A buffer solution contains 0.444 M NH4Br and 0.365 M NH3 (ammonia). Determine the pH change when 0.084 mol NaOH is added to 1.00 L of the buffer. pH after addition − pH before addition = pH change =

A 12.0M HCl solution has a density of 1.18g/ml. what is the concentration of this solution in the following units?

a) weight percent

b) molality

thank you

Write the balanced NET IONIC equation for the reaction that occurs when nitrous acid and potassium hydroxide are combined.

The extent of this reaction is: .
This reaction is classified as .
A. Strong Acid + Strong Base
B. Weak Acid + Strong Base
C. Strong Acid + Weak Base
D. Weak Acid + Weak Base

A. ... Below 50%
B. ... 50%
C. ... Above 50%
D. ... 100%

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Retry Entire Group

How can the peak area be used to quantitatively analyze a sample using GC?

What is the concentration of hydronium ion, H3O + , in 0.10 M HClO at 25°C?

A. 3.0 × 10−8 M

B. 3.0 × 10−7 M

C. 5.5 × 10−5 M

D. 1.7 × 10−4 M

E. 0.10 M

Define the following concepts and provide an exaple for each: solid-liquid extraction, liquiid-liquid extraction, partition coefficient, miscible solvents, immiscible solvents.

What are two systematic and two random errors present in the experimental procedure?

Remeber how you learned that a pure liquid distills within a narrow boiling point range, but that narrow boiling point doesnt necessarily imple a pure liquid? Keeping that lesson in mind, explain this: you know without a doubt from spectroscopic technique that your product mixture contains 2 distinct products... yet your TLC plate shows only one spot. How is this possible? The, your research advisor tells you thats its really not that unusual to encounter this kind of conflicting data and that it is often easily resolved with a little more bench work. What should you do to clear up the issue using the TLC?

Consider the following question and answer.

Give an example of a homogeneous mixture: "WATER, because it is made up of two different elements - hydrogen and oxygen, and the comeposition is even throughout."

Which aspect of the students answer are correct? Which are incorrect?

7) How many grams of boric acid should be used in compounding the following prescription: (4 points) Rx Lidocaine HCl 1% (E=0.20) Pilocarpine HCl 0.5 % (E= 0.24) Boric acid qs (E=0.52) Purified water ad 60 mL Make isotonic solution Sig: 1 drop in each eye

Calculate the enthalpy of the reaction 4B(s)+3O2(g)→2B2O3(s) given the following pertinent information: B2O3(s)+3H2O(g)→3O2(g)+B2H6(g), ΔH∘A=+2035 kJ 2B(s)+3H2(g)→B2H6(g), ΔH∘B=+36 kJ H2(g)+12O2(g)→H2O(l), ΔH∘C=−285 kJ H2O(l)→H2O(g), ΔH∘D=+44 kJ

A 100.0 mL sample of 0.20 M HF is titrated with 0.10 M KOH. Determine the pH of the solution after the addition of 200.0 mL of KOH. The Ka of HF is 3.5 × 10-4.

Answer: 8.14 but how do I get this?? I'm so lost!

Consider the following reaction. It is occuring in a closed system and it is currently at equilibrium:

Label each of the following statements with is effect on the reaction
shift towards products or shift towards reactants or no change: Removing oxygen gas.
shift towards products or shift towards reactants or no change:  Cooling the reaction vessel.
shift towards products or shift towards reactants or no change:  Removing water vapor from the vessel.
  shift towards products or shift towards reactants or no change:  Increase the size of the vessel.
  shift towards products or shift towards reactants or no change:  Decrease the pressure on the reaction vessel

The ethyl mercaptan, C2H5SH, concentration in a mixture was determined by shaking a 1.534-g sample with 60.0 mL of 0.01293 M I2 in a tightly stoppered flask:

2C₂H₅SH + I₂ → 2C₂H₅SSC₂H₅ + 2I^- + 2H⁺

The excess I2 was back-titrated with 10.72 mL of 0.01425 M Na₂S₂O₃:

2S₂O₃^2- + I₂ → S₄O₆^2- + 2I^-

Calculate the percentage of C₂H₅SH (FM = 62.13 g/mol) in the mixture.

(a) 5.67% (b) 3.32% (c) 1.24% (d) 4.33%

(please show work)