21.69mL - 20.70mL = .99mL Fe
7.8 g / .99 mL = 7.9g/mL
Answer
D
Explanation:
They take up usable forms of nitrogen found in soil
At room temperature, O2 is in gaseous state.
a gas has no definite volume or definite shape. It occupies volume of container and attains shape of container only.
Thus
It has no definite volume and takes the shape of its container.
Its particles move fast enough to overcome the attraction between them.: the gas molecules have minimum intermolecular interactions and have high kinetic energy.
It has more energy than it would at a cooler temperature: the kinetic energy of gas molecules increases with increase in temperature. Thus the energy increases with temperature and decreases with decrease in temperature.
Answer: Molarity increases
Explanation:
Molarity, also known as concentration in moles/dm3 or g/dm3, is calculated by dividing the amount of solute dissolved by the volume of solvent. So, Molarity (c) = amount of solute (n) / volume (v)
i.e c = n/v
Hence, molarity is directly proportional to the amount of solute dissolved, and inversely proportional to the volume of solvent.
Thus, at same volume, any increase in solute amount increases molarity while a decrease will also decreases molarity.
<u>Answer:</u> The
for the reaction is -1835 kJ.
<u>Explanation:</u>
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.
The given chemical reaction follows:

The intermediate balanced chemical reaction are:
(1)
( × 4)
(2)

The expression for enthalpy of the reaction follows:
![\Delta H^o_{rxn}=[4\times (-\Delta H_1)]+[1\times \Delta H_2]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B4%5Ctimes%20%28-%5CDelta%20H_1%29%5D%2B%5B1%5Ctimes%20%5CDelta%20H_2%5D)
Putting values in above equation, we get:

Hence, the
for the reaction is -1835 kJ.