Answer:
d. ΔH° > 0, process is endothermic.
Explanation:
Cold packs contain ammonium nitrate (NH₄NO₃). When this salt dissolves in water, it decreases the temperature of the surroundings. This happens because the process is endothermic (absorbs heat from the surroundings). By convention, when a process is endothermic, the standard enthalpy carries a positive sign (ΔH° > 0).
<u>Question 1</u>
The formula mass of methanol is 
g/mol.
Therefore, in 5.0 grams of methanol, there are 
moles.
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<u>Question 2</u>
The formula mass of copper(II) carbonate is 
g/mol.
This means that in 9.0 grams of copper(II) carbonate, there are 
moles.
Using Avogradro's number, there are 
molecules.
<u>Question 3</u>
The formula mass of cyclohexane is 
g/mol.
So, 3.0 grams of cyclohexane is the same as 
moles.
<u>Question 4</u>
The formula mass of benzene is 
g/mol.
This means that 4.00 moles of benzene has a mass of 
grams.
<u>Question 5</u>
1000 atoms of calcium is the same as 
moles.
This is equal to 
grams.
Answer:
B
Explanation:
the pH scale is based on the function
1x10-14
So since pH is neutral the concentration of OH and H must be equal hence the only option in which the concetration would [OH]{H}= 1x10-14 would be when both are equal so it cannot be a or d and when they are expressed in concetration so the only option is B.
The littoral zone of a lake is the area closest to the shore. It has very little biological activity but includes a lot of oxygen. The water in the lake's littoral zone is freshwater, free of living organisms such as plants and fish.
