<span>85% ethanol | 25% ethanol | 50% ethanol
x | y | 20 gal
use x and y because you don;t know how much she needs.
0.85x | 0.25y | 20(0.5)
85% is 85/100 or 0.85, and you need that much of x, same goes for the 25% and 50% mixtures so now you can make up 2 equations
1) x + y = 20 2) 0.85x + 0.25y= 10 (you get 10 when you multiply 20 by 0.5) now you can solve for x or y using substitution.
first rewrite 1) in terms of x or y: x+ y= 20 ----> y= 20 - x now you can substitute 20- x for y in the second equation.. 0.85x + 0.25y= 10 0.85x + 0.25(20-x)= 10 distribute here..(0.25 * 20 and 0.25 * (-x) ) 0.85x + 5 - 0.25x = 10 combine like terms 0.6x +5 = 10 move the 5 over to the other side 0.6x= 10 -5 0.6x = 5 divide both sides by 0.6 x= 25/3 or 8.3 now you know the amount of x so you can substitue this back into the first equation to find y. 0.85x + 0.25y= 10 0.85(25/3) +0.25y= 10 85/12 + 0.25y= 10 0.25y = 10- 85/12 0.25y= 35/12 y= 35/3 or 11.6 you can check by putting these values into the euations: 1) x+ y= 20 25/3 + 35/3 =20 20= 20 good so far 2) 0.85x + 0.25y= 10 0.85(25/3) + 0.25(35/3)=10 10 = 10
so our values for x and y work
x= 25/3 and y= 35/3</span>
Answer: the area of the telescope lens is \textit{0,08507 ft}
Explanation: Happy I could help!
Answer:
chromium:oxygen=1:2
Explanation:
total mass=2.16g
mass of chromium=1.34g
mass of oxygen=2.16g-1.34g=0.82g
chromium oxygen
mass:1.34g 0.82
RAM:52 16
divide the mass with the RAM
0.02577 0.05125
divide by smallest number to find ratio
1 2
ratio of chromium to oxygen=1:2
Answer:
0.124 M
Explanation:
The reaction obeys second-order kinetics:
![r = k[BrO^-]^2](https://tex.z-dn.net/?f=r%20%3D%20k%5BBrO%5E-%5D%5E2)
According to the integrated second-order rate law, we may rewrite the rate law in terms of:
![\dfrac{1}{[BrO^-]_t} = kt + \dfrac{1}{[BrO^-]_o}](https://tex.z-dn.net/?f=%5Cdfrac%7B1%7D%7B%5BBrO%5E-%5D_t%7D%20%3D%20kt%20%2B%20%5Cdfrac%7B1%7D%7B%5BBrO%5E-%5D_o%7D)
Here:
is a rate constant,
![[BrO^-]_t](https://tex.z-dn.net/?f=%5BBrO%5E-%5D_t)
is the molarity of the reactant at time t,
![[BrO^-]_o](https://tex.z-dn.net/?f=%5BBrO%5E-%5D_o)
is the initial molarity of the reactant.
Converting the time into seconds (since the rate constant has seconds in its units), we obtain:
Rearranging the integrated equation for the amount at time t:
![[BrO^-]_t = \dfrac{1}{kt + \dfrac{1}{[BrO^-]_o}}](https://tex.z-dn.net/?f=%5BBrO%5E-%5D_t%20%3D%20%5Cdfrac%7B1%7D%7Bkt%20%2B%20%5Cdfrac%7B1%7D%7B%5BBrO%5E-%5D_o%7D%7D)
We may now substitute the data:
![[BrO^-]_t = \dfrac{1}{0.056 M^{-1}s^{-1}\cdot 60.0 s + \dfrac{1}{0.212 M}} = 0.124 M](https://tex.z-dn.net/?f=%5BBrO%5E-%5D_t%20%3D%20%5Cdfrac%7B1%7D%7B0.056%20M%5E%7B-1%7Ds%5E%7B-1%7D%5Ccdot%2060.0%20s%20%2B%20%5Cdfrac%7B1%7D%7B0.212%20M%7D%7D%20%3D%200.124%20M)
1.53 moles of Fe is your solution hope it helps!
