Introducción (2 puntos): Enumere al menos tres medios de análisis cualitativo que se utilizan para identificar metales. ¿Qué les sucede a los electrones cuando se calienta un elemento? Cuál es el significado de "estado excitado" de un átomo. Explique la diferencia visual entre los espectros de emisión y los espectros de absorción. Qué es la onda de longitud y cómo se relaciona con la energía. Referencias (0,5 ptos)

if two electrons have the same n, the same ℓ, and the same ml, then they are in the same orbital. the pauli exclusion principle states that no two identical fermions (a fancy word for electrons and other subatomic particles like electrons) may occupy the same quantum state in an atom simultaneously.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2