That is, by definition, true.
Answer:
133 g
Explanation:
Step 1: Write the balanced equation
2 Al(s) + 3 Br₂(l) ⇒ 2 AlBr₃(s)
Step 2: Calculate the moles corresponding to 15.0 g of Al
The molar mass of aluminum is 26.98 g/mol. The moles corresponding to 15.0 g of Al are:

Step 3: Calculate the moles of Br₂ that react with 0.556 moles of Al
The molar ratio of Al to Br₂ is 2:3. The moles of bromine that react with 0.556 moles of aluminum are:

Step 4: Calculate the mass corresponding to 0.834 moles of Br₂
The molar mass of bromine is 159.81 g/mol. The mass corresponding to 0.834 moles of Br₂ is:

Answer:
What does that even mean?
Explanation:
To completely describe an electron in an atom, four quantum numbers are needed: energy (n), angular momentum (ℓ), magnetic moment (mℓ), and spin (ms). The first quantum number describes the electron shell, or energy level, of an atom.