Answer:
10 million years
Explanation:
For a sample to decay to 25% of its original amount, 2 half lives must have passed. Since one half life is 5 million years, multiplying this by 2 gives us that 2 half lives is 10 million years.
Answer:
There are no options but the question can be answered based on general understanding of experimentation.
Group A: Control group
Group B: Experimental group
Explanation:
In an experiment, there are two groups viz: the control group and the experimental group. A control group is the group that does not receive any experimental treatment. It is considered the normal group while the experimental group is the group that is subjected to experimental treatment.
N.B: The experimental treatment in this case is the "Oxygen level"
According to the question, out of 20 petri-dishes used to grow bacteria, half (10) of the petri-dishes were placed in a container with normal atmosphere while the other 10 petri-dishes were placed in another container that have double the normal oxygen level. The first group of bacteria labelled GROUP A are the CONTROL GROUP because they were not given any treatment i.e placed under normal conditions while GROUP B are the EXPERIMENTAL GROUP because they are the group that received the experimental treatment (increased oxygen level).
Answer:
k = -0.0525 s⁻¹
Explanation:
The equaiton for a first order reaction is stated below:
ln[A]=−kt+ln[A]₀.
[A] = 5.50 x 10⁻³ M
[A]₀ = 7.60 x 10⁻² M
t = 85.0 - 35.0 = 50.0 s
The rate constant is represented by k and can be calculated substituting the values given above:
k = (ln[A]₀ - ln[A])/t
k = (ln5.50 x 10⁻³ M - ln7.60 x 10⁻² M)/50.0s
k = -0.0525 s⁻¹
The answer is C. more better. Like I'm better everyday :D
GIVE ME MORE QUESTIONS FOR MORE POINTS PLEASE :D
have a nice day :) happy new year