I just need B and C...posting A so you can see the whole question...Suppose a gr
ID: 988402 • Letter: I
Question
I just need B and C...posting A so you can see the whole question...Suppose a group of volunteers is planning on building a park near a local lake. The lake is known to contain low levels of arsenic (As). Therefore, prior to starting construction, the group decides to measure the current level of arsenic in the lake. a) If a 15.5 cm3 sample of lake water is found to have 176.9 ng As, what is the concentration of arsenic in the sample in parts per billion (ppb), assuming that the density of the lake water is 1.00 g/cm3? One of the volunteers suggests hiring an on-site water treatment company to remove the arsenic from the lake. The company claims their process takes 2.94 days to remove 51.40 kg of As from a water source. b) Calculate the total mass (in kg) of arsenic in the lake that the company will have to remove if the total volume of water in the lake is 0.370 km3 c) Based on the company's claim and the concentration of arsenic in the lake, how many years will it take to remove all of the arsenic from the lake, assuming that there are always 365 days in a year?
Explanation / Answer
Solution:
Content: 164.5 ng As in 15.7 cm3
We are asked to find the amount of arsenic in 0.370 km3.
Step 1 :
Conversion of mass of arsenic in kg.
Mass of As = 164.5 ng * ( 1 E-12 kg / 1 ng) =1.64 E-10 kg
Step 2 :
Conversion of given volume to cm3
=0.370 km3 x( (1000)3m3 /1km3) x ((100)3cm3/1m3))
=3.7 E14
Calculation of mass in given volume
Mass of As =( 1.64 E-10 kg /15.7 cm3 ) x ( 3.7 E14 cm3)
=3876.7 kg
Mass of As = 3876.7 kg