Answer:
% = 76.75%
Explanation:
To solve this problem, we just need to use the expressions of half life and it's relation with the concentration or mass of a compound. That expression is the following:
A = A₀ e^(-kt) (1)
Where:
A and A₀: concentrations or mass of the compounds, (final and initial)
k: constant decay of the compound
t: given time
Now to get the value of k, we should use the following expression:
k = ln2 / t₁/₂ (2)
You should note that this expression is valid when the reaction is of order 1 or first order. In this kind of exercises, we can assume it's a first order because we are not using the isotope for a reaction.
Now, let's calculate k:
k = ln2 / 956.3
k = 7.25x10⁻⁴ d⁻¹
With this value, we just replace it in (1) to get the final mass of the isotope. The given time is 1 year or 365 days so:
A = 250 e^(-7.25x10⁻⁴ * 365)
A = 250 e^(-0.7675)
A = 191.87 g
However, the question is the percentage left after 1 year so:
% = (191.87 / 250) * 100
<h2>
% = 76.75%</h2><h2>
And this is the % of isotope after 1 year</h2>
Calcium is stored in bones in the body
Answer:
Their particles exhibit the same type of intermolecular interaction
Explanation:
In chemistry, we commonly say that 'like dissolves like'. This implies that polar solvents dissolves polar solutes while nonpolar solvents dissolve nonpolar solutes.
This phenomenon of 'like dissolves like' is possible because, the dissolution of one substance in another involves intermolecular interaction between the solute and solvent molecules.
If the molecules of solute and solvent are both nonpolar and have about the same magnitude of intermolecular (dispersion) forces, interaction between the both molecules is significant hence the solute dissolves completely in the solvent.
Answer is: C. The FDA tests give reliability to the results of improved health obtained by each company.
The FDA (The Food and Drug Administration) is a federal agency of the United States Department of Health and Human Services.
The FDA controls food safety, tobacco products, dietary supplements, prescription, pharmaceutical drugs, vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices, cosmetics and animal food.
Answer: 79.6 g
mwof 02 is 16 and mw of H2O is 18.
