Answer:
13 years
Explanation:
From;
0.693/t1/2 = 2.303/t log (No/N)
Where;
t1/12 = half-life of Cobalt-60 = 5.3 years
t = time taken = the unknown
No = mass of radioactive material originally present = 5.2 g
N = mass of radioactive material at time t = 0.95 g
Substituting values;
0.693/5.3 = 2.303/t log (5.2/0.95)
0.131 = 2.303/t(0.738)
0.131 = 1.6996/t
t = 1.6996/0.131
t = 12.97 years
t = 13 years(to the nearest whole number)
From the calculations, we can see that, the change in the freezing point is -0.634°C.
<h3>What is freezing point?</h3>
The term freezing point refers to the temperature at which a liquid is changed to solid.
Given that;
ΔT = K m i
Number of moles sucrose = 35.0 g/ 342.30 g/mol = 0.1 moles
molality = 0.1 moles/ 300.0 * 10^-3 Kg
= 0.33 m
Thus;
ΔT = -1.86°C/mol * 0.33 m * 1
= -0.634°C
Learn more about freezing point:brainly.com/question/3121416
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When an electron quickly occupies an strength state increased than its ground state, it is in an excited state. An electron can end up excited if it is given greater energy, such as if it absorbs a photon, or packet of light, or collides with a close by atom or particle.
