Answer:
Explanation:Rocks are heated and melt.
Some magma move sideways in opposite directions.Magma cools and sinks.Magma expands and rises at divergent boundaries.Magma expands and rises at divergent boundaries.
For a neutral solution,
[H+][OH-] = 1 x 10⁻¹⁴
Answer: journals
explanation: A publication is defined as anything that has been published: a book. a research paper, a news article. A research paper describes the output of research. If it is published in a Journal or conference, then it is a published research paper, or a publication.
Answer:
D
Explanation:
The resolution of a light microscope is approximately 200 nanometers due to the wavelength of light. A eukaryotic cell is approximately 1 – 5 micrometers. This means that light can be used to view a eukaryotic cell because the wavelength of light is smaller than the size of the cell. The other options are of a smaller size than the light wavelength and hence lower wavelength beams (such as those of electron microscope) or laser can be used to view them.
The answer is pH = 7.37.
Solution:
First, we set up an ICE table for the reaction:
F- + H2O → HF + OH-
Initial 0.00378 0 0
Change -x +x +x
Equilibrium 0.00378-x x x
We can calculate Kb from the given Ka, since we know that Kw = Ka*Kb = 1.0 x 10^-14 at 25°C:
Kb = Kw/Ka = 1.0x10^-14 / 6.80x10^-4 = 1.471 x 10^-11
Kb = 1.471 x 10^-11 = [OH-][HF] / [F-] = (x)(x) / (0.00378-x)
Approximating that x is negligible compared to 0.00378 simplifies the equation to
1.471x10^-11 = (x)(x) / 0.00378
1.471 x 10-11 = x2 / 0.00378
Then we solve for x that is also equal to [OH-]:
x2 = (1.471 x 10^-11)(0.00378)
x = sqrt[(1.471 x 10^-11)(0.00378)] = 2.358x10^-7 = [OH-]
in which 0.0000002358 is indeed negligible compared to 0.00378.
We can now calculate for pOH:
pOH = -log [OH-] = -log (2.358x10^-7) = 6.63
Therefore, the pH is
pH = 14 - pOH = 14 - 6.63 = 7.37
