You will want to find how many grams are in a whole mole so you know which element it is. To do this, find out how much of a mole you have.
4.95 x 10^23 atoms / 6.022 x 10^23 atoms (one whole mole of any element) = .8219860511 or ~82% of 1 mole
Now we know that, find what to multiply 20 g by to get the rest of the mole.
1 mole / .8219860511 mole = 1.216565657
20 g x 1.216565657 = ~24.33 g / mol
Now that you have grams per mole, you can look at the periodic table and the molar masses to see which this number is closely aligned.
Your answer is Magnesium (Mg), which has a molar mass of 24.305 g
by radiation from the Earth's surface
Answer : The time passed in years is 
Explanation :
Half-life of carbon-14 = 5730 years
First we have to calculate the rate constant, we use the formula :



Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = 
t = time passed by the sample = ?
a = initial amount of the reactant disintegrate = 15.3
a - x = amount left after decay process = 14.8
Now put all the given values in above equation, we get


Therefore, the time passed in years is 
The process is not a redox reaction.
The reaction between ammonia
and hydrochloric acid (HCl) to produce ammonium chloride (
) has modified the oxidation number of no atom in the reactants. As a base, ammonia interacts easily with hydrochloric acid to produce ammonium chloride salt. A neutralization reaction between an acid and a base is what the described process is, and it is NOT a redox reaction.
A reaction is referred to as a redox reaction if two or more reactants belonging to a single reaction exchange one or more electrons, i.e., one reactant releases one or more additional electrons while the other obtains one or additional electrons. The reacted substance that releases electrons is oxidized and becomes a reducing substance. A reduced oxidizing agent is the reactant that accepts electrons.
Learn more about redox reaction: brainly.com/question/13293425
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I believe the answer is 50.5 molecules