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
o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante
assuming that your periodic table has eighteen columns, you should highlight the four elements in the third column from the left of the table.explanation
neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.
by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.
potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.
a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.