CHEM FINAL flashcards

All 50 cards

1. Card 1

   A gas occupies a volume of 2.50 L at 1.00 atm and 298 K. If the pressure is increased to 3.00 atm and the temperature is raised to 350 K, what will be the new volume of the gas? Show your step-by-step working.

   First, use the combined gas law: (P1V1)/T1 = (P2V2)/T2. Given P1 = 1.00 atm, V1 = 2.50 L, T1 = 298 K, P2 = 3.00 atm, T2 = 350 K. Rearranging for V2: V2 = (P1V1T2) / (P2T1). Plugging in the values: V2 = (1.00 atm * 2.50 L * 350 K) / (3.00 atm * 298 K) = 0.98 L. The new volume of the gas will be 0.98 L.

2. Card 2

   Explain the fundamental difference between a strong electrolyte, a weak electrolyte, and a nonelectrolyte in terms of their dissociation in an aqueous solution.

   A strong electrolyte completely dissociates into ions when dissolved in water, leading to high electrical conductivity. A weak electrolyte only partially dissociates into ions, resulting in lower electrical conductivity compared to strong electrolytes. A nonelectrolyte does not dissociate into ions at all when dissolved in water, meaning it does not conduct electricity.

3. Card 3

   A reaction consumes 15.0 g of hydrogen gas (H2) and 120.0 g of oxygen gas (O2) to produce water (H2O). Which reactant is the limiting reactant? What is the theoretical yield of water in grams? (Atomic masses: H = 1.008 g/mol, O = 16.00 g/mol)

   First, write the balanced equation: 2H2(g) + O2(g) -> 2H2O(l). Calculate moles of reactants: Moles H2 = 15.0 g / (2 * 1.008 g/mol) = 7.44 mol. Moles O2 = 120.0 g / (2 * 16.00 g/mol) = 3.75 mol. From stoichiometry, 2 moles of H2 react with 1 mole of O2. For 3.75 mol O2, 2 * 3.75 = 7.50 mol H2 are needed. Since only 7.44 mol H2 are available, hydrogen is the limiting reactant. The theoretical yield of water is calculated from the limiting reactant: 7.44 mol H2 * (2 mol H2O / 2 mol H2) * (18.016 g H2O / 1 mol H2O) = 134 g H2O.

4. Card 4

   Define the term 'enthalpy of reaction (ΔHrxn)' and explain how its sign (positive or negative) relates to whether a reaction is endothermic or exothermic.

   Enthalpy of reaction (ΔHrxn) is the heat change that occurs during a chemical reaction at constant pressure. A negative ΔHrxn indicates an exothermic reaction, meaning heat is released from the system to the surroundings. A positive ΔHrxn signifies an endothermic reaction, where heat is absorbed by the system from the surroundings.

5. Card 5

   Which of the following statements accurately describes Dalton's atomic theory with respect to modern atomic theory? A) Atoms are indivisible and indestructible. B) All atoms of a given element are identical in mass and properties. C) Atoms of one element can be converted into atoms of another element in chemical reactions. D) Compounds are formed when atoms of different elements combine in simple whole-number ratios.

   D) Compounds are formed when atoms of different elements combine in simple whole-number ratios. While Dalton's theory had limitations (e.g., isotopes show atoms of an element can have different masses, and atoms are divisible), the postulate regarding definite composition in compounds remains fundamentally correct and consistent with modern atomic theory.

6. Card 6

   A student measures the mass of a substance three times, obtaining 10.2 g, 10.3 g, and 10.1 g. The known true value for the mass is 12.5 g. Evaluate the precision and accuracy of these measurements, explaining the roles of systematic and random error.

   The measurements (10.2 g, 10.3 g, 10.1 g) are precise because they are close to each other, indicating low random error. However, they are not accurate because they are significantly different from the true value of 12.5 g. This suggests the presence of a systematic error, which consistently causes the measurements to deviate in the same direction from the true value, rather than random fluctuations.

7. Card 7

   How does the kinetic-molecular theory explain the origin of pressure in a gas and the relationship between temperature and molecular speed?

