Question

A student dissolves 9.4 g of resveratrol (C14H12O3) in 450. mL of solvent with a density of 0.85g/mL. The student notices that the volume does not change when the resveratrol dissolves in it. Calculate the molarity and molarity of the students solution. Round answer to 2 significant digits

Answer #1

A student dissolves 3.7g of biphenyl C12H10 in 500.mL of a
solvent with a density of 0.91/gmL. The student notices that the
volume of the solvent does not change when the biphenyl dissolves
in it. Calculate the molarity and molality of the student's
solution. Be sure each of your answer entries has the correct
number of significant digits.

A chemistry graduate student is given 450.mL of a 1.20M ammonia
NH3 solution. Ammonia is a weak base with Kb=1.8x10^−5.
What mass of NH4Cl should the student dissolve in the NH3
solution to turn it into a buffer with pH =9.40?
You may assume that the volume of the solution doesn't change
when the NH4Cl is dissolved in it. Be sure your answer has a unit
symbol, and round it to 2 significant digits.

A chemistry graduate student is given 450.mL of a 0.90M acetic
acid HCH3CO2 solution. Acetic acid is a weak acid with
Ka=1.8x10^−5.
What mass of KCH3CO2 should the student dissolve in the HCH3CO2
solution to turn it into a buffer with pH =4.35?
You may assume that the volume of the solution doesn't change
when the KCH3CO2 is dissolved in it.
Be sure your answer has a unit symbol, and round it to 2
significant digits.

A student dissolves 5.00 g calcium hydroxide to make 100.0 mL of
solution. If 63.5 mL of this solution is required to neutralize
150.0 mL of a hydrofluoric acid solution, what is the concentration
of the original HF solution? (The molar mass of Ca(OH)2 is 74.10
g/mol.)
I need help with this asap please.

The density of a 40 wt% solution of ethanol in water is 0.937
g/mL. The density of n-butanol is 0.810 g/mL. What is the
concentration of n-butanol in ppm if you dissolve 15 μL of this
alcohol in a 40 wt% solution of Ethanol in water. The final volume
of the solution is 25 mL. Assume that the density of the ethanol
solution does not change upon dissolution of the butanol. Use the
correct number of significant figures!

Suppose 3.10g of sodium iodide is dissolved in 250.mL of a
73.0mM aqueous solution of silver nitrate. Calculate the final
molarity of iodide anion in the solution. You can assume the volume
of the solution doesn't change when the sodium iodide is dissolved
in it. Round your answer to 2 significant digits.

A student dissolves 0.326 g of a powdered antacid in 32.36 mL of
0.1034 M HCl. The student boils the mixture and then allows it to
cool. Lastly, the student adds phenolphthalein indicator to the
mixture.
Suppose 11.72 mL of 0.1506 M NaOH is required to turn the
solution from colorless to pale pink. Calculate the total moles of
OH- added.

Suppose 0.829g of ammonium iodide is dissolved in 250.mL of a
30.0mM aqueous solution of potassium carbonate.
Calculate the final molarity of iodide anion in the solution.
You can assume the volume of the solution doesn't change when the
ammonium iodide is dissolved in it.
Round your answer to 3 significant digits.

Suppose
1.87g
of ammonium iodide is dissolved in
300.mL
of a
45.0mM
aqueous solution of potassium carbonate.
Calculate the final molarity of ammonium cation in the solution.
You can assume the volume of the solution doesn't change when the
ammonium iodide is dissolved in it.
Round your answer to
3
significant digits.

A chemistry student weighs out 0.0432 g of formic acid (HCHO2)
into a 250 mL volumetric flask and dilutes to the mark with
distilled water. He plans to titrate the acid with 0.0700
M NaOH solution. Calculate the volume of NaOH solution
that the student will need to add to reach the equivlence point. Be
sure your answer has the correct number of significant digits.

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