<h3><u>Answer;</u></h3>
1 × 10^-8 M
<h3><u>Explanation</u>;</h3>
pH is given by the -log[H+] while
pOH is given by the -log[OH-]
But;
pH + pOH = 14
Thus; if pH is 6, then pOH = 8
pOH = 8
-log[OH-] = 8
[OH-] = 10^-8 M
The concentration of OH- ions at a pH of 6 is 1 × 10^-8 M
Answer:
The time taken to reach the maximum height is 3.20 seconds
Explanation:
The given parameters are;
The initial height from which the volcano erupts the lava bomb = 64.4 m
The initial upward velocity of the lava bomb = 31.4 m/s
The acceleration due to gravity, g = 9.8 m/s²
The time it takes the lava bomb to reach its maximum height, t, is given by the following kinematic equation as follows;
v = u - g·t
Where;
v = The final velocity = 0 m/s at maximum height
u = The initial velocity = 31.4 m/s
g = The acceleration due to gravity = 9.8 m/s²
t = The time taken to reach the maximum height
Substituting the values gives;
0 = 31.4 - 9.8 × t
∴ 31.4 = 9.8 × t
t = 31.4/9.8 ≈ 3.204
The time taken to reach the maximum height rounded to three significant figures = t ≈ 3.20 seconds
Answer : The energy of one photon of hydrogen atom is, 
Explanation :
First we have to calculate the wavelength of hydrogen atom.
Using Rydberg's Equation:
Where,
= Wavelength of radiation
= Rydberg's Constant = 10973731.6 m⁻¹
= Higher energy level = 3
= Lower energy level = 2
Putting the values, in above equation, we get:
Now we have to calculate the energy.
where,
h = Planck's constant = 
c = speed of light = 
= wavelength = 
Putting the values, in this formula, we get:
Therefore, the energy of one photon of hydrogen atom is,
Answer:
Energy= 46.08KJ
Explanation:
Given that the power needed to light each bulb is 32W
We know that Power = 
The energy needed to light one bulb=
Given time = 1minute = 60 seconds
Energy = 
=1920J
Therefore energy needed to light one bulb is 1920J
The energy needed to light 24 bulbs = 
=46080J=46.08KJ
