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Chemistry

Kate Cause Chemistry Year 12 Englisch 200 Karten

Karten in diesem Stapel (200)

  1. 1What is the purpose of the external circuit in electrochemical cells?Allows for electrons to move from the anode to the cathode
  2. 2What is reduction?Reduction is the gain of electrons
  3. 3What occurs at the anode?Oxidation (Loss of electrons) occurs at the anode
  4. 4What are galvanic cells used for?Source of electrical energy, batteries
  5. 5How is the potential cell difference of a galvanic cell calculated?By subtracting the cell potential of the anode from the cathode, the cell potential of the galvanic cell as a whole can be calculated.
    E0 = E0 reduction - E0 oxidation
  6. 6What is oxidation?Oxidation is the loss of electrons
  7. 7What occurs at the cathode?Reduction (gain of electrons) occurs at the cathode
  8. 8What is a galvanic cell?A cell in which spontaneous oxidation-reduction reactions produce electrical energy.
  9. 9What type of chemical reaction occurs in a galvanic cell, Spontaneous, or non-spontaneous?Spontaneous
  10. 10What type of electrochemical cell contains a salt bridge?Galvanic Cell
  11. 11What does it mean when the Kc is greater than 1 (Kc > 1)Favours Products at Equilibrium
  12. 12What does it mean when the Kc is less than 1 (Kc < 1)Favours Reactants at Equilibrium
  13. 13What does it mean when the Kc equals 1 (Kc = 1)Products = Reactants at Equilibrium
  14. 14What is the Acid Dissociation ConstantKa
  15. 15What is the Base Dissociation ConstantKb
  16. 16Equilibrium ConstantKc
  17. 17What is the Equilibrium Law expressionProducts/Reactants
  18. 18What is Le Chatelier's Principle?If equilibrium system is subjected to change, the system will adjust itself to partially oppose the effect of the change
  19. 19What happens when you increase the concentration of a solution?Shift away from increase
  20. 20What happens when you decrease the concentration of a solution?Shift towards decrease
  21. 21What happens when you increase the pressure of a solution?Shift towards side with less gaseous moles
  22. 22What happens when you decrease the pressure of a solution?Shift towards side with more gaseous moles
  23. 23What happens when you increase the temperature of a solution?Shift to favour endothermic
  24. 24What happens when you decrease the temperature of a solution?Shift to favour exothermic
  25. 25What happens when the pH of a solution is equal to the pKa of an indicator?The indicator will change colour
  26. 26What type of substance does this indicator represent? BOH = B+(aq) + OH-(aq)Weak Base
  27. 27What is the definition of a weak base in terms of its Kb?Low Kb – Weak Bases
  28. 28What can be changed in a reaction to alter the equilibrium position?Concentration
    Temperature
    Volume
    Pressure
  29. 29What happens to the equilibrium position when the product concentration is increased?The reverse reaction increases and equilibrium moves to the left
  30. 30What is the relationship between the pH range of an acid-base indicator and its pKa value?A higher pKa correlates to a higher end point of the indicator
  31. 31What is the definition of a weak acid in terms of its Ka?Ka < 1 – Weak Acids
  32. 32What happens to the equilibrium position when the reactant concentration is increased?The forward reaction increases and equilibrium moves to the right
  33. 33On an equilibrium graph how do you know the reaction has reached equilibrium?When equilibrium is established the concentration lines are horizontal.
  34. 34What is a Conjugate Acid?An acid formed when a base accepts a proton (H+).
  35. 35What is an amphiprotic substance?A substance that can act as either an acid or a base
  36. 36What is an example of a common amphiprotic substance?Examples could include - water, amino acids and hydrogen carbonate ions
    (HCO3-).
  37. 37What is a conjugate pair?Two species that differ by a proton (H+)
  38. 38Identify the acid in this reaction: NH4+ + OH- ⇌ NH3 + H2OH2O
  39. 39What is a Conjugate Base?A base formed by removing a proton (H+) from an acid.
