Complete Question:
To aid in the prevention of tooth decay, it is recommended that drinking water contain 0.800 ppm fluoride. How many grams of F− must be added to a cylindrical water reservoir having a diameter of 2.02 × 102 m and a depth of 87.32 m?
Answer:
2.23x10⁶ g
Explanation:
The concentration of the fluoride (F⁻) must be 0.800 ppm, which is 0.800 parts per million, so the water must have 0.800 g of F⁻/ 1000000 g of the solution. The density of the water at room temperature is 997 kg/m³ = 997x10³ g/m³. So, the concentration of the fluoride will be:
0.800 g of F⁻/ 1000000 g of the solution * 997x10³ g/m³
0.7976 g/m³
The volume of the reservoir is the volume of the cylinder: area of the base * depth. The base is a circumference, which has an area:
A = πR², where R is the radius = 1.01x10² m (half of the diameter)
A = π*(1.01x10²)²
A = 32047 m²
The volume is then:
V = 32047 * 87.32
V = 2.7983x10⁶ m³
The mass of the F⁻ is the concentration multiplied by the volume:
m = 0.7976 * 2.7983x10⁶
m = 2.23x10⁶ g
Answer:
Outer planets are significantly colder than other planets! The answer is B.
Explanation:
The main difference between inner and outer planets is that inner planets have a high temperature compared to outer planets.
1. Compound. 2. Dividing. 3. Relative Formula Mass. 4. Hundred.
Answer:
A.
Explanation:
Miners were happy due to the result of the gold rush. they labored very hard for very little profit. Working in the Yukon Territory was not safe. To reach it, the ground had to be dug. Then the dirt had to be removed to get the gold.
In paragraph 2, what does the phrase "miners of all shapes and sizes" mean that many people were invited. This included food, clothing, transportation equipment, etc.