   The kinetic-molecular theory explains that gas pressure arises from the constant collisions of gas particles with the walls of their container. Each collision exerts a force, and the sum of these forces over the area of the walls constitutes the pressure. Furthermore, the average kinetic energy of gas particles is directly proportional to the absolute temperature, meaning as temperature increases, the average molecular speed and the frequency/force of collisions also increase, leading to higher pressure.

8. Card 8

   Calculate the molarity of a solution prepared by dissolving 25.0 g of potassium hydroxide (KOH) in enough water to make 750.0 mL of solution. (Atomic masses: K = 39.10 g/mol, O = 16.00 g/mol, H = 1.008 g/mol)

   First, calculate the molar mass of KOH: 39.10 + 16.00 + 1.008 = 56.108 g/mol. Next, convert grams of KOH to moles: 25.0 g / 56.108 g/mol = 0.4455 mol KOH. Convert the volume from mL to L: 750.0 mL = 0.7500 L. Finally, calculate molarity (moles/volume): 0.4455 mol / 0.7500 L = 0.594 M. The molarity of the solution is 0.594 M.

9. Card 9

   Distinguish between physical changes and chemical changes, providing an example of each that illustrates the key difference.

   A physical change alters the form or appearance of a substance but does not change its chemical composition; for example, melting ice into liquid water is a physical change as H2O molecules remain intact. A chemical change results in the formation of new substances with different chemical compositions and properties; for instance, burning wood is a chemical change because wood reacts with oxygen to form ash, carbon dioxide, and water, which are entirely new substances.

10. Card 10

    A sample of an unknown gas has a density of 1.96 g/L at STP. Calculate the molar mass of the gas. (R = 0.08206 L·atm/(mol·K))

    At STP, T = 273.15 K and P = 1.00 atm. The ideal gas law can be rearranged to find molar mass (M) using density (d): M = (dRT)/P. Plugging in the values: M = (1.96 g/L * 0.08206 L·atm/(mol·K) * 273.15 K) / 1.00 atm. M = 43.9 g/mol. The molar mass of the unknown gas is 43.9 g/mol.

11. Card 11

    What are the four postulates of Dalton's atomic theory, and how has modern atomic theory refined or contradicted each of them?

    Dalton's postulates are: 1) Each element is composed of tiny, indestructible particles called atoms (refined: atoms are divisible into subatomic particles and can be destroyed in nuclear reactions). 2) All atoms of a given element have the same mass and other properties (refined: isotopes show atoms of the same element can have different masses). 3) Atoms combine in simple, whole-number ratios to form compounds (still largely true). 4) Atoms of one element cannot be converted into atoms of another element (refined: nuclear reactions can convert atoms).

12. Card 12

    A reaction has a ΔHrxn of -150 kJ. If the reaction is reversed and the stoichiometric coefficients are doubled, what will be the new enthalpy change for the reaction?

    According to the rules for manipulating reaction enthalpies, reversing a chemical equation changes the sign of ΔHrxn, so it becomes +150 kJ. Doubling the stoichiometric coefficients means multiplying ΔHrxn by 2. Therefore, the new enthalpy change will be +150 kJ * 2 = +300 kJ. The reaction would now be endothermic with a larger magnitude of energy change.

13. Card 13

    Which of the following is an example of a homogeneous mixture? A) Sand and water B) Oil and vinegar C) Air D) Granite

    C) Air. A homogeneous mixture has a uniform composition throughout, meaning its components are evenly distributed and indistinguishable, like the gases in air. Sand and water, oil and vinegar, and granite are all heterogeneous mixtures because their components are not uniformly distributed and can be visually distinguished.

14. Card 14

    Define 'precision' and 'accuracy' in the context of experimental measurements, and explain how random error and systematic error affect each.

    Precision refers to how close multiple measurements of the same quantity are to one another, indicating the reproducibility of the measurements. It is primarily affected by random error, which causes measurements to fluctuate unpredictably around the true value. Accuracy refers to how close a measured value is to the true or accepted value. It is affected by both random error and systematic error, where systematic error consistently shifts measurements in one direction from the true value, leading to poor accuracy even if precision is high.

