Consider the titratkon of 50.0 mL of 0.200 M HC₂H₃O₂ (K_a = 1.8 x 10^-5) with 0.100 M NaOH.

(A.) Calculate the pH of the HC₂H₃O₂ before the addition of NaOH

(B.) Calculate the pH of the solution after the addition of 20.0 mL of 0.100 M NaOH.

(C.) Calculate the pH of the solution after the addition of 50.0 mL of 0.100 M NaOH.

(D.) Calculate the pH of the solution after the addition of 100.0 mL of 0.100 M NaOH.

(E.) Calculate the pH of the solution after the addition of 150.0 mL of 0.100 M NaOH.

AP Chemistry Algorithmic Question 27

Part A

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide:
2Mg(s)+O2(g)→2MgO(s)
When 5.50 g of magnesium burns, the theoretical yield of magnesium oxide is ________ g.

Part B

If the percent yield for the following reaction is 75.0%, and 40.0 g of NO2 are consumed in the reaction, how many grams of nitric acid, HNO3(aq) are produced?
3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g)

Part C

Balance the chemical equation given below, and calculate the volume of nitrogen monoxide gas produced when 8.00 g of ammonia is reacted with 9.00 g of oxygen at 25°C. The density of nitrogen monoxide at 25°C is 1.23 g/L.
________ NH3(g) + ________ O2(g) →________ NO(g) + ________ H2O(l)

A solution of household bleach contains 5.25% sodium hypochlorite, NaOCl, by mass. Assuming that the density of bleach is the same as water, calculate the volume in mL of household bleach that should be diluted with water to make 500.0 mL of a pH = 9.80 solution.

Compute the pressure in bar of hydrogen gas produced at 311 K in a container of volume 1.59 L that results when 2.34 g of aluminum react with 103 mL of a 0.359 mol L^-1 sulfuric acid solution.
You must write the chemical equation, balance it, work the stoichiometry problem and finally use the ideal gas law. The reaction produces aluminum sulfate and hydrogen gas.

P = _____________bar

Based on your observations following the addition of (a) Fe(NO₃)₃, (b) NH₄SCH, (c) SnCl₂, (d) AgNO₃, (e) Na₂HPO₄, and (f) NH₃, which way did each of these reagents causethe equilibrium to shift? Considering Le Chatelier's Principle, provide a chemical explanation for the direction of the shift in each case.

How to calculate the weight percent Na2CO3 in impure base sample???

I did my calculations but it somehow doesnt make sense

First we find the moles of HCl

=0.1M HCl x volume of HCl used to titrate

       =0.1M x 10.5mL HCl

       =1.05 mol HCl

The ratio between Na2CO3 and Hcl is 1:2

Moles Na2CO3

= moles of HCl/2

=1.05mol HCl/2

=0.525mol Na2CO3

Mass Na2CO3

= moles of Na2CO3 x 105.9906 g/mol

       =0.525 mol Na2CO3 x 105.9906 g/mol

       =55.65 g

%    = mass of Na2CO3 x100/mass of sample from the impure solid

       =55.65g x 100/ 0.1328g = 41905.1205 ???

What did I do wrong??? (do I need to include the fact that that the impure base was first mixed with 25 mL of distilled water??? The HCl used is 0.1M for titrate to its endpoint)

1) A power plant with an efficiency of 65% combusts 500,000 metric tons (MT) of anthracite coal per year to generate electricity. It has been established that this type of coal has the capacity to generate electrical energy at 19 GJ/MT.

a) How much energy in GJ (giga joules) does this plant generate in one year?

b) Estimate the annual emissions of criteria pollutants including SO2, NOx, PM and greenhouse gases including CO2 and CO using the appropriate emission factors given in the below table.

2) The Power Company has recommended a plant conversation to switch to using natural gas as fuel to generate the same amount of energy. Your firm has been asked to review the economics and perform and sensitivity analysis for the proposed switch and make a recommendation to the regional Utility Board of Directions. If the natural gas to be used has an energy capacity of 43 MJ/m³ (mega joules per cubic meter of gas)

a) Estimate the volume of natural gas needed in m³/yr.

b) Calculate the annual emissions of criteria pollutants including SO2, NOx, PM and greenhouse gases including CO2 and CO using the appropriate emissions factors given in the below table.

