If the heat of combustion for a specific compound is -1460.0 kJ/mol and its molar mass is 55.75 g/mol, how many grams of this compound must you burn to release 900.20 kJ of heat?

1460 kJ/mol x ? mol = 900.25

Solve for ? mol and convert to grams by
g = mols/molar mass.

To calculate the grams of the compound that must be burned to release 900.20 kJ of heat, you can use stoichiometry.

Stoichiometry is a mathematical method that relates the amounts of substances involved in a chemical reaction. The balanced equation for the combustion of the compound directly relates the moles of the compound to the heat released.

First, we need to determine the number of moles of heat released by dividing the given heat value by the heat of combustion for the compound:

Moles of heat released = Heat released / Heat of combustion
= 900.20 kJ / -1460.0 kJ/mol (note that I used the negative value to indicate that heat is being released)
= -0.61662 mol (rounded to five decimal places)

Since the heat of combustion is given per mole, we know that for every mole of this compound, -1460.0 kJ of heat is released.

Next, we can use the molar mass of the compound to convert moles to grams. The molar mass is the mass of one mole of a substance.

Grams of compound = Moles of compound × Molar mass
= -0.61662 mol × 55.75 g/mol (rounded to five decimal places)
= -34.346 g (rounded to three decimal places)

Note that the negative sign indicates the heat is being released, and so the mass is also negative.

Therefore, you would need to burn approximately 34.346 grams (rounded to three decimal places) of this compound to release 900.20 kJ of heat.