Radioactive decay => C = Co { e ^ (- kt) |
Data:
Co = 2.00 mg
C = 0.25 mg
t = 4 hr 39 min
Time conversion: 4 hr 39 min = 4.65 hr
1) Replace the data in the equation to find k
C = Co { e ^ (-kt) } => C / Co = e ^ (-kt) => -kt = ln { C / Co} => kt = ln {Co / C}
=> k = ln {Co / C} / t = ln {2.00mg / 0.25mg} / 4.65 hr = 0.44719
2) Use C / Co = 1/2 to find the hallf-life
C / Co = e ^ (-kt) => -kt = ln (C / Co)
=> -kt = ln (1/2) => kt = ln(2) => t = ln (2) / k
t = ln(2) / 0.44719 = 1.55 hr.
Answer: 1.55 hr
Answer:
I believe the answer is B
Explanation:
A nucleus of an atom has protons and neutrons. We know that a proton has a charge of +1 , while a neutron has no charge, or 0 . Therefore, the nucleus of an atom will always have a positive charge.
The molarity of a solution in which 55. 49 g of calcium chloride is dissolved in enough water to make 500. ml of solution is 1M.
<h3>What is molarity? </h3>
It is defined as number of moles of solute divided by volume of solution.
Given,
Mass of CaCl2 =55.49g
Molar mass of CaCl2 =40+35+35=110g
Mole= given mass/ molar mass
= 55.49/110=0.50mol.
Now, putting all values we get the molarity
Molarity =0.5×1000/500=1M
Thus, the molarity of given solution is 1M.
learn more about Molarity:
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Answer:
This is site for English speakers. Этот сайт на английском, поэтому вопрос могут удалить
Explanation:
1. 2)
2. 3)
3. 4) Sr
4. 3)
5. 4)
6. 2)
7. 1)
8. 4)
9. 3)
10. 3)
11. SO3, H2SO4, Na2SO4
12.
A) оксид меди (II) 2) CuO
Б) хлорид меди(II) 4) CuCl2
В) сульфит меди (II) 3) CuSO 3
Г) гидроксид меди (II) 1) Cu(OH)2
13.
1. Fe+HCl= б) FeCl 2 +H 2
2.Fe+O2= в) Fe 3 O 4
3. Fe(OH) 3 = г)Fe 2 O 3 +H 2O
4. FeCl 2 +NaOH= а) Fe(OH) 2 +NaCl
14. 2Ca + O2 = 2CaO
CaO + H2O = Ca(OH)2
Ca(OH)2 + 2HCl = CaCl2 + 2H2O