3) The NG plant conversion is estimated to cost $25 million. Given that the cost of Anthracite coal is $750/MT and natural gas is $15/m³ calculate the plant operating costs per year and the annual fuel cost difference for switching to natural gas. Additionally, it has been determined that the cap and trade program for SO2 reduction will provide a credit benefit for $150/MT-SO2 reduced. Also, the plant is looking ahead and planning for the implementation of a similar cap and trade program similar to the European model for CO2 emissions. The expected credit benefit for CO2 emission reduction will be market based and can range from $100 to $300/MT-CO2 reduced. Determine the NPV, payout and rate of return for the plant conversion project incorporating the capital an operating costs and emissions program credit for SO2 with a 4% interest rate. If the carbon cap and trade system is implemented, how does that change the economic outcomes?

Based on the emission estimates and costs and benefits, what is your recommendation to the utility board?

(a) A mixture containing 2.15 g each of CH₄(g), C₂H₄(g) and C₄H₁₀(g) is contained in a 1.50 L flask at a temperature of 25°C.

Calculate the partial pressure of each of the gases in the mixture.

Calculate the total pressure of the mixture.
___ atm

(b) A mixture of gases contains 1.06 g of N₂, 2.22 g of H₂, and 1.22 g of NH₃. If the total pressure of the mixture is 4.12 atm, what is the partial pressure of each component?

Consider the titration of the weak acid HA with NaOH. At what fraction of Ve does pH = pKa -1? At what fraction of Ve does pH = pKa +1? Use these two points, plus Vb = 0, 1/2Ve, Ve, and 1.2Ve to sketch the titration curve for the reaction of 100 mL of 0.100M anilinium bromide ("aminobenzene x HBr") with 0.100M NaOH.

You are removing imidazole from your pooled nickel column samples by dialysis. The
volume of the pooled sample is 32 mL and the imidazole concentration is 0.5 M.

a. What is the concentration of imidazole after exposure to three consecutive dialyses
against 1 L of buffer?
b. If the imidazole at the start is 3.4% (w/v), what is the concentration in
weight percent at the end of the dialysis (three consecutive exposures to one liter
of buffer)?

Predict the effect on each of the following if the product was not completely dried after the recrystallization:
(a) percent yield; (b) melting point; (c) IR spectrum.

importance of discussion in study

Using 1.0 nM enzyme X for the enzyme kinetics experiments, you obtained the reaction rates at different concentrations of substrate (shown in the following table). Assume that the enzyme X follows a typical Michaelis-Menten kinetics.

[substrate] (μM) Reaction rate (μmol/s)

2 7

5 17

10 29

20 44

50 67

100 80

200 89

500 95

1000 98

a) Estimate the Vmax and Km values of the enzyme X in this reaction using the double reciprocal plot.

b) If 5.0 nM of the enzyme X is used in the experiment, what will be the Vmax and Km values of the enzyme X?

Rank the following from highest to lowest boiling point

1. 0.18 m NH4CH3COO

2. 0.14 m Cr(CH3COO)2

3. 0.13 m CuBr2

4. 0.45 m Urea(nonelectrolyte)

Absorbance at 540 nm of Bromocresol Purple Dilution Series

1. The point 0/0 is an important and valid point on this graph. Why? (Explain)  Explain how a hand-drawn graph and excel graph are similar or different.

2. How is the Beer’s Law equation similar to that of a straight line? Explain each component using the letter of the component and using a set of your experimental values. BCP: 0.015M

3. Evaluate your data using the Beer’s Law equation: use the absorbance reading for the highest concentration of a solution, determine the extinction coefficient for the BCP solution you were given. Do you get the same answer if you make this calculation at another concentration?

4. Select 2 random absorbance readings on your line (that you did not actually measure) and explain two different ways you can use your graph to determine the concentration of BCP (µg/mL) of the unknown solutions that might have the selected absorbance values.  ***Provide the results; what values do you determine to be the concentrations of your 2 random absorbance readings?

5. Explain why we refer to a graph such as the one you just constructed as a “standard      curve” or a “calibration curve.” How would a graph such as this one be useful?