Answer: 243 hours
Explanation:
Expression for rate law for first order kinetics is given by:

where,
k = rate constant
t = age of sample
a = initial amount of the reactant = 
a - x = amount left after decay process = 
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.


b) for reducing the mass to 10.00 % of its original mass



The time taken to reach 10.00 % of its original mass is 243 hours
Answer:
Try a hard reset: Press and hold both the power button and the volume button (plus the other 2 as well perhaps) for about 10 seconds and then release. Check if the earphones will then either show that they are charging (with the cable inserted of course) or that they will turn on if the Power button is pressed. Explanation:Hope this helped you
Equation :
PbF2 ------> Pb2+ + 2F-
Solubility product is given as:
Ksp = [Pb2+][F-]^2
let x = [Pb2+]
Ksp = x(2x)^2 = 4(x)^3 = 4(2.08*10^-3)^3
Ksp = 3.60*10^-8
The solid state where particles are more compact
The unit expressed in 660 nm of light represents the wavelength of light. If you want to determine the frequency, you use the speed of light to relate the two. The formula is:
c = λν
where
λ is the wavelength
ν is the frequency
c is the speed of light = 3×10⁸ m
Apply SI units:
(3×10⁸ m) = (660×10⁻⁹ m)(ν)
Solving for ν,
<em>ν = 4.55×10¹⁴ s⁻¹</em>