Answer:
12.5%
Explanation:
Initial percentage of carbon 14 = 100%
Final percentage = ?
Time passed = 17.1 * 1000 years = 17100 years
Half life of carbon 14 = 5,730 years.
So how many Half lives are in 17100 years?
Number of Half lives = Time passed / Half life = 3.18 ≈ 3
First Half life;
100% --> 50%
Second Half life;
50% --> 25%
Third Half life ;
25% --> 12.5%
B
Protect themselves from predators
Answer:
Option E!
Explanation:
If we were to draw the lewis dot structure for IBr2 -, we would first count the total number of valence electrons ( " available electrons " ). Iodine has 7 valence electrons, and so does Bromine, but as Bromine exists in 2, the total number of valence electrons would be demonstrated below;
Don't forget the negative on the Bromine!
Now go through the procedure below;
1 ) Place Iodine in the middle and draw single bonds to each of the bromine.
2 ) Add three lone pairs on each of the Bromine's
3 ) Now we have 6 electrons left, if we were to exclude the electrons shared in the " single bonds. " This can be placed as three lone pairs on Iodine ( central atom )!
The molecular geometry can't be linear, as there are lone pairs on the atoms. This makes it bent.
Preparing 15 mg/gl working standard solution from a 20 mg/dl stock solution will require the application of the dilution principle.
Recalling the principle:
initial volume x initial molarity = final volume x final molarity
Since we were not given any volume to work with, we can as well just take an arbitrary volume to be prepared. Let's assume that the stock solution is 10 mL and we want to prepare 15 mg/gl from it:
Applying the dilution principle:
10 x 20 = final volume x 15
final volume = 200/15
= 13.33 mL
This means that in order to prepare 13.33 mL, 15 mg/l working standard solution from 10 ml, 20 mg/dl stock solution, 3.33 mL of the diluent must be added to the stock solution.
More on dilution principle can be found here: brainly.com/question/11493179
