Enthalpy And Beyond Flashcards

1
Q

What is the law of conservation?

A

No energy can be created or destroyed

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2
Q

What type of reaction has a larger reactant energy than product energy?

A

Exothermic

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3
Q

What is the specific heat capacity of water?

A

4.18J

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4
Q

What is enthalpy?

A

Chemical energy stored in the bonds of substances

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5
Q

What is the formula PV=nRT used for?

A

It is the ideal gas law. Used to find one of the values when given the other values

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6
Q

What is the combined gas law and what is it used for?

A

P1V1/T1 = P2V2/T2. To find a new V, T, or P.

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7
Q

What is Hess’s Law and what is it used for?

A

🔼H = H(products) - H(reactants). Also written as (sum of) products - (sum of) reactants. Used to calculate the change in enthalpy.

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8
Q

What is change in enthalpy?

A

How much energy is absorbed or released in the form of heat

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9
Q

What can you use to calculate change in enthalpy using the formula: 🔼H = (sum of reactants) - (sum of products)?

A

Average bond enthalpies in formula and data booklet

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10
Q

What is the difference between a saturated, unsaturated, and supersaturated solution?

A

Saturated is when there is no more solute able to be dissolved. An unsaturated solution is when the solution contains less than the maximum amount of solute capable of being dissolved. A supersaturated solution contains more than the solute capable of being dissolved at a given temperature.

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11
Q

What are decimetres cubed?

A

Litres

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12
Q

What is C=n/V used for?

A

Calculating concentration, moles, or volume in solutions when given the other two values

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13
Q

What is molarity (M)

A

Basically just the concentration

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14
Q

What does R stand for in PV=nRT?

A

The ideal gas constant found in formula and data booklet

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15
Q

What is the steric number and what does it determine?

A

The number of other atoms bonded to the central atom. Used to determine the geometry of a molecule

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16
Q

What determines molecular shape?

A

The number of bonding atoms in the molecule

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17
Q

Are double bonds counted as two bonding atoms when determining shape of a molecule?

A

No, they are only counted as one bonding pair

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18
Q

What are the names of the different geometry’s in order (1, 2, 3, 4)?

A

1 = Linear, 2 = Linear, 3 = Trigonal planar, 4 = tetrahedral

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19
Q

If a molecule has a tetrahedral geometry, what are the four possible shapes in order (1, 2, 3, 4 bonding pairs)?

A

1 = Linear, 2 = bent, 3 = trigonal pyrimidal, 4 = tetrahedral

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20
Q

If a molecule has a trigonal planar geometry, what are the different shapes it may have in order (1, 2, 3 bonding pairs)?

A

1 = linear, 2 = bent, 3 = trigonal planar

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21
Q

If a molecule has a linear geometry, what will it’s shape be (1 or 2 bonding pairs)?

A

Always linear

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22
Q

What is electronegativity?

A

A measure of the tendency of an atom to attract a bonding pair of electrons

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23
Q

What are the three intermolecular forces a molecule may have?

A

Dispersion, dipole-dipole, and hydrogen bonds

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24
Q

What does a molecule require to be considered polar?

A

Polar bonds and unsymmetrical (resultant vector)

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25
Q

What do you need to remember to write when drawing a polar molecule?

A

Resultant vector arrows, the electronegativities, and the weird S+ and S- on each end of the molecule (S- for the end drawing the electrons to it, S+ for the end losing electrons)

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26
Q

What are the properties of molecules controlled by IMFs?

A

Boiling point (more IMF = higher), viscosity (more IMF = higher), melting point (more IMF = higher), surface tension (more IMF = more resistance to increase its surface area), and solubility (more IMF = greater solubility)

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27
Q

What is a solution?

A

A mixture resulting when a solute dissolves in a solvent

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28
Q

What is an aqueous solution?

A

A solution in which water acts as the solvent

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29
Q

What is the unit of concentration?

A

The number of moles of a substance per litre of solvent

30
Q

What is a solvent?

A

A substance that has the ability to dissolve a solute to form a solution with it

31
Q

What does M stand for (not Molar Mass)?

A

Molarity (mol/L)

32
Q

How do you convert from moles/L to mass/L?

