Answer:
Subbituminous coal can form at temperatures as low as 35 to 80 °C (95 to 176 °F) while anthracite requires a temperature of at least 180 to 245 °C (356 to 473 °F).
Sub-types: Cannel coal
Child material class: Lignite
Explanation:
Answer:
D. 37 reports
Explanation:
Last month, he wrote 9 reports, and this month he wrote 28 reports. To find how many he wrote over the past two months, add his reports from last month and this month.
last month + this month
9 reports +28 reports
37 reports
So, he wrote 37 reports, or choice D
Answer:
0.371
Explanation:
number of moles = mass / Ar
= 23.8g / 32.1 + (16.0 × 2)
= 0.37129485179 = 0.371 (3 s.f).
hope it helps :)
Answer : The enthalpy change of reaction is -1800 kJ
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.
The given final reaction is,

The intermediate balanced chemical reaction will be,
(1)

(2)

First we will multiply reaction 1 by 2 and reverse reaction of reaction 2 by 3 then adding both the equation, we get :
The expression for final enthalpy is,
![\Delta H=[n\times \Delta H_1]+[n\times (-\Delta H_2)]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Bn%5Ctimes%20%5CDelta%20H_1%5D%2B%5Bn%5Ctimes%20%28-%5CDelta%20H_2%29%5D)
where,
n = number of moles
![\Delta H=[2mole\times (-1680kJ/mole)]+[3\times -(-520kJ/mole)]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B2mole%5Ctimes%20%28-1680kJ%2Fmole%29%5D%2B%5B3%5Ctimes%20-%28-520kJ%2Fmole%29%5D)

Therefore, the enthalpy change of reaction is -1800 kJ
150 g SO₂ = 2.36 mol SO₂
M_r = 32.06 + 2×16.00 = 32.07 + 32.00 = 64.06
Moles of SO₂ = 151 g SO₂ × [1 mol SO₂/64.06 g SO₂] = 2.36 mol SO₂