Answer:
pH = 12.8
Explanation:
HF + NaOH → F⁻ + Na⁺ + H₂O
<em>1 mole of HF reacts with 1 mole of NaOH</em>
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Initial moles of HF and NaOH are:
HF = 0.018L × (0.308mol / L) = 5.544x10⁻³mol HF
NaOH = 0.023L × (0.361mol / L) = 8.303x10⁻³mol NaOH
That means moles of NaOH remains after reaction are:
8.303x10⁻³mol - 5.544x10⁻³mol = <em>2.759x10⁻³moles NaOH</em>
Total volume is 18.0mL + 23.0mL = 41.0mL = 0.0410L
Molar concentration of NaOH is
2.759x10⁻³moles NaOH / 0.0410L = 0.0673M = [OH⁻]
pOH = - log [OH⁻] = 1.17
As pH = 14 - pOH
<em>pH = 12.8</em>
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Answer:
1. Dmitri Mendeleev
2. Johann Dobhereiner
3. John Newlands
4. Henry Moseley
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Answer: The metal is Calcium.
Explanation:
To calculate the specific heat of substance during the reaction.
where,
q = heat absorbed = 789.75 J
c = specific heat of metal = ?
m = mass of substance = 18.0 g
= final temperature - initial temperature = 
Now put all the given values in the above formula, we get:
As specific heat is characteristic of each metal and thus the metal is calcium which has specific heat of 
Answer:
Concepts: Physical Forces
- In order for an object to be balanced, then it must be in equilibrium which means that no additional forces are being exerted.
- A ball sitting motionless would result in a balanced force that exerts no additional forces.
Answer:18.02 grams
The average mass of one mole of H2O is 18.02 grams.
Explanation: we need to find the moles of water in 1 L of water or 1000mL of water. Taking the density of water to be 1g/mL, 1000mL of water= 1000g water.
Therefore, number of moles= given mass of water(1000)/molecular mass of water(18)
Moles =1000/18= 55.55
So total molecules in 55.55 moles= 55.55* 6.022*10^23 = 334.52*10^23 molecules
=3.34*10^25 molecules of water.
:)
