Answer:
electrons fill lower energy levels first before occupying higher energy levels.
Explanation:
The Aufbau's principle describes that electrons fill lower energy levels first before occupying higher energy levels.
In writing the electronic configuration of atoms, the Aufbau's principle is one of the most important principles to consider.
It states that "sublevels with with lower energies are filled up before those with higher energies".
Sublevels do not fill up in numerical order.
Amphetamine was developed initially as a substitute for a closely-related chemical derived from the Chinese herb ma huang. That chemical is Ephedrine.
<h3>
What is Ephedrine?</h3>
Ephedrine is a stimulant medication that can be considered an amine chemical compound and substituted amphetamine.
Ephedrine is used in sports to stimulate the central nervous system (C_NS) and as energy supplier.
Ep_hedrine use is prohibited and chronic usage of this substance may have problems the health.
Learn more about Ephedrine here:
brainly.com/question/1122074
Answer:
2 Al + 3 Pb(NO3)2 > 2 Al(NO3)3 + 3 Pb
Explanation:
Answer:
the Molar heat of Combustion of diphenylacetylene 
= 
Explanation:
Given that:
mass of diphenylacetylene = 0.5297 g
Molar Mass of diphenylacetylene = 178.21 g/mol
Then number of moles of diphenylacetylene = 
= 
= 0.002972 mol
By applying the law of calorimeter;
Heat liberated by 0.002972 mole of diphenylacetylene = Heat absorbed by 
+ Heat absorbed by the calorimeter
Heat liberated by 0.002972 mole of diphenylacetylene = msΔT + cΔT
= 1369 g × 4.184 J g⁻¹°C⁻¹ × (26.05 - 22.95)°C + 916.9 J/°C (26.05 - 22.95)°C
= 17756.48 J + 2842.39 J
= 20598.87 J
Heat liberated by 0.002972 mole of diphenylacetylene = 20598.87 J
Heat liberated by 1 mole of diphenylacetylene will be = 
= 6930979.139 J/mol
= 6930.98 kJ/mol
Since heat is liberated ; Then, the Molar heat of Combustion of diphenylacetylene =
Answer:
84.24 g
Explanation:
Given data:
Mass of oxygen = 75 g
Mass of Al required to react = ?
Solution:
Chemical equation:
4Al + 3O₂ → 2Al₂O₃
Number of moles of oxygen:
Number of moles = mass/ molar mass
Number of moles = 75 g/ 32 g/mol
Number of moles = 2.34 mol
Now we will compare the moles of oxygen with Al.
O₂ : Al
3 : 4
2.34 : 4/3×2.34 = 3.12 mol
Mass of Al required:
Mass = number of moles × molar mass
Mass = 3.12 mol × 27 g/mol
Mass = 84.24 g
