Answer:
The pH of the sweater containing Hydrogen ion concentration
![[H^{+}]=1\times 10^{-8}](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D%3D1%5Ctimes%2010%5E%7B-8%7D)
is
<u>8</u>
<u></u>
Explanation:
pH = It is the negative logarithm of activity (concentration) of hydrogen ions.
pH = -log([H+])
Now, In the question the concentration of [H+] ions is :
use the relation:
pH = 8
Note : <em><u> 1 times 10 to the power of 8 must be" 1 times 10 to the power of -8"</u></em>
If the concentration is
![[H^{+}]=1\times 10^{8}](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D%3D1%5Ctimes%2010%5E%7B8%7D)
Then pH = -8 , which is not possible . So in that case the pH calculation is by other method
Answer:
Percent yield = 89.1%
Explanation:
Based on the equation:
Cl₂ + 2KI → 2KCl + I₂
<em>1 mole of Cl₂ reacts with 2 moles of KI to produce to moles of KCl</em>
<em />
To solve this quesiton we must find the moles of each reactant in order to find the limiting reactant. With the limiting reactant we can find the moles of KCl and the mass:
<em>Moles Cl₂:</em>
8x10²⁵ molecules * (1mol / 6.022x10²³ molecules) = 133 moles
<em>Moles KI -Molar mass: 166.0028g/mol-</em>
25g * (1mol / 166.0028g) = 0.15 moles
Here, clarely, the KI is the limiting reactant
As 2 moles of KI produce 2 moles of KCl, the moles of KCl produced are 0.15 moles. The theoretical mass is:
0.15 moles * (74.5513g / mol) =
11.2g KCl
Percent yield is: Actual yield (10.0g) / Theoretical yield (11.2g) * 100
<h3>Percent yield = 89.1%</h3>
Answer:
0.0025moles
Explanation:
Molarity of a solution (M) = number of moles (n) ÷ volume (V)
According to this question, to make 250 mL of a 0.01 M solution of CaCl, the following number of moles is needed:
Volume = 250mL = 250/1000 = 0.250Litres.
Using; molarity = n/V
0.01 = n/0.250
n = 0.0025
n = 2.5 × 10^-3 moles.
Answer: SO₂ + H₂O → HSO₃ ⁻ + H⁺
Justification:
1) Ionization means formation of ions.
2) Ions are species that are not neutral, they are charged, in virtue of having less or more electrons than protons.
3) Ionization may happen in different environments.
4) Ionic compunds, like Mg(OH)₂ dissociate into ions (ionize) in water. That is the example shown in the fourth option:
Mg(OH)₂ → Mg ²⁺ + 2OH⁻
5) How much a ionic compound dissociates in water (ionize) depends on the Ksp (product solubility constant) which measures the concentrations of the ions that can be in the solution.
6) The Ksp for Mg(OH)₂ is very low, meaning that it will slightly ionize.
7) SO₂ + H₂O forms H₂SO₄, which is a strong acid, meaning that it will ionize fully in water, into the ions HSO₃ ⁻ and H⁺, so the third option is a good example of ionization.
<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.
