Pd-99 has a half-life of 22.3 hours. how many grams of a 89.8 gram sample would have decayed after exactly three half-lives?

78.875 g

Explanation:

First half life is the time at which the concentration of the reactant reduced to half.

Second half reaction is the time at which the remaining concentration reduced to half or the initial concentration reduced to 1/4.

Third half life is the time at which the remaining concentration reduced to half or the initial concentration reduced to 1/8.

The initial mass of the sample = 89.8 g

After 3 half-lives, the mass should reduce to 1/8.

So the concentration left = 1/8 of 89.8 g = 11.225 g

So, the mass of the sample decayed = 89.8 g - 11.225 g = 78.875 g

11.23 grams

Explanation:

Answer via Educere/ Founder's Education

specific gravity is the density of a substance divided by the density of water. since (at standard temperature and pressure) water has a density of 1 gram/cm3, and since all of the units cancel, specific gravity is usually very close to the same value as density

so "c" is the answer

plz give brainliest

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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