15. Card 15

    A titration of 25.00 mL of an unknown concentration of HCl requires 32.50 mL of 0.150 M NaOH to reach the equivalence point. Calculate the concentration of the HCl solution.

    The balanced neutralization reaction is HCl(aq) + NaOH(aq) -> NaCl(aq) + H2O(l), showing a 1:1 mole ratio. First, calculate moles of NaOH: Moles NaOH = Molarity * Volume = 0.150 mol/L * 0.03250 L = 0.004875 mol NaOH. Due to the 1:1 ratio, moles HCl = 0.004875 mol HCl. Finally, calculate the concentration of HCl: Molarity HCl = Moles HCl / Volume HCl = 0.004875 mol / 0.02500 L = 0.195 M. The concentration of the HCl solution is 0.195 M.

16. Card 16

    Explain why the physical and chemical properties of a compound are typically different from the elements from which it is composed.

    The physical and chemical properties of a compound are different from its constituent elements because, in forming a compound, atoms undergo chemical bonding, which rearranges their electron configurations and creates new molecular or ionic structures. This bonding fundamentally changes the way the atoms interact with each other and with external forces, leading to entirely new emergent properties that are distinct from the individual elements.

17. Card 17

    Identify the oxidizing agent and reducing agent in the following redox reaction: 2Na(s) + Cl2(g) → 2NaCl(s). Justify your answer by assigning oxidation states.

    In 2Na(s), Na has an oxidation state of 0. In Cl2(g), Cl has an oxidation state of 0. In 2NaCl(s), Na has an oxidation state of +1 and Cl has an oxidation state of -1. Sodium's oxidation state increased from 0 to +1, so Na was oxidized and is the reducing agent. Chlorine's oxidation state decreased from 0 to -1, so Cl2 was reduced and is the oxidizing agent.

18. Card 18

    Determine the empirical formula for a compound that contains 40.0% Carbon, 6.7% Hydrogen, and 53.3% Oxygen by mass. (Atomic masses: C = 12.01 g/mol, H = 1.008 g/mol, O = 16.00 g/mol)

    Assume a 100 g sample. Moles C = 40.0 g / 12.01 g/mol = 3.33 mol C. Moles H = 6.7 g / 1.008 g/mol = 6.65 mol H. Moles O = 53.3 g / 16.00 g/mol = 3.33 mol O. Divide by the smallest number of moles (3.33): C: 3.33/3.33 = 1, H: 6.65/3.33 = 1.99 ≈ 2, O: 3.33/3.33 = 1. The empirical formula is CH2O.

19. Card 19

    An unknown pure substance is found to be a liquid at room temperature, has a definite volume but an indefinite shape, and its particles are close together but able to move past one another. How would you classify this matter based on its state, and what is the primary characteristic that differentiates it from a solid or a gas?

    This substance would be classified as a liquid. The primary characteristic differentiating it from a solid is the ability of its particles to move past one another, giving it an indefinite shape while maintaining a definite volume. Compared to a gas, the particles in a liquid are much closer together, resulting in a definite volume, unlike the indefinite volume and shape of a gas.

20. Card 20

    Calculate the mass percent of carbon in glucose (C6H12O6). (Atomic masses: C = 12.01 g/mol, H = 1.008 g/mol, O = 16.00 g/mol)

    First, calculate the molar mass of glucose: (6 * 12.01) + (12 * 1.008) + (6 * 16.00) = 72.06 + 12.096 + 96.00 = 180.156 g/mol. The total mass of carbon in one mole of glucose is 6 * 12.01 g/mol = 72.06 g/mol. Mass percent of carbon = (mass of carbon / molar mass of glucose) * 100%. Mass percent C = (72.06 g/mol / 180.156 g/mol) * 100% = 39.99%. The mass percent of carbon in glucose is 39.99%.

21. Card 21

    Describe the key differences in the experimental setups and the quantities measured between constant-volume calorimetry (bomb calorimeter) and constant-pressure calorimetry (coffee-cup calorimeter).

