how many grams of NAOH are needed to make a 2.00 molal solution?
I got stuck here
2.00 molal=2.00 mole/kg
molecular weight of NAOH= 40g/mol
(2.00 g/molecular weight x kg) x 40 g/mol= stuck
thanks jim
You cant answer the question without knowing the amount of the 2m solution you need.
molality=molessolute/kgsolvent
molessolute=molalitiy*kgsovent
masssolute=molmassSolute*molality*kgsolvent
masssolute=40*2*kgsolvent
Doesn't it depend upon the amount of water you intend to use or the amount of solution one needs? (It does.)
So molal = # moles/kg solvent.
If you want 1 kg solvent, one needs 2.00 moles and that is 40.0 g. So 40.0 g NaOH/1.00 kg water makes a 2.00 m solution.
damn i never thought of kg of solution. your so smart.
2.00mol x 40 g/m= 80grams dissolved in water. so 80 grams of solute and 1000 water.
Chemistry doesnt make sense too me sometimes. Im use to thinking water =ml. But kg can be a solution too if you weigh it on an analytical balance.
Can help me learn to volumetric pipette. I can\t seem to control the water with my finger. It always goes over line. Very fustrating to start over and over.
To find out how many grams of NaOH are needed to make a 2.00 molal solution, you need to use the equation:
molality (m) = moles of solute (n) / mass of solvent in kilograms (kg)
First, you already know that the molality (m) is equal to 2.00 molal.
Next, you need to convert the molality to moles of solute (NaOH) per kilogram (kg) of solvent.
Since molality is defined as moles of solute per kilogram of solvent, you can rearrange the equation to solve for moles of solute:
moles of solute (n) = molality (m) * mass of solvent in kilograms (kg)
Therefore,
moles of solute (NaOH) = 2.00 molal * kg
Now, you also know the molecular weight (MW) of NaOH is 40 g/mol.
To convert the moles of NaOH to grams, you can use the equation:
mass (g) = moles of solute (n) * molecular weight (MW)
Therefore,
mass of NaOH (g) = moles of solute (NaOH) * molecular weight (40 g/mol)
Now you can substitute the known values into the equation:
mass of NaOH (g) = (2.00 molal * kg) * (40 g/mol)
To continue, you need to know the mass of the solvent in kilograms (kg). Assuming you have that information, you can substitute it into the equation.
For example, if the mass of the solvent is 1 kg, you would have:
mass of NaOH (g) = (2.00 molal * 1 kg) * (40 g/mol)
mass of NaOH (g) = 80 g
Therefore, to make a 2.00 molal solution, you would need 80 grams of NaOH.
Please note that if you have a different mass of the solvent, you should substitute that value instead.