The radium isotope 223Ra, an alpha emitter, has a half-life of 11. 43 days. You happen to have a 1. 0 g cube of 223Ra, so you decide to use it to boil water for tea. You fill a well-insulated container with 460 mL of water at 16∘ and drop in the cube of radium

Respuesta :

The time taken for the water to boil at the given rate of the alpha decay is 0.08 s.

Number of radium atom

The number of radium atom in 1.0 g is calculated as follows;

[tex]N = N_A(\frac{m}{M} )\\\\N = (6.02 \times 10^{23})(\frac{1}{223} )\\\\N = 2.7 \times 10^{21} \ atoms[/tex]

Decay constant of the radium

[tex]\lambda = \frac{ln2}{t_{1/2}} \\\\\lambda = \frac{ln 2}{(11.43 \times 86400)} \\\\\lambda = 7.02 \times 10^{-7} \ s^{-1}[/tex]

Rate of the alpha decay

R = λN

R = (7.02 x 10⁻⁷) x (2.7 x 10²¹)

R = 1.895 x 10¹⁵ atoms/s

Change in the mass of the Radium

Δm = m(Ra₂₂₃) - [m(Rn₂₁₉) + m(α)]

Δm = 223.018u - (219.008u + 4.0026u)

Δm = 0.0074u

Energy released in the alpha decay

[tex]E =\Delta mc^2\\\\E = 0.0074u \times c^2\\\\E = 0.0074 \times931.5\ MeV/c^2 \times c^2\\\\E = 6.893 \ MeV\\\\E = 6.893 \times 10^6 \times 1.6\times 10^{-19} \\\\E= 1.103 \times 10^{-12} \ J[/tex]

Rate at which energy is released

P = E/t = ER

P = (1.103 x 10⁻¹²)(1.895 x 10¹⁵)

P = 2,089.99 J/s

Mass of the boiled water

mass = density x volume

mass = (1 g/L) x (0.46 L)

mass = 0.46 g

Heat absorbed by the water

Q = mcΔT

Q = 0.46 x 4.184 x (100 - 16)

Q = 161.67 J

Time taken for the water to boil

Pt = Q

t = Q/P

[tex]t = \frac{161.67}{2,089.99} \\\\t = 0.08 \ s[/tex]

Thus, the time taken for the water to boil at the given rate of the alpha decay is 0.08 s.

The complete question is below:

How long will it take the water to boil?

Learn more about alpha decay here: https://brainly.com/question/17796856