Answer:
A
Explanation:
A chemical change is when a new substance is created, which often has its own chemical properties, so A is the correct answer.
Common based on their location in Periodic Table;
Potassium has an atomic number 19. Its electronic configuration is as follow;
1s², 2s², 2p⁶, 3s², 3p⁶, 4s¹
And Krypton has an atomic number of 36. Its electronic configuration is as follow;
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶
It is concluded that both Potassium and Krypton has their valence electrons in 4rth shell or they have same Principle Quantum Number.
Difference based on their location in Periodic Table;
As observed in electronic configuration Potassium has one valence electron in its valence shell (i.e. 4s¹) while, Krypton has eight valence electrons in its valence shell (i.e. 4s², 4p⁶). Therefore, they are different in the number of valence electrons.
Answer:8
Everything after the decimal place is a significant figure here
Answer:
Mass = 0.004 g
Explanation:
Given data:
Mass of zinc sulfide = 46.32 g
Mass of oxygen = 15.5172 g
Mass of zinc oxide = ?
Solution:
Chemical equation:
2ZnS + 3O₂ → 2ZnO + 2SO₂
Number of moles of ZnS:
<em>Number of moles = mass/ molar mass</em>
Number of moles = 46.32 g/ 97.5 g/mol
Number of moles = 0.46 mol
Number of moles of Oxygen:
<em>Number of moles = mass/ molar mass</em>
Number of moles = 15.5172 g/ 32 g/mol
Number of moles = 0.48 mol
Now we will compare the moles of oxygen and zinc sulfide with zinc oxide.
ZnS : ZnO
2 : 2
0.46 : 0.46
O₂ : ZnO
3 : 2
0.48 : 2/3×0.48 =0.32 mol
The number of moles of zinc oxide produced by oxygen are less so it will limiting reactant.
Mass of zinc oxide:
Mass = number of moles / molar mass
Mass = 0.32 mol / 81.38 g/mol
Mass = 0.004 g
