<span>Boiling point- 100 ℃, or <span>373.15K</span></span>
I believe the correct answer from the choices listed above is option D. The modern atomic model is sometimes called the electron cloud or quantum mechanics model. It <span>uses complex shapes of orbitals (sometimes called electron clouds), volumes of space in which there is likely to be an electron. </span>
Hope this answers the question. Have a nice day.
Answer:
NO, they are not the same compound
Explanation:
Given that;
Compound A melts at 220.5 °C - 222.1 °C; &
Compound B melts at 221.2 °C - 223.4 °C
It is seen from above that there is little difference in the melting point of Compound A and B. This little difference can be as a result of factors associated when carrying the melting process or because different methods were employed in the establishing their melting points.
Also, we were told that when they were both mixed together , the mixture of compound A and B melts at 216.4 °C - 224.6 °C.
This statement has largely indicated that both compounds are not the same at all, because if they were, the mixture of compound A and B melting point must be identical to one of the individual compound's melting point either from compound A or from compound B.
Answer:
Explanation:
2Al(s) + Fe₂O₃(s) ⟶ Al₂O₃(s) + 2Fe(s); ΔᵣH = ?
The formula for calculating the enthalpy change of a reaction by using the enthalpies of formation of reactants and products is
2Al(s) + Fe₂O₃(s) ⟶ Al₂O₃(s) + 2Fe(s)
ΔfH°/kJ·mol⁻¹: 0 -824.3 -1675.7 0
![\begin{array}{rcl}\Delta_{\text{r}}H^{\circ} & = & [1(-1675.7) + 2(0)] - [2(0) - 1(-824.3)]\\& = & -1675.7 + 824.3\\& = & \textbf{-851.4 kJ/mol}\\\end{array}\\\text{The enthalpy change is } \large \boxed{\textbf{-851.4 kJ/mol}}](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Brcl%7D%5CDelta_%7B%5Ctext%7Br%7D%7DH%5E%7B%5Ccirc%7D%20%26%20%3D%20%26%20%5B1%28-1675.7%29%20%2B%202%280%29%5D%20-%20%5B2%280%29%20-%201%28-824.3%29%5D%5C%5C%26%20%3D%20%26%20-1675.7%20%2B%20824.3%5C%5C%26%20%3D%20%26%20%5Ctextbf%7B-851.4%20kJ%2Fmol%7D%5C%5C%5Cend%7Barray%7D%5C%5C%5Ctext%7BThe%20enthalpy%20change%20is%20%7D%20%5Clarge%20%5Cboxed%7B%5Ctextbf%7B-851.4%20kJ%2Fmol%7D%7D)
Answer:
A
Explanation:
Quaternary structure of proteins is composed of two or more polypeptide chains. Insulin has two; one alpha and one beta chain. The two chains are joined together by disulfide bonds at two points (at cysteines). Other examples of quaternary proteins structures are DNA polymerase and hemoglobin.
