1. Molten rock flows onto the seafloor and hardens as it cools.
2. Hot, molten rock is forced upward toward the seafloor at a mid-ocean ridge
3. New seafloor moves away from the ridge, cools, becomes denser and sinks.
4. Molten rock pushes sideways in both directions as it rises, moving the mantle with it.
Directions: Complete the concept map using the terms in the list below.
mid-ocean ridges
volcanic islands major earthquakes
rift valleys
deep-sea trenches
volcanic mountains
Plate boundaries
include
include
include
trans

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

they are called fossil fuels