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).
If the value of H is positive, it means you have to add that much heat to complete the reaction. If H is negative, it means that much heat is released during the chemical process. Because it is -73 kJ, 73 kJ of heat are released in the reaction.
<h2><u>
Answer:</u></h2>
0.126 Liters
<h2><u>
Explanation:</u></h2>
V = mRT / mmP
First, convert the 2.25g of Nitrogen gas into moles. (m in the equation above)
2.25g x 1 mole / 28.0g = 0.08036 moles = m
28.0g = mm
Next, convert the 273 Celsius into Kelvin. (T in the equation above)
273 Celsius + 273.15 = 546.15K = T
R = 0.08206L*atm/mol*K
(Quick Note: The R changes depending on the Pressure Unit so do not use this number every time.)
Now, plug everything into the equation.
V = (0.08036)(0.08206)(546.15)/(28.0)(1.02)
V = 0.126 L
The line segment is describe as a line which joints two points. The word segment is denotes the end points of the line. The symbol of the line segment is AB. This symbol is indicating a line from the point A to the point B.
- Generally, the line segment has two endpoints. The meeting point of two line segments is called as the vertex and also it is considered as a common endpoint on the other hand line is a straight path of points that goes on and on in two directions
- Vertex is a point where two rays meet OR where the sides of a polygon meet OR the point where three or more edges of a solid figure meet and the angle is Formed by two rays that have the same endpoint
To know more about line segment visit :
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Answer:
The attractive forces must be overcome are :
Explanation:
For the compound to dissolve the attractive forces existing between atoms of the compound must be reduced
<u>CsI is ionic compound </u><em>and its molecules are held together by ionic(electrostatic) force . These force must be weakened for its dissolution</em>
Forces in HF <em>:</em>
<em>1 .Hydrogen Bonding : In HF strong intermolecular Hydrogen Bonding exist between the electronegative F and Hydrogen</em>
2. Dipole - dipole : <em>HF is polar . So it is a permanent dipole and has dipole diople interaction</em>
