Answer:
Q3. A bridge is built without expansion gaps.
Explain what could happen to the bridge if the temperature became:
a) much hotter than the day it was built.
b) much colder than the day it was built.
P.s. (this is not a select option question, explain each according to the question)
VB theory does not indicate that the diatomic molecule He₂ is a viable species.
Helium has atomic number 2, it has 2 protons and 2 electrons.
Electron configuration of helium atom: ₂He 1s².
Helim (He) is a noble gas.
Noble gases (group 18) are in group 18: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). They have very low chemical reactivity.
Noble gases have very stable electron configuration and does not need to gain electrons, only when they gain energy.
Valence bond (VB) theory explains chemical bonding.
Helium atom is stable and does not form molecule.
More about valence bond (VB) theory: brainly.com/question/23129240
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Answer:
tin (IV) oxide octahydrate contains 8 part water
What is the percent composition of water found in tin (IV) oxide octahydrate?
Answer:
Amount of pyridine required = 0.0316 M
Explanation:
pH of a buffer solution is calculated by using Henderson - Hasselbalch equation.
![pH=pK_a+log\frac{[Conjugate\ base]}{[weak\ acid]}](https://tex.z-dn.net/?f=pH%3DpK_a%2Blog%5Cfrac%7B%5BConjugate%5C%20base%5D%7D%7B%5Bweak%5C%20acid%5D%7D)
Pyridinium is a weak acid and in the presence of its conjugate base, it acts as buffer.
Henderson - Hasselbalch equation for pyridine/pyridinium buffer is as follows:
![pH=pK_a+log\frac{[Py]}{PyH^+]}](https://tex.z-dn.net/?f=pH%3DpK_a%2Blog%5Cfrac%7B%5BPy%5D%7D%7BPyH%5E%2B%5D%7D)
pH = 4.7
(Pyridinium)=0.100 M
Substitute the values in the formula
![pH=pK_a+log\frac{[Py]}{PyH^+]}\\4.7=5.2 log\frac{[Py]}{0.100}](https://tex.z-dn.net/?f=pH%3DpK_a%2Blog%5Cfrac%7B%5BPy%5D%7D%7BPyH%5E%2B%5D%7D%5C%5C4.7%3D5.2%20log%5Cfrac%7B%5BPy%5D%7D%7B0.100%7D)
![4.7-5.2=log\frac{[Py]}{0.100} \\-0.5=log\frac{[Py]}{0.100}\\\frac{[Py]}{0.100}=antilog -0.5\\\frac{[Py]}{0.100}=0.316](https://tex.z-dn.net/?f=4.7-5.2%3Dlog%5Cfrac%7B%5BPy%5D%7D%7B0.100%7D%20%5C%5C-0.5%3Dlog%5Cfrac%7B%5BPy%5D%7D%7B0.100%7D%5C%5C%5Cfrac%7B%5BPy%5D%7D%7B0.100%7D%3Dantilog%20-0.5%5C%5C%5Cfrac%7B%5BPy%5D%7D%7B0.100%7D%3D0.316)
![\frac{[Py]}{0.100} =0.316](https://tex.z-dn.net/?f=%5Cfrac%7B%5BPy%5D%7D%7B0.100%7D%20%3D0.316)
[Py]=0.0316\ M
Amount of pyridine required = 0.0316 M
The answer is B. Unit cell.
Hoped I Helped!