  40. 40Identify the conjugate base in this reaction: NH4+ + OH- ⇌ NH3 + H2ONH3
  41. 41How does the Brønsted-Lowry model define an acid and a base?- Acids as any species that can donate protons (H+)
    - Bases as any species that accept protons
  42. 42What is the conjugate base of CH3COOH?CH3COO-
  43. 43What is the conjugate acid of the following base: OH-?H2O
  44. 44Why is water a weak electrolyte?It can self-ionise
  45. 45What is Kw?Kw is the ionic product constant of water. It is the equilibrium constant for the self-ionisation of water. Kw can be used to calculate the concentration of hydrogen ions from the concentration of hydroxide ions in a solution.
  46. 46How is pH calculated?The pH of a solution can be calculated from the concentration of hydrogen ions using the relationship
    pH = –log10 [H+]
  47. 47How is pOH calculated?pOH= -log10 [OH-]
  48. 48Under what circumstances could the numerical value of Kw differ?Different Temperatures
  49. 49What is self-ionisation of water?Self-ionisation of water refers to the reaction in which a water molecule loses a hydrogen ion (OH-) and the hydrogen ion immediately reacts with another water molecule to form a hydronium ion
    (H3 O+).
  50. 50What is pH?pH is a figure expressing the acidity or alkalinity of a solution on a logarithmic scale.
  51. 51How is [H+] calculated?[H+ ]= 10^-pH
  52. 52How is [OH-] calculated?[OH-] can be obtained using the pH or pOH value:
    pH + pOH = 14
    pOH = 14 – pH
    ∴, pOH= -log10 [OH-]
    [OH- ]=10^(-pOH)
  53. 53pH + pOH = ?14
  54. 54How do you calculate Kw?Kw = Ka x Kb
  55. 55How do you calculate concentration?C = n/v
  56. 56What are acid-base indicators?Weak acids or bases, which dissociate slightly in water and form ions
  57. 57How are strong acids defined?Strong acids are defined as having Ka > 1
  58. 58How are weak bases defined?Weak bases are defined as having a low Kb
  59. 59How do you calculate Ka?Ka = [H3O+][A-]/[HA]
  60. 60How do you calculate Kb?Kb = [BH+][OH-]/[B]
  61. 61How are weak acids defined?Weak acids are defined as having Ka < 1
  62. 62How are strong bases defined?Strong bases are defined as having a high Kb
  63. 63What type of substance does this indicator represent? Hln(aq) = H+(aq) + ln-(aq)A weak acid
  64. 64What do oxidation numbers represent?They represent the gain or loss of electrons
  65. 65What is the common oxidation number of Group 1 metals?Group 1 is + 1
    Including - Li+, Na+
  66. 66What makes a solution saturated?Only contains 1 carbon bond (single bond)
  67. 67What makes a solution unsaturated?Contain double to triple carbon bonds
  68. 68When is Hydrogen’s oxidation number not equal to +1?In metal hydrides, hydrogen has a oxidation number of -1
    Including - LiH
  69. 69For monoatomic ions, how is the oxidation number determined?The oxidation number is determined by the charge on the ion
    e.g., Cu2+ has an oxidation number of +2
  70. 70What happens to the oxidation states when the atom undergoes reduction?Oxidation states decrease
  71. 71What molecule has oxidation number of 0?Elements
    Including – He, Fe, Li, O2
  72. 72What is the common oxidation number of Group 2 metals?Group 2 is +2
    Including – Mg2+, Ca2+
  73. 73When is Oxygen’s oxidation number not equal to -2?In peroxide (H2O2), oxygen has an oxidation number of -1
  74. 74What happens to the oxidation states when the atom undergoes oxidation?Oxidation states increase
  75. 75What is the dissociation expression for an acid?Ka = products / reactants
  76. 76What industrial situations use electrolytic cells?Some examples of industrial situations in which electrolytic cells would be of use include metal plating and copper purifications.
  77. 77What are E^o values?The symbol represents the Cell Potential. It shows the voltage produced in a Galvanic Cell.
