What volume of 0.550 M barium hydroxide is required to neutralize 30.50 mL of 0.289 M

perchloric acid ?

A 0.249g pellet of potassium hydroxide, KOH, is added to 64.0g water in a Styrofoam coffee cup. The water temperature rises from 23.5 to 24.4 ?C. [Assume that the specific heat of dilute KOH(aq)is the same as that of water.] What is the approximate heat of solution of KOH, expressed as kilojoules per mole of KOH?

Part A:

Balance the following redox reactions occurring in acidic aqueous solution.

MnO4−(aq)+Al(s)→Mn2+(aq)+Al3+(aq)

Part B:

What mass of lead sulfate is formed in a lead-acid storage battery when 1.40 g of Pb undergoes oxidation?

Calculate the mass of solid sodium acetate and how much of 1.0 M of acetic acid required to mix with 100.0 mL to prepare a pH 4 buffer and total common ion concentration= 0.200 M (Show all work). 1. How many grams of solid sodium acetate is needed? 2. How much mL of 1.0 M acetic acid is needed?

1. The pH of a 0.50 M solution of ethylamine CH3CH2NH2 is 12.22. Calculate the Kb of ethylamine. Use “E” for scientific notation.
2. A 0.050 M solution of pyruvic acid, an intermediate in metabolism, has a pH of 1.93. Calculate Ka for pyruvic acid, a weak monoprotic acid. Use “E” for scientific notation.
3. Calculate the pH of a 0.17 M solution of HClO, with Ka1= 3.5x10.
4. At 25°C, 2.29E0 grams of sodium hydroxide is dissolved in enough water to make 500. mL of solution. Calculate ​[H3O+]. Do not enter units as part of your answer.

11.A student was given a sample of crude salicylic acid to recrystallize. The initial mass of the the crude acid was 161 mg. The mass after recrystallization was 121 mg. Calculate the percent recovery from recrystallization.

2.A student measures out exactly 0.109 g of salicylic acid and runs the experiment as dictated in the lab manual. They obtain 0.119 g of aspirin. What is the percent yield for their reaction

3.If 91.0 g of oxalic acid and 79.0 g of methanol react to form 89.0 g of dimethyl oxalate, what is the percent yield?(Molar mass of oxalic acid=90.04g/mol,MM of methanol=32.04,MM of dimethyl oxalate=118.1,MM of water=18.02)

Maria Gonzales is a 57-year-old operating room nurse who works full-time at a local hospital. She is 65 inches tall and weighs 160 pounds. She has a family history of diabetes and heart disease, and was recently diagnosed with high blood cholesterol. Maria has declined the cholesterol-lowering medication that her doctor prescribed, explaining that she would like to explore other methods for lowering her cholesterol first. After reading an article on the Internet a few weeks ago, Maria has been taking a tablespoon of coconut oil every day in the hopes that it will lower her cholesterol. She admits that she has little time or energy to exercise. Her diet history reveals that she often skips breakfast or buys a bagel with cream cheese and flavored coffee on her way to work. While at work, she drinks at least one more cup of coffee with cream and sugar before noon. Lunch is a salad with crackers and iced tea with sugar in the hospital cafeteria. When Maria arrive homes, she occasionally drinks one or two glasses of wine in the evening, especially after a stressful day. She lives alone and relies on frozen dinners or other convenience foods for dinner. An analysis of her diet reveals an average daily intake of 200 grams carbohydrate, 50 grams protein, and 80 grams of fat.
Which of Maria's habits involves the use of functional food?
What percentages of Maria's daily calories are provided by carbohydrates, protein, and fat?

a. carbohydrates: 36%; protein: 22%; and fat: 42%

b. carbohydrates: 46%; protein: 12%; and fat: 42%

c. carbohydrates: 36%; protein: 32%; and fat: 32%

d. carbohydrates: 56%; protein: 12%; and fat: 32%

e. carbohydrates: 56%; protein: 22%; and fat: 22%
Compare the composition of Maria's diet with the Acceptable Macronutrient Distribution Ranges (AMDR). How would you characterize her intake?

