33)

(a) A piston at 5.9 atm contains a gas that occupies a volume of 3.5 L. What pressure would have to be placed on the piston to force the volume to adjust to 0.32 L?
_____________ atm

(b) A piston at -44.0°C contains a gas that occupies a volume of 2.5 L. To what temperature would the gas have to be heated to increase the volume to 4.4 L at constant pressure?
__________ °C

(c) A piston at 795 torr contains a gas that occupies a volume of 4.7 L. What pressure would have to be placed on the piston to force the volume to adjust to 0.78 L?
___________atm

a. 0.130 g of HCl is in 35.0 mL of water. This is mixed with 50.0 mL of 0.185 M Sr(OH)₂. What is the pH of the resulting solution?

b. Calculate the pH of a solution prepared by mixing 125.0 mL of 0.0120 M HCl with 25.0 mL of 0.0420 M Ba(OH)_2?

_c.

Explain the process that occur in a coagulation bath, use PAN as an example.

8. What kinds of functional groups or coatings are available in SPE cartridges and how does one elute the sample through the cartridges?

Answer the following multiple choice questions below:

1a. Increasing the flow rate of the mobile phase would:

1b. Reverse phase HPLC of a multi-component solute usually uses:

1c. When two analytes, A and B, are passed through a chromatography column, A emerges first. We can then say:

1d. In a given chromatographic column,

1e. In a gas chromatography experiment using a non-polar stationary phase:

Given the reactivity difference for the 4- position versus the 1-position, do you think that the chlorine atom stabilizes, destabilizes or has no effect on an adjacent radical? Is it the Resonance or Inductive effect?

Use: 1,4-dichlorobutane, 1,3-dichlorobutane, 1,2-dichlorobutane and 1,1-dichlorobutane

Calculate the pH of a 0.0290 M aqueous solution of the weak base triethylamine ((C2H5)3N, Kb = 5.20×10-4). pH = ?

4. A solution of benzene and toluene at 25C and 760mmHg has a total vapor pressure (P_total) of 71.08 torr (mmHg). If the partial pressures of benzene (P_benzene) and toluene (P_toulene) are 60.86 torr and 122 torr respectively, what are the percentages of a. benzene; and b. toluene, in the corresponding vapor above the liquid. Please show all the calculations.

(b) If the vapor pressure of pure benzene is always higher than the vapor pressure of pure toluene when they are both at the same temperature and applied pressure, which of the two (benzene or toluene) should always have the higher temperature? Why?

A chemist isolated 0.7886 g of isoamyl acetate from a reaction of 0.8235 g of isoamyl alcohol and 1.5 mL of acetic acid.

What is the percent yield for the reaction above?

4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(g)

A scientist adds 7.00 atm of NH₃(g) and 8.00 atm of O₂(g) to a 5.0 L container at 473 K. What will the pressure of H₂O(g) be if the reaction goes to completion? Assume that the temperature remains constant.

Select one:

a. 6.40 atm

b. 9.60 atm

c. 10.5 atm

d. 0.90 atm

e. 15.0 atm

Question 3: Draw the titration curve (pH versus mL of NaOH added) that would be obtained from the titration of 30 mL of a 0.10 M solution of an unknown triprotic acid, H3A (Ka1 = 1.26 x 10–3; Ka2 = 5.6 x 10–6; Ka3 = 3.32 x 10–10) with 0.10 M NaOH. Indicate the volume needed to reach the first, second, and third equivalence points and the pH at the half equivalence points for the three titration regions.

The heating value of combustible fuels is evaluated based on the quantities known as the higher heating value (HHV) and the lower heating value (LHV). The HHV has a higher absolute value and is obtained by assuming that the water formed in the combustion reaction is formed in the liquid state. The LHV has a lower absolute value and is obtained by assuming that the water formed in the combustion reaction is formed in the gaseous state. The LHV is therefore the sum of the HHV (which is negative) and the heat of vaporization of water for the number of moles of water formed in the reaction (which is positive). The table below lists the enthalpy of combustion (which is equivalent to the HHV) for several closely related hydrocarbons. Use the information in the table to answer the following questions.

Part A

Given the provided data, complete and balance the combustion equation for the combustion of butane, CH3CH2CH2CH3CH3CH2CH2CH3, using whole-number coefficients for CO2CO2 and H2OH2O, assuming liquid water forms:

CH3CH2CH2CH3(g)+O2(g)→     ––– +      –––CH3CH2CH2CH3(g)+O2(g)→     _ +      _

Express your answer as a balanced chemical equation using the smallest whole-number coefficients including phases.

View Available Hint(s)

Part B

The following table lists heat of formation values for select compounds:

Part C

Calculate ΔHΔH for the combustion of one mole of butane gas, C4H10C4H10, assuming H2O(l)H2O(l) is produced instead of H2O(g)H2O(g).

Express the change in enthalpy in kilojoules to five significant figures.

Part D

Calculate ΔHΔH for the combustion of one mole of butane gas, C4H10C4H10, assuming H2O(g)H2O(g) is produced instead of H2O(l)H2O(l).

Express the change in enthalpy in kilojoules to five significant figures.

Because of the toxicity of mercury compounds, mercury(I) chloride is used in antibacterial salves. The mercury(I) ion (Hg2 2+ ) consists of two bound Hg+ ions.

a. What is the chemical formula of mercury(I) chloride? (1 mark)

b. Calculate [Hg2 2+ ] in a saturated solution of mercury(I) chloride (Ksp = 1.5 x 10-18 ).

c. Seawater contains 0.03 kg of NaCl per litre. Using a suitable approximation, find [Hg2 2+ ] if the seawater is saturated with mercury(I) chloride.

d. How many grams of mercury(I) chloride are needed to saturate 4900 km3 of water (the volume of Lake Michigan)? e. How many grams of mercury(I) chloride are needed to saturate 4900 km3 of seawater?

Calculate the expected pH when 0.5 mL of 0.1 M HCL is added to 30.0 mL pure water. Do the same calculation when the same amount of HCl is added to 30.0 mL of your original .05M buffer. Compare the calculated pH to the actual measured pH.

My buffer has a pH of 5.09 and I used acetic acid which has a pKa of 4.76

2.
If you have 50 mL of .05M potassium phosphate buffer pH 7.0 and you added 2.0 mL of 0.1M HCl what would the final pH be? What would the pH be if 2.0 mL of 0.1M NaOH was added to the same amount of the original buffer?