If the cube is 3 cm on each side, then it has a volume of 27 cm^3 (3 x 3 x 3). Density is mass divided by volume, so its density is 72.9/27 = 2.7 g/cm^3.
<span>Going by the density, the cube is made of Aluminium - density is a fairly unique quantity</span>
Al
Explanation:
The limiting reactant will be Al:
4Al + 3O₂ → 2Al₂O₃
The limiting reactant is the reactant in short supply in a chemical reaction.
Given parameters:
Mass of Al = 30g Molar mass = 27g/mol
Number of moles =
= 
Number of moles of Al = 1.111 mole
Mass of O₂ = 30g, molar mass = 32g/mol
Number of moles =
= 0.94mol
In the reaction:
4 moles of Al reacted with 3 moles of O₂
1.11moles of Al will require
= 0.83mole to react
But we have been given 0.94mole of O₂. This is more than required.
Therefore O₂ is in excess and Al is the limiting reactant.
Learn more:
Limiting reagents brainly.com/question/6078553
#learnwithBrainly
A) - heat makes particles move faster, which usually makes the substance as a whole expand, but if the gas cannot expand the pressure will increase instead
No, because the appearance has nothing to do with system as well as the fact that appearance is only how it looks
(Btw, that toga picture is like... ughhhh!) hope this helps you ♥︎☀︎☁︎♨︎