Lab: Plate Boundaries and Movement Instruction Active
Understanding Convection Currents
Which statement accurately describes the movement of Earth's plates due to convection currents?
Material near the core cools as heat is transferred toward the crust.
Heated materials become denser, causing them to rise toward the surface.
As heated material gets closer to the surface, it begins to cool.
As materials cool, they become less dense and sink back toward the core.
Which

The correct answer is C. As heated material gets closer to the surface, it begins to cool.

Explanation:

Convection currents involve the flow and movement of particles in gases or liquids due to changes in temperature and density. This occurs on the Earth's mantle, which is partially liquid and it is located between the core (center of Earth) and the crust composed of plates.

In this way, molten material that is near the core heats and rises as it is less dense, but once it reaches the crust it cools, and after some time it sinks again as the magma increases its density. This cycle is constant and causes the movement of the plates in the crust, that might move apart or toward other plates. According to this, the only accurate statement is "As heated material gets closer to the surface, it begins to cool".

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