شرح درس
Calculation of chemical formula
CHEMISTRY - Secondary 1
In This part we will study
Calculation of the percentage of actual yield
On carrying out any chemical reaction:
• The amount of the substance which is being obtained practically in the lab through this chemical reaction is known as the actual yield (or the practical yield or product).
• The amount of the substance which is expected to be obtained according to the mathematical calculations of the reaction equation is called the theoretical yield.

The actual yield is mostly less than the theoretical yield, this is due to a number of reasons, among which are:
- Reactants may contain impurities.
- Volatilization of a part of the products during the reaction.
- Some side reactions may take place resulting in the consumption of a part of the products.
- Sticking of a part of the products to the walls of the reaction container.

Example (1) :
Methyl alcohol CH3OH is prepared according to the reaction :
CO(g) + 2H2(g) → CH3OH(l)
Calculate the percentage of the actual yield of the reaction, if you know that when 1.2 g of hydrogen gas reacts with excess of carbon monoxide gas it produces 6.1 g of methyl alcohol. [C = 12 , H = 1 , O = 16]
Solution

Example (2) :
Ammonia gas reacts with excess of oxygen gas forming nitric oxide gas according to the equation:
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(v)
Calculate the mass of ammonia gas, knowing that the mass of the actual yield of nitric oxide gas is 5 g and its percentage is 40%
Solution

Best wishes to you
Mr.Ahmed Elbasha

كيمياء الصف الاول الثانوي لغات - الفصل الدراسي الاول
شرح كيمياء لغات اولي ثانوي - مستر احمد الباشا
كيمياء لغات - الصف الاول الثانوي - كيمياء اولي ثانوي الترم الاول - كيمستري اولي ثانوي الترم الاول