CHEM 1211L Lab Manual-Page 105 Quantitative Chemical Reactions Pre-Lab Exercises
ID: 229411 • Letter: C
Question
CHEM 1211L Lab Manual-Page 105 Quantitative Chemical Reactions Pre-Lab Exercises 1) Define the term Molarity- mel untyisthe Cnectber oF Selutie 2) What is the chemical definition of a solution. 3) On what page are the solubility rules located in your textbook. 4) Calculate the mass of calcium chloride dihydrate needed to make 250.0-mL of a 1.25 M solution. 5) The formula for calculating a dilution of a solution is M1V1-M2V2, use this equation to calculate the volume of a 2.0 M solution of sodium carbonate required to make 100 mL of a 0.25 M solution.Explanation / Answer
1. Molarity
Molarity is defined as numbe of moles of solute is dissolved in one litre of the solution.
Molarity = number of moles of solute/volume in L
but number of moles of solute= mass of solute/molar mass of solute
Molarity = mass of solute/molar mass of solute x1000/volume in ml
2)
solution is defined as a homogeneous mixture of two or more components.
The two components are present in a solution is called binary solution.
In a binary solution , one component is called as solute and another one is called as solvent'
In a solution, the substance which is present in less quantity is called solute , and large quantity is called as solvent.
for example , NaCl is dissolved in water to form Nacl solution. In this NaCl is a solute and Water as a solvent
4.)
volume = 250.0ml
Molarity = 1.25M
molar mass of CaCL2.2H2O = 147.0 gram/mole
Molarity = mass of solute /molar mass x1000/ V ml
mass of solute = Molarity x molar mass x Vml/1000
Mass of solute = 1.25 x147.0x250.0/1000 = 45.94
Mass of solute = 45.94 grams.
5.
Initial final
M1= 0.25M M2= 2.0M
V1= 100 ml V2=
M1V1=M2V2
V2= M1V1/M2= 0.25 x100/2.0 = 12.5 ml
volume = 12.5 ml