The answer should be Pure substance
Answer:
Explanation:
from the way the trees look, i would say A: Wind from the sky, it seems B: Clouds and in the distance C:Precipitation(rain)
Two months later 13.8 milligrams of the barium-131 still be radioactive.
<h3>How is the decay rate of a radioactive substance expressed ? </h3>
It is expressed as:

where,
A = Amount remaining
A₀ = Initial Amount
t = time
T = Half life
Here
A₀ = 0.50g
t = 2 months = 60 days
T = 11.6 days
Now put the values in above expression we get



= 0.50 × 0.0277
= 0.0138 g
= 13.8 mg [1 mg = 1000 g]
Thus from the above conclusion we can say that Two months later 13.8 milligrams of the barium-131 still be radioactive.
Learn more about the Radioactive here: brainly.com/question/2320811
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Question: Suppose that 0.50 grams of ban that 0.50 grams of barium-131 are administered orally to a patient. Approximately many milligrams of the barium would still be radioactive two months later? The half-life of barium-131 is 11.6 days.
Answer: Groundwater that forms caves because it is slightly acidic.
Explanation:
The water under the ground present inside the cracks and spaces in sand, soil and rocks is called ground water.
When ground water moves through the soil it results in the formation of acid. Further, this acid helps minerals to get dissolve. These minerals get deposited on other places as well.
This process of deposition and erosion helps in the formation of caves.
Thus, it can be concluded that groundwater that forms caves because it is slightly acidic.