Because the moon gets between the Sun and the Earth so you can't see the moon
Answer:
b. 11.90 Liters
Explanation:
- The balanced equation for the mentioned reaction is:
<em>3O₂ + 4Al → 2Al₂O₃,</em>
It is clear that 3.0 moles of O₂ react with 4.0 moles of Al to produce 2.0 Al₂O₃.
- Firstly, we need to calculate the no. of moles (n) of 36.12 g of Al₂O₃:
<em>n = mass/molar mass</em> = (44.18 g)/(101.96 g/mol) = <em>0.4333 mol.</em>
<u><em>using cross multiplication:</em></u>
3.0 mol of O₂ produces → 2.0 mol of Al₂O₃.
??? mol of O₂ produces → 0.4333 mol of Al₂O₃.
<em>∴ The no. of moles of O₂ needed to produce 36.12 grams of Al₂O₃</em> = (3.0 mol)(0.4333 mol)/(2.0 mol) = <em>0.65 mol.</em>
- Now, we can find the volume of O₂ used during the experiment:
We can use the general law of ideal gas: <em>PV = nRT.</em>
where, P is the pressure of the gas in atm (P = 1.3 atm).
V is the volume of the gas in L (V = ??? L).
n is the no. of moles of the gas in mol (n = 0.65 mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K),
T is the temperature of the gas in K (T = 290 K).
<em>∴ V = nRT/P </em>= (0.65 mol)(0.0821 L.atm/mol.K)(290 K)/(1.3 atm) = <em>11.9 L.</em>
<em>So, the right choice is: b. 11.90 Liters.</em>
The process is called fractional distillation. It works by heating up the crude oil inside a chamber to a boil (vaporizing it). Due to the fact that each component of crude oil has a different boiling point, each component of the crude oil will condense at a different height inside the chamber since the chamber gets colder the further up you go away from the heat source. Since each component condenses at different heights in the chamber, there are places to collect condensing liquid at different heights in the chamber (The heights correspond to the boiling point of each component). These collection areas will collect only the component of crude oil that condenses at that temperature. The condensing point is basically the boiling point which means the lower in the chamber that component condenses at, the higher the boiling point for that component is and therefore the heavier that component is (the heavier components get collected near the bottom of the chamber while the lighter components get collected near the top of the chamber).
I hope this helps. Let me know if anything is unclear.
Answer:
![[A_0]=10\ mg](https://tex.z-dn.net/?f=%5BA_0%5D%3D10%5C%20mg)
![[A_t]=0.08245\ mg](https://tex.z-dn.net/?f=%5BA_t%5D%3D0.08245%5C%20mg)
Explanation:
Given that:
Half life = 10.4 hours
Where, k is rate constant
So,
The rate constant, k = 0.06664 hour⁻¹
Time = 24 hours
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
Where,
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
is the concentration at time t = 2 mg
![[A_0]](https://tex.z-dn.net/?f=%5BA_0%5D)
is the initial concentration = ?
So,
![2\ mg=[A_0]\times e^{-0.06664\times 24}](https://tex.z-dn.net/?f=2%5C%20mg%3D%5BA_0%5D%5Ctimes%20e%5E%7B-0.06664%5Ctimes%2024%7D)
Now, time = 3 days = 3*24 hours = 72 hours ( 1 day = 24 hours)
Thus,
![[A_t]=10\times e^{-0.06664\times 72}\ mg=0.08245\ mg](https://tex.z-dn.net/?f=%5BA_t%5D%3D10%5Ctimes%20e%5E%7B-0.06664%5Ctimes%2072%7D%5C%20mg%3D0.08245%5C%20mg)
