chem II test 4

3.09

A 1.00 L buffer solution is 0.250 M in HF and 0.250 M in NaF. Calculate the pH of the solution after the addition of 100.0 mL of 1.00 M HCl. The Ka for HF is 3.5 × 10-4.

a central metal ion bound to one or more ligands.

A complex ion contains

Silver chloride will precipitate out of solution, leaving a saturated AgCl solution

A solution containing AgNO3 is mixed with a solution of NaCl to form a solution that is 0.10 M in AgNO3 and 0.075 M in NaCl. What will happen once these solutions are mixed? Ksp (AgCl) = 1.77 × 10-10.

without ongoing outside intervention

A spontaneous reaction occurs

has a positive ΔHsys and a negative ΔSsurr.

An endothermic reaction is a process that

has a negative ΔHsys and a positive ΔSsurr.

An exothermic reaction is a process that

carbonic acid and bicarbonate ion.

An important buffer in the blood is a mixture of

Buffer capacity

Buffer capacity is the amount of acid or base that can be added to a buffer without destroying its effectiveness.

3.47

Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M HCHO2 with 100.0 mL of 0.20 M LiCHO2. The Ka for HCHO2 is 1.8 × 10-4.

8.98

Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M NH4Cl with 100.0 mL of 0.20 M NH3. The Kb for NH3 is 1.8 × 10-5.

9.06

Calculate the pH of a solution formed by mixing 250.0 mL of 0.15 M NH4Cl with 200.0 mL of 0.12 M NH3. The Kb for NH3 is 1.8 × 10-5.

This reaction will be spontaneous at all temperatures.

Consider a reaction that has a negative ΔH and a positive ΔS. Which of the following statements is TRUE?

This reaction will be nonspontaneous at all temperatures

Consider a reaction that has a positive ΔH and a negative ΔS. Which of the following statements is TRUE?

This reaction will be nonspontaneous only at low temperatures.

Consider a reaction that has a positive ΔH and a positive ΔS. Which of the following statements is TRUE?

This reaction will be spontaneous only at high temperatures.

Consider a reaction that has a positive ΔH and a positive ΔS. Which of the following statements is TRUE? This reaction will be nonspontaneous only at high temperatures. This reaction will be spontaneous at all temperatures. This reaction will be nonspontaneous at all temperatures. This reaction will be spontaneous only at high temperatures. It is not possible to determine without more information

Q = Ksp

Give the equation for a saturated solution in comparing Q with Ksp.

Q > Ksp

Give the equation for a supersaturated solution in comparing Q with Ksp.

Q < Ksp

Give the mathematical relationship for an unsaturated solution in comparing Q with Ksp.

reversible reaction

Give the name of the reaction that achieves the theoretical limits with respect to free energy in thermodynamics.

significant amounts of both a weak acid and its conjugate base

Identify a good buffer.

frying an egg

Identify a process that is NOT reversible.

crystal violet

Identify the indicator that can be used at the lowest pH.

phenolphthalein

Identify the most common indicator.

the phase transition from a solid to a gas

Identify the process in which the entropy increases.

vaporization

Identify the process that is endothermic.

rusting of iron

Identify the process that is spontaneous.

HOCH2CH2OH

Identify the structure for antifreeze.

[HCHO2] > [NaCHO2]

If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.11, which of the following is TRUE?

[HCHO2] < [NaCHO2]

If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.89, which of the following is TRUE?

20

In the blood, the concentration of bicarbonate is ________ times higher than the concentration of carbonic acid.

water freezing

In which of the following processes do the molecules become more orderly?

second

The ________ Law of Thermodynamics states that for any spontaneous reaction, the entropy of the universe increases.

first

The ________ Law of Thermodynamics states the energy is conserved in chemical processes.

third

The ________ Law of Thermodynamics states the entropy of a perfect crystal at absolute zero is zero.

Ksp is the value of the product at equilibrium and Q is the value of the product under any condition.

The difference between Q and Ksp is

all of the above

What can change the direction of a reversible reaction involving gases? change in temperature change in volume change in pressure all of the above none of the above

positive

What is the sign of Δuniv for a living biological system?

pH will be equal to 7 at the equivalence point.

When titrating a strong monoprotic acid and KOH at 25°C, the

pH will be less than 7 at the equivalence point ..

When titrating a weak base with HCl at 25°C, the ..

pH will be less than 7 at the equivalence point.

When titrating a weak base with a monoprotic acid at 25°C, the

pH will be greater than 7 at the equivalence point.

When titrating a weak monoprotic acid with NaOH at 25°C, the

A buffer is most resistant to pH change when [acid] = [conjugate base]

Which of the following is TRUE? An effective buffer has a [base]/[acid] ratio in the range of 10 - 100. A buffer cannot be destroyed by adding too much strong base. It can only be destroyed by adding too much strong acid. None of the above is true. An effective buffer has very small absolute concentrations of acid and conjugate base. A buffer is most resistant to pH change when [acid] = [conjugate base]

The equivalence point is where the amount of acid equals the amount of base during any acid-base titration.

Which of the following is TRUE? An indicator is not pH sensitive. None of the above is true. At the equivalence point, the pH is always 7 The equivalence point is where the amount of acid equals the amount of base during any acid-base titration. A titration curve is a plot of pH vs. the [base]/[acid] ratio.

There is a "heat tax" for every energy transaction.

Which of the following statements is TRUE? The entropy of a system always decreases for a spontaneous process. A spontaneous reaction is always a fast reaction. There is a "heat tax" for every energy transaction. Perpetual motion machines are a possibility in the near future. None of the above is true.

Entropy

________ is a thermodynamic function that increases with the number of energetically equivalent ways to arrange components of a system to achieve a particular state.