<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:
That is, the molar mass of a substance is the mass (in grams per mole) of 6.022 × 10 23 atoms, molecules, or formula units of that substance. In each case, the number of grams in 1 mol is the same as the number of atomic mass units that describe the atomic mass, the molecular mass, or the formula mass, respectively.
Answer:
548s = t
Explanation:
A first-order reaction has as general equation:
![ln \frac{[A]_t}{[A]_0} = -kt](https://tex.z-dn.net/?f=ln%20%5Cfrac%7B%5BA%5D_t%7D%7B%5BA%5D_0%7D%20%3D%20-kt)
Where ![[A]_t](https://tex.z-dn.net/?f=%5BA%5D_t)
is the concentration of the reactant in the time t, ![[A]_0](https://tex.z-dn.net/?f=%5BA%5D_0)
is the initial concentration of the reactant, k is rate constant and t is time. Replacing with values of the problem:
-1.65 = -3.00x10⁻³s⁻¹×t
<em>548s = t</em>
<em></em>
I hope it helps!
To completely describe an electron in an atom, four quantum numbers are needed: energy (n), angular momentum (ℓ), magnetic moment (mℓ), and spin (ms). The first quantum number describes the electron shell, or energy level, of an atom.
Answer : The number of glucose molecule are, 
Explanation : Given,
Mass of 
= 1273 g
Molar mass of = 180.156 g/mole
First we have to calculate the moles of .
Now we have to calculate the number of molecules of glucose.
As, 1 mole of glucose contains 
number of glucose molecules
So, 7.066 mole of glucose contains 
number of glucose molecules
Hence, the number of glucose molecule are,
