Cyclopropane and propylene isomers both have the formula c3h6. based on the molecular structures shown, which of these isomers would you expect to have the higher standard molar entropy at 25 oc

The measure of randomness or uncertainty  of the substance is known as the entropy of the substance.

Under the standard state, the entropy of one mole of substance is known as its standard molar entropy.

The structure of cyclopropane and propylene is shown in the attached image.

Since, the structure of propylene is an open chain structure thus, possessing high randomness. Whereas the structure of cyclopropane is ring (closed) structure and thus, not that much free to move and has less randomness.

Hence, the structure of propylene will have the higher standard molar entropy.

Propylene having an open chain structure has a greater molar entropy than cyclopropane having a closed structure.

Entropy is a measure of the extent of disorder in a system. When a system is more disorderly, the entropy is higher. For a molecule, the degree of restriction of atoms in the molecule affects its entropy.

For open chain structures, there is a greater degree of randomness due to less restriction of atoms in the molecule than closed chain structures. Hence, propylene having an open chain structure has a greater molar entropy than cyclopropane having a closed structure.

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c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%