question 18

Will molecules that have non polar and polar sections dissolve in water?

Answer 18

Yes, however the size of the non polar section decreases its ability to dissolve in water

Question 19

Name of molecule thats both polar and non polar

Answer 19

Amphipathic

Question 20

What three diff types of attractions must occur for something to dissolve

Answer 20

• Attraction of solvent to solvent
• Attraction of solvent to solute
• Attraction of solute to solute

Question 21

To dissolve 1 substance in another three things must occur:

Answer 21

forces holding solute particles together must break

forces holding solvent particles break

attractions between solvent and solute must form

Question 22

What factors affect rate of dissolving

Answer 22

1) solubility
2) temperature
3) surface area
4) stirring

Question 23

how does solubility affect dissolving rate

Answer 23

things that are more soluble will disolve faster than those less soluble

Question 24

how does temperature affect dissolving rate

Answer 24

solid solutes will disolve faster in warmer water
** fast water molcules keep solid suspended

gas solute are less soluble in warm water
** fast moving gas molecules separate from solvent

Question 25

how does surface area affect dissolving rate

Answer 25

when you increase surface are you increase solubility (exposes more solute to solvent)

Question 26

how does stirring affect dissolving rate

Answer 26

dissolves faster because particles are moving faster

Question 27

what is molarity (M)

Answer 27

#moles solute/1L solution

Question 28

Units of solubility

Answer 28

1) g solute/ml solution 2) g solute/ g solutoin 3) PPM: parts per million - typical in gases

Question 29

What is a precipitate

Answer 29

a solid that is formed in a chemical reaction

Question 30

What are spectator ions?

Answer 30

ions that dont participate in chemical reactions but are still there #bystanders!

Question 31

Example of a precipitation reaction

Answer 31

(aq) + (aq) --> (aq) + (s)

Question 32

why does precipitation reactions occur

Answer 32

when solute ions are more attracted to eachother than to the solvent molcules they stick together forming clusters (the precipitate)

Question 33

what is a total ionic equation

Answer 33

this shows all the things involved in a reaction

Question 34

what is a net ionic equation?

Answer 34

an equation that only shows the things that are involved in the solute reaction

Question 35

Steps to precipiate problems:

Answer 35

1) identify precipitate 2) find mass of precipitate 3) find concentration of excess ions 4) find concentration of spectator ions

Question 36

what does identifying precipitate entail

Answer 36

1) make balanced chemical equation 2) using solubility table find precipitate

Question 37

how to find mass of precipitate:

Answer 37

1) write net ionic equation 2) calculate moles of each ion 3) determine the limiting ion by calculating mass of precipitate

Question 38

how to determine the concentration of excess ion

Answer 38

1) find moles of ion in excess 2) calculate total volume of solution 3) calculate concentration of excess ions (moles/volume= Molarity)

Question 39

how to determine the concentration of the spectator ions

Answer 39

1) calculate moles of each spectator ion in solution 2) calciulate concentration of the spectator ions (moles/volume=Molarity)

Question 40

All solutions have the qualities that they do because of 3 properties:

Answer 40

1) molecular structure 2) pressure 3) temperature

Question 41

what is molality (m)?

Answer 41

mol solute/kg solvent (mol/kg)

Question 42

What is mass precent

Answer 42

mass solute/mass solution * 100%

Question 43

Why does pop go flat faster on the counter than in fridge

Answer 43

it will have greater solubility in cooler temp therefore on counter the co2 will want to escape faster

Question 44

what order should you add acid and water

Answer 44

always add acid to water

Question 45

What is a saturated solution?

Answer 45

A solution that has dissolved as much solute as it can therefore if you add more it will not be dissolved

Question 46

what is a super-saturated solution

Answer 46

a solution that has more dissolved solute than there would typically be.

Question 47

What diff is there between an ionic substance dissolving in water and a polar one?

Answer 47

Ionic substances dissociate into individual ions whereas polar substances form either dipole dipole or h bonds

Question 48

what is a way to increase solubility in most substances

Answer 48

by increasing the pressure and the temp

Question 49

What does dilution involve

Answer 49

Adding more solvent into a solution

Question 50

What doesnt change during dilution?

Answer 50

The number of MOLES!

Question 51

What is the dilution calculation?

Answer 51

M1*V1=M2*V2

Question 52

What is conductivity

Answer 52

somethings ability to conduct electricity

Question 53

What are solutions that conduct electricity called?

Answer 53

electrolytes

Question 54

Why do some solutions carry electric charge

Answer 54

because they have charged particles

Question 55

What are two solutions that have high conductivity?

Answer 55

Ionic compounds and strong acids and bases

Question 56

What are solutions that dont conduct electricity called?

Answer 56

Nonelectrolytes -- No ions are present

Question 57

What is a solution that wont conduct electricity

Answer 57

polar covalent compounds Ex: ethanol and water

Question 58

What are colligative properties

Answer 58

These are things that only rely on the concentration of the solute rather than what the solute actually is

Question 59

name two colligative properties

Answer 59

1) Boiling point elevation - adding solute to water increases boiling point 2) Freezing point depression - adding solute to water decreases freezing point

Question 60

Which of the following would melt ice the best? C6H12O6 NaCl CaCl2

Answer 60

CaCl1 because it has most particles when dissolved

Question 61

What is titration

Answer 61

Titration is a process used to determine the concentration of an unknown solution

Question 62

How does titration work?

Answer 62

One reacts a measured amount with a known concentration until their concentrations are equal!

Question 63

When is titration commonly used?

Answer 63

During neutralization reactions to know the concentration of an acid or base

Question 64

How to do acid based titration

Answer 64

1) In Erlenmeyer flask put the accuratly measured unknown concentration 2) The solution you know put in a burette 3) Add indicator to unknown solution 4) Add known solution until reaction is complete 5) Using known solution calculate unknown concentration