What is the molality of a 0.9 NaCl solution?

With this molality calculator you can quickly calculate the molality - one way of measuring the concentration of a solute in a solution (not to be confused with molarity). Simply type the number of moles of your solute substance and mass of the solvent and the tool will calculate the molality. If you don't know how many moles of a substrate you have, use the advanced mode to calculate it with the use of mass and molar mass of the compound. Are you still unsure what's the molality definition, its units and formula - or simply how to calculate molality step by step? Keep reading and you'll find the answer!

Molality, also called molal concentration, is defined as the amount of substance of solute, divided by the mass of the solvent m solvent:

Molality = nsolute / m solvent = msolute / (W solute * m solvent)

where

• nsolute is amount of the solute (in moles)
• msolvent is a mass of the solvent (in kg)
• msolute is a mass of the solute (in g)
• W solute is a molar mass of the solute (in g/mol).

The molality unit from SI system is mol/kg, sometimes the name molal is used (though it's considered obsolete).

Molality plays a significant role in calculating the ionic strength of a solution.

Molarity and molality are similar concepts - both are measures of the concentration of a solution. However, there is one main difference between those terms: molarity is expressed as the amount of substance per unit volume of solution, whereas molality defines the concentration as the amount of substance per unit mass of the solvent.

We've put all most important differences between those two terms into a short molarity vs molality table:

To change between molarity and molality you can use the following relation:

M = m * d / (1 + (m * W))

where

• M - molarity
• m - molality
• W - molar mass of the solute
• d - mass density of the solution

Let's show on the example how to calculate molality:

1. Choose your substance. Let's assume it's table salt - sodium chloride (NaCl).
2. Calculate its molar mass. For sodium chloride it's equal to 58.44 g/mol (as Na = 22.99 g/mol and Cl = 35.45 g/mol).
3. Convert grams to moles. Use the formula moles = mass of solute / molar mass. Assume we want to dissolve 70.128 grams of salt in 1.5 kg of water. so moles NaCl = 70.128 g / (58.44 g/mol) = 1.2 mol.
4. Plug moles value and the mass of the solvent into the molality formula. Divide 1.2 mol by 1.5 kg, and you'll find out that the molality of the NaCl solution is 0.8 molal (in standard molality units: 0.8 mol/kg).
5. Or save yourself some time and use our molality calculator (choose an advance mode to enter also the molar mass and solute mass).

As you know, molarity is defined as moles of solute, which in your case is sodium chloride, #"NaCl"#, divided by liters of solution.

Now, a weight by volume percent concentration is defined as mass of solute per volume of solution. In this case, a #"0.90%w/v"# saline solution will contain #"0.9 g"# of sodium chloride for every #"100 mL"# of solution.

Now, since molarity is determined by liters of solution, it's easier to take a #"1.00-L"# sample of this saline solution and figure out how many moles of sodium chloride it contains.

Since you know that #"1.00 L"# of saline solution contains #"9.000 g"# of sodium chloride, use the compound's molar mass to determine how many moles you have

#9.000color(red)(cancel(color(black)("g NaCl"))) * "1 mole NaCl"/(58.44color(red)(cancel(color(black)("g NaCl")))) = "0.154 moles NaCl"#

This means that the sample's molarity will be

#c = n/V#

#c = "0.154 moles"/"1.00 L" = color(green)("0.154 M")#

I'll leave the answer rounded to three sig figs, despite the fact that you only have two sig figs for the percent concentration of the solution.

SIDE NOTE The result must be exactly the same regardless of the volume sample you pick for the solution. I recommend using different volume samples to test this out.

0.15 M
For example, 0.9% NaCl contains 0.9 g NaCl per 100 ml of solution or 9 g NaCl/l. This can be converted to molarity by dividing by molecular weight: 0.9% NaCl = (9g/l)/(58.5g/mole) = 0.15 M NaCl.

What is the molarity of 9.8 moles of NaCl in 1 liter?

Here n=9.8 moles, v = 3.62 L — so, molarity is 9.8/3.62=2.7 mol/L.

What is the molarity and osmolarity of a 0.9 NaCl solution?

So in our example, the osmolarity of the 0.9% NaCl solution is 0.15M * 2 = 0.3 Osm.

What is the molarity of a 1.0 solution of sodium chloride?

Molarity (M) is defined as the number of moles of solute divided by the number of LITERS of solution. FOR EXAMPLE: 1.0 mole of sodium chloride, added to enough water to make 1.0 liter of solution, produces a 1.0 M solution of sodium chloride.

How do you calculate molarity and osmolarity?

Multiply the number of particles produced from dissolving the solution in water by the molarity to find the osmolarity (osmol). For instance, if your have a 1 mol solution of MgCl2: 1 x 3 = 3 osmol. Repeat multiplying the molarity by the number of particles for the other solution to find the osmolarity.

How do you find the molarity?

To calculate the molarity of a solution, you divide the moles of solute by the volume of the solution expressed in liters. Note that the volume is in liters of solution and not liters of solvent. When a molarity is reported, the unit is the symbol M and is read as “molar”.

How to calculate the molarity of sodium chloride?

Calculate molar concentration (molarity) of 0.9% (weight/ volume) sodium chloride (NaCl) solution. 0.9% = 0.9 grams/ 100 ml solution. 0.9% = 9 grams/ 1000 ml solution = 9 g/ liter. Molar mass ( molecular weight ) of sodium chloride = 58.44 g/ mole. Number of moles = 9 g/ (58.44 g/ mole) = 0.15 mole.

How to make a 0.9% solution of NaCl?

What is the molarity of a 0.9% solution of sodium chloride? 1 Dissolve 9 g NaCl (mw 58.44) in 700 ml deionized or distilled water in clean container. 2 Add water to bring total solution volume to 1000 ml. 3 Make 10 ml aliquots in sterile 15 ml culture tubes.

How is the molar concentration of a solute measured?

This is the same with molar concentration and represents the concentration of a solute in a solution. It is defined as the number of moles in a solution. Unit of measurement : SI: [mol/L] The concentration may also be expressed in different fractions of the molar concentration such as mmol/L (mM), μmol/L (μM), nmol/L (nM), pmol/L (pM).

How to calculate the molar mass of a compound?

To convert grams to moles, the molecular weight of the solute is needed. From the periodic table the molar masses of the compounds will be extracted. For KMnO4: What other calculations you can do with the molarity calculator? Mass (g) = Concentration (mol/L) x Volume (L) x Molecular Weight (g/mol)

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