Half life of the reaction is :-101.9 min
a→b
25% reacted means 75% remains
t=42 min
Rate constant
k=(2.303/t)(log a/a-x)
k=(2.303/42)(log 100/100-25 )
k=(0.054) (log 100/75)
k=(0.054)(0.1249)
k=0.0068per min
half life
t1/2=(0.693/k)
=(0.693/0.0068)
=101.9 min
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Density is defined by the above term
Answer:
In 4.5 grams of tetraphosphorus decoxide we have 3.85 * 10^22 phosphorus atoms
Explanation:
Step 1: Data given
tetraphosphorus decoxide = P4O10
Molar mass of P4O10 = 283.89 g/mol
Mass of P4O10 = 4.5 grams
Number of Avogadro = 6.022 * 10^23 / mol
Step 2: Calculate moles of P4O10
Moles P4O10 = mass P4O10 / molar mass P4O10
Moles P4O10 = 4.5 grams / 283.89 g/mol
Moles = 0.016 moles
Step 3: Calculate moles of P
For 1 mol P4O10 we have 4 moles of phosphorus
For 0.016 moles P4O10 we have 4*0.016 = 0.064 moles P
Step 4: Calculate number of P atoms
Number of P atoms = moles P * number of Avogadro
Number of P atoms = 0.064 moles * 6.022*10^23
Number of P atoms = 3.85 * 10^22 atoms
In 4.5 grams of tetraphosphorus decoxide we have 3.85 * 10^22 phosphorus atoms
Grams per milliliter is the most common unit.
