Answer:
im stuck on it too unfortunatley
Explanation:
Answer:
D ultra violet rays cause sunburn
I think this is the answer. I tried. T<span>he railway managers agreed to use </span>four time zones<span> for the continental United States: Eastern, Central, Mountain, and Pacific.</span>
Explanation:
(1) When a proton is converted into neutron then the positron emission takes place as follows.
A positron is represented by the symbol . Therefore, when a positron emission occurs then the resultant nuclei atomic number decreases by a unit mass.
General equation representing positron emission is as follows.
Hence, Fluorine-18 decays by positron emission as follows.
Therefore, when 18F undergoes positron emission, the product nucleus is, .
(2) Expression for the half-life of a isotope is as follows.
Initial activity, () = 4.00 millicuries
Activity after 95% =
= 0.20 millicuries
t = 7.912 hrs
Thus, we can conclude that it will take 7.91 hrs for 95% of the 18F to decay.
Answer:
0.0845 M
Explanation:
First we <u>convert 4.27 grams of potassium iodide into moles</u>, using its <em>molar mass</em>:
- Molar Mass of KI = 166 g/mol
- 4.27 g ÷ 166 g/mol = 0.0257 mol
Now we <u>calculate the molarity of the solution</u>, using <em>the number of moles and the given volume</em>:
- Molarity = moles / liters
- Molarity = 0.0257 mol / 0.304 L = 0.0845 M