<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:
option C is correct = 1.14 × 10²² molecules of CO₂
Explanation:
Given data:
Number of moles of CO₂ = 0.0189 mol
Number of molecules = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
For given question:
1 mole of CO₂ = 6.022 × 10²³ molecules of CO₂
0.0189 mol of CO₂ × 6.022 × 10²³ molecules of CO₂ / 1mol
1.14 × 10²² molecules of CO₂
Thus, option C is correct.
Answer:
35
Explanation:
because it's is still the same amount even if you freeze it
Answer:
NH3 has greater water solubility due to intermoleculate interactions
Explanation:
Hi:
If we represent the structures of NH3 and SbH3 we can see that they are similar to the naked eye, this is because N and Sb belong to the same group of the periodic table (group 15).
However, the electronegativity of N is greater than that of Sb. The NH3 molecule is polar and can form an intermolecular interaction called hydrogen bridge with water.
Sb is less electronegative than N. The SBH3 molecule forms an intermolecular interaction with water called dipole-induced dipole.
The zone with positive charge density of the water molecule (hydrogens) is oriented towards the zone with positive charge density of SBH3 (the pair of electrons not shared)
Stronger intermolecular junctions allow greater solubility of NH3 molecules.
Successes in your homework
D. Sublimation is a solid turning directly into a gas
