Ok, after doing an immense amount of research I came up with the most logical answer.
A. Is indicated by a negative enthrall sign.
Reasoning: an endothermic reaction is ice melting and the energy being more than its surroundings. Not specified to ice but as an example, ice is endothermic. That puts d and b out of the running leaving you left with a and c.
When I searched up enthalpy, it said “When a substance changes at constant pressure, enthalpy tells how much heat and work was added or removed from the substance.” Which is similar to c, right? Yeah, meaning both a and c are similar in that aspect.
The reason I decided to go with a is because heat is NOT released into the surrounding, exothermic reactions release energy and heat into the surrounding.
The chemical formula of a compound express the atoms by which the molecule is formed and the ratio of the atoms in which they are combined.
The space filling model of a compound describe the electron density in the compound of each atom.
The ball and stick arrangement of a compound describe the way in which the molecules are present in three dimensions.
The structural formula state the number of atoms present in the molecule, the type of element or atom present in the molecule and the way in which they are arranged closely which is the bond.
Thus only the structural formula only will cover all the options as stated.
How much it has to drop and how heavy it is. Hope this is what you're looking for:)
While metallic bonds have the strong electrostatic force of attractions between the cation or atoms and the delocalized electrons in the geometrical arrangement of the two metals. ... Metallic bonds are malleable and ductile, while covalent bonds and ionic bonds non-malleable and non-ductile.
Answer:- HBr is limiting reactant.
Solution:- The given balanced equation is:

From this equation, There is 2:6 mol or 1:3 mol ratio between Al and HBr. Since we have 8 moles of each, HBr is the limiting reactant as we need 3 moles of HBr for each mol of Al.
The calculations could be shown as:

= 24 mol HBr
From calculations, 24 moles of HBr are required to react completely with 8 moles of Al but only 8 moles of it are available. It clearly indicates, HBr is limiting reactant.