  78. 78E^o values are measured under specific conditions. What are they?1M concentration of electrolyte, 298K and 1 atmosphere
  79. 79Why is molten electrolysis rarely seen/used?It requires a large amount of energy to both run the cell as well as to keep the solution molten.
  80. 80In an electrolytic cell what charge does the anode have?The anode has a positive charge
  81. 81What type of electrochemical cell uses energy from an external source?Electrolytic Cell
  82. 82What are electrolytes?An ionic substance which is either molten or an aqueous solution
  83. 83What type of electrode is needed for a molten electrolytic cell?The electrode must be an inert material; have a higher metaling point then the molten solution.
  84. 84What type of reaction occurs in electrolytic cells?A forced non-spontaneous reaction
  85. 85What charge does the cathode have in an electrolytic cell?The cathode has a negative charge in electrolytic cells
  86. 86What are examples of Strong Acids?Hydrochloric Acid (HCl)
    Nitric Acid (HNO3)
    Sulfuric Acid (H2SO4)
  87. 87What are examples of Strong Bases?All group 1 hydroxides (LiOH, NaOH, KOH, RbOH, CsOH)
    Barium Hydroxide (Ba(OH)2)
  88. 88What is the dissociation expression for a base?Kb = products / reactants
  89. 89What is the definition of a strong acid in terms of its Ka?Ka > 1 – Strong Acids
  90. 90Which Acid and Bases (strong or weak) completely ionise in water?Strong Acids and Bases
  91. 91What are examples of Weak Acids?Carboxylic Acid (C(=O)-OH)
    Carbonic Acid (H2CO3)
    Aqueous Carbon Dioxide (CO2 (aq))
  92. 92What are examples of Weak Bases?Ammonia (NH3)
    Amines
  93. 93What substance states are included in a dissociation expression?Aqueous (aq)
  94. 94What is the definition of a strong base in terms of its Kb?High Kb – Strong Bases
  95. 95The strength of an acid is explained by the degree of…Ionisation at equilibrium in an aqueous solution
  96. 96Are the strongest reducing agents positive or negative?Negative
  97. 97Standard electrode potentials are generally written as?Reduction half equation
  98. 98Define the standard electrode potential of a half-cell (Eθ)?The standard electrode potential of a half-cell is the voltage of a half-cell compared with a standard hydrogen electrode.
  99. 99What can you do to increase the concentration of gas in a closed system?Decrease the volume
  100. 100What are the units for standard electrode potentials?Voltage (V)
  101. 101What equation calculates the overall cell potential?The cell potential is the difference between the reduction potentials:
    Eocell=Eored−Eooxid
  102. 102What is the standard electrode potential of a half-cell a measure of?This potential is a measure of the energy per unit charge which is available from the oxidation/reduction reactions to drive the reaction
  103. 103What is the difference between cell potential and standard cell potential?The cell potential is the measure of the potential difference between two half cells in an electrochemical cell
    A cell's standard potential is the potential of the cell under standard state conditions
  104. 104What does Eθ have to equal to be considered a spontaneous reaction?Positive Value
  105. 105What happens to the equilibrium position for an endothermic reaction when heat is added?The equilibrium position will move towards the product side as heat is stored in the molecule
  106. 106What is meant by an “open system”?An open system allows matter and energy to be exchanged with the surroundings
  107. 107Are all reactions reversible?NO!
  108. 108What is a “closed system”?A reaction vessel that does not allow the reactant or product particles to escape
  109. 109Give an example of an “open” system.A flask with no lid that allows heat and gas products escape
  110. 110What is the use of calculating cell potentials?To compare cells constructed from different materials.
  111. 111What is meant by the term “reversible reaction”?Reactions in which the conversion of reactants to products and products to reactants occur simultaneously
  112. 112Are physical changes reversible?Generally, yes
  113. 113Why is a substance in a system more likely to react when the temperature is higher?The particles of that substance have more kinetic energy, causing them to collide more often with the other particles in the system, making the reaction occur
  114. 114What is an element more likely to undergo when it has a more negative standard electrode potential?The element is more likely to undergo oxidation and be the reducing agent.
