The mole fraction of KCl in the solution is 0.1051
calculation
mole fraction of KCl in solution = moles of KCl / total number of moles(moles of KCl +moles of H2O)
moles=mass/molar mass
mass of KCl=32.7g
molar mass of KCl= 39 +35.5
moles of KCl is therefore= 32.7g/74.5 g/mol=0.439 moles
find the moles of H2O= mass of H2O/molar mass
mass of H2O=100-32.7=67.3g
molar mass of H2O=( 1 x2) +16=18 g/mol
moles = 67.3/18 =3.739 moles
total moles=3.739+0.439=4.178 moles
mole fraction is therefore=0.439/4.178=0.1051
Answer:
81 °C
Explanation:
This is a calorimetry question so a few things you will need for this. The calorimetry equation q=mcΔT & the specific heat of water (4.2J/g•°C). Other definitions are:
q = heat added/released by a sample
m = mass of sample
c=specific heat of sample
ΔT = change in temperature
from here we can rearrange the equation to state:
q/(mc) = ΔT
1200J/((20.0g)(4.2J/g•°C)) = ΔT
14°C = ΔT
If the starting temperature was 95.0°C and we know that the temperature was cooled by 14°C then the final temperature of the water would be 81.
The option that distinguishes a nuclear reaction from a chemical reaction is D. there is a change in the nucleus.
During a nuclear reaction, two light nuclei combine in order to create a new, heavier one which is different than those two original ones and has additional particles that it didn't have originally. This is what makes the difference between these two reactions.
Answer:
a) 1,6%
b) 64,775 g/mol
c) 3,6×10⁻² M
d) 2,3×10⁻³ g/mL
Explanation:
a) The mass fractium of helium is obtained converting the moles of the four gases to grams with molar weight and then caculating of the total of grams how many are of helium, thus:
- Helium: 0,25 moles ×
= 1 g of Helium - Argon: 0,25 moles ×
= 10 g of Argon - Krypton: 0,25 moles ×
= 20,95 g of krypton - Xenon: 0,25 moles ×
= 32,825 g of Xenon
Total grams: 1g+10g+20,85g+30,825g= 62,675 g
Mass fraction of helium:
× 100 = <em>1,6%</em>
<em />
<em>The mass fraction of Helium is 1,6%</em>
<em />
<em>b)</em><em> </em>Because the mole fraction of all gases is the same the average molecular weight of the mixture is:
= 64,775 g/mol
c) The molar concentration is possible to know ussing ideal gas law, thus:
= M
Where:
P is pressure: 150 kPa
R is gas constant: 8,3145![\frac{L.kPa}{K.mol}](https://tex.z-dn.net/?f=%5Cfrac%7BL.kPa%7D%7BK.mol%7D)
T is temperature: 500 K
And M is molar concentration. Replacing:
M = 3,6×10⁻² M
d) The mass density is possible to know converting the moles of molarity to grams with average molecular weight and liters to mililiters, thus:
3,6×10⁻²
×
×
=
2,3×10⁻³ g/mL
I hope it helps!
Answer:
hydrated ferric oxide is ferric hydoxide sol and is positively charged. When aqueous solution of NaCl is added to it,the Cl- ions neutralise the positive charge on the sol particles. In the absence of charge, brown precipitate is formes due to colloids can be coagulation of particles.Nov 11, 2020
Explanation: hope this help