General Chemistry Answers

1. How many grams of Lactic acid (C₆H₁₀O₅) should be dissolved in 650g of cyclohexane (C₆H₁₂) to raise the boiling point to 84.91⁰C? The normal boiling point of cyclohexane is 81⁰C and its molal boiling point is 2.75 ⁰C/m.

1. You add 1 kg of ethylene glycol (C₂H₆O₂) antifreeze to 4500g of H₂O in your car’s radiator. What would be the freezing point of the solution?

1. A solution prepared by adding 10g of an unknown non-volatile, non-electrolyte solute to 150 g of water. The Boiling point of the solution is elevated by 0.433 ⁰C above the normal boiling point of the solvent. What is the molar mass of the unknown substance?

1. What is the vapor pressure of the pure solvent if the vapor pressure of a solution of 15g sucrose (C₁₂H₂₂O₁₁) in 100g of ethanol (C₂H₅OH) is 58 mmHg?

1.  mL of nitric acid, HNO₃, are required to react with 50 mL of a 1.25 M Barium hydroxide, Ba(OH)₂ solution:

2 HNO_3 (aq)           +      Ba(OH)_{2 (aq)} -->    2 H₂O _(aq)    +      Ba(NO₃)_{2 (aq)}

Determine the concentration (Molarity) of the nitric acid solution (HNO₃).

1. How many mL of 0.250 M barium nitrate are required to precipitate as barium sulfate all the sulfate ions from 50 mL of 0.350 M aluminum sulfate?

3 Ba(NO₃)_{2 (aq)}           +       Al₂(SO₄)_3 (aq)     -->   3 BaSO_{4 (s)}  + 2 Al(NO₃)_{3 (aq)}

Hydrogen peroxide (H₂O₂) is a powerful oxidizing agent used in concentrated solution in rocket fuels and in diluted solutions is hair bleach. An Aqueous solution of 25% (m/m) has a density of 1.05 g/ml. Calculate the concentration in terms of:

n ethanol solution is prepared by dissolving 15 mL of ethanol (C₂H₅OH) (density: 0.850 g/ml) in a sufficient volume of water to produce 120 mL of solution with a density of 0.980 g/mL. What is the concentration of ethanol in this solution expressed as:

Phosphoric acid (H_{3}*P * O_{4}) can be prepared from phosphorus triiodide (P*l_{3}) according to the reaction:

PI 3 (s)+H 2 O(l) H 3 PO 4 (aq)+HI(g)

Balance the equation. If 150 grams of Pl_3 ( MM=411.7 g/mol) is added to 250 milliliters og H 2 O(MM=18.01 g / mol , rho=1.00 g mL ) identify the limiting and excess reagents. How many grams of H3PO4 (MM=97.99 g / mol ) will be theoretically produced?

The neutralization reaction between hydrochloric acid (HCI) and calcium hydroxide [Ca(OH) 2 ] produces calcium chloride (CaCl_{2}) and water.

2HCl(aq) + Ca(OH)₂(s) → 2H₂O(l) + CaCl₂(aq)

If 0.75 grams of Ca(OH) 2 is used in the reaction, determine the following:

a.) number of moles of HCI(MM = 36.46 g/mol) needed to completely react with Ca(OH) 2 . The molar mass of Ca(OH) 2 is 74.10 g/mol.

b.) mass of CaCl₂ (MM 110.98 g/mol) formed in the reaction.