Answer:
A.) ![K_b = \frac{[CH_3NH_3^+][OH^-]}{[CH_3NH_2]}](https://tex.z-dn.net/?f=K_b%20%3D%20%5Cfrac%7B%5BCH_3NH_3%5E%2B%5D%5BOH%5E-%5D%7D%7B%5BCH_3NH_2%5D%7D)
Explanation:
The general Kb expression is:
![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)
In this equation
-----> Kb = equilibrium constant
-----> [HA] = acid
-----> [A⁻] = base
Since liquids are not included in equilibrium expressions, H₂O should not be present. The products are in the numerator while the reactant are in the denominator. In this reaction, CH₃NH₂ is acting as a base and CH₃NH₃⁺ is acting as an acid.
As such, the expression is:
![K_b = \frac{[CH_3NH_3^+][OH^-]}{[CH_3NH_2]}](https://tex.z-dn.net/?f=K_b%20%3D%20%5Cfrac%7B%5BCH_3NH_3%5E%2B%5D%5BOH%5E-%5D%7D%7B%5BCH_3NH_2%5D%7D)
An independent variable<span> is the </span>variable<span> that is changed or controlled in a scientific </span>experiment<span> to test the effects on the </span>dependent variable<span>. </span>
Absorbance measures the ability of the substance to absorb light at a specific wavelength.
Absorbance is also equal to the product of molar absorptivity, path length and molar concentration.
The mathematical expression is given as:
(1)
where, A = absorbance
= molar absorptivity
l = path length
c = molar concentration.
The above formula is said to Beer's Law.
Absorptivity of protein x = 
Path length = 1 cm
Molar concentration = 
Put the values in formula (1)

= 
Thus, absorbance at 280 nm = 
Answer:
65.18% is the percent yield for this reaction.
Explanation:

Moles of salicyclic acid = 
According to reaction 1 mole of salicyclic acid gives 1 mole of aspirin .
Then 0.01449 mole of salicylic acid will give :
of asprin
Mass of 0.01449 moles of aspirin :
= 0.01449 mol × 180 g/mol = 2.6082 g
Theoretical yield of aspirin = 2.6082 g
Experimental yield of aspirin = 1.7 g
The percent yield for this reaction:


65.18% is the percent yield for this reaction.
Hey there!:
mass = 41.2 g
Volume = 8.2 cm³
Therefore:
D = m / V
D = 41.2 / 8.2
D = 5.02 g/cm³