<span>The student should
follow following steps to make 1 L of </span>2.0 M CaCl₂.<span>
<span>
1. First he should
calculate the number of moles of 2.0 M CaCl</span></span>₂ in 1 L solution.<span>
</span>Molarity of the solution = 2.0 M<span>
Volume of solution which should be prepared = 1 L
Molarity =
number of moles / volume of the solution
Hence, number of moles in 1 L = 2 mol
2. Find
out the mass of dry CaCl</span>₂ in 2 moles.<span>
moles =
mass / molar mass
Moles of CaCl₂ =
2 mol</span><span>
Molar mass of CaCl₂ = </span><span>110.98 g/mol
Hence, mass of CaCl</span>₂ = 2 mol x <span>110.98 g/mol
= 221.96
g
3. Weigh the mass
accurately
4. Then take a cleaned and dry1 L volumetric flask and place a funnel top of it. Then carefully add the salt into the volumetric flask and
finally wash the funnel and watch glass
with de-ionized water. That water also should be added into the volumetric
flask.
5. Then add some
de-ionized water into
the volumetric flask and swirl well until all salt are
dissolved.
<span>6. Then top up to
mark of the volumetric flask carefully.
</span></span>
7. As the final step prepared solution should be labelled.
Answer:
it is necessary to keep our sense organ clean and healthy for if don't clean our sense organ clean we may suffer from many disease like if we don't clean eyes we can't see anything, if we don't clean ear we can't listen anything, and if we don't clean nose it hard for breathing, and if we don't cleanour tounge should be dry and become our breathe smell is very bad, and if we don't clean skin we may suffer from many disease and that may we get cancer also.
I believe it would weigh less if it’s blown up with helium because helium is lighter than air
The volume of a 6.67 m nacl solution
that contains 3.12 mol nacl is 0.468.
You just need to follow this formula:
C = n / V
So, it will be
V = n / C
<span> = 3.12 / 6.67 moles / Liter </span>
<span> = 0.468 L</span>
Answer:
There is 2.52 kJ of energy released (option 4)
Explanation:
Step 1: Data given
The enthalpy of fusion of methanol (CH3OH) is 3.16 kJ/mol
Mass of methanol = 25.6 grams
Molar mass of methanol = 32.04 g/mol
Step 2: Calculate moles of methanol
Moles methanol = mass methanol / molar mass methanol
Moles methanol = 25.6 grams / 32.04 g/mol
Moles methanol = 0.799 moles
Step 3: Calculate energy transfer
Energy transfer = moles * enthalpy of fusion
Energy = 0.799 moles * 3.16 kJ/mol
Energy = 2.52 kJ released
There is 2.52 kJ of energy released
