Answer:
Dissolve 226 g of KCl in enough water to make 1.5 L of solution
Explanation:
1. Calculate the moles of KCl needed

2. Calculate the mass of KCl

3. Prepare the solution
- Measure out 224 g of KCl.
- Dissolve the KCl in a few hundred millilitres of distilled water.
- Add enough water to make 1.5 L of solution.
Mix thoroughly to get a uniform solution.
Your question is incomplete. However, I found a similar problem fromanother website as shown in the attached picture.
To solve this problem, you must know that at STP, the volume for any gas is 22.4 L/mol. So,
Moles O₂: 156.8 mL * 1 L/1000 mL* 1 mol/22.4 L = 0.007 moles
Mass calcium: 0.007 mol O₂ * 2 mol Ca/1 mol O₂ * 40 g/mol Ca =
<em> 0.56 g Ca</em>
Answer:
2
3
Explanation:
To infer the last energy of the given atoms, we need to write their electronic configuration:
For N = 1S² 2S² 2P³
Mg = 1S² 2S² 2P⁶ 3S²
The energy levels are usually designated as;
n = 1
n = 2
n = 3
n =4
For N, the last energy level is 2
Mg, the last energy level is 3
We can also determine this number by the periods the atoms can be found.
7.86 is the pOH of water at this temperature of 100 degrees celsius.
Option E is the right answer.
Explanation:
Data given:
Kw = 51.3 x 
pOH = ?
we know that pure water is neutral and will have pH pf 7.
The equation for relation between Kw and H+ and OH- ion is given by:
Kw = [H+] [OH-}
here the concentration of H+ ion and OH- ion is equal
so, [H+]= [OH-]
Putting the values in the equation of Kw
pKw = -log[Kw]
pKw = -log [51.3 x
]
pKw = 12.28
since H+ ion OH ion concentration is equal the pH of water is half i.e. 6.14
Now, pOH is calculated by using the equation:
14 = pOH + pH
14- 6.14 = pOH
pOH = 7.86
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