  115. 115How are equilibrium reactions symbolised?Equilibrium reactions are symbolised by ⇌
  116. 116What is activation energy?The minimum amount of energy required in the collision between reactants for a reaction to occur
  117. 117What can you measure using observation in equilibrium reactions?You can observe whether the forward or reverse reaction has occurred if the reactants and products have different colours
  118. 118In a reaction where a gas is produced what type of system is required for equilibrium to be reached?A closed system
  119. 119What does Kc represent?The equilibrium constant
  120. 120When is a state of dynamic equilibrium reached?A state of equilibrium is reached when the rate of the forward and reverse reactions are equal
  121. 121How can you measure the concentration of an equilibrium using pH?You can measure the change in pH and calculate the H3O+ concentration, then use simple stoichiometry
  122. 122Can forward and reverse reactions occur at the same time?Yes, a forward and reverse reaction can occur at the same time if the reaction occurs within a closed system
  123. 123What is the impact on the equilibrium position when a catalyst is added to a reaction in a closed system?There is no impact on the equilibrium position. Equilibrium will only be reached faster
  124. 124What concentrations are not included when calculating the equilibrium constant?Concentrations of pure liquids and solids are not included
  125. 125When elements lose their valence electrons, do they act as oxidising or reducing agents?The elements are oxidised and act as reducing agents
  126. 126Where can the elements with the lowest ionisation energy be found on the periodic table?Bottom left
    e.g. Cs, Rb, Ba
  127. 127What kind of ionisation energy makes elements lose electrons more readily?Low ionisation energy
  128. 128What type of chemical reactions are redox reactions?Single displacement, combustion
    Electrochemical cells
    corrosion
  129. 129Is the equilibrium constant value largest when the concentration of reactants is larger than the products?False
  130. 130What energy is required to remove an electron from an element?First ionisation energy
  131. 131True or False? The stronger the electronegativity, the more readily the element will accept electronsTrue
  132. 132Can oxidation happen by itself?No
    Reduction also occurs
  133. 133What is a corrosion reaction?Process where metal reacts with chemicals in the atmosphere. The metal must be more stable as an ion than a solid
  134. 134If Kc is larger than 10^4 is there significantly more reactant or product?Product
  135. 135True or false? Is the Kc of a reaction temperature dependent?True
  136. 136What is the Bronsted-Lowry definition of an acid?A proton donor
  137. 137What is a diprotic acid?An acid that can donate two protons per molecule
  138. 138What is a polyprotic acid?An acid that can donate more than one proton per molecule
  139. 139Name an example of a triprotic acidH3PO4 – Phosphoric acid
  140. 140What does RICE stand for?Reaction, initial concentration, change in concentration, equilibrium concentration
  141. 141What is a monoprotic acid?An acid that can donate one proton per molecule
  142. 142Name an example of a monoprotic acidHCl – hydrochloric acid
    HBr – hydrogen bromide
    HNO3 – nitric acid
    CH3COOH – ethanoic acid
  143. 143Name an example of a diprotic acidH2SO4 – sulphuric acid
    H2CO3 – carbonic acid
  144. 144What is meant by the “strength” of an acid or a base.The level of dissociation that occurs in the acid or base
  145. 145If an acid or a base completely ionises in water what is it called?Strong acid or base
  146. 146What is hydronium?H3O+
  147. 147What does it mean if an acid is dilute?It means it has a small number of moles of the acid in a litre of water
  148. 148Why are acids and bases good electrolytes?They can dissociate into positive and negative ions which means they can conduct an electrical charge
  149. 149What type of substance has a pH of 1?Strong Acid
  150. 150If an acid or a base only partially ionises in water what is it called?Weak acid or base
  151. 151What does it mean if an acid is concentrated?It means it has a large number of moles of the acid in a litre of water
  152. 152What can be tested experimentally to determine the strength of an acid or base?The electrical conductivity of the acid or base
  153. 153Which have better electrical conductivity, strong or weak acids (or bases)?Strong acids (or bases)
  154. 154What type of substance has a pH of 7?A neutral substance
  155. 155What type of substance has a pH of 13?Strong Base
