Questions
what's the effect of change in mobile phase flow rate in HPLC and the effect of...

what's the effect of change in mobile phase flow rate in HPLC

and the effect of change of injection volume in HPLC?

In: Chemistry

Find the identity of a solid, weak acid, HY. The following information is obtained a) Write...

Find the identity of a solid, weak acid, HY. The following information is obtained a) Write the dissociation equation for HY in water and its equilibrium expression (Ka). b) A sample of 0.2702 g of HY is titrated and found to require 30.00 mL of 0.10 M KOH solution to reach the equivalence point. Calculate the molar mass of HY c) After 6.00 mL of the base is added, the pH of the solution is 3.25. What is the value for Ka of HY? d) At the equivalence point of the reaction, will the solution be acidic, basic, or neutral? Justify your answer. e) What is the identity of the acid (HY)

In: Chemistry

GRIGNARD REACTION: Precise mass (in grams) of the bromobenzene used: .21g Precise mass (in grams) of...

GRIGNARD REACTION:

Precise mass (in grams) of the bromobenzene used: .21g

Precise mass (in grams) of the magnesium used: .054g

Precise mass (in grams) of the benzophenone used: .350g

Precise mass (in grams) of the product: .011g

What is the percent yield? (show all calculations)

In: Chemistry

For my chemistry final, we're identifying 5 unknowns, one acid, one base, one chloride salt, one...

For my chemistry final, we're identifying 5 unknowns, one acid, one base, one chloride salt, one nitrate salt, and one sodium salt . On the list of possible unknowns, there are:
three acids (HCl, HNO3, or HSO4)
three bases (NaOH, NH3, or NaS)
three chloride salts (NaCl, BaCl, or CuCl)
three nitrate salts (AgNO3, Cu(NO3)2, or Fe(NO3)3
three sodium salts (NaI, Na2SO4, or Na2CO3)

We will be given 5 test tubes each containing one of the substances from each category above. If anyone could provide a flowchart and/or explaination (IN Steps) on how I could identify each unknown category, please help???

Please dont give me this answer https://answers.yahoo.com/question/index?qid=20140527021948AAsGNL8
i copy and paste my question from there, I wanted another insight unless there's no other way other than that way?

In: Chemistry

Phosphoric acid, H3PO4(aq), is a triprotic acid, meaning that one molecule of the acid has three...

Phosphoric acid, H3PO4(aq), is a triprotic acid, meaning that one molecule of the acid has three acidic protons. Estimate the pH, and the concentrations of all species in a 0.500 M phosphoric acid solution.

pKa1= 2.16 pKa2=7.21 pKa3= 12.32

What's: H3PO4, H2PO4-, HPO4-2, PO4-3, H, OH, and pH

-Thanks!

In: Chemistry

For a monochromator with a 0.540 meter focal length equipped with a 2200 gr/mm grating that...

For a monochromator with a 0.540 meter focal length equipped with a 2200 gr/mm grating that measures 100m x 100m

(a) Calculate first order reciprocal linear dispersion

(b) A substance has two emission lines at 2024.41 angstrom and 2024.81; is it theoretically possible to just resolve these spectral features using the grating described?

(c) If a 25 micrometer entrance and exit slits are used in order to have sufficient light throughput for a detectable signal, is it possible to baseline resolve the two spectral lines

In: Chemistry

You have 500.0 mL of a buffer solution containing 0.20 M acetic acid and 0.30 M...

You have 500.0 mL of a buffer solution containing 0.20 M acetic acid and 0.30 M sodium acetate. What will the pH of the solution be after the addition of 20.0 mL of 1.00 M NaOH solution. Ka (CH3COOH) = 1.8x105

Please answer the question using ICE tables, I am unsure of whether to use 1 ICE table or 2 ICE Tables. Thank you.

In: Chemistry

Cyclohexane has a freezing point of 6.50 ∘C and a Kf of 20.0 ∘C/m. What is...

Cyclohexane has a freezing point of 6.50 ∘C and a Kf of 20.0 ∘C/m. What is the freezing point of a solution made by dissolving 0.771 g of biphenyl (C12H10) in 25.0 g of cyclohexane?

In: Chemistry

Would we expect that the co-polymer produced by anionic polymerization of butadiene and styrene to be...

Would we expect that the co-polymer produced by anionic polymerization of butadiene and styrene to be easily cross-linked? Yes or No and please explain why

In: Chemistry

7. (8%) How to dispense one liter of 3 M HCl solution if you have a...

7. (8%) How to dispense one liter of 3 M HCl solution if you have a bottle of HCl that you find in the chemical stores? The bottle contains the following information: “37% w / w HCl (aq), density: 1.19 kg / L, molecular weight of HCl = 36.5 g / mol. ”

In: Chemistry

The half-life of cesium-137, released as a result of the Fukushima Daiichi nuclear disaster, is 30.2...

The half-life of cesium-137, released as a result of the Fukushima Daiichi nuclear disaster, is 30.2 years. Determine the number of years it would take for the amount of cesium-137 to decrease to 7 % of the original amount released in the disaster. Round your answer to the nearest number of years.

In: Chemistry

A 50.0 mL solution of 0.199 M KOH is titrated with 0.398 M HCl. Calculate the...

A 50.0 mL solution of 0.199 M KOH is titrated with 0.398 M HCl. Calculate the pH of the solution after the addition of the following amounts of HCl.

a) 0.00 mL HCl
b) 7.00 mL HCl
c) 12.5 mL HCl
d) 20.0 mL HCl

In: Chemistry

A. What is the ? (alpha)- helical dipole and what is the molecular origin of that...

A. What is the ? (alpha)- helical dipole and what is the molecular origin of that dipole?

B. Identify two amino acids that are preferred in ? (beta)- sheets. Why might these amino acids be preferred?

C. Peptide bonds are believed to by hydrated by three water molecules, with one hydrogen bond donated from the N-H and two hydrogen bonds being accepted by the lone pairs of electrons in the carbonyl group. Would you expect a significant entropic component to be associated with the formation of secondary structures like alpha-helicies and beta-sheets. Explain.

In: Chemistry

How much of each of the solutions is needed to make the buffer? Final volume is...

How much of each of the solutions is needed to make the buffer? Final volume is 10 mL.

stock solutions

1 M HEPES (pH 7.9)

5 M NaCl

1 M BME

100 mM EDTA

750 mM MgCl2

50% glycerol

C) nuclear extraction buffer

20 mM HEPES

1 M NaCl

1 mM BME

0.5 mM EDTA

1.5 mM MgCl2

25% glycerol

In: Chemistry

Two moles of nitrogen gas at 25°C, confined within a cylinder by a piston maintaining a...

Two moles of nitrogen gas at 25°C, confined within a cylinder by a piston maintaining a constant pressure of 1 atm, is heated with 5.30 kJ of energy. Assume all the energy is used to do work of expansion of the gas at 1 atm. What will be the final temperature of the gas? Recall ∆H = ∆E + P∆V and watch your units!

In: Chemistry