The formation of nitric acid from nitrogen, hydrogen, and oxygen can be written as,
N₂ + H₂ + 3O₂ --> 2HNO₃
The net enthalpy of formation of nitric acid is calculated by,
Hrxn = Hproduct - Hreactant
Since all the reactants are in their elemental forms, the simplified equation would be,
Hrxn = Hproduct
Substituting,
Hrxn = (-186.81 kJ/mol)(2 mols)
<em>Answer: -372.42 kJ</em>
A is obviously out because it leads to a volume of 125.0 milliliters of the new solution and gives you a lower concentration than you were aiming for.
D is out because you are adding 75 milliliters of the stock solution, so your concentration would be too high. You only need 25.0 milometers of stock solution per 100 milliliters of the new solution.
C is also out because it leads to 50.0 milliliters stock solution per 100 milliliters of the new solution and hence the wrong concentration.
B is by default the correct answer. It also details the correct technique. First you add the stock solution (This you know from your calculations to be 25 milliliters.) then you add the water up to the volume you needed. (Because the calculations only tell you the total volume of water not what you need to add) You also add the water last so you can rinse the neck of the flask to make sure you also get all the stock solution residue into the stock solution.
I would add the final step of stirring, but B is the only answer that can be correct.
"A contactor is a electrically controlled switch which uses an electromagnetic coil to pull in the contacts.”
"A motor starter is a contactor, plus an overload relay that will drop out the coil voltage if the motor overloads. If there is not overload relay, it is not a starter any longer, it's back to being just a contactor."
Well to find speed you have to do distance /time. So, in this case you do 112m /29s which it will be 3.862 which if you round it, it will be 3.86 m/s
Answer:
Explanation:
We have the number 
. Standard notation would basically be this number without the 
part.
To get rid of this part, we need to move the decimal point 6 places to the left (we go left because it's negative 6, indicating division).
So, when we move the decimal point 6 places to the left, the resulting number is: , with 5 zeros after the decimal point before a nonzero number.
Thus, the answer is .