  156. 156What is a conjugate acid?An acid formed when a base accepts an H+
  157. 157What is the conjugate base of ammonium (NH4+)?NH3
  158. 158What does amphiprotic mean?A molecule or ion that can donate and accept a proton. Therefore it acts as both an acid and a base
  159. 159What substance make up a buffer?A weak acid and its conjugate base or a weak base and its conjugate acid
  160. 160What is the Bronsted-Lowy definition of a base?Species that accepts protons
  161. 161What is a conjugate base?A base formed by removing an H+ from an acid
  162. 162What is the conjugate acid of hydroxide (OH-)?H2O
  163. 163What is a buffer solution?A solution that resists changes in pH when small quantities of acids or bases are added to it
  164. 164What does Ka represent?The equilibrium constant for the dissociation of an acid in an aqueous solution
  165. 165Is the conjugate base of a weak acid, strong or weak?Strong
  166. 166Is Kw temperature dependent?Yes
  167. 167What is pKb a measure of?The strength of a base
  168. 168Is a base strong or weak if its pKb is large?Weak
  169. 169What strength is an acid or base that is used as an indicator?They are weak acids and bases
  170. 170True or False – the conjugate acid of a weak base is a strong acidTrue
  171. 171What is pKa a measure of?The strength of an acid
  172. 172Is an acid strong or weak if it has a low pKa?Strong
  173. 173What is an indicator?A chemical substance that changes colour at different pH values
  174. 174How are the acid and its conjugate base different in indicatorsThey are different colours
  175. 175At what point does an indicator change colour?When the pKa of the indicator is equal to the pH of the solution
  176. 176What is the equivalence point?The point in a titration when neutralisation is reached
  177. 177What is the analyte?The solution in a titration whose concentration is unknown
  178. 178When choosing an indicator for a titration what are you looking for?An indicator whose end point is close to the equivalence point
  179. 179What is the buffer point on a weak acid or weak base titration curve?It is the point where pH = pKa
  180. 180What is a titration?A technique used to determine the unknown concentration of a solution
  181. 181What is the “end point” ?The point in a titration when the indicator changes colour
  182. 182What is the titrand?The solution in a titration whose concentration is known
  183. 183What is meant by a standard solution in a titration?A solution whose concentration is accurately known
  184. 184What does the buffer region look like on a weak acid or base titration curve?It is the horizontal area that occurs before the equivalence point
  185. 185What impact does having water in the burette have in a titration?It will decrease the concentration of the titrant and therefore a greater volume will be needed to neutralise the analyte
  186. 186What is an aliquot?A fixed volume of liquid measured by a pipette
  187. 187How often should a titration be performed?Until you have obtained three titres that differ by 0.1mL
  188. 188Elements in group 1 and 2 of the periodic table are more likely to – oxidise or reduce?Oxidise
  189. 189What is an oxidising agent?A reactant that causes another reactant to lose electrons and be oxidised and is itself reduced
  190. 190What impact does having water in the flask holding the analyte have in a titration?No impact as the number of moles of the substance remains the same
  191. 191What is parallax error?When the volume of a liquid is read when the eye level is above or below the meniscus. It leads to inaccurate volumes being determined
  192. 192What is a REDOX reaction?One where both reduction and oxidation occurs simultaneously
  193. 193What occurs to a reducing agent?Oxidation
  194. 194What is oxidation?The loss of electrons
  195. 195What is reduction?The gain of electrons
  196. 196Will atoms with high electronegativities tend to oxidise or reduce?Undergo reduction
  197. 197What should be the sum of the oxidation numbers in a neutral compound equal?zero
  198. 198What is a half-equation?An equation that represents either oxidation or reduction
  199. 199What is an overall redox equation made up of?The oxidation and reduction half equations and added together
  200. 200What does OILRIG stand for?Oxidation is loss of electrons
    Reduction is gain of electrons

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Year 12 Chemistry Karteikarten am Chemistry, erstellt von Kate Cause am 05/09/2024.
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Kate Cause
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