Answer:
4Fe + 3O₂ → 2Fe₂O₃
Explanation:
Fe → ²⁺
O → ²⁻
But Iron III is Fe³⁺
So we have Fe³⁺ and O²⁻, the formula for the oxide must be Fe₂O₃ so the equation can be:
4Fe + 3O₂ → 2Fe₂O₃
<span>B.by arranging the elements according to atomic number instead of atomic mass</span> awnser is B
Answer:
11.39
Explanation:
Given that:


Given that:
Mass = 1.805 g
Molar mass = 82.0343 g/mol
The formula for the calculation of moles is shown below:

Thus,


Given Volume = 55 mL = 0.055 L ( 1 mL = 0.001 L)


Concentration = 0.4 M
Consider the ICE take for the dissociation of the base as:
B + H₂O ⇄ BH⁺ + OH⁻
At t=0 0.4 - -
At t =equilibrium (0.4-x) x x
The expression for dissociation constant is:
![K_{b}=\frac {\left [ BH^{+} \right ]\left [ {OH}^- \right ]}{[B]}](https://tex.z-dn.net/?f=K_%7Bb%7D%3D%5Cfrac%20%7B%5Cleft%20%5B%20BH%5E%7B%2B%7D%20%5Cright%20%5D%5Cleft%20%5B%20%7BOH%7D%5E-%20%5Cright%20%5D%7D%7B%5BB%5D%7D)

x is very small, so (0.4 - x) ≅ 0.4
Solving for x, we get:
x = 2.4606×10⁻³ M
pOH = -log[OH⁻] = -log(2.4606×10⁻³) = 2.61
<u>pH = 14 - pOH = 14 - 2.61 = 11.39</u>
Answer:
1) chemical indicators won't work above it's pH range so therefore it probably won't change colour.
2) the solution should be clear and colourless to see colour change.
3) indicators tend to be of low accuracy so it's not 100% reliable.
nuclear fusion
Stars produce their energy through nuclear fusion. For most stars, this process is dominated by a process called the "proton-proton chain," a sequence of events that transforms four hydrogen atoms into one helium atom.