1. based on the information from the movie, what can you conclude about the most common chemical compound on earth?

a. it's oxygen
b. it's hydrogen gas
c. it's carbon dioxide
d. it's water

2. what is true of a compound?

a. it does not always retain the properties of the substances that make it up
b. it must have water as one of its components
c. it requires heat energy to make
d. it requires electrical energy to make

1.   d. It's water

2.  a. It does not always retain the properties of the substances that make it up

Explanation:

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