Answer:
A
Explanation:
Recall that Δ<em>H</em> is the sum of the heats of formation of the products minus the heat of formation of the reactants multiplied by their respective coefficients. That is:
Therefore, from the chemical equation, we have that:
![\displaystyle \begin{aligned} (-317\text{ kJ/mol}) = \left[\Delta H^\circ_f \text{ N$_2$H$_4$} + \Delta H^\circ_f \text{ H$_2$O} \right] -\left[3 \Delta H^\circ_f \text{ H$_2$}+\Delta H^\circ_f \text{ N$_2$O}\right] \end{aligned}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cbegin%7Baligned%7D%20%28-317%5Ctext%7B%20kJ%2Fmol%7D%29%20%3D%20%5Cleft%5B%5CDelta%20H%5E%5Ccirc_f%20%5Ctext%7B%20N%24_2%24H%24_4%24%7D%20%2B%20%20%5CDelta%20H%5E%5Ccirc_f%20%5Ctext%7B%20H%24_2%24O%7D%20%20%5Cright%5D%20%20%20-%5Cleft%5B3%20%5CDelta%20H%5E%5Ccirc_f%20%5Ctext%7B%20H%24_2%24%7D%2B%5CDelta%20H%5E%5Ccirc_f%20%5Ctext%7B%20N%24_2%24O%7D%5Cright%5D%20%5Cend%7Baligned%7D)
Remember that the heat of formation of pure elements (e.g. H₂) are zero. Substitute in known values and solve for hydrazine:
![\displaystyle \begin{aligned} (-317\text{ kJ/mol}) & = \left[ \Delta H^\circ _f \text{ N$_2$H$_4$} + (-285.8\text{ kJ/mol})\right] -\left[ 3(0) + (82.1\text{ kJ/mol})\right] \\ \\ \Delta H^\circ _f \text{ N$_2$H$_4$} & = (-317 + 285.8 + 82.1)\text{ kJ/mol} \\ \\ & = 50.9\text{ kJ/mol} \end{aligned}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cbegin%7Baligned%7D%20%28-317%5Ctext%7B%20kJ%2Fmol%7D%29%20%26%20%3D%20%5Cleft%5B%20%5CDelta%20H%5E%5Ccirc%20_f%20%5Ctext%7B%20N%24_2%24H%24_4%24%7D%20%2B%20%28-285.8%5Ctext%7B%20kJ%2Fmol%7D%29%5Cright%5D%20-%5Cleft%5B%203%280%29%20%2B%20%2882.1%5Ctext%7B%20kJ%2Fmol%7D%29%5Cright%5D%20%5C%5C%20%5C%5C%20%5CDelta%20H%5E%5Ccirc%20_f%20%5Ctext%7B%20N%24_2%24H%24_4%24%7D%20%26%20%3D%20%28-317%20%2B%20285.8%20%2B%2082.1%29%5Ctext%7B%20kJ%2Fmol%7D%20%5C%5C%20%5C%5C%20%26%20%3D%2050.9%5Ctext%7B%20kJ%2Fmol%7D%20%5Cend%7Baligned%7D)
In conclusion, our answer is A.
Answer and Explanation:
Ions are electrically charged particles that are formed from the removing and addition of electrons. It can be a positively or negatively charged atom.
Kc = [H3O+][HCO3-] / [H2CO3]
Remember that Kc is products over reactants. Also, you do not include liquid water in a Kc expression, since liquid water has no concentration.
Answer:
<h3>The answer is 0.622 mL</h3>
Explanation:
The volume of a substance when given the density and mass can be found by using the formula
From the question
mass = 12 g
density = 19.30 g/mL
We have
We have the final answer as
<h3>0.622 mL</h3>
Hope this helps you
Answer:GASEOUS, LOWERING ,EMITTED AS HEAT, DOWN,DO NOT RELEASE,DECREASES,NEGATIVE.
Explanation: Filling the blanks gives
Lattice energy is associated with forming a crystalline lattice of alternating cations and anions from the _GASEOUS___________ ions.
Because the cations are positively charged and the anions are negatively charged, there is a LOWERING of potential- as described by Coulomb's law-when the ions come together to form a lattice energy.That energy is EMITTED AS HEAT when the lattice forms.
As the ionic radii increases as you move DOWN a group, ions cannot get as close to each other and therefore DO NOT RELEASE as much energy when the lattice forms. Thus the lattice energy DECREASES (becomes less) NEGATIVE as the radius increases.
The above gives the definition of Lattice Energy and how it relates to atomic and ion charge.
