Calculate the amount of heat released to convert 150.0 g of to water to ice at 0ºC.
-50100 J

-339,000 J

-627 J

-307.5 J

There correct answer is option 1 (-50100 J)

Explanation:

Step 1: Data given

Mass of water = 150.0 grams

ΔHfus = 334 J/g

Temperature = 0°C

ΔHfus = the amount of energy needed to change phase of 1 mol water to ice

Step 2: Calculate the amount of heat required

Q = m*ΔHfus

⇒Q = the amount of heat reuired = TO BE DETERMINED

⇒m =the mass of water = 150.0 grams

⇒ΔHfus = 334 J/g

Q = 150.0 grams * 334 J/g

Q = 50100 J  of heat required

Step 3: Calculate heat released

Qrequired = -Q released

Qreleased = -50100 J

There correct answer is option 1 (-50100 J)

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.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).