Ra (radium) is the most reactive
Answer:
66.7s
Explanation:
Let's bring out the parameters we were given...
Half life = ?
Initial Concentration = 0.0576 M
Final Concentration = 0.0249 M
Time for the concentration change to occur = 97.8s - 17.1s = 80.7s
Formular for half life (t1/2) is given as;
t1/2 = ln2 / k ≈ 0.693 / k
where k = rate constant
From the formular of first order reactions;
ln[A] = ln[A]o − kt
where [A] = Final Concentration and [A]o = Initial Concentration
Inserting the values, we have;
ln(0.0249) = ln(0.0576) - k(80.7)
Upon solving for k, we have;
-0.8387 = -k(80.7)
k = 0.01039 s−1
t1/2 = 0.693 / k = 0.693 / 0.01039 = 66.7s
The given information in the question is :
Frequency = 170 Hz
1 Hz = 
Frequency = 170 
Wavelength given = 2 m
Speed is unknown which we need to calculate.
Speed can be calculated by using the formula : Speed = wavelength X frequency
By plugging the value of wavelength and frequency in the above formula we get :
Speed = 
Speed = 340
Explanation:
The use of microorganism in our day to day life is making medicine.
Explanation:
Equation of the reaction:
Br2(l) + Cl2(g) --> 2BrCl(g)
The enthalpy change for this reaction will be equal to twice the standard enthalpy change of formation for bromine monochloride, BrCl.
The standard enthalpy change of formation for a compound,
ΔH°f, is the change in enthalpy when one mole of that compound is formed from its constituent elements in their standard state at a pressure of 1 atm.
This means that the standard enthalpy change of formation will correspond to the change in enthalpy associated with this reaction
1/2Br2(g) + 1/2Cl2(g) → BrCl(g)
Here, ΔH°rxn = ΔH°f
This means that the enthalpy change for this reaction will be twice the value of ΔH°f = 2 moles BrCl
Using Hess' law,
ΔH°f = total energy of reactant - total energy of product
= (1/2 * (+112) + 1/2 * (+121)) - 14.7
= 101.8 kJ/mol
ΔH°rxn = 101.8 kJ/mol.