Question

Hydrogen-3 has a half-life of 12.35 years. What mass of hydrogen-3 will remain form a 100.0 MG initial sample after 5.0 years?
A) 7 MG
B) 24 MG
C) 76 MG
D) 18 MG

Answer 1

@wio

Answer 2

@souvik

Answer 3

Can someone please help me with it

Answer 4

Plz

Answer 5

We will have to use the following \[\huge \frac{ m_f }{ m_i } = \left( \frac{ 1 }{ 2 } \right)^{\left( \frac{ t }{ T^{1/2} } \right)}\] where \[T^{1/2} = \text{half life}\]
\[t =\text{ time}\]
\[m_f = \text{final mass}\]
\[m_i = \text{initial mass}\]

Answer 6

So let me ask you, what are we solving for here?

Answer 7

Final mass

Answer 8

Right!

Answer 9

So our formula then becomes \[\huge m_f = m_i \left( \frac{ 1 }{ 2 } \right)^{\frac{ t }{ T^{\frac{ 1 }{ 2 }} }}\] right?

Answer 10

Now at this stage, you just need to plug in the values

Answer 11

and evaluate

Answer 12

So what u get

Answer 13

I think you can at least do that much.

Answer 14

Wait what we put for T 1/2

Answer 15

Don't let the 1/2 confuse you, I put it there to represent half life, that is 12.35 years

Answer 16

Oh ok

Answer 17

I am getting a very big number

Answer 18

\[\huge m_f = (100MG)(1/2)^{\frac{ 5.0 }{ 12.35 }}\]

Answer 19

Know I get 76

Answer 20

Yup :)

Answer 21

Thnx alot

Answer 22

Np