Asubstance decays so that the amount a of the substance left after t years is given by: a = a 0 · (0.9) t , where a 0 is the original amount of the substance. what is the half-life (the amount of time that it takes to decay to half the original amount) of this substance rounded to the nearest tenth of a year?

I think the correct form of the equation is given as:

a = a0 * (0.9)^t

where t is an exponent of 0.9 since this is an exponential decay of 1st order reaction

Now to solve for the half life, this is the time t in which the amount left is half of the original amount, therefore that is when:

a = 0.5 a0

Substituting this into the equation:

0.5 a0 = a0 * (0.9)^t

0.5 = (0.9)^t

Taking the log of both sides:

t log 0.9 = log 0.5

t = log 0.5 / log 0.9

t = 6.58 years

half life = 6.58 years

the answer is: they rebelled against saddam hussein’s rule.

kurds opposed saddam rule and wanted independence. kurds in the north and shiites in the south revolt against hussein.

for example, the halabja attack in 1988 conducted against the kurdish people by the iraqi regime under saddam hussein, where between 4000 people are killed and around 9000 are injured.

the molecules move in straight line until they collide with each other or with the walls of the container. collisions are perfectly elastic; when two molecules collide, they change their directions and kinetic energies, but the total kinetic energy is conserved.

explanation: