Flouride is known to prevent tooth decay so it is added to the city water supply for drinking. A medium sized city is populated with 150,000 people. Each person uses approximately 660.0 L of water each day. How many kg of NaF must be added to the water supply each year to have the required flouride concentration of 1.0 ppm?

Question

Chemistry

Aimee

12 May, 12:09

Flouride is known to prevent tooth decay so it is added to the city water supply for drinking. A medium sized city is populated with 150,000 people. Each person uses approximately 660.0 L of water each day. How many kg of NaF must be added to the water supply each year to have the required flouride concentration of 1.0 ppm?

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Hayley Frank · Answer 1

3.6 * 10^4 kg NaF

Step 1. Calculate the daily volume of water used

Volume = 150 000 persons * (660.0 L/1 person) = 9.90 * 10^7 L

Step 2. Calculate the daily mass of the water

Mass of water = 9.90 * 10^7 L water * (1.00 kg water water/1 L water)

= 9.90 * 10^7 kg water

Step 3. Calculate the daily mass of NaF

Daily mass of NaF = 9.90 * 10^7 kg water * (1.0 kg NaF/10^6 kg water)

= 99.0 kg NaF

Step 4. Calculate the yearly mass of NaF

Yearly mass of NaF = (99.0 kg NaF/1 day) * (365.25 days/1 yr)

= 3.6 * 10^4 kg NaF