Thursday

November 27, 2014

November 27, 2014

Posted by **Jazmin** on Monday, May 30, 2011 at 8:52pm.

a.10 min

b.20 min

c.30 min

d.40 min

the answer is a.10 min but i would like to know why, please help.

- Chemistry -
**DrBob222**, Monday, May 30, 2011 at 10:21pmln(No/N) = kt

No = 80 mg

N = 10 mg

t = 30 min

solve for k, then

k = 0.693/t_{1/2}

Substitute k from above and solve for t_{1/2}

10 min is correct.

- Chemistry -
**shemelis**, Tuesday, October 2, 2012 at 3:33am10 minute is correct

**Answer this Question**

**Related Questions**

chemistry - A particular radioactive substance has a half-life of 4 minutes. How...

Chemistry - Gallium65, a radioactive isotope of gallium, decays by first order-...

math - 289 min = 4 hr and 49 min 213 min = 3 hr and 33 min 345 min = 5 hr and 45...

chemistry - If there are 80 milligrams of a radioactive element decays to 10 ...

Chemistry(Please check) - The units of a rate constant for zero, first, and ...

Chemistry - Calculate the average disappearance of A between t=0 min and t=10 ...

Physics - From t = 0 to t = 5.00 min, a man stands still, and from t = 5.00 min ...

MATH!! - TO be on the 1-km race team, Celia must have a mean time less than 5 ...

Math - Please help me solve these problem i have no idea how to do this. 720m/d...

Trigonometry - LONESTAR - The figure below is a model of a Ferris wheel. The ...