Answer:
2835 kilograms of sodium hypochlorite must be added to the water supply each week to produce the required chlorine level of 1 ppm.
Explanation:
Volume of water used by 1 person = 750 L
Volume of water used by 1.8 million persons : V
![V=1.8\times 10^6\times 750 L=1.35\times 10^{9} L](https://tex.z-dn.net/?f=V%3D1.8%5Ctimes%2010%5E6%5Ctimes%20750%20L%3D1.35%5Ctimes%2010%5E%7B9%7D%20L)
Density of water,d = 1 kg/L
Mass of water used by 1.8 million persons = m
![m=d\times V=1 kg/L\times 1.35\times 10^{9} L=1.35\times 10^{9} kg](https://tex.z-dn.net/?f=m%3Dd%5Ctimes%20V%3D1%20kg%2FL%5Ctimes%201.35%5Ctimes%2010%5E%7B9%7D%20L%3D1.35%5Ctimes%2010%5E%7B9%7D%20kg)
1 kilogram of chlorine per million kilograms of water. (Given)
Concentration of chlorine in water = 1 kg/ 1000,000 kg of water
In 1000,000 kg of water = 1 kg of chlorine
Then
of water have x mass of chlorine:
![\frac{x}{1.35\times 10^{9} \text{kg of water}}=\frac{1 kg}{1000,000 \text{kg of water}}](https://tex.z-dn.net/?f=%5Cfrac%7Bx%7D%7B1.35%5Ctimes%2010%5E%7B9%7D%20%5Ctext%7Bkg%20of%20water%7D%7D%3D%5Cfrac%7B1%20kg%7D%7B1000%2C000%20%5Ctext%7Bkg%20of%20water%7D%7D)
Mass of chlorine in water of mass
Percentage of chlorine in hypochlorite = 47.62%
![47.62\%=\frac{1.35\times 10^{3} kg}{\text{Total mass of sodium hypochlorite}}\times 100](https://tex.z-dn.net/?f=47.62%5C%25%3D%5Cfrac%7B1.35%5Ctimes%2010%5E%7B3%7D%20kg%7D%7B%5Ctext%7BTotal%20mass%20of%20sodium%20hypochlorite%7D%7D%5Ctimes%20100)
Total mass of sodium hypochlorite = ![2834.94 kg\approx 2835 kg](https://tex.z-dn.net/?f=2834.94%20kg%5Capprox%202835%20kg)
2835 kilograms of sodium hypochlorite must be added to the water supply each week to produce the required chlorine level of 1 ppm.