    Constant-volume calorimetry, using a bomb calorimeter, measures the change in internal energy (ΔE) because the volume is fixed, meaning no pressure-volume work is done. It measures the temperature change of the surrounding water, from which the heat released or absorbed by the reaction at constant volume is calculated. Constant-pressure calorimetry, typically using a coffee-cup calorimeter, measures the enthalpy change (ΔH) because the reaction occurs at constant atmospheric pressure. It also measures the temperature change of the solution, from which the heat exchanged at constant pressure is determined, representing ΔH.

22. Card 22

    Which of the following is a characteristic of an ionic compound? A) Consists of discrete molecules held by covalent bonds. B) Typically has low melting and boiling points. C) Forms between a metal and a nonmetal, involving electron transfer. D) Dissolves well in nonpolar solvents.

    C) Forms between a metal and a nonmetal, involving electron transfer. Ionic compounds are characterized by the electrostatic attraction between positively charged metal ions and negatively charged nonmetal ions formed through the transfer of electrons. They typically form crystal lattices, have high melting/boiling points, and dissolve well in polar solvents like water.

23. Card 23

    A sample of neon gas at 2.00 atm and 25.0 °C occupies a volume of 10.0 L. How many moles of neon gas are in the sample? (R = 0.08206 L·atm/(mol·K))

    First, convert the temperature to Kelvin: T = 25.0 °C + 273.15 = 298.15 K. Use the ideal gas law, PV = nRT, and rearrange to solve for moles (n): n = PV / RT. Plug in the values: n = (2.00 atm * 10.0 L) / (0.08206 L·atm/(mol·K) * 298.15 K). n = 20.0 / 24.465 = 0.817 mol. There are 0.817 moles of neon gas in the sample.

24. Card 24

    Explain the concept of 'significant figures' in a measurement and how they are carried through a calculation involving both multiplication/division and addition/subtraction.

    Significant figures represent all the certain digits in a measurement plus one estimated digit, reflecting the precision of the measuring instrument. When performing multiplication or division, the result should be reported with the same number of significant figures as the measurement with the fewest significant figures. For addition or subtraction, the result should be rounded to the same number of decimal places as the measurement with the fewest decimal places.

25. Card 25

    Using the solubility rules, predict whether a precipitate will form when aqueous solutions of lead(II) nitrate (Pb(NO3)2) and potassium iodide (KI) are mixed. If so, write the net ionic equation for the reaction.

    When Pb(NO3)2(aq) and KI(aq) are mixed, a double displacement reaction occurs. The potential products are PbI2 and KNO3. According to solubility rules, nitrates (NO3-) are generally soluble, so KNO3 will be soluble. However, most iodides (I-) are soluble, but lead(II) iodide (PbI2) is an exception and is insoluble. Therefore, a precipitate of PbI2 will form. The molecular equation is Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq). The total ionic equation is Pb2+(aq) + 2NO3-(aq) + 2K+(aq) + 2I-(aq) → PbI2(s) + 2K+(aq) + 2NO3-(aq). The net ionic equation is Pb2+(aq) + 2I-(aq) → PbI2(s).

26. Card 26

    A reaction has a standard free energy change (ΔG°) of -150 kJ/mol at 298 K. Calculate the equilibrium constant (K) for this reaction. (R = 8.314 J/mol·K)

    To calculate the equilibrium constant (K), we use the relationship ΔG° = -RTlnK. Rearranging for K, we get K = e^(-ΔG°/RT). Plugging in the values, K = e^(-(-150000 J/mol) / (8.314 J/mol·K * 298 K)) = e^(60.55). Therefore, K is approximately 2.3 x 10^26.

27. Card 27

    Define a complex ion and a ligand, and explain their relationship in the formation of coordination compounds.

    A complex ion is an ion containing a central metal cation bonded to one or more molecules or ions, known as ligands. Ligands are typically Lewis bases that donate a pair of electrons to the central metal atom to form coordinate covalent bonds. The combination of the central metal ion and its ligands forms a coordination compound.

