Question

A laboratory technician needs to prepare 500 milliliters of a 2 M solution of sodium hydroxide (NaOH) in a flask. The flask has a volume of exactly 500 milliliters. Which quantity does the laboratory technician need to measure before making the solution? A. the mass of the solute B. the mass of the solvent C. the mass of the solution D. the mass of the flask

Answer 1

Answer:

$\huge {\mathbb{\pink{Hello!!}}}$

Explanation:

Answer : The laboratory technician need to measure before making the solution is the mass of the solute.

Explanation :

Given : Molarity of NaOH = 2 M = 2 mole/L

Volume of solution = 500 ml

Molar mass of NaOH = 40 g/mole

For making the solution, we need the mass of NaOH.

Molarity : It is defined as the number of moles of solute present in on liter of solution.

Formula used : M=\frac{w_1\times 1000}{M_1\times V_s}M=

M

1

×V

s

w

1

×1000

where,

M = molarity of the NaOH

w_1w

1

= mass of NaOH

M_1M

1

= molar mass of NaOH

V_sV

s

= volume of solution

Now put all the given values in this formula, we get the mass of NaOH.

2mole/L=\frac{w_1\times 1000}{(40g/mole)\times (500)L}2mole/L=

(40g/mole)×(500)L

w

1

×1000

w_1=40gw

1

=40g

Therefore, the mass of NaOH is 40 gram.

As we know the molarity of solute, volume of solution and molar mass of the solute. Hence, the laboratory technician will need to measure only mass of the solute before making the solution.!

#ʍɨss քɛʀʄɛċt❤tɦaռҡs !!!