When a COVALENT compound (such as ICE or WAX) MELTS, this is due to... [NONE of these] the LIQUEFACTION of the atoms themselves the breaking of the INTERMOLECULAR FORCES the breaking of the COVALENT BONDS within the molecule

Which of the following are double displace- ment reactions?

7) Which box from Model 2 represents an element? * 1 point \( A \) B C D E 8) Which box from Model 2 represents a mixture of 2 elements? * 1 point A B C D E

\begin{tabular}{l} EMESTRADA \\ EXAMENESDE \\ SELECTIVIDAD \\ En la reacción del oxigeno molecular gaseoso con el cobre para formar óxido de cobre(II) se \\ desprenden \( 2,30 \mathrm{~kJ} \) por cada gramo de cobre que reacciona, a 298 K y 760 mmHg . Calcule: \\ a) La entalpía de formación del óxido de cobre(II). \\ b) El calor desprendido a presión constante cuando reaccionan 100 L de oxígeno, medidos a 1,5 \\ atm y \( 27^{\circ} \mathrm{C} \). \\ Datos: \( \mathrm{R}=0^{\prime} 082 \mathrm{~atm} \cdot \mathrm{~L} \cdot \mathrm{~mol}^{-1} \cdot \mathrm{~K}^{-1} \). Masa atómica Cu=63,5 \\ QUÍMICA. 2013 . JUNIO. EJERCICIO 6. OPCIÓN A \\ \hline\end{tabular}

QuEsTION (a) Write the product(s) in the followins reactions: CH3 (i) \( \mathrm{CH}_{3}-\mathrm{CH}-\mathrm{O}-\mathrm{CH}_{2}-\mathrm{CH}_{3} \xrightarrow{\mathrm{HH}_{3}} \) ? + ?

[3-441] Hydrocyanic acid is one of the weak acids which is incompletely ionized, and its ionization is according to the following equation: \[ \mathrm{HCN}_{(\mathrm{aq})}+\mathrm{H}_{2} \mathrm{O}_{(0)} \rightleftharpoons \mathrm{H}_{3} \mathrm{O}^{+}(\mathrm{aq})+\mathrm{CN}^{-}(\mathrm{aq}) \] On adding drops of \( \mathrm{H}_{2} \mathrm{SO}_{4} \) solution: the concentration of \( \mathrm{CN}^{-} \)will ...... and on adding drops of KOH solution: the concentration of \( \mathrm{CN}^{-} \)will ...... a) decreases, increases b) increases, increases c) increases, decreases d) decreases, decreases