Question

What heat is liberated in the formation of 10.0 grams of sulfur hexafluoride, SF6, from the elements sulfur and fluorine?

Answer 1

83.5 kJ

Step-by-step explanation:

Molar mass is 146.053. Moles of 10.0 g = 0.0685 mol. Multiply by 1220 kJ/mol for the answer of 83.5 kJ.

Answer 2

`Q=-76.7kJ`

Step-by-step explanation:

Hello,

In this case, for such formation of sulfur hexafluoride, the standard enthalpy of formation is -1220.47 kJ/mol (data extracted from NIST database). Next, we compute the moles in 10.0 grams of sulfur hexafluoride as shown below:

`n_(SF_6)=10.0gSF_6*(1molSF_6)/(146.06 gSF_6)=0.0685mol`

Next, for the given energy, we compute the total heat that is liberated:

`Q=-1220.47(kJ)/(mol)*0.0685 mol\\\\Q=-76.7kJ`

Finally, we conclude such symbol has sense since negative heat is related with liberated heat.

Best regards.