Half-life is the time taken for the concentration of the substance to reduce by 50%. The original sample of strontium had a mass of 1.6 gms. Thus, option d is correct.
<h3>What is half-life?</h3>
The half-life of any radioactive substance is the time period at which the concentration will get reduced to half the initial amount. The initial mass of Sr-90 is calculated as,

Given,
Quantity of the remaining substance N (t) = 0.40 gm
Initial radioactive substance quantity
=?
Time duration (t) = 56 years
Half-life = 28 years
Substituting values above:

= 1.6 gm
Therefore, option d. the initial mass of Sr is 1.6 gm.
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Answer:
a scientific question
Procedure
Conclusion.
Explanation:
Scientific investigation is usually carried out to explain and give answers to natural phenomenon. Now, this scientific investigation is performed through the three main types as described in the question.
With that being said, the most common parts of all types of investigation are :
1. Scientific question: In this stage, questions are usually asked on the basis of observation made which could be answered.
2. Procedure: In this stage, the dimension of the steps are followed to answer and test the scientific question.
3. Conclusion: This is the primary aim that we check when done with our sample values
Answer:
16.56g.
Explanation:
You need to compare the number of coefficient of the reaction product to find how much water produced. The reaction formula will produce 6 carbon dioxide(CO2) and 6 water (H2O).
If the reaction produces 0.92 moles of carbon dioxide, then the amount of water produced in moles will be: 0.92 moles * (6/6)= 0.92 moles
The molar mass of water is 18g/mol, so the calculation of moles to mass will be: 0.92 moles * (18g/mol)= 16.56g.
Answer:
nuclear decay I believe not 100% sure though.
Explanation: