Answer:
70 mL of 5% HCl and 30 mL of 15% HCl
Explanation:
We will designate x to be the fraction of the final solution that is composed of 5% HCl, and y to be the fraction of the final solution that is composed of 15% HCl. Since the percentage of the final solution is 8%, we can write the following expression:
5x + 15y = 8
Since x and y are fractions of a total, they must equal one:
x + y = 1
This is a system of two equations with two unknowns. We will proceed to solve for x. First, an expression for y is found:
y = 1 - x
This expression is substituted into the first equation and we solve for x.
5x + 15(1 - x) = 8
5x+ 15 - 15x = 8
-10x = -7
x = 7/10 = 0.7
We then calculate the value of y:
y = 1 - x = 1 - 0.7 = 0.3
Thus 0.7 of the 100 mL will be the 5% HCl solution, so the volume of 5% HCl we need is:
(100 mL)(0.7) = 70 mL
Similarly, the volume of 15% HCl we need is:
(100 mL)(0.3) = 30 mL
Answer:
16,,24Mg 17,,a24.1 18a mass number of the most abundant isotope
Explanation:
atomic number of Mg is 12 ,therefore its mass number should be the value that is very close to 24.
24.1 is the value of thee most abundant isotope.
Other predators? or other factors that affect the food chain ie extinction of whatever source the rabbits feed off of
Answer:D. Compound.
Explanation:
A compound is defined as a pure substance: formed when two or more elements chemically combine to form bonds between their atoms.
The pH scale for acids and bases ranges from 1 - 14. The answer is letter C. The rest of the choices do not answered the question above. There are quite a few relationships between [H+] and [OH−] ions. And because there is a large range of number between 10 to 10-15 M, the pH is used. pH = -log[H+] and pOH = -log[OH−]. In aqueous solutions, [H+ ][OH- ] = 10-14. From here we can derive the values of each concentration.
-log[H+ ] + -log[OH- ] = -log[10-14]
pH + pOH = 14
So pH = 14 – pOH and pOH = 14 –
pH
It would be B.