28. Card 28

    Distinguish between a voltaic (galvanic) cell and an electrolytic cell in terms of spontaneity and energy transformation.

    A voltaic (galvanic) cell generates electricity from a spontaneous chemical reaction, converting chemical energy into electrical energy. In contrast, an electrolytic cell uses electrical energy to drive a nonspontaneous chemical reaction, converting electrical energy into chemical energy. The key difference lies in the spontaneity of the redox process.

29. Card 29

    What is the standard hydrogen electrode (SHE), and what is its significance in electrochemistry?

    The standard hydrogen electrode (SHE) is a reference electrode with an assigned standard electrochemical potential of 0.00 V. Its significance lies in its use as a benchmark to determine the standard electrode potentials of other half-reactions. By pairing an unknown half-cell with the SHE, the potential difference measured directly corresponds to the standard potential of the unknown half-cell.

30. Card 30

    A certain radioactive isotope has a half-life of 15 years. If a sample initially contains 100 grams of this isotope, how much will remain after 45 years?

    After one half-life (15 years), 50 grams will remain. After two half-lives (30 years), 25 grams will remain. After three half-lives (45 years), 12.5 grams will remain. Alternatively, using the formula N = N₀ * (1/2)^(t/t₁/₂), N = 100 g * (1/2)^(45/15) = 100 g * (1/2)^3 = 100 g * 0.125 = 12.5 g.

31. Card 31

    Explain the concept of crystal field splitting in octahedral complexes and its relationship to the color of transition metal complexes.

    In octahedral complexes, the ligands cause the d-orbitals of the central metal ion to split into two energy levels: a lower energy t2g set and a higher energy eg set. The energy difference between these sets is the crystal field splitting energy (Δo). When visible light passes through the complex, electrons absorb photons corresponding to Δo, promoting them from t2g to eg. The color observed is the complementary color of the light absorbed.

32. Card 32

    Which of the following statements about spontaneity and speed is correct?

    C) Spontaneity is dictated by thermodynamics, while speed is dictated by kinetics. A spontaneous process will occur without external intervention, but its rate (speed) is determined by the reaction's kinetics, which can be very slow.

33. Card 33

    Balance the following redox reaction in acidic solution: MnO₄⁻(aq) + C₂O₄²⁻(aq) → Mn²⁺(aq) + CO₂(g)

    First, separate into half-reactions: MnO₄⁻ → Mn²⁺ and C₂O₄²⁻ → CO₂. Balance atoms other than O and H. Then balance O with H₂O and H with H⁺. Balance charge with electrons. MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O. C₂O₄²⁻ → 2CO₂ + 2e⁻. Multiply to equalize electrons (x2 for Mn, x5 for C). Finally, combine: 2MnO₄⁻(aq) + 5C₂O₄²⁻(aq) + 16H⁺(aq) → 2Mn²⁺(aq) + 10CO₂(g) + 8H₂O(l).

34. Card 34

    A galvanic cell consists of a Zn/Zn²⁺ half-cell and a Cu/Cu²⁺ half-cell. Given E°(Zn²⁺/Zn) = -0.76 V and E°(Cu²⁺/Cu) = +0.34 V, calculate the standard cell potential (E°cell) and predict the direction of electron flow.

    The standard cell potential is E°cell = E°cathode - E°anode. Copper has a higher reduction potential, so Cu²⁺/Cu is the cathode (+0.34 V) and Zn/Zn²⁺ is the anode (-0.76 V). E°cell = +0.34 V - (-0.76 V) = +1.10 V. Electrons flow from the anode (Zn) to the cathode (Cu).

35. Card 35

    Define the first law of thermodynamics and explain the concept of a state function in this context.

    The first law of thermodynamics states that energy cannot be created or destroyed, only transferred or transformed (ΔE = q + w). Internal energy (E) is a state function, meaning its value depends only on the current state of the system, not on the path taken to reach that state. Therefore, the change in internal energy (ΔE) is independent of how the heat (q) and work (w) are transferred.

