Percent strength (% w/w) of a solution is defined as the amount of solute present in 100 g of the solution.
Given data:
Mass of the solute, potassium chloride = 62.5 g
Volume of water (solution) = 187.5 ml
We know that the density of water = 1 g/ml
Therefore, the mass corresponding to the given volume of water
= 187.5 ml * 1 g/1 ml = 187.5 g
We have a solution of 62.5 g of potassium chloride in 187.5 g water
Therefore, amount of solute in 100 g of water= 62.5 * 100/187.5 = 33.33
The percentage strength = 33.33 %
To solve for the absolute temperature, we assume ideal gas
behaviour so that we use the equation:
PV = nRT
or T = PV / nR
So calculating:
T = [6.6 atm * 0.40 L] / [(2.4g / 28g/mol) * 0.08205746 L
atm / mol K]
<span>T = 375.35 K</span>
The theoretical yield of Ca(OH)₂ : 42.032 g
<h3>Further explanation</h3>
Given
31.8 g of CaO
Required
The theoretical yield of Ca(OH)₂
Solution
Reaction
CaO + H₂O⇒Ca(OH)₂
mol CaO (MW=56 g/mol) :
= mass : MW
= 31.8 g : 56 g/mol
= 0.568
From equation, mol Ca(OH)₂ = mol CaO = 0.568
Mass Ca(OH)₂ (MW=74 g/mol) :
= 0.568 x 74
= 42.032 g
Answer:
N=3.05*10^-3g
Explanation:
Using Ln(No/N)=0.693/t½*t
Ln(No/N)=0.693/3*45
No/N=exp(10.396)
100/exp(10.396)=N
100/32695.7=N
N=3.05*10^-3g
