Half life worksheet answer key 1. how long does it take a 100.00g sample of as-81 to decay to 6.25g?

132 seconds ( 2 Minutes 12 seconds).

Explanation:

Half life is basically the time it takes for a compound to decay to half of it's original mass.

In this problem, the compound is As. The half life of As-81 is 33 seconds. This means it takes 33 seconds for 100 g of As-81 to decay to 50g. The question however id to find the time it takes for it to decay to 6.25g.

We find how many half life's it would take,

100 --> 50 (First half life)

50 --> 25  (Second half life)

25 --> 12.5 (Third half life)

12.5 --> 6.25 (Fourth half life)

This means the total time is 4 * 33 (Half life) = 132 seconds ( 2 Minutes 12 seconds).

1.consider the following balanced equation and answer parts a through. show calculations for each part.  

3 ag(s) + 4 hno3(aq) → 3 agno3(aq) + no(g) + 2 h2o(l)  

a. calculate the number of moles of agno3 produced by the reaction of 3 moles of ag with excess hno3. if the number to the left of the compound represents the number of moles of the compound which are present, then 3 moles of ag react with 4 moles hno3 to produce 3 moles agno3 (aq).

so the answer to a would be 3 moles.

b. calculate the number of moles of agno3 produced by the reaction of 108 grams of ag with excess hno3.  

i'm not sure how to plug in the grams of silver into an equation using moles to find how many moles are produced.

c. calculate the number of grams of agno3 produced by the reaction of 108 grams of ag with excess hno3  

d. calculate the number of moles of no produced as a byproduct of the reaction of 108 grams of ag with excess hno3.  

e. calculate the number of grams of no produced as a byproduct starting with 108 grams of ag and excess hno3.  

explanation:

the answer is b. dilution