Response:
The pKa value is 13.0.
Clarification:
pKa + pKb = 14
For trimethylamine, Kb = 6.3 × 
Calculating pKb: pKb = - log (6.3 ×
)
= 1.0
Thus, pKa = 14 - pKb = 14 - 1.0
pKa = 13.0
Verification: The typical range for pKa in weak acids is from 2 to 13.
Answer: The mass of Si in kilograms is, 
Explanation:
Given that the Si concentration in an Fe-Si alloy is 0.25 weight percent, this translates to:
Mass of Si = 0.25 g = 0.00025 kg
Mass of Fe = 100 - 0.25 = 99.75 g = 0.09975 kg
Density of Si = 
Density of Fe = 
Next, we need to find the quantity of Si in kilograms per cubic meter of alloy.
Si concentration in kilograms = 
Si concentration in kilograms = 
By substituting all the provided values into this formula, we arrive at:
Si concentration in kilograms = 
Si concentration in kilograms = 
Hence, the mass of Si in kilograms is, 
Answer :
The percentage ionic character (%IC) equals 10%, indicating the bond is mostly covalent with slight polarity.
Percent Ionic Character:
This reflects the fraction of ionic nature within a polar covalent bond. The formula for %IC (% ionic character) is:

Here, Xa is the electronegativity of atom A and Xb is that of atom B.
Given: The compound is TiAl₃.
Electronegativity of Ti = 2.0
Electronegativity of Al = 1.6 (as shown in the provided image)
Substitute these values into the formula:



The value of e⁻¹ equals 0.90.
Therefore, percent ionic character = (1 - 0.90) × 100
Percent Ionic Character = 10%
Because the % IC is only 10%, which is relatively low, the bond is classified as covalent with minimal polarity.
Response:
9.9 ml of 0.200M NH₄OH(aq)
Reasoning:
3NH₄OH(Iaq) + FeCl₃(aq) => NH₄Cl(aq) + Fe(OH)₃(s)
What volume in ml of 0.200M NH₄OH(aq) will fully react with 12ml of 0.550M FeCl₃(aq)?
1 x Molarity of NH₄OH x Volume of NH₄OH Solution(L) = 2 x Molarity of FeCl₃ x Volume of FeCl₃ Solution
1(0.200M)(Volume of NH₄OH Soln) = 3(0.550M)(0.012L)
=> Volume of NH₄OH Soln = 3(0.550M)(0.012L)/1(0.200M) = 0.0099 Liters = 9.9 milliliters
Solution:
Washing Clothes & Dissolving Sugar
Clarification:
Consider each scenario:
1) For washing clothes, water is essential; without it, washing is ineffective.
2) Connecting brake pedals to brake pads requires solids, not liquids.
3) To deodorize a space, one would likely reach for an aerosol spray, which is a gas.
4) Sculpting involves solid tools and a solid medium.
5) Dissolving sugar necessitates a liquid to be effective!
6) While one might assert that paint is a liquid, it still might not fit the category; I would categorize this application as solid.
7) Gears employed in machinery are solid components!