36. Card 36

    A concentration cell is constructed with two Ag/Ag⁺ half-cells. One half-cell has [Ag⁺] = 0.10 M, and the other has [Ag⁺] = 0.0010 M. Calculate the cell potential at 298 K. (E° = 0 for concentration cells, n = 1 for Ag⁺/Ag)

    For a concentration cell, E°cell = 0. The cell potential is calculated using the Nernst equation: E = E° - (0.0592/n)logQ. Here, Q = [Ag⁺]dilute / [Ag⁺]concentrated = 0.0010 / 0.10 = 0.010. So, E = 0 - (0.0592/1)log(0.010) = -0.0592 * (-2) = +0.1184 V. The cell potential is +0.1184 V.

37. Card 37

    What is the third law of thermodynamics, and how does it relate to standard molar entropies?

    The third law of thermodynamics states that the entropy of a perfect crystalline substance at absolute zero (0 K) is zero. This law provides a reference point for determining absolute entropies. Standard molar entropies (S°) are tabulated values for substances at standard conditions, which are based on this absolute scale, allowing for the calculation of entropy changes in reactions.

38. Card 38

    A 1.00 L vessel contains 0.100 mol of N₂ gas at 273 K. If the volume is decreased to 0.500 L and the temperature is increased to 300 K, what is the new pressure? (Assume ideal gas behavior, R = 0.0821 L·atm/(mol·K))

    We can use the combined gas law or apply the ideal gas law twice. Initial state: P₁V₁ = nRT₁. Since n and R are constant, P₁V₁/T₁ = P₂V₂/T₂. First, find initial pressure: P₁ = (0.100 mol * 0.0821 L·atm/(mol·K) * 273 K) / 1.00 L = 2.24 atm. Now, P₂ = P₁V₁T₂ / (V₂T₁) = (2.24 atm * 1.00 L * 300 K) / (0.500 L * 273 K) = 4.92 atm. The new pressure is 4.92 atm.

39. Card 39

    Explain the difference between specific heat capacity and molar heat capacity.

    Specific heat capacity is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius (or Kelvin). Molar heat capacity, on the other hand, is the amount of heat required to raise the temperature of one mole of a substance by one degree Celsius (or Kelvin). The former is per unit mass, while the latter is per unit amount of substance.

40. Card 40

    Under what conditions does the ideal gas law break down, and why does it break down based on the postulates of the kinetic molecular theory?

    The ideal gas law breaks down at high pressures and low temperatures. According to the kinetic molecular theory, ideal gas particles have negligible volume and no intermolecular forces. At high pressures, the volume of the gas particles becomes significant relative to the container volume. At low temperatures, the kinetic energy of particles decreases, making intermolecular forces more significant, leading to deviations from ideal behavior.

41. Card 41

    Define the terms 'effusion' and 'diffusion' for gases, and explain how their rates are related to molar mass.

    Effusion is the process by which a gas escapes through a tiny hole into a vacuum. Diffusion is the process by which gas molecules spread out from an area of higher concentration to an area of lower concentration. According to Graham's Law, the rates of both effusion and diffusion are inversely proportional to the square root of the gas's molar mass. Lighter gases effuse and diffuse faster than heavier gases.

42. Card 42

    An endothermic reaction has a ΔH of +120 kJ/mol and a ΔS of +300 J/mol·K. At what temperature (in °C) will this reaction become spontaneous?

    For a reaction to be spontaneous, ΔG must be negative. We use ΔG = ΔH - TΔS. For spontaneity, ΔH - TΔS ΔH/ΔS. Convert ΔH to J: 120,000 J/mol. T > (120,000 J/mol) / (300 J/mol·K) = 400 K. To convert to °C, 400 K - 273.15 = 126.85 °C. The reaction becomes spontaneous above 126.85 °C.

43. Card 43

    What are the common geometries of complex ions, and how are they determined?

    The common geometries of complex ions include linear, tetrahedral, square planar, and octahedral. These geometries are primarily determined by the coordination number (number of ligands attached to the central metal ion) and the electronic configuration of the central metal ion. For example, a coordination number of 4 can lead to tetrahedral or square planar, while 6 typically leads to octahedral.

