1.How to evaluate the following 3log_2(1/2) -2log_2(1/4)2.Determine the pH

1.How to evaluate the following

3log_2(1/2) -2log_2(1/4)

2.Determine the pH

of a solution with a hydrogen ion concentration of 0.00101 mol/L. 

3.How many times more intense, to two decimal places, was the 2011 earthquake in Japan that measured 9.0 on the Richter scale than the 1905 earthquake in San Francisco that measured 8.1 on the Richter scale? 

4.Due to employee safety negligence at a nuclear waster facility, 2000 tons of a radioactive element is spilled into the nearby pond. The half-life of the radioactive element is 36 days. In order to be declared safe for swimming, based on its size and the amount of water, there must be less than 100 tons of the material found in the pond. How long, to the nearest day, until it is safe to swim again.