Testing of an unknown solid shows that it has the properties listed below. (1) low melting point (2) nearly insoluble in water (3) nonconductor of electricity (4) relatively soft solid a State the type of bonding that would be expected in the particles of this substance.] b Explain in terms of attractions between particles why the unknown solid has a low melting point. c Explain why the particles of this substance are poor conductors of electricity.

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