The half-life of Th-232 is 1.405 × 10¹⁰ years
Time elapsed = 2.8 x 10⁹ years
Equation of radioactive decay:
A = A₀ = (1/2)^ t/t₁/₂
where A₀ is the initial amount, A is the amount after time t, t₁/₂ is the half file
The fraction of thorium-232 that remains in the rock after 2.8 billions years is,
A/A₀ = (1/2) ^ (2.8 x 10⁹/ 1.405 × 10¹⁰) = 0.871
Therefore, the percentage of thorium-232 in the rock that was dated at 2.8 billions year = 87.1%
The independent variable as we can see from the experiment that have been described in this case is the brand of fertilizer that was used in the study.
<h3>What is an experiment?</h3>
When we talk about an experiment, we are talking about the way by which the relation ship between the dependent and the independent variable could be studied. In the experiment, there is a dependent variable which would change values when the variable that is under study in the particular experiment changes value. We have to know that in the realm if science, it is only by the means of experiments that we can be able to establish cause and effect relationships.
In this case, we can see that the experiment that the students were working on has to do with trying to actually find out if brand X fertilizer will affect the growth of Lily plants. This means that they were studying the effect of a fertilizer brand on the growth of the crops.
Learn more about independent variable:brainly.com/question/1479694
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Answer:
the answer is 3.33⋅1023 molecules of Cl2. Note that 6.022⋅1023 is also known as Avogadro's number, and it can be referred to as the number of molecules in one mole of that substance. Also, I calculated 70.9 because 35.45 g/mol (the mass of one Chlorine atom) times 2 is 70.9 g/mol (Cl2 has two Chlorine atoms).
Explanation:
Answer:
10
Explanation:
the capacity for each shell for the first 20 elements can be given by
2.8.8.2
2 electrons in the first shell
8 in the 2nd and in the 3rd
and 2 in the 4th
so if both the first and 2nd shells are full,
2+8=10 electrons