Answer:
Molality = 7.5 mol/kg
Explanation:
Given data:
Mass of NH₄Cl = 6.30 g
Mass of water = 15.7 g (15.7/1000 =0.016 kg)
Molality = ?
Solution:
Formula of molality:
Molality = Moles of solute / mass of solvent in gram
Now we will first calculate the number of moles of solute( NH₄Cl )
Number of moles = mass/ molar mass
Molar mass of NH₄Cl = 53.491 g/mol
Number of moles = 6.30 g/ 53.491 g/mol
Number of moles = 0.12 mol
Now we will calculate the molality.
Molality = Moles of solute / mass of solvent in gram
Molality = 0.12 mol / 0.016 kg
Molality = 7.5 m
or (m=mol/kg)
Molality = 7.5 mol/kg
The strong Base with a pH of 12 is reduced by 4 units upon being added with solution Y. If you added a strong acid to the strong base, all ions are present in the solution, yes? So every OH- is neutralised by every H+ for example, meaning the resultant pH should be 7. The resultant pH is only 8 however, so solution Y must be a <em>weak acid </em>only!
Delta T= T final - T initial
Tfinal= -101.1 °C
Tinitial= -0.5 °C
•Delta T = -101.1°C - (-0.5°C)
=100.6°C
Kelvin= °C + 273
= -100.6 + 273
= 172.4 Kelvin
Answer: 0.174 g
Explanation:
First of all understand that charge on an atom like here 2+ will not vary molar mass. because ions are formed by loss or gain of electrons and electrons do not contribute to the mass of an atom or ion. so losing or gaining electron doesnt create any difference.
molar mass of Fe, i.e. mass of 1 mole of Fe is 56 g. So, mass of 1 mole of Fe2+ will also be 56 g.
given is 0.003109 moles of Fe2+,
Use maths,
1 mole of Fe2+ weighs 56 g
So, 0.003109 moles will weigh = (56 g / 1 mol ) x 0.003109 = 0.174 g.
