A b A or just the person above me said
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>
Answer:
2.13 x 10³moles
Explanation:
Given parameters:
Number of molecules in AlF₃ = 1.28 x 10²⁷molecules
Unknown:
Number of moles = ?
Solution:
A mole is a quantitative unit in chemistry used of taking measurements.
A mole of a substance is the amount of that substance that contains the avogadro's number of particles.
The particles can be molecules, atoms, neutrons, protons, electrons or formula units.
Number of moles = ![\frac{number of molecules }{Avogadro's number}](https://tex.z-dn.net/?f=%5Cfrac%7Bnumber%20of%20molecules%20%7D%7BAvogadro%27s%20number%7D)
Number of moles =
= 2.13 x 10³moles
When ice melts, the physicals state changes from solid to liquid. The energy or the heat required (q) required to change a unit mass (m) of a substance from solid to liquid is known as the enthalpy or heat of fusion (ΔHf). The variables; q, m and ΔHf are related as:
q = m * ΔHf
the mass of ice m = 65 g
the heat of fusion of water at 0C = ΔHf = 334 J/g
Therefore: q = 65 g * 334 J/g = 21710 J
Now:
4.184 J = 1 cal
which implies that: 21710 J = 1 cal * 21710 J/4.184 J = 5188.8 cal
Hence the heat required is 5188.8 cal or 5.2 Kcal (approx)
The two resonating structures of Nitrous Acid are shown below. Lone pair of electrons, single and multiple bonds and non zero formal charges (red color) are also specified.
Among these two structures the structure on the left lacking formal charge is the most stable form. The instability of second resonating structure is due to the fact that it contains two formal charges (the lesser the number of formal charges the greater is the stability). Secondly in this structure one oxygen atom is having +1 formal charge. Oxygen being more electronegative feel hostile towards positive formal charge.