Question

key A 0.150 M sodium chloride solution is referred to as a physiological saline solution because it has the same concentration of salts as normal human blood. Calculate the mass of solute needed to prepare 275.0 mL of a physiological saline solution.

Answer 1

Answer:

2.41065 grams

Explanation:

Here we have to apply molarity, particularly in reference to the equation molarity = moles of solute / volume. I would like to rewrite this formula, but with respect to the units - grams = moles / Liters,

We can use molarity to determine the number of moles. After doing so, we can determine the mass of the solute with respect to the formula moles = mass / molar mass. The molar mass of NaCl is 58.44 grams.

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275 mL = 0.275 L,

Number of Moles of NaCl = 0.150 * 0.275 = 0.04125 moles,

Mass = 0.04125 * 58.44 = 2.41065 grams,

Solution - Mass of NaCl = 2.41065 grams

Hope that helps!

Answer 2

Answer:

2.41g

Explanation:

Data obtained from the question include the following:

Molarity of NaCl = 0.150M

Volume = 275mL

Mass of NaCl =..?

Next, we shall determine the number of mole of NaCl in the solution. This is illustrated below:

Molarity of a solution is simply defined as the mole of solute per unit litre of the solution. Mathematically, the molarity is expressed as:

Molarity = mole /Volume

Molarity = 0.150M

Volume = 275mL = 275/1000 = 0.275L

Mole =..?

Molarity = mole /Volume

0.150 = mole /0.275

Cross multiply

Mole = 0.15 x 0.275

Mole = 0.04125 mole

Therefore, the number of mole of solute, NaCl in the solution is 0.04125 mole.

Finally, we shall convert 0.04125 mole of NaCl to farms. This is illustrated below:

Molar mass of NaCl =23 + 35.5 = 58.5g/mol

Mole of NaCl = 0.04125 mole

Mass of NaCl =..?

Mole = mass/molar mass

0.04125 = Mass /58.5

Cross multiply

Mass = 0.04125 x 58.5

Mass = 2.41g

Therefore, the mass of the solute, NaCl needed to prepare the solution is 2.41g