In comparison to molecules that interact by london dispersion forces only, the melting point of similar-sized molecules forming hydrogen bonds would most likely be
about the same.
unpredictable.
lower.
higher.

Molecules forming hydrogen bonds will have higher melting point.

Explanation:

Decreasing order of intermolecular forces in terms of their strength:

Ion-on > Hydrogen bond > dipole-dipole > London dispersion force

Hydrogen bonding is a combination of pure ionic bond and pure covalent bond. London dispersion force arises from weak dipole dipole interaction created due to polarizability of electrons during rotation around nucleus.

Hence molecules forming hydrogen bond will have higher intermolecular force. Therefore more temperature is required to melt it by disrupting intermolecular hydrogen bonds.

So, molecules forming hydrogen bonds will have higher melting point.

c. electrical charges of ionic bonds.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol