Answer:
<em>There must be added 500 cm3 of alcohol to bring the concentration to 80%.</em>
Explanation:
<u>Concentration</u>
The concentration of a solution is a measure of the amount of solute that has been dissolved in a given amount of solution.
In the container, there are 2 liters (2000 cubic centimeters) of a solution, 75% of which is alcohol (solute) and 25% of water (solvent).
The original amount of alcohol is:
H = 2000*75% = 1500 cc
The original amount of water is:
W = 2000*25% = 500 cc
When we add x cc of pure alcohol, there are 1500+x cc of alcohol out of 2000+x cc of solution.
The new concentration is calculated as:
![\displaystyle \frac{1500+x}{2000+x}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7B1500%2Bx%7D%7B2000%2Bx%7D)
And it's known this concentration is 80% (0.8), thus:
![\displaystyle \frac{1500+x}{2000+x}=0.8](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7B1500%2Bx%7D%7B2000%2Bx%7D%3D0.8)
Multiplying by 2000+x:
![1500+x = 0.8(2000+x)](https://tex.z-dn.net/?f=1500%2Bx%20%3D%200.8%282000%2Bx%29)
Operating:
![1500+x = 1600+0.8x](https://tex.z-dn.net/?f=1500%2Bx%20%3D%201600%2B0.8x)
Rearranging:
![x-0.8x=1600-1500](https://tex.z-dn.net/?f=x-0.8x%3D1600-1500)
![0.2x=100](https://tex.z-dn.net/?f=0.2x%3D100)
![x=100/0.2](https://tex.z-dn.net/?f=x%3D100%2F0.2)
x= 500
There must be added 500 cm3 of alcohol to bring the concentration to 80%
Answer:
The strengths become greater, as the number of turn increases,
Answer:
C
Explanation:
fission requires slowing down neutrons so they hit more nuclei (easy), but fusion requires speeding up nuclei so they hit each other (hard).
Answer:
(1) how thick the fluid is <u>viscosity</u>
Explanation:
This is a type of friction experienced within liquids and gases. It depends on:__________.
(1) how thick the fluid is_______?
(2) how the shape of the object?
(3) how the speed of the object?
the thickness of a fluid is known as viscosity. the more viscous a fluid is the more frictional force is exerted on an object by the fluid
frictional force is an opposing force that resist the movement of two surfaces in contact, there are to types 0f frictional force
1. static frictional force
2. dynamic frictional force