A

Multiply by molar mass

33
Q

What is dissociation?

A

When an ionic salt dissolves in water, breaking down into its ions

34
Q

All hydrocarbons form:

A

Carbon dioxide (CO2) and water (H2O)

35
Q

What are dispersion forces?

A

A temporary attractive force that forms a temporary dipole

36
Q

What is a dipole?

A

A bond or molecule with oppositely charged ends

37
Q

Which molecule is more soluble in water? Polar or non-polar?

A

Polar molecules are much more soluble in water because water is a polar molecule. Polar molecules go together better, it is the same with non-polar molecules. “Like-dissolves-like”

38
Q

What is precipitation?

A

The formation of a solid when two aqueous solutions are added together (called a precipitate). When a cation and an anion join to form an insoluble product.

39
Q

If the product is soluble, does it form a liquid?

A

Yes

40
Q

What is pH dependent on?

A

The concentration of hydrogen ions in a solution

41
Q

What is an acid?

A

A hydrogen-containing compound that ionizes to yield hydrogen ions (loses electrons to form H+) in an aqueous solution

42
Q

What is a base?

A

Compounds that ionise to yield hydroxide ions (OH-) in aqueous solutions

43
Q

How do you convert from mass in grams to mass in ppm (parts per million)?

A

Multiply by 1000

44
Q

What are some properties of an acid?

A

sour taste, produce hydrogen in a reaction with a metal (H2), produce carbon dioxide (CO2) in a reaction with a carbonate, produce water (H2O) in a reaction with a base, and neutralises a base

45
Q

What are some properties of a base?

A

Bitter taste, feels slippery, neutralises an acid

46
Q

What does a basic solution have more of? (OH- or H+)?

A

OH- because that is what a base yeilds

47
Q

What is a neutral solution?

A

A solution with equal amounts of H+ and OH-

48
Q

What is the difference between strong and weak acids/bases?

A

Strong acids and bases fully dissociate into their ions whilst weak acids and bases partially dissociate into their ions

49
Q

What is the difference between concentrated and dilute solutions?

A

Concentrated = a large amount of solute is dissolved in the solvent. Dilute = a small about of solute is dissloved in the solvent

50
Q

What is the pH scale?

A

A way of expressing the strength of acids and bases

51
Q

If pH is over 7 it is:

A

Acidic. It is basic if it is under 7 and being right on 7 means it is neutral

52
Q

What do you need to do to write a net ionic equation?

A

Remove all of the spectator ions

53
Q

What is the collision theory?

A

Particles must collide, they must collide at the right orientation, and they must collide with enough energy

54
Q

What are the factors that influence the collision of particles (rate of reaction)?

A

Surface area of reactants, concentration of reactants, temperature of the reactants (kinetic energy), nature of the reactants (stronger bonds are slower to break), and catalysts.

55
Q

What does Q stand for in Q=mc🔼T?

A

Enthalpy measured in Joules (J)

56
Q

What does m stand for in Q=mc🔼T?

A

The mass of the substance being heated

57
Q

What are the different types of reactions?

A

Synthesis, decomposition, single replacement, double replacement, and combustion

58
Q

If pressure stays the same but temperature increases, what happens?

A

Volume increases

59
Q

If volume stays the same but temperature increases, what happens?

A

Pressure increases

60
Q

What does an acid and carbonate make?

A

CO2 + H2O + ionic substance

61
Q

What does an acid and base make?

A

H2O and an ionic substance

62
Q

What does an acid and metal make?

A

H2 and an ionic substance

63
Q

What are some examples of strong acids?

A

HCl, HNO3, and H2SO4

64
Q

What is a weak acid?

A

CH3COOH

65
Q

mol/L multiplied by moles gives:

A

Litres by themselves

66
Q

What does strength of an acid mean?

A

How likely it is to dissociate (same meaning as ionise)

67
Q

What does concentration of an acid mean?

A

The amount of solute dissolved into the solvent

68
Q

More collisions causes rate of reaction to:

A

Increase

69
Q

What happens when water molecules being moving faster (water is heated)?

A

The water molecules push the gas molecules out (fish dying because water is too hot so no oxygen)

70
Q

Why does ice float on water?

A

Because it has a larger volume and, therefore, a lower density