a. adequate carbohydrate, inadequate protein, and high fat

b. inadequate carbohydrate, inadequate protein, and high fat

c. adequate carbohydrate, adequate protein, and high fat

d. adequate carbohydrate, adequate protein, and adequate fat

e. inadequate carbohydrate, inadequate protein, and adequate fat

Maria explains that she learned about the effects of coconut oil on the Internet, while reading an online article about a well-known movie star who claims it helped him lower his bad cholesterol. What are these types of testimonials called?

a. anecdotes

b. correlations

c. hypotheses

d. controls

e. theories

Hide Feedback

A solution is prepared by dissolving 15 ml of methanol in 150.0 ml water at 25 degree celsius. Assume the volumes are additive. The densities of methanol and water at this temperature are 0.782 g/ml and 1.00 g/ml, respectively. For the solute , calculete molarity, molality, and more fraction?

Calculate the concentration of nickel(II) ion in solution after the addition of 25.0 mL of 0.200 M NaCN to 60.0 mL of 0.0100 M Ni(NO3)2. (Kf is 2.0 × 1031 for [Ni(CN)4] 2─)

I crushed acetamide and heated until melted, i let it cool and started again.

A. Describe your results for the melting point of acetamide. Were your results consistent? What was the range of values?

B. The published melting point of acetamide is 81°C, calculate the percent error between your experimental values and the published (theoretical) value. Show your work.

C. Describe what occurs to the particles of a substance when the substance melts. Explain why this occurs.

D. When performing this experiment, when is the acetamide in a condensed phase? Explain your answer.

E. Based on your observations of acetamide when it reformed a solid after melting, does acetamide form a crystalline or amorphous solid? Explain the difference between these two terms as part of your answer.

F. Give some examples of how it might be useful to know the melting or boiling points of a substance. Think in terms of both scientific and commercial/industrial settings.

G. Describe any possible sources of error for this exercise.

Calculate the pH change when a) 100 mL of 0.0500M NaOH and b) 100 mL of 0.0500 M HCL are added to a 400.0 mL of a solution that contains .300 M ammonium chloride and .300 M ammonia (Kb,= 1.76 x 10^-5) Show work to get a good rating please

The full three-dimensional Schrödinger equation is

−ℏ22m(∂2∂x2ψ(x,y,z)+∂2∂y2ψ(x,y,z)+∂2∂z2ψ(x,y,z))+U(x,y,z)ψ(x,y,z)=Eψ(x,y,z).

By using the substitutions from the introduction, this becomes

−ℏ22m(∂2∂x2ψxψyψz+∂2∂y2ψxψyψz+∂2∂z2ψxψyψz)+(Ux+Uy+Uz)ψxψyψz=Eψxψyψz

What is ∂2∂x2ψxψyψz? To make entering the expression easier, use D2x in place of d2ψxdx2, D2y in place of d2ψydy2, and D2z in place of d2ψzdz2.

Answer in terms of ψx,ψy,ψz,D2x,D2y,andD2z

The Arrhenius equation shows the relationship between the rate constant k and the temperature T in kelvins and is typically written as

k=Ae−Ea/RT

where R is the gas constant (8.314 J/mol⋅K), A is a constant called the frequency factor, and Eais the activation energy for the reaction.

However, a more practical form of this equation is

lnk2k1=EaR(1T1−1T2)

which is mathmatically equivalent to

lnk1k2=EaR(1T2−1T1)

where k1 and k2 are the rate constants for a single reaction at two different absolute temperatures (T1 and T2).

Part A

The activation energy of a certain reaction is 46.7 kJ/mol . At 26  ∘C , the rate constant is 0.0120s−1. At what temperature in degrees Celsius would this reaction go twice as fast?

Express your answer with the appropriate units.

Part B

Given that the initial rate constant is 0.0120s−1 at an initial temperature of 26  ∘C , what would the rate constant be at a temperature of 180  ∘C for the same reaction described in Part A?

Express your answer with the appropriate units.

PLEASE explain Spectrophotometry and what is soo important about 400nm

PLEASE explain how absorbance and beer's law relate

Relate Beer’s law to the equation of a line on a standard curve.

Why is the line forced through zero on the standard curve?

What does the R2 value for the graph says about the experiment?