The amount left after 20 years = 154.15 mg
<h3>Further explanation
</h3>
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually radioactive elements have an unstable atomic nucleus.
The main particles are emitted by radioactive elements so that they generally decay are alpha (α), beta (β) and gamma (γ) particles
The decay formula for isotope :

Then for t=20 years, the amount left :

Answer:
C
Explanation:
A diatomic element in that list is Bromine
The first one has 35 atoms and the elements hydrogen, oxygen and chlorine
The second one has 9 atoms and the elements sodium, carbon, and helium
Answer:

Explanation:
Hello there!
In this case, since the combustion of B2H6 is:

Thus, since there is 1:2 mole ratio between the reactant and product, the produced grams of the latter is:


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Answer:
<h2>
C) may be hidden
</h2>
Explanation:
A gene is a unit of heredity which is transferred from parents to offspring and it control the traits.
Alternative form of gene are known as alleles.
Gene may be dominant or recessive
Dominant gene expresses in both homozygous as well as in heterozygous condition, while recessive gene expresses in homozygous condition only, when it present with dominant gene, its effect is hidden by dominant gene. Dominant gene is represented by capital letter while recessive gene is represented by small letter.