Answer:
0.36 M
Explanation:
Let's consider the following neutralization reaction.
HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)
25 mL of 0.83 M NaOH reacted. The moles of NaOH that reacted are:
0.025 L × 0.83 mol/L =0.021 mol
The molar ratio of NaOH to HCl is 1:1. The moles of HCl that reacted are 0.021 moles.
0.021 moles are contained in 58 mL of HCl. The molar concentration of HCl is:
M = 0.021 mol/0.058 L
M = 0.36 M
Answer:
<h2>118,438.5 moles</h2>
Explanation:
To find the number of moles in a substance given it's number of entities we use the formula

where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have

We have the final answer as
<h3>118,438.5 moles</h3>
Hope this helps you
Molality is a measure of concentration that relates the moles of solute to the kilograms of solvent, it is described by the following equation:

We are given the molality(2.50m) and kilograms of solvent(0.500kg), so we solve for moles of solute from the equation:


To make a 2.50molal NaOH solution would be needed 1.25moles of solute
Answer: 1.25 moles