General Chemistry Answers

You will often see athletes being treated with disposable cold packs if they injure themselves in an event. These cold packs contain water and ammonium nitrate. Ammonium nitrate has an enthalpy of solution of 25.7 kJ/Mol. Determine the temperature change of solution if 45.0g of ammonium nitrate is dissolved in 150ml of water, and thus the temperature of the cold pack if it's initial temperature is 20.0oC. Assume that the specific heat of the solution is the same as water 4.186.

Assume that after you made your measurements, you realized that your solid rod had a nick in the side and a portion was missing. When comparing the density that would be calculated using the ruler method with the result of the displacement method of the rod, would the calculated density for the ruler method be higher, lower or the same as the water displacement density? Explain.

concentration if 34.50 mL of the acid is required to neutralise 25.0 mL of a solution of 0.150 M sodium carbonate solution.

How many moles of methane in a 2.5 L sample of liquid methane?

Calculate the joules released when 155 g

g of steam condenses at 100 

∘

C

∘C and the liquid cools to 15.0 

∘

C

∘C .

The electrolyte in automobile lead batteries is a 4.04 M sulfuric acid (H ₂SO ₄) solution. Calculate the mass percent of solute if the density of the solution is 1.161 g/mL. Express final answer in two decimal places.

(With Solution)

1.A 100 mL solution contains 5.7g MgCl2(MM = 94 g/mol). The density of the solution is 1.03 g/mL. Express the concentration in:

a.% by mass

b.Molarity

2.A 68.8 g H2SO4(MM = 98 g/mol) is added to H2O to make a 500 mL solution. If the density of the solution is 1.2 g/mL, calculate the molality.