Answer:
0.570 L
Explanation:
Given:
Concentration of the HCl solution = 0.750 M
Mass of NaCl in the reaction = 25.0
Number of moles of NaCl in the reaction = Mass of NaCl / Molar mass of NaCl
also,
Molar mass of NaCl = 22.98 + 35.45 = 58.43 grams
thus,
Number of moles of NaCl in the reaction = 25 / 58.43 = 0.4278 moles
now,
1 mol of NaCl reacts to form 1 mol of HCl
thus,
0.4278 moles of NaCl reacts to form 0.4278 mol of HCl
also,
Concentration = Moles / volume of solution
0.750 = 0.4278 / volume of solution
or
volume of solution = 0.570 L
When forming an ion, this sodium atom will lose 1 electron, as it is the easiest way to form a full shell, as opposed to gaining 7 electrons.
Explanation:
1) Initial mass of the Cesium-137== 180 mg
Mass of Cesium after time t = N
Formula used :
Half life of the cesium-137 = = initial mass of isotope
N = mass of the parent isotope left after the time, (t)
= half life of the isotope
= rate constant
Now put all the given values in this formula, we get
Mass that remains after t years.
Therefore, the parent isotope remain after one half life will be, 100 grams.
2)
t = 70 years
N = 35.73 mg
35.73 mg of cesium-137 will remain after 70 years.
3)
N = 1 mg
t = ?
t = 224.80 years ≈ 225 years
After 225 years only 1 mg of cesium-137 will remain.
The last one is the answer I think