Sodium (chemical symbol Na) is atomic number 11 and is in the first column of the periodic table so it has one valence electron.
2 answers:
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Answer:
HC₂H₃O₂/KC₂H₃O₂
Explanation:
Considering the Henderson- Hasselbalch equation for the calculation of the pH of the basic buffer solution as:
For a best pair, the pKa value must be equal to pH.
NH₃/NH₄Cl forms a basic buffer and cannot account for pH = 5
out of the acidic buffer given,
So, HF , Ka = 3.5 × 10⁻⁴ , So pKa = 3.46
HC₂H₃O₂ , Ka = 1.8 × 10⁻⁵ , So pKa = 4.77
<u>The best pair to show pH = 5 is HC₂H₃O₂/KC₂H₃O₂</u>
Answer:
Here's what I get
Explanation:
You want to dilute the original solution by a factor of 25 in two steps, so you could dilute it by a factor of 5 in the first step, then dilute the new solution by another factor of 5.
A. First dilution
Use a 10 mL pipet to transfer 10 mL of the original solution to a 50 mL volumetric flask. Make up to the mark with distilled water. Shake well to mix.
Use the dilution formula to calculate the new concentration.
B. Second dilution
Repeat Step 1, using the 0.003 970 mol·L⁻¹ solution.
3. Check:
Compare the final concentration with the original
Answer:
Value of coefficient of kinetic friction is 0.26 .
Explanation:
Given:
Mass of wooden crate, m = 12.5 kg.
Horizontal force to keep the block moving with constant velocity, F = 32.0 N.
Since, the block is moving with constant velocity.
So, net force experience by it is zero.
Therefore, fore of friction is equal to applied force.
Now, force of friction , ( here
is coefficient of kinetic friction and N is normal force)
Therefore,
Now, both forces are equal.
The value of coefficient of kinetic friction is 0.26 .
Hence, it is the required solution.