Yes, it is possible to decrease the resistance of a wire without changing the material it made out of. This is because, there are many factors which affect the resistance of a wire. These factors can be manipulated to change the resistance of the wire. The factors include: cross sectional area of the wire, length of the wire, temperature and the material of the wire. The other three factors can be manipulated to change the resistance of the wire without changing the material of the wire.
Answer:
6.8 mole of O₂
Explanation:
Given expression:
2H₂ + O₂ → 2H₂O
Number of moles of H₂ = 13.6moles
Unknown:
Number of moles of O₂ = ?
Solution:
In the given problem, we are to find the number of moles of oxygen gas that will use up 13.6mole of hydrogen gas;
From the reaction equation;
2 mole of H₂ will completely react with 1 mole of O₂
13.6 moles of H₂ will completely be used up by mole of O₂
= 6.8 mole of O₂
Answer:
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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).