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Chemistry 20 > Unit C: Matter as Solutions, Acids and Bases: Solutions Introduction > Flashcards

Unit C: Matter as Solutions, Acids and Bases: Solutions Introduction Flashcards

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1
Q

What is a solution?

A

A homogenous mixture with a uniform composition.

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2
Q

What is a solvent?

A

The substance that is present in the largest quantity, (V/M/amount).

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3
Q

What is a solute?

A

A substance that is dissolved in the solvent.

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4
Q

Types of Solutions

What are the types of solutions? Provide examples.

A
  • Gas: Gas Ex: Air
  • Gas: Liquid Ex: Pop
  • Gas: Solid Ex: Hydrogen in Platinum
  • Liquid: Liquid Ex: Alcohol in water
  • Liquid: Solid Ex: Amalgrams-mercury in silver
  • Solid: Liquid Ex: Sugar in water
  • Solid: Solid Ex: Alloy
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5
Q

Types of Solutions

The substance known as the universal solvent is …and why?

A

Water because the majority of the time it is the solvent in a solution.

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6
Q

Energy and Dissolving

Forces between the particles in the solvent break which…..

A

…requires energy. In an ionic solid, the forces holding the ionic are together are ionic bonds. In a molecular solid, the forces holding the molecules together are intermolecular forces such as dipole-dipole bonding.

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7
Q

Energy and Dissolving

Some of the intermolecular forces in the solvent break. Because this breaks bonds, this means that this process…?

A

is endothermic.

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8
Q

Energy and Dissolving

Forces of attraction between the particles in the solute and the solvent result in the formation…

A

of new chemical bonds. This step always releases energy. Processes that release energy are called exothermic processes. For aqueous solutions, the dissolving process is called solvation or hydration.

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9
Q

Energy and Dissolving

Energy absorbed during the endothermic steps is considered…

A

to be positive and the energy released during the exothermic steps is considered to be negative.

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10
Q

Energy and Dissolving

The overall energy for the process is found by…

A

calculating the sum of the energy changed that take place during the three steps.

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11
Q

Energy and Dissolving

If more energy is absorbed then is released…

A

the process is considered endothermic. If more energy is released then is absorbed the process is considered exothermic.

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12
Q

What are electrolytes?

A

Substances that dissolve in water to form solutions that conduct electric currents

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13
Q

What are non-electrolytes?

A

Substances that do not conduct electric current when they dissolve in water.

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14
Q

Dissolving

What is dissolving?

A

When substances are dissolved in water to make aqueous solutions, the solution has the same conductivity as the solute.

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15
Q

Dissolving

Polar molecules tend to dissolve in water and non-polar molecules do not. Remember for molecular compounds…

A

like dissolves like.

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16
Q

Dissociation

What is dissociation?

A

When electrolytes dissolve in water they differ in that they break down, freeing ions, because these free ions are charged and can move around in solution, they are able to conduct electronic current.

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17
Q

Dissociation

In dissociation, the ionic structure is changed in that the ions are separated from each other. Provide an example.

A

NaCl(s) →Na+(aq) + Cl-(aq)

If the ionic compound is insoluble then the ionic compound will remain in a solid state.

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18
Q

Ionization

What is ionization?

A

When a solution forms ions.

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19
Q

Ionization
Some acidic compounds form ions when they are placed in water, this is called ionization. They are considered strong acids, there are six of them which include:

A

-Perchloric acid(HClO4)
-Hydrochloric acid(HCl)
-Hydrobromic acid(HBr)
-Hydroiodic acid(HI)
-Nitic acid(HNO3)
-Sulfuric acid(H2SO4)
All other acids stay as a molecule in solution and are considered weak acids.

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20
Q

Ionization

Show an example of a strong acid ionizing.

A

HI(aq)→H+(aq) + I-(aq)

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21
Q

Ionization
All other acids stay as a molecule in solution and are considered weak acids.
Show an equation for a dissolved weak acid.

A

H2CO3(aq)→H2CO3(aq)

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22
Q

Solubillity

What is a saturated solution?

A

A solution that contains the maximum amount of dissolved solute at a given temperature in the presence of undissolved solute.

23
Q

Solubility

What is an unsaturated solution?

A

A solution that is not saturated and, therefore, can dissolve more solute at that particular temperature.

24
Q

Solubility

What is a supersaturated solution?

A

A solution that contains more dissolved solute than its solubility at a given temperature.

25
Q

Saturated Solutions and Equilibrium
When a solution is saturated, it is when the maximum solute is dissolved in the solvent in the presence of the excess solute. This is because to know that the maximum solute is dissolved there must be solute on the bottom of the container, otherwise, you do not know if more could d dissolve. At this point, the solution contains both dissolved and undissolved solute.

