Solvent vessels must be purged before maintenance personnel enter in order to ensure that: (1) sufficient oxygen is available for breathing; (2) vapor concentrations are below the flash point; (3) vapor concentrations are below the Occupational Safetey and Health Administration (OSHA) limits if breathing apparatus is not to be used. Assuming that a 8 m^3 fixed-roof solvent tank has just been drained of all liquid and that the vapor phase is initially saturated at 22 degrees celsius, estimate the length of purge necessary with 2 m^3/min of gas at 0.1 MPa and 22 degrees celsius to reach the OSHA 8-hr exposure limit.

(a) Choloroform 50 ppm

Aqueous hydrochloric acid

HCl

reacts with solid sodium hydroxide

NaOH

to produce aqueous sodium chloride

NaCl

and liquid water

H2O

. If

0.314g

of water is produced from the reaction of

0.73g

of hydrochloric acid and

1.3g

of sodium hydroxide, calculate the percent yield of water.

Be sure your answer has the correct number of significant digits in it.

A.) Calculate the pH of 1.0 L of the solution, upon addition of 49.00 mL of 1.0 MHCl.

Calculate the pH of the solution upon addition of 19.1 mL of 1.00 MHCl to the original buffer

B.)For each of the following solutions, calculate the initial pH and the final pH after adding 0.005 mol of NaOH.

1.) 300.0 mL of pure water

2.)300.0 mL of a buffer solution that is 0.210 M in HCHO2 and 0.290 M in KCHO2

3.)300.0 mL of a buffer solution that is 0.295 M in CH3CH2NH2 and 0.270 M in CH3CH2NH3Cl

1. The equilibrium constant, K_p, for the following reaction is 10.5 at 350 K:

2CH₂Cl₂(g) <--->CH₄(g) + CCl₄(g)

Calculate the equilibrium partial pressures of all species when CH₂Cl₂(g) is introduced into an evacuated flask at a pressure of 0.865 atm at 350 K.

2. The equilibrium constant, K_p, for the following reaction is 0.215 at 673 K:

NH₄I(s) <----> NH₃(g) + HI(g)

Calculate the equilibrium partial pressure of HI when 0.413 moles of NH₄I(s) is introduced into a 1.00 L vessel at 673 K.

P_HI = ____atm

1. VOLUME TECHNIQUE: This method is based on the volume of carbon dioxide produced and collected.
2. MASS TECHNIQUE: This method is based on the difference in mass before and after the reaction.

The mass of carbon dioxide calculated using the volume technique will not be identical to the mass of the carbon dioxide calculated using the mass technique. In this discussion, compare and contrast the two techniques and the mass of carbon dioxide obtained by each technique. Also discuss reasons for the difference in masses.

Briefly explain what you would observe if you used the test described in (a) on a solution that needed more NaOH solution

A 39.0%/61.0% by volume propane/n-butane mixture is cooled from 291°C to 115°C. Assume ideal behavior.

a) What is the average molar mass of the mixture?

b) What is the change in specific enthalpy of pure propane from 291°C to 115°C?

c) What is the change in specific enthalpy of pure n-butane from 291°C to 115°C?

d) What is the change in specific enthalpy of the mixture from 291°C to 115°C?

e) What is the change in enthalpy of the mixture from 291°C to 115°C in kJ/kg?

Rank each substance above from strongest to weakest intermolecular force. Do not look up these substances' physical properties...determine the ranking based on general intermolecular force principles. If you predict an "anomaly" (i.e. a "LDF only" molecule with greater intermolecular forces than a dipole-dipole or hydrogen bonding molecule), you must briefly state your reasoning. Please justify why you put each molecule in its order.

CCl₄   BH₃   SF₄ CH₃NH₂   CO₂ N₂O (NNO) CH₃OH

Suppose we add 0.001M glucose to one side of an osmometer and 0.001M hemoglobin to the other side. Will the water change? Why or why not?

Identify major classes of biomolecules and characteristic functional groups

Draw the structure of water molecules including atoms, orbital hybridization, bonds, lone pairs, partial charges, and dipole moments

Match the following aqueous solutions with the appropriate letter from the column on the right. Assume complete dissociation of electrolytes.

How would you use a DEPT spectrum and a {¹H}¹³C spectrum to deduce how many quaternary carbon atoms you have?

Write the combustion reaction for uracil (C4H4N2O2 (s)) and calculate the standard enthalpy for the combustion reaction of uracil at 298.15 K, using only the standard formation enthalpies for uracil (s), CO2 (g) and H2O (l), which you will find online.

Use the general integral balance equation to derive an integral balance equation for the concentration, c, of some substance that diffuses through boundaries of the control volume. The substance may also be produced or consumed within the control volume by chemical reactions

(a)Define the surface fluxes and volumetric source/sink and explain your choice

(b)Write out the final form of the integral balance

(c)Explain what additional information or models would be required in order to solve this equation for the volume-averaged concentration, {c}.

Can someone help me with this, not sure how to attempt.

What is the hydroxide-ion concentration in a 0.20 M solution of Na₂CO₃? For carbonic acid, K_a1 = 4.2