Answer:
Molecules in the cake are moving faster than molecules in the skin.
Explanation:
When a cake is baked, the energy is absorbed. This is known as an endothermic reaction. When things are hot, it means that the molecules are in motion. When the cake is taken out from the oven, the molecules are continuously moving and absorbing energy. When the student touches the cake, the heat is flown into the student's body. This happens because of the difference in the temperature between the two.
Answer:
[HOCl] = 0.001 127 mol·L⁻¹; [H₂O] = [Cl₂O] = 0.003 76 mol·L⁻¹
Explanation:
The balanced equation is
H₂O + Cl₂O ⇌ 2HOCl
Data:
Kc = 0.0900
[H₂O] = 0.004 32 mol·L⁻¹
[Cl₂O] = 0.004 32 mol
1. Set up an ICE table.
2. Calculate the equilibrium concentrations
![K_{\text{c}} = \dfrac{\text{[HOCl]$^{2}$}}{\text{[H$_{2}$O][Cl$_2$O]}} = \dfrac{(2x)^{2}}{(0.00432 - x)^{2}} = 0.0900\\\\\begin{array}{rcl}\dfrac{4x^{2}}{(0.00432 - x)^{2}} &=& 0.0900\\ \dfrac{2x }{0.00432 - x} & = & 0.300\\2x & = & 0.300(0.00432 - x)\\2x & = & 0.001296 - 0.300x\\2.300x & = & 0.001296\\x & = & \mathbf{5.63\times 10^{-4}}\\\end{array}](https://tex.z-dn.net/?f=K_%7B%5Ctext%7Bc%7D%7D%20%3D%20%5Cdfrac%7B%5Ctext%7B%5BHOCl%5D%24%5E%7B2%7D%24%7D%7D%7B%5Ctext%7B%5BH%24_%7B2%7D%24O%5D%5BCl%24_2%24O%5D%7D%7D%20%3D%20%5Cdfrac%7B%282x%29%5E%7B2%7D%7D%7B%280.00432%20-%20x%29%5E%7B2%7D%7D%20%3D%200.0900%5C%5C%5C%5C%5Cbegin%7Barray%7D%7Brcl%7D%5Cdfrac%7B4x%5E%7B2%7D%7D%7B%280.00432%20-%20x%29%5E%7B2%7D%7D%20%26%3D%26%200.0900%5C%5C%20%5Cdfrac%7B2x%20%7D%7B0.00432%20-%20x%7D%20%26%20%3D%20%26%200.300%5C%5C2x%20%26%20%3D%20%26%200.300%280.00432%20-%20x%29%5C%5C2x%20%26%20%3D%20%26%200.001296%20-%200.300x%5C%5C2.300x%20%26%20%3D%20%26%200.001296%5C%5Cx%20%26%20%3D%20%26%20%5Cmathbf%7B5.63%5Ctimes%2010%5E%7B-4%7D%7D%5C%5C%5Cend%7Barray%7D)
[HOCl] = 2x mol·L⁻¹ = 2 × 5.63 × 10⁻⁴ mol·L⁻¹ =0.001 127 mol·L⁻¹
[H₂O] = [Cl₂O] = (0.004 32 - 0.000 563) mol·L⁻¹ = 0.003 76 mol·L⁻¹
Check:
OK.
The area where she is flying in windless conditions along the equator is called doldrums. Doldrums is a windless zone at the equator caused by warm rising air. The zone experience bands of showers and storms due to the hot air that rises and cools.
Ok so I’m going to break it up so it’s a bit easier to read through:
The colours are from the different rocks and minerals that make up the sand.
The little fragments of rock come from for example surrounding mountains.
It could also because sand is simply the product from erosion of the rocks rubbing each other under the action of the waves.
So if the bottom of the ocean is made of black lava for example in Hawaii, there’s a good chance of the sand being black.
In California, the sand usually looks white because it has minerals like quartz and pieces of shell that are made of calcium carbonate.
Hope this helps :)
<u>Ans: Acetic acid = 90.3 mM and Sodium acetate = 160 mM</u>
Given:
Acetic Acid/Sodium Acetate buffer of pH = 5.0
Let HA = acetic acid
A- = sodium acetate
Total concentration [HA] + [A-] = 250 mM ------(1)
pKa(acetic acid) = 4.75
Based on Henderson-Hasselbalch equation
pH = pKa + log[A-]/[HA]
[A-]/[HA] = 10^(pH-pKa) = 10^(5-4.75) = 10^0.25 = 1.77
[A-] = 1.77[HA] -----(2)
From (1) and (2)
[HA] + 1.77[HA] = 250 mM
[HA] = 250/2.77 = 90.25 mM
[A-] = 1.77(90.25) = 159.74 mM
