It would be D.the food chain
Hey there!
A half-life means after a certain amount of time, half of that substance will be gone/changed after that time.
If 50%, or half, of the element remains after 4000 years, that means the half life must be 4000 years.
Hope this helps!
Answer:
On edge nuity, it is 79.
Explanation:
Please read the explanation.
Since u have no coefficients, this problem is super easy.
You just add your products, 115.5+69.91 = 185.41
Then add your reactants: 49.8+56.5= 106.3
Then subtract your reactants from your product and round to the nearest whole number.
106.3-185.41=79
It's really easy. Once u understand it, you can do any problem like this. If there is coefficients, just multiply the coefficient by the amount given to you in the problem.
Percent error is the difference between the measured and known value, divided by the known value, multiplied by 100%.
So first, we take our measured value, .299 cm, minus our known value, .225 cm.
.299 cm - .225 cm=.004 cm
Next, we divide that by our known value

Finally, multiply your answer by 100
.0177777778 x 100= 1.77777778 %
Round to three significant figures, and you're done.
=1.78 % error