Answer:
0.6749 M is the concentration of B after 50 minutes.
Explanation:
A → B
Half life of the reaction = 
Rate constant of the reaction = k
For first order reaction, half life and half life are related by:


Initial concentration of A = ![[A]_o=0.900 M](https://tex.z-dn.net/?f=%5BA%5D_o%3D0.900%20M)
Final concentration of A after 50 minutes = ![[A]=?](https://tex.z-dn.net/?f=%5BA%5D%3D%3F)
t = 50 minute
![[A]=[A]_o\times e^{-kt}](https://tex.z-dn.net/?f=%5BA%5D%3D%5BA%5D_o%5Ctimes%20e%5E%7B-kt%7D)
![[A]=0.900 M\times e^{-0.02772 min^{-1}\times 50 minutes}](https://tex.z-dn.net/?f=%5BA%5D%3D0.900%20M%5Ctimes%20e%5E%7B-0.02772%20min%5E%7B-1%7D%5Ctimes%2050%20minutes%7D)
[A] = 0.2251 M
The concentration of A after 50 minutes = 0.2251 M
The concentration of B after 50 minutes = 0.900 M - 0.2251 M = 0.6749 M
0.6749 M is the concentration of B after 50 minutes.
Answer:
The probability of spinning red with the spinner or rolling an odd number with the die is 
Explanation:
Given that,
Total color in spinner = 4
Let the area of four parts is equal in the spinner.
We need to calculate the probability of spinning red
Using formula of probability

Put the value into the formula

We need to calculate the probability of odd number of the die
Using formula of probability

Put the value into the formula


We need to calculate the probability of spinning red with the spinner or rolling an odd number with the die
Using formula of probability of two events which is independent

Put the value into the formula


Hence, The probability of spinning red with the spinner or rolling an odd number with the die is 
Answer:
B:the second answer
Explanation:
Because the all have leaves
1.question, 2.observe, 3.hypothesize, 4.experiment 5.conclusion, 6. record.