The characteristics of a certain gas are listed in the table.
Characteristics of a Gas
Characteristic Description
Compound
Oxygen gas
Condition
STP
Mass
4.8 grams
What is the expected density of the above sample of gas?
O 1.90 g/L
O 1.82 g/L
O 1.56 g/L
O 1.43 g/L

1.56 g/L sample of gas in grams

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.

the answer is 303.15 or 303