44. Card 44

    Define standard temperature and pressure (STP) and the molar volume of an ideal gas at STP.

    Standard temperature and pressure (STP) are defined as 0 °C (273.15 K) and 1 atm pressure. At STP, one mole of any ideal gas occupies a volume of 22.4 L, which is known as the molar volume of an ideal gas. This value is useful for stoichiometric calculations involving gases under standard conditions.

45. Card 45

    Calculate the mass of copper deposited at the cathode when a current of 5.0 A flows through a CuSO₄ solution for 30 minutes. (Molar mass of Cu = 63.55 g/mol, Faraday constant = 96485 C/mol e⁻)

    First, convert time to seconds: 30 min * 60 s/min = 1800 s. Calculate total charge: Q = I * t = 5.0 A * 1800 s = 9000 C. For Cu²⁺ + 2e⁻ → Cu, 2 moles of electrons are required per mole of Cu. Moles of electrons = 9000 C / 96485 C/mol e⁻ = 0.09328 mol e⁻. Moles of Cu = 0.09328 mol e⁻ / 2 = 0.04664 mol Cu. Mass of Cu = 0.04664 mol * 63.55 g/mol = 2.96 g. Approximately 2.96 g of copper is deposited.

46. Card 46

    Distinguish between structural isomers and stereoisomers in coordination compounds.

    Structural isomers have the same molecular formula but different connectivity of atoms. Examples include coordination isomers (ligands and counterions exchange positions) and linkage isomers (a ligand binds through different atoms). Stereoisomers, on the other hand, have the same connectivity but different spatial arrangements of atoms. These include geometric isomers (cis/trans) and optical isomers (enantiomers).

47. Card 47

    How does Dalton's Law of Partial Pressures apply to a mixture of ideal gases?

    Dalton's Law of Partial Pressures states that the total pressure exerted by a mixture of non-reacting ideal gases is equal to the sum of the partial pressures of the individual gases. The partial pressure of each gas is the pressure it would exert if it were alone in the container. This law is based on the assumption that ideal gas particles do not interact with each other.

48. Card 48

    Why does Hess's Law work, and how is it used to calculate the enthalpy change for a reaction?

    Hess's Law works because enthalpy (ΔH) is a state function, meaning the total enthalpy change for a reaction depends only on the initial and final states, not on the pathway taken. It is used to calculate the enthalpy change for a reaction by summing the enthalpy changes of a series of steps that add up to the overall reaction. If a reaction is reversed, the sign of ΔH changes; if multiplied by a factor, ΔH is multiplied by the same factor.

49. Card 49

    Predict the sign of the standard entropy change (ΔS°rxn) for the following reaction and explain your reasoning: N₂(g) + 3H₂(g) → 2NH₃(g)

    The sign of ΔS°rxn is expected to be negative. The reaction involves 4 moles of gas reactants (1 N₂ + 3 H₂) forming 2 moles of gas products (2 NH₃). A decrease in the number of moles of gas generally leads to a decrease in disorder or randomness, hence a negative entropy change.

50. Card 50

    Define the terms 'high spin' and 'low spin' in transition metal complexes, and explain their relationship to crystal field splitting and magnetic properties.

    High spin and low spin refer to how electrons populate the d-orbitals in coordination complexes, particularly in octahedral geometry. In a high-spin complex, electrons occupy all d-orbitals singly before pairing, often occurring with weak-field ligands and small crystal field splitting (Δo). In a low-spin complex, electrons pair up in the lower energy t2g orbitals before occupying the higher energy eg orbitals, occurring with strong-field ligands and large Δo. This difference affects the number of unpaired electrons, which determines the complex's magnetic properties.

More flashcard decks

• CHEM (EXAM 4) flashcards (50 cards)
• Science Exam Final Les Yeux flashcards (30 cards)
• Systme Nerveux Sxience Exam Final flashcards (18 cards)
• Histoire exam final Bloc 1 flashcards (14 cards)
• Thermochemistry and Thermodynamics flashcards (149 cards)
• Género Bacillus y Clostridium flashcards (100 cards)

Browse every shared deck