Number of moles of FeCl2 used = mass/ molar mass
Number of moles = 507/126.751 = 4.
If one mole of Fe reacts with two moles of sodium
Then 4 moles of Fe produces 8 moles of sodium.
Number of moles of sodium = mass/molar mass
Molar mass of sodium chloride = 23 +35.5 = 58.5 g/mol
Hence mass = 8 * 58.5 = 468 g. Hence Option A.
Answer:
6.66 s will it take for [AB] to reach 1/3 of its initial concentration 1.50 mol/L.
Explanation:
The order of the reaction is 2.
Integrated rate law for second order kinetic is:
Where, is the initial concentration = 1.50 mol/L
is the final concentration = 1/3 of initial concentration = = 0.5 mol/L
Rate constant, k = 0.2 L/mol*s
Applying in the above equation as:-
<u>6.66 s will it take for [AB] to reach 1/3 of its initial concentration 1.50 mol/L.</u>
Given :
Mass of caffeine at dangerous level , m = 3 g .
Coffee contains , 21.5 mg/oz OF caffeine .
Mass of cup , 8 oz/cup .
To Find :
Number of cups till dangerous level .
Solution :
Caffeine in a cup of coffee is given by :
Now , number of cups at the dangerous level is given by :
Now , number of cups should be integer .
Therefore , 18 cups of coffee per day is dangerous .