What is the enthalpy change if 25.0 g of methane are burned? 890kJ of heat released for every mole of methane that reacts. CH4 + 2O2 = CO2 + 2H2O
To determine the enthalpy change when 25.0 g of methane (CH4) is burned, we need to follow a few steps:
1. Calculate the number of moles of methane (CH4):
To find the number of moles, we can use the molar mass of methane, which is approximately 16.04 g/mol. Divide the given mass (25.0 g) by the molar mass:
25.0 g CH4 / 16.04 g/mol CH4 = 1.56 mol CH4 (rounded to two decimal places)
2. Use the stoichiometry of the reaction to determine the ratio between methane (CH4) and heat released:
According to the balanced equation:
1 mole of CH4 reacts to produce 890 kJ of heat.
So, 1.56 moles of CH4 would release:
1.56 mol * 890 kJ/mol = 1388.4 kJ (rounded to one decimal place)
Therefore, the enthalpy change when 25.0 g of methane is burned is approximately 1388.4 kJ of heat released.
To calculate the enthalpy change when 25.0 g of methane (CH4) is burned, we need to follow these steps:
Step 1: Determine the molar mass of methane (CH4).
The molar mass of carbon (C) is approximately 12.01 g/mol, and the molar mass of hydrogen (H) is approximately 1.01 g/mol. Since methane (CH4) contains one carbon atom and four hydrogen atoms, the molar mass of methane is:
(1 * 12.01 g/mol) + (4 * 1.01 g/mol) = 16.05 g/mol
Step 2: Convert the given mass of methane to moles.
Using the molar mass of methane calculated in Step 1, we can convert the mass of methane (25.0 g) to moles:
25.0 g / 16.05 g/mol = 1.558 moles
Step 3: Use the stoichiometry of the balanced chemical equation to determine the moles of heat released.
From the balanced equation:
1 mole of CH4 produces 890 kJ of heat.
Therefore, 1.558 moles of CH4 will produce:
1.558 moles * 890 kJ/mole = 1389.62 kJ
Therefore, the enthalpy change when 25.0 g of methane are burned is approximately 1389.62 kJ of heat released.
25g/molmassMethane=H/890kJ
solve for H