The answer is "A. Volcanic Neck"
1. Rocks near mid-ocean ridge were younger than rock near trenches
2.Matching bands of magnetic rocks were found on either side the mid-ocean ridge; bands like tree rings - record changes in earth's magnetic field over time
3. Earthquake data showed oceanic crust is sinking on to the mantle at trenches
Answer:
4.02g of Na2CO3⸱2H2O must be added completing the volume of the solution to 100mL
Explanation:
A 3%(w/v) solution contains 3g of solute (In this case, Na2CO3) in 100mL of solution.
Assuming we require 100mL of solution we must add 3g of Na2CO3. The reactant that is available is its dihydrate, with molar mass:
106g/mol + 2*MW H2O
106g/mol + 2*18g/mol = 142g/mol
That means the mass of Na2CO3.2H2O that must be added to prepare the solution is:
3g Na2CO3 * (142g/mol Na2CO3.2H2O / 106g/mol Na2CO3) =
<h3>4.02g of Na2CO3⸱2H2O must be added completing the volume of the solution to 100mL</h3>
Explanation:
The relation between change in entropy and is as follows.
The given data is as follows.
mass = 500 g
= 24.4 J/mol K
= 500 K
= 250K
As, atomic mass of copper = 63.54 g /mol. Therefore, number of moles of copper will be calculated as follows.
Number of moles =
=
= 7.86 moles
Hence,
= 750
For the metal block A,
=
= -3.04 J/ K mol
For the block B,
= 4.296
Therefore, calculate the change in entropy as follows.
Total entropy change = 4.296 + (-3.04)
= 1.256 J/Kmol
Thus, we can conclude that the change in entropy for given two blocks of copper is 1.256 J/Kmol
.