We want to write the nuclear equation for the beta decay of Aluminium-25.
The equation is:
First, as you may know, in a beta decay the number of protons is increased by one. Aluminium has 13 of them, so after the decay, we will have 14 protons.
This means that the aluminium will transform into silicon, then the nuclear equation is just:
Where the:
Is an electron, which is the emitted particle in the beta decay.
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I think the best one is B
Atomic <span>mass He = 4.002 u.m.a
4.002 g --------------- 6.02x10</span>²³ atoms
50 g ------------------ ? atoms
50 x ( 6.02x10²³) / 4.002
= 3.01x10²⁵ / 4.002
= 7.52x10²⁴ atoms of He
We can use a simple equation to solve this problem.
d = m/v
Where d is the density, m is the mass and v is the volume.
d = ?
m = 87.47 mg = 87.47 x 10⁻³ g
v = 0.03 mL
By applying the equation,
d = 87.47 x 10⁻³ g
/ 0.03 mL
d = 2.92 g/mL
Hence, the density of the mixture is 2.92 g/mL.
