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%
A molecular formula represents the exact number of atoms present for each element in the compound.
For carbon atom: 
= 
( as molar mass of carbon is 12 g/mol)
Now, 6 carbon atoms are present and rest are hydrogen atoms i.e. 6
Thus, formula becomes 
( 
Now, check for unsaturation:
Degree of unsaturation = 
Substitute the value of x and y,
Degree of unsaturation = 
= 
= 
implies one ring and three double bonds.
Thus, formula comes out to be i.e. benzene ring.
Answer:Iron is extracted from iron ore in a huge container called a blast furnace. Iron ores such as haematite contain iron(III) oxide, Fe 2O 3. The oxygen must be removed from the iron(III) oxide in order to leave the iron behind. Reactions in which oxygen is removed are called reduction reactions.
Oh we have just done this in biology recently... photolysis occurs where it splits apart water molecules to make electrons and hydrogen ions (the H+ is used to reduce NaDP later on) and also O₂ is made as a by product
basically this is the equation 2H₂O⇒4e⁻ + 4H⁺ where the electrons replace the lost ones in chlorophyll
hope this helped :)
