Answer : The value of 
of the weak acid is, 4.72
Explanation :
First we have to calculate the moles of KOH.
Now we have to calculate the value of of the weak acid.
The equilibrium chemical reaction is:
Initial moles 0.25 0.03 0
At eqm. (0.25-0.03) 0.03 0.03
= 0.22
Using Henderson Hesselbach equation :
![pH=pK_a+\log \frac{[Salt]}{[Acid]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BSalt%5D%7D%7B%5BAcid%5D%7D)
![pH=pK_a+\log \frac{[HK]}{[HA]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BHK%5D%7D%7B%5BHA%5D%7D)
Now put all the given values in this expression, we get:
Therefore, the value of of the weak acid is, 4.72
1. The world without boron would be like a "turtle hiding inside it's shell" Almost everything that we need biologically would not be supplied. There would be plant disorder because of lack of boron that is needed for plants growth. And it would be widespread around the world and causes large of scarcity of food production resulting to chain of reaction to other factors that is part of our daily lives. We are not that high-tech as now and the transition of technology would not be as what we would be expecting in the years to come. We may obtain some of it naturally but it would not be enough later on as the population keeps on growing.
2. Life is still life because we still have other resources we need but it would be quite different as Boron plays a vital role since the earth's formation. As it has many uses in the beginning of civilization as we relies on borates for almost everything. Probably, widespread of plant disorder, poor production of food, rampant of sickness may happen, increasing of pestilence that some of the key ingredient of household products relies on it.
This question is asking for an element with 5 valence electrons. Just go to the row it is in (excluding transition metals) and count over.
The answer would be c. P
Answer:
- 618.8 J.
Explanation:
- To solve this problem, we can use the relation:
<em>Q = m.c.ΔT,</em>
where, Q is the amount of heat released by steam (Q = ??? J).
m is the mass of the steam (m = 15.5 g).
c is the specific heat of the steam (c of steam = 1.996 J/g.°C).
ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = 100.0°C - 120.0°C = - 20.0°C).
<em>∴ Q = m.c.ΔT</em> = (15.5 g)(1.996 J/g.°C)(- 20.0°C) =<em> - 618.8 J.</em>
