Answer:
The correct answer is - Frequency is the number of wavelengths, which is measured in hertz.
Explanation:
Frequency is the number of waves that go through a fixed point at a particular time. Hertz is the SI unit for frequency which means that one hertz is equal to a unit number of waver passes in a unit time to a fixed point.
As the frequency of a wave increases which means the number of waves increases in the unit time, the shorter the wavelength will be.
a higher frequency wave has more energy than a lower frequency wave with the same amplitude.
Answer:
The boiling point increases with increased pressure up to the critical point, where the gas and liquid properties become identical.
Answer :
The correct answer for primary component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .
<u>Buffer solution :</u>
It is a solution of mixture of weak acid and its conjugate base OR weak base and its conjugate acid . It resist any change in solution when small amount of strong acid or base is added .
<u>Capacity of a good buffer : </u>
A good buffer is identified when pH = pKa .
From Hasselbalch - Henderson equation which is as follows :
![pH = pka + log \frac{[A^-]}{[HA]}](https://tex.z-dn.net/?f=pH%20%3D%20pka%20%2B%20log%20%5Cfrac%7B%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
If [A⁻] = [HA] ,
pH = pka + log 1
pH = pKa
This determines that if concentration of weak acid and its conjugate base are changed in small quantity , the capacity of buffer to maintain a constant pH is greatest at pka . If the amount of [A⁻] or [HA] is changed in large amount , the log value deviates more than +/- 1M and hence pH .
Hence Buffer has best capacity at pH = pka .
<u>Phosphate Buffer : </u>
Phosphate may have three types of acid-base pairs at different pka ( shown in image ).
Since the question is asking the pH = 7.4
At pH = 7.4 , the best phosphate buffer will have pka near to 7.4 .
If image is checked the acid - base pair " H₂PO₄⁻ and HPO₄²⁻ has pka 7.2 which is near to pH = 7.4 .
Hence we can say , the primary chemical component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .
Answer:
Technician B.
Explanation:
The claim of technician B that the PCM will add fuel if the IAT indicates that the incoming air temperature is cold is correct.
Answer:
114.48g
Explanation:
Step 1:
Data obtained from the question:
Volume (V) = 162 L
Pressure (P) = 1.20 atm
Temperature = 100°C = 100°C+ 273 = 373K
Number of mole (n) of H2O =?
Recall:
Gas constant (R) = 0.082atm.L/Kmol
Step 2:
Determination of the number of mole of H2O i.e steam.
Using the ideal gas equation, the number of mole of H2O can be obtained as follow:
PV = nRT
1.2x 162 = n x 0.082 x 373
Divide both side by 0.082 x 373
n = (1.2x 162) /(0.082 x 373)
n = 6.36 moles
Step 3:
Determination of mass of H2O i.e steam:
This is illustrated below:
Molar Mass of H2O = (2x1) + 16 = 2 + 16 = 18g/mol
Number of mole H2O = 6.36 moles
Mass of H2O =?
Mass = number of mole x molar Mass
Mass of H2O = 6.36 x 18
Mass of H2O = 114.48g
Therefore, the mass of H2O i.e steam required to fill the drum of crude oil is 114.48g
