Answered

If you have 10.0 g of a substance that decays with a half-life of 14 days, then how much will you have after 42 days?

A0.10 g
B0.31 g
C1.25 g
D2.50 g

Verified Answer :

naǫ

The formula for the mass that remains:
\(m=m_0 \times (\frac{1}{2})^\frac{t}{T}\)
m₀ - the initial mass, t - time, T - the half-life

\(m_0=10 \ g \\ T=14 \ d \\ t=42 \ d \\ \\ m=10 \times (\frac{1}{2})^\frac{42}{14}=10 \times (\frac{1}{2})^3=10 \times \frac{1}{8}=10 \times 0.125=1.25\)

The answer is c. 1.25 g.

The amount remained after 42 days is 1.25 g. The correct option is c.

What is half life?

Half life is the time taken by a radioactive material for the radioactivity of to reduce by half its original value.

The half life equation is:

A = A₀ (½)^(t / T)

where A is the final amount, A₀ is the initial amount, t is the amount of time, and T is the half life.

Given is the value of  A₀ = 10.0g, and T = 14 days.

A = 10 (½)^(t42/ 14)

A =10 x  ½^(3)

A = 1.25 g

Thus, final amount left 1.25 g

Learn more about half life.

https://brainly.com/question/24710827

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