General Chemistry Answers

Calculate the molarity of a KF (aq) solution containing 116.2 g of KF in 3.00 L of solution? [1] 0.02585 M

[2] 0.667 M

[3] 38.7 M

[4] 58.1 M

[5] None of the above

What is the molarity of glacial acetic acid (CH3COOH, Mr = 60.05 g/mol) at 25°C given that the density of acetic acid at that temperature is 1.049 g/mL?

[1] 0.0174 M

[2] 0.057 M [3] 57.2 M

[4] 60.1 M

[5] None of the above

25.00 cm3 of a 0.7892 mol.dm-3 solution of potassium hydroxide is transferred to an empty 350.00 cm3 volumetric flask. This flask is made up to the mark with distilled water and then shaken well. The concentration of the potassium hydroxide in this second flask is:

[1] 0.01109 mol.dm-3

[2] 0.05637 mol.dm-3

[3] 0.7892 mol.dm-3

[4] 17.74 mol.dm-3

[5] None of the above.

If I prepare a solution by adding 25 mL of 2.0 M NaOH into a 500 mL volumetric flask, and filling the flask to the mark with water, what will the final concentration of the solution be? [1] 0.05 M

[2] 0.1 M

[3] 0.5 M

[4] 2.0 M

[5] 40.0 M 

Suppose that a solution is prepared by mixing 25 mL (0.22 mol, 16 g) of pentane (the solute) with 45 mL (0.34 mol, 30 g) of hexane (the solvent). If the volumes add on mixing,

What is the mole fraction of the pentane?

[1] 0.35

[2] 0.39

[3] 0.64

[4] 39%

[5] 64 % 

Suppose that a solution is prepared by mixing 25 mL (0.22 mol, 16 g) of pentane (the solute) with 45 mL (0.34 mol, 30 g) of hexane (the solvent). If the volumes add on mixing,

Calculate the molarity of the pentane?

[1] 3.1 mol/kg

[2] 7.3 mol/kg

[3] 3.1 mol/L

[4] 7.3 mol/L

[5] 45.8 mol/L

Suppose that a solution is prepared by mixing 25 mL (0.22 mol, 16 g) of pentane (the solute) with 45 mL (0.34 mol, 30 g) of hexane (the solvent). If the volumes add on mixing.

Calculate the molality of the pentane

[1] 3.1 mol/kg

[2] 4.8 mol/kg

[3] 7.3 mol/kg

[4] 3.1 mol/L

[5] 7.3 mol/L 

The value of a solution concentration unit that may change with temperature is

[1] molarity.

[2] mole fraction.

[3] molality.

[4] mole percentage.

[5] weight percentage.

Suppose that the actual moles of MgO produced was 0.5 mol, what is the percentage yield of MgO?

[1] 0.62%

[2] 1.2%

[3] 10%

[4] 25%

[5] 50%

Calculate how many moles of the excess reagent remain unreacted.

[1] 1 mol

[2] 2 mol

[3] 4 mol

[4] 5 mol

[5] No excess reagent remains unreacted