Answer: 
.
Explanation:
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
(1)
![S_{monoclinic}+O_2(g)\rightarrow SO_2(g)/tex] [tex]\Delta H^0_2=-296.36kJ](https://tex.z-dn.net/?f=S_%7Bmonoclinic%7D%2BO_2%28g%29%5Crightarrow%20SO_2%28g%29%2Ftex%5D%20%5Btex%5D%5CDelta%20H%5E0_2%3D-296.36kJ)
(2)
The final reaction is:
(3)
By subtracting (1) and (2)
Hence the enthalpy change for the transformation S(rhombic) → S(monoclinic) is 0.3kJ
Answer:
Explanation:
To convert form grams to moles, the molar mass must be used. This is the mass (in grams) in 1 mole of a substance.
We can use the values on the Periodic Table. First, find the molar masses of the individual elements: carbon and oxygen.
- C: 12.011 g/mol
- O: 15.999 g/mol
Check for subscripts. The subscript of 2 after O means there are 2 oxygen atoms, so we have to multiply oxygen's molar mass by 2 before adding.
- O₂: 2* (15.999 g/mol)=31.998 g/mol
- CO₂: 12.011 g/mol + 31.998 g/mol =40.009 g/mol
Use the molar mass as a ratio.
Multiply by the given number of grams.
Flip the fraction so the grams of carbon dioxide cancel.
The original measurement of grams has 2 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.
The ten thousandth place has a 5, so we round the 4 to a 5.
2.4 grams of carbon dioxide is about 0.055 moles.
Answer:
0.46M NaS₂O₃ (Assuming KIO₃ solution with a concentration of 1.0M)
Explanation:
Based on the reaction:
6 Na₂S₂O₃ + KIO₃ + 5 KI + 3 H₂SO₄ → 3 Na₂S₄O₆ + 3 H₂O + 3 K₂SO₄ + 6 NaI
<em>6 moles of Na₂S₂O₃ react per mole of KIO₃</em>
Assuming the molarity of the KIO₃ solution is 0,1M:
Moles of KIO₃: = 5.0x10⁻³L ₓ (0.1 mol / L) = <em>5.0x10⁻⁴ moles</em>
As 6 moles of thiosulfate reacted per mole of iodate:
5.0x10⁻⁴ moles KIO₃ ₓ (6 moles Na₂S₂O₃ / 1 mole KIO₃) =
<em>3.0x10⁻³ moles of Na₂S₂O₃. </em>In 6.5mL (6.5x10⁻³L):
3.0x10⁻³moles Na₂S₂O₃ / 6.5x10⁻³ L = 0.46M NaS₂O₃
Answer:
p = 1.5 atm
Explanation:
pV = nRT
p = nRT/V = [1.8 mol×(0.082 atm L/mol K)×247.8 K]/24.5 L
p = 1.5 atm
