D=m/v ⇒ m=d*v
d=density
m=mass
v=volume
d(ether)=0.71 gr/cm³=0.71 gr/ ml
v=130 ml
m=d*v
m=0.71 gr/ml*(130 ml)=92.3 g
Solution: m=92.3 g
To work this out you do 400÷20=20
Answer: |x+2|=xF2+4
Explanation: not sure if this is right im just guessing
Answer: a. 0.26mol
b. 0.000479mol
c. 1.12mol
Explanation: Please see attachment for explanation
The formula for kinetic energy is KE=1/2(mv²). Since both mass and velocity are multiplied by each other, particle with a larger mass needs to be moving slower than a particle with less mass if both have the same kinetic energy. You can think of it as 2KE/m=v² or 2KE/v²=m, If you increase the mass the velocity needs to decrease to keep the same KE value.
I hope this helps. Let me know in the comments if anything is unclear.