Because in rock salt, the molecules are packed together and they take longer time to separate and dissolve. As for table salt the molecules are less packed together and take less time to dissolve. Think it like this. The more packed or tightly the substance/object is, the longer it will take for the object to dissolve. The less packed the object/substance is the faster it takes to dissolve. Hope this helped :)
1. 100N to the right
2. 10N to the left
3. 0N they are balanced
4. 0N they are balanced
B) energy is absorbed by the reaction
is right answer.
Half life is the time taken by a radioactive isotope to decay by half its original mass. In this case, the halflife of the radioactive isotope is 5000 years.
Initially the mass is 100 %; thus the mass that will be left will be given by;
New mass = Original mass × (1/2)^n where n is the number of half lives;
n = 10000/5000 = 2
New mass = 100% ×(1/2)^2
= 100 % × 1/4
= 25%
Therefore; the mass left after 10000 years is 25% or 1/4 of the original mass.
The sand provides a rough surface on top of the ice for the cars' tires to grip onto. It provides more friction. Salt melts the ice and often provides more friction (the disadvantage is that it eats concrete!).
