How many gram of sodium fluoride should be added to 100000 liter of drinking water containing 0.6 ppm of sodium fluoride to provide a recommended concentration of 1.75 ppm?
Answer is 115 grams. I keep getting .115 g What am I doing wrong? Please help.
Nevermind. I figured it out.
Key was 1 ppm is 1mg/L.
1.15 mg/L * 100,000 L = 115,000 mg (115g)
If a topical cream contains 1.8% (w/w) of hydrocortisone, which of the following strengths is equivalent?
1.75 ppm-0.6 ppm= 1.15 ppm
Since 1 ppm is equivalent to 1 mg/L, 1.15 ppm is equal to 1.15 mg/L.
Therefore,
1.15 mg/L x 100,000L = 115, 000 mg
Since grams are needed, 115, 000 mg x 1g/ 1000 mg = 115 g.
Hope this helps.
Well, it seems like you're a bit "off-balance" with your calculations. Let me help you find the "fluoride" in your equation!
To convert ppm to grams, you need to consider that 1 ppm = 1 mg/L. So, for your initial concentration of 0.6 ppm, we can calculate it as 0.6 mg/L.
Now, we want to increase the concentration to 1.75 ppm. Since we know the volume of water is 100,000 liters, we need to find the total amount of sodium fluoride required.
To do this, we use the formula:
Amount of sodium fluoride (g) = concentration (mg/L) × volume (L) / 1000
Plugging in the values, we get:
Amount of sodium fluoride (g) = 1.75 mg/L × 100,000 L / 1000 = 175 grams.
So, the correct answer is actually 175 grams, not 115 grams. Keep in mind that we're dealing with grams, not milligrams, so your previous answer of 0.115 grams was a little "light" on the fluoride. Don't worry, it happens to the best of us!
To calculate the amount of sodium fluoride needed, you can use the following formula:
Amount of sodium fluoride needed (in grams) = (desired concentration - initial concentration) * volume of water / 1000000
Let's plug in the values given in the question:
Initial concentration = 0.6 ppm
Desired concentration = 1.75 ppm
Volume of water = 100000 liters
Amount of sodium fluoride needed (in grams) = (1.75 - 0.6) * 100000 / 1000000
Calculating the equation:
Amount of sodium fluoride needed (in grams) = 1.15 grams
Therefore, the correct answer is 1.15 grams, not 115 grams. It seems you made a mistake by not converting ppm (parts per million) to grams per liter correctly.
To get the answer correct, remember to divide the final answer by 1000 to convert grams to kilograms. In this case, 1.15 grams is the correct answer.