Answer:
12 mmilligrams of Po-218 was the mass of the original starting material
Explanation:
The half-life of a radioactive material is the time taken for half the amount ofnthe original material present in a radioactive material to decay or disintegrate.
After each half-life, half the original material present at the start remains.
For the radioactive polonium-218 having a half-life of 3.04 minutes, it means that if 1 g is the starting material, after 3.04 minutes, 1/2 g will be remaining; after, 6.08 minutes 1/2 of 1/2 which is 1/4 of the starting material will be remaining; and after 9.12 minutes, 1/2 of 1/4 = 1/8 g will be remaining.
From the question, number of half-lives undergone after 9.12 minutes = 9.12/3.04 = 3 half-lives.
After 3 half-lives, 1/8 of the original material is remaining.
1/8 = 1.50 mg
The original mass of the sample at the start = 1.50 mg × 8 = 12 mg
Therefore, 12 milligrams of Po-218 was the mass of the original starting material.
Explanation:
Molecular mass of NO2= 14+16×2=46
1 mole NO2 = 46 gm of NO2
9.4 moles of NO2= 46×9.4 gm= 432.4 gm NO2.
Answer:
All flowering is regulated by the integration of environmental cues into an internal sequence of processes. These processes regulate the ability of plant organs to produce and respond to an array of signals. The numerous regulatory switches permit precise control over the time of flowering.
Explanation:
Answer:
I am not sure about 7) but I know the rest
Explanation:
7) I think it is because both eat each other. (Eventually). For example, the wolf eats some sort of decomposer, but when the wolf dies the decomposer eats the wolf remains.
8) A producer creates its own food. Most producers are plants, and they use photosynthesis to create the sugar they need to survive. (you should know how photosynthesis works)
9) A consumer eats producers, and other consumers. A bunny is a consumer because he eats plants, and plants are producers. A wolf is a consumer because he eats a bunny.
I hope this helps :D you can come at me in the comments if you don't like me. :)