Answer:
a) 129.14 g/mol
b) 8.87
Explanation:
Given that:
mass of the ionic compound [NaA] = 18.08 g
Volume of water = 116.0 mL = 0.116 L
Let the mole of the acid HCl = 0.140 M
Volume of the acid = 500.0 mL = 0.500 L
pH = 4.63
= 1.00 L
Equation for the reaction can be represented as:
From above; 1 mole of an ionic compound reacts with 1 mole of an acid to reach equivalence point = 0.140 M × 1.00 L
= 0.140 mol
Thus, 0.140 mol of HCl neutralize 0.140 mol of ionic compound at equilibrium
Thus, the molar mass of the sample = 
= 129.14 g/mol
b) since pH = pKa
Then pKa of HA = 4.63
Ka = ![10^{-4.63]](https://tex.z-dn.net/?f=10%5E%7B-4.63%5D)
= 
![[A^-]equ = \frac{0.140M*1.00L}{1.00L+0.116L}](https://tex.z-dn.net/?f=%5BA%5E-%5Dequ%20%3D%20%5Cfrac%7B0.140M%2A1.00L%7D%7B1.00L%2B0.116L%7D)
= 0.1255 M
of HA =
+ 
+ 
Initial 0.1255 0 0
Change - x + x + x
Equilibrium 0.1255 - x x x
![K_b = \frac{[HA][OH^-]}{[A^-]}](https://tex.z-dn.net/?f=K_b%20%3D%20%5Cfrac%7B%5BHA%5D%5BOH%5E-%5D%7D%7B%5BA%5E-%5D%7D)
![4.35*10^{-10} = \frac{[x][x]}{[0.1255-x]}](https://tex.z-dn.net/?f=4.35%2A10%5E%7B-10%7D%20%3D%20%5Cfrac%7B%5Bx%5D%5Bx%5D%7D%7B%5B0.1255-x%5D%7D)
As 
is very small, (o.1255 - x) = 0.1255
[OH⁻] = 
But pOH = - log [OH⁻]
= - log [
]
= 5.13
pH = 14.00 = 5.13
pH = 8.87
Since it is stated that nitrogen is the limiting reactant (sometimes called limiting reagent), you only have to worry about the amount of nitrogen since we know that there is excess silicon.
Since this is a stoichiometry question, the first thing to do is turn the mass of nitrogen gas into moles by dividing the mass of nitrogen gas by its molar mass. (14.33g)/(28g/mol)=0.5118mol nitrogen gas. Then you have to convert moles of nitrogen gas to moles of silicon nitride by using the fact that 2 moles of nitrogen gas turn into 1 mole of silicon nitride (i got that ratio from the chemical equation given). (0.511mol N₂)x(1mol Si₃N₄/2mol N₂)=0.2555mol Si₃N₄. Know you just need to find the mass of silicon nitride by multiplying the number of moles of silicon nitride by its molar mass. (0.2555mol)x(140g/mol)=35.85g
Therefore the amount of silicon nitride produced from this reaction 35.85g.
I hope this helps
Answer:
Generally, the atomic radius decreases across a period from left to right and increases down a given group. ... This causes the atomic radius to decrease. Moving down a group in the periodic table, the number of electrons and filled electron shells increases, but the number of valence electrons remains the same.
Answer:
The answer to your question is: P = 419933.5 Pa
Explanation:
Data
R = 0.287 KJ/Kg°K = 287 J/Kg°K
mass = 2 kg
T = 35 °C = 308°K
Container = 0.750 meters each side
Volume = l x l x l
= 0.750 x 0.750 x 0.750
= 0.421 m³
P = mRT / V
P = (2)(287)(308) / 0.421
P = 176792 / 0.421
P = 419933.5 Pa
Answer is: <span>the molecular formula for a glucose polymer is C</span>₆₀H₁₀₂O₅₁.<span>
For every link one molecule of water is released, so if we have ten molecules of glucose, there is nine links and nine molecules of water (H</span>₂O)<span> are released.
molecular formula = 10</span>·<span>C</span>₆H₁₂O₆ - 9·H₂O.
<span>carbon atoms = 10 </span>· 6 = 60.
<span>hydrogen atoms = 10 </span>· 12 - 9 · 2 = 102.
<span>oxygen atoms = 10 </span>· 6 - <span>9 </span>· 1 = 51.<span>
</span>
