Answer:
-800 kJ/mol
Explanation:
To solve the problem, we have to express the enthalpy of combustion (ΔHc) in kJ per mole (kJ/mol).
First, we have to calculate the moles of methane (CH₄) there are in 2.50 g of substance. For this, we divide the mass into the molecular weight Mw) of CH₄:
Mw(CH₄) = 12 g/mol C + (1 g/mol H x 4) = 16 g/mol
moles CH₄ = mass CH₄/Mw(CH₄)= 2.50 g/(16 g/mol) = 0.15625 mol CH₄
Now, we divide the heat released into the moles of CH₄ to obtain the enthalpy per mole of CH₄:
ΔHc = heat/mol CH₄ = 125 kJ/(0.15625 mol) = 800 kJ/mol
Therefore, the enthalpy of combustion of methane is -800 kJ/mol (the minus sign indicated that the heat is released).
Answer:
You are mostly correcet but im pretty sure that the nonmetals are brittle because they can break easily
Explanation:
If it is incomplete or complete combustion. Normally the problems question with tell you.
EX:
"In the presence of plenty of oxygen" is complete combustion
"Not enough oxygen present" is incomplete combustion
Answer:
Limestone is easily eroded from above and below.
Explanation:
The Florida bedrock is largely made of limestone. Because limestone is a rock that is easily eroded, the landscape of a great part of Florida is classified as karstic.
Karstic landscapes are dotted by sinkholes, underground rivers, caves, and springs. The more acidic the groundwater or rainwater, the faster and more easily the limestone will succumb to erosion.
In this way, underground rivers, streams, runoff, rain, and underground water pooled in caves have all carved out gaps and caverns in the weak limestone bedrock.
