Answer:
Percentage yield = 85.2%
Explanation:
Given data:
Mass of Mg = 21.3 g
Actual yield of MgO = 30.2 g
Percentage yield = ?
Solution:
Chemical equation:
2Mg + O₂ → 2MgO
Number of moles of Mg = mass/molar mass
Number of moles of Mg = 21.3 g / 24.3 g/mol
Number of moles of Mg = 0.88 mol
Now we will compare the moles of MgO with Mg.
Mg : MgO
2 : 2
0.88 : 0.88
Mass of MgO:
Mass of MgO= moles × molar mass
Mass of MgO= 0.88 mol × 40.3g/mol
Mass of MgO = 35.46 g
Actual yield of MgO = 30.2 g
Percentage yield:
Percentage yield = Actual yield/theoretical yield × 100
Percentage yield = 30.2 g/ 35.46 g × 100
Percentage yield = 85.2%
Answer:
The Aufbau Principle
Explanation:
In the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy level before occupying higher-energy levels.
The density of ice is less than the density of water (liquid). We generally observe that the density of a solid substance is more than its liquid form as volume of a solid is generally less than the liquid, However in case of water this is not true.
The volume of ice is less than that of liquid water due to an open cage like structure in ice which gives its a wide structure. This cage like structure is due to presence of hydrogen bond (more extensive) in ice.
The maximum density of water is observed at 4 degree celsius
Answer: The correct answer is (D).
Explanation:
Space photography help astronomers:
- To visualize and observe the position and appearance of celestial objects like: path of orbiting planets ,dim stars which invisible to naked eyes ,far away galaxies etc.
- To observe any phenomena which is occurring at macro level for example: collision of steroids and meteors etc.
