Sulfate (SO4^2-) concentration is 10 mg SO4^2-/L and monohydrogen sulfide (HS-) concentration is 2 mg HS-/L. What is the total inorganic sulfur concentration in mg S/L?

Why would the actual coefficients of a ferrous ammonium sulfate hexahydrate and the potassium iron oxalate complex in a balanced chemical equation describing the overall process not be required to compute the predicted weight of the product?

What is the difference between the Normal Hydrogen Electrode (NHE) and the Reversible Hydrogen Electrode (RHE)?

- Also, if a redox happens at the NHE of 0.2 V, please calculate the potential for the RHE at pH = 1.

1.In today experiment you will perform the aldol condensation between benzaldehyde (PhCHO) and acetone to synthesize dibenzalacetone. Answer the following questions regarding this reaction:

a.This reaction is an example of a mixed aldol condensation. Why is only one product formed and no mixture of compounds are obtained like in other aldol condensations? (Hint: Benzaldehyde cannot undergo “ALDOL” reaction by itself in presence of strong base (NaOH). Why?)

b.Look at the mmols of the reagents used in this reaction and specify the limiting reagent.

c.Explain why the NaOH is a catalyst in this reaction, rather than a reagent. (Hint - look at the reaction mechanism.)

d.Usually an aldol condensation must be heated in order to dehydrate the beta-hydroxy ketone to form the C=C. What is different about this product that causes it to dehydrate at room temperature?

e.Why does this product have a yellow color?

f.The IR spectrum of dibenzalacetone shows the C=O peak at lower wavenumbers (1639 cm^-1) than standard C=O frequency (1715 cm^-1)? Why do you think?

g. How would you change the procedures in this experiment if you wished to synthesize benzalacetone, C₆H₅CH=CHCOCH₃? Benzalacetophenone, C₆H₅CH=CHCOC₆H₅?

h.The name dibenzalacetone does not completely characterize the molecules made in this experiment. There are 3 isomeric dibenzalacetones, one melting at 100-110 °_max 330 nm,34,300; another melting at 60 °C, _max= 295 nm20,000; and a third, a liquid with_max= 287 nm Draw the structures of the three geometric isomers of dibenzalacetone (Z,Z; Z,E; E,E), and assign each one to the three molecules described in the previous paragraph.

i.Write the detailed mechanism for the formation of dibenzalacetone from benzalacetone and benzaldehyde.

Consider the titration of 30.0 mL of 0.0700 M (CH₃)₃N (a weak base; K_b = 6.40e-05) with 0.100 M HCl. Calculate the pH after the following volumes of titrant have been added:

The vapor pressure of liquid methanol, CH3OH, is 100 mm Hg at 294 K. A 5.59×10-2 g sample of liquid CH3OH is placed in a closed, evacuated 490 mL container at a temperature of 294 K. Calculate what the ideal gas pressure would be in the container if all of the liquid methanol evaporated in mm Hg Assuming that the temperature remains constant, will all of the liquid evaporate? What will the pressure in the container be when equilibrium is reached in mm Hg?

Predict whether aqueous solutions of the following compounds are acidic, basic, or neutral.

Calculate [OH ^-] and pH for each of the following solutions.



(a) 0.0034 M RbOH

(b) 0.0872 g of KOH in 510.0 mL of solution

(c) 79.8 mL of 0.00719 M Sr(OH)₂ diluted to 900 mL

(d) A solution formed by mixing 64.0 mL of 0.000880 M Sr(OH)₂ with 36.0 mL of 2.6 x 10^-3 M RbOH

What are the Ksp values for below 2.0×10−3 M AgNO3;RbCl 8.5×10−2 M CaI2;K2SO4

This is a Physical Chemistry Problem: For a particle in a cubic box of length a, how many states have energy in the range of 0 to 16(h²/8ma²)?

initial temperature = 24.3 degree celcuis

final temperature = 35.7 degree celcuis

50.0 ml of 0.740 M phospheric acid +50.0ml of 2.00M of sodium hydroxide

change in temperature = 11.4 degree celcius

calculate the following

1- what is the mass mixture in thecup ?

2-heat flowof the system in cup in KJ?

3- heat of system in cup (qrxn)in KJ?

4-initial moles of H3PO4 in the cup?

5- initial moles of NaOH in the cup?

6-delta H rxn in KJ(experimental)?

7-delta Hrxn in KJ (theoretical)

8- percent error?

Zn is to be recovered from an ore containing ZnS. The ore is first roasted with oxygen to produce ZnO, which is leached with aqueous H2SO4 to produce water - soluble ZnSO4 and an insoluble, worthless residue called gangue. The decanted sludge of 20,000 kg/h contains 5 wt% water, 10 wt% ZnSO4, and balance as gangue. This sludge is to be washed with water in a continuous, countercurrent washing system to produce an extract, called a strong solution, of 10 wt% ZnSO4 in water, with a 98% recovery of ZnSO4. Assume that underflow from each washing stage contains, by weight, two parts of water (sulfate - free basis) per part of gangue. Determine the stages required.

Calculate the percent composition and determine the molecular formula and the empirical formula for the nitrogen-oxygen compound that results when 12.04 g of nitrogen is reacted with enough oxygen to produce 39.54 g of product. The molar mass of the product is 92.02 g. Proper significant figures when needed.

Percent Oxygen:
Percent Nitrogen:
Empirical Formula:
Molecular Formula:

A photocell, such as that illustrated in Figure 6.7(b), is a device used to measure the intensity of light. In a certain experiment, when light of wavelength 560 nm is directed on to the photocell, electrons are emitted at the rate of 9.6 ✕ 10^-13 C/s. Assume that each photon that impinges on the photocell emits one electron.
How many photons per second are striking the photocell?
photons/s
How much energy per second is the photocell absorbing?J/s