Answer:
Ionul de hidroniu este un factor important atunci când avem de-a face cu reacții chimice care apar în soluții apoase. Concentrația sa în raport cu hidroxidul este o măsură directă a pH-ului unei soluții. Se poate forma atunci când un acid este prezent în apă sau pur și simplu în apă pură. Formula chimică este H3O +
Explanation:
The hydronium ion is an important factor when dealing with chemical reactions that occur in aqueous solutions. Its concentration relative to hydroxide is a direct measure of the pH of a solution. It can be formed when an acid is present in water or simply in pure water. It's chemical formula is H3O+
marke me as brainliest please
The answer to this item is TRUE. This can be explained through the Graham's law. This law states that the rate at which gases diffuse is inversely proportional to the square root of their densities which is also related to their molecular masses.
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
Molarity is simply the ratio of the number of moles of a
substance over the total volume of the solution. Assuming that the addition of
0.850 moles does not change the overall volume of 1.70 L, therefore molarity is
simply:
Molarity = 0.850 moles / 1.70 L = 0.5 moles / L = 0.5 M
In order to help the
student expand his/her knowledge I will help answer the question. This in hope
that the student will get a piece of knowledge that will help him/her through his/her homework or future tests. The ________ have a single electron in the highest
occupied energy level. The missing word to complete this statement and make it
true is Alkali Metals.
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I hope it helps,
Regards.</span>