A

During this some of the solute that is undissolved will dissociate during dissolving:
NaCl(s)→ Na+(aq) + Cl-(aq)

And some of the solutes that were dissolved will crystalize, the reverse of dissolving:
Na+(aq) + Cl-(aq)→NaCl(s)

26
Q

Saturated Solutions and Equilibrium
In a saturated solution, the rate at which the undissolved solutes dissociate equals the rate at which the solute crystallized. A saturated solution is said to be at a state of equilibrium as we do not visibly see any more solute forming or dissociating as the changes are taking place at the same rate but if you could see the molecular level changes are taking place.

A

Overall this process can be combined into one equilibrium reaction with a double-headed arrow representing that the forward and reverse processes are occurring at the same time:
NaCl(s)⇋ Na+(aq) + Cl-(aq)

27
Q

Gases and Solubility

What are gases and solubility?

A

Under nearly any criteria of ionic compounds, gases would have to be considered insoluble, however, some gas will dissolve into water. Polar gases will dissolve into polar solvents and non-polar gases will dissolve into non-polar solvents

28
Q

Temperature and Solubility

The solubility of most solids…

A

increases with temperature.

29
Q

Temperature and Solubility

The solubility of most liquid is …

A

not greatly affected by temperature.

30
Q

Temperature and Solubility

The solubility of gases …

A

decreases at higher temperatures.

31
Q

Pressure and Solubility

Pressure changes have very little effect…

A

on the solubility of solids and liquids.

32
Q

Pressure and Solubility

Pressure changes affect the solubility of a gas.

A

The solubility of gas is directly proportional to the partial pressure of that gas above the liquid.

33
Q

Examples of Writing Dissociation Equations

Write 2 soluble ionic compounds in solution.

A

NaCl(s) → Na+(aq) + Cl-(aq)

Ba(OH)2(s) → Ba2+(aq) + 2OH-(aq)

34
Q

Examples of Writing Dissociation Equations

Write 2 soluble covalent compounds in solutions.

A

C3H7OH(l) → C3H7OH(aq)

C12H22O11(s) → C12H22O11(aq)

35
Q

Examples of Writing Dissociation Equations

Write two soluble acids in solution (one weak and one strong).

A

SA: HCl(g)→ H+(aq) + Cl-(aq)
WA: HF(g)→ HF(aq)

36
Q

Examples of Writing Dissociation Equations

Write 2 insoluble ionic compounds in water.

A

AgCl(s)→ AgCl(s)

Ca(OH)2→Ca(OH)2(s)

37
Q

Examples of Writing Dissociation Equations

Write an insoluble covalent compound in solution.

A

C25H52(s)→ C25H52(s)

38
Q

Name the solute and the solvent in the solution, Orange juice.

A

Solute: Orange crystals or concentrate.
Solvent: Water

39
Q

Name the solute and the solvent in the solution, CO2 in air.

A

Solute: CO2
Solvent: Nitrogen Gas

40
Q

Name the solute and the solvent in the solution, Coffee.

A

Solute: Coffee ground
Solvent: Water

41
Q

Name the solute and the solvent in the solution, bronze metal.

A

Solute: Tin
Solvent: Copper

42
Q

Name the solute and the solvent in the solution, Iodine tincture(antiseptic).

A

Solute: Tin
Solvent: Iodine

43
Q

Name the solute and the solvent in the solution, the ocean.

A

Solute: Salt
Solvent: Water

44
Q

List some properties that could be used to construct diagnostic tests to identify the type of solute in the following solution. An aqueous solution of a molecular substance.

A
  • Test for electric conduction (negative=molecular)
  • Heat the solution a gaseous solute will bubble out of the solution
  • Test for low boiling point
45
Q

List some properties that could be used to construct diagnostic tests to identify the type of solute in the following solution. An aqueous solution of a neutral ionic compound.

A
  • Test conductivity (positive= ionic)

- Test for high boiling point

46
Q

List some properties that could be used to construct diagnostic tests to identify the type of solute in the following solution. An aqueous solution of an acid.

A

-Test for pH lower than 7

47
Q

List some properties that could be used to construct diagnostic tests to identify the type of solute in the following solution. An aqueous solution of a base.

A

-Test for pH higher than 7

48
Q

Define dissolving.

A

A substance breaks down in a solvent.

49
Q

Define dissociation.

A

A solute breaks down its bonds with its molecules.

50
Q

Define ionization.

A

When a solvent breaks down into its ions.

51
Q

Define endothermic.

A

When a reaction produces heat (releases energy).

52
Q

Define exothermic.

A

When a reaction takes in heat (absorbs energy).

53
Q

Suppose you place a sugar cube(sucrose) and a lump of salt (sodium chloride) into separate glasses of water. How is the dissolving similar/different for both substances?

A

The molecular substance will not ionize but will dissolve. The ionic substance will ionize and dissolve creating an equilibrium of the ions with the molecules of the solvent.

Chemistry 20 (27 decks)

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