Which of the following is a physical or chemical characteristic of a mineral?

Final answer:

The half-life of sodium-25, when 1.00 gram of a 16.00-gram sample remains unchanged after 237 seconds, is approximately 59.3 seconds. This solution was found by calculating the number of times the sample halved and dividing the total time by this figure.

Explanation:

The question asks for the half-life of sodium-25 if 1.00 gram of a 16.00-gram sample remains unchanged after 237 seconds. In nuclear physics and nuclear chemistry, the half-life is the amount of time it takes for half of a sample of a radioactive substance to undergo decay.

Given that sodium-25 has gone from 16 grams to 1 gram, we can see that 1/16th of the original amount is left after 237 seconds. In other words, the quantity of sodium-25 has halved approximately 4 times. Therefore, the half-life will be the total time divided by the number of half-lives.

By dividing 237 seconds by 4, we get 59.25 seconds. So, the closest accurate answer is (2) 59.3s.

Learn more about Half-life here:

brainly.com/question/24710827

#SPJ11

Answer:

Noble gases

Explanation:

The noble gases are non-metals that requires the highest amount of energy to remove an electron from their shells.

The reason for this difficult is that their electronic configuration confers a stable configuration them.

• The ionization energy is the energy required to remove the most loosely held electrons in an atom.
• Due to the special stability of noble gases, it is very difficult to remove electrons from an atom of noble gases.

Answer:

7.5 moles of hydrogen is required

Explanation:

Given data:

Number of moles of H₂ needed = ?

Number of moles of NH₃ = 5 mol

Solution:

Chemical equation:

N₂ + 3H₂     →     2NH₃

Now we will compare the moles of ammonia and hydrogen.

         NH₃       :         H₂  

          2           :          3

          5           :         3/2×5 = 7.5 mol

Thus, 7.5 moles of hydrogen is required.

Answer:

Explanation:

Formic acid (HCOOH) is a weak electrolyte when dissolved in water. In an aqueous solution of formic acid, it partially ionizes into its constituent ions. The solutes present in this solution are the ions produced during ionization.

The chemical equation for the ionization of formic acid (HCOOH) in water is as follows:

HCOOH (aq) ⇌ H⁺ (aq) + HCOO⁻ (aq)

In this equation:

HCOOH represents formic acid molecules.

H⁺ represents the hydrogen ions (protons) that are formed when a molecule of formic acid loses a hydrogen ion (H⁺).

HCOO⁻ represents the formate ion, which is the conjugate base formed when a molecule of formic acid donates a hydrogen ion (H⁺).

Since formic acid only partially ionizes in water, not all molecules of formic acid dissociate into ions. This is why it is considered a weak electrolyte.