What happens when the chemicals inside an instant cold pack mix together A. the mixture inside the pack gives off coldness
B. the mixture generates static electricity
C. the mixture absorbs thermal energy from the surroundings
D. the mixture releases thermal energy into the surroundings.

the answer is C

Explanation:

there is no such thing as COLD exept absolute ZERO. anything that feels COLD, perse, is just tranfering your thermal energy into it, since it is lacking that energy

answer by yourhope:

how do models compare to real-world objects?

d. most models represent a real-world object in a simpler way.

: )

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