Explain how heat transfer is occurring through convection, radiation and conduction in this picture.

Heat is type of energy can be transferred in three different ways:

1) direction contact through collisions (also called conduction).  

Thermal conductuction is the transfer of heat through physical contact.

Thermal conduction is the transfer of heat by microscopic collisions of particles.

Heat spontaneously flows from a hotter (in this example hot liquid) to a colder body (in this example spoon).

2) through a fluid making a current created by less dense fluids floating and more dense fluids sinking (also called convection).  

Stirring hot liquid with spoon.

3) by waves traveling with or without a medium (also called radiation).

Waves radiate from hot liquid.

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