Answer: Chemical change
Explanation:
Physical change is a change in which there is no rearrangement of atoms and thus no new substance is formed. There is only change in physical state of the substance. The change can be reversed using physical methods.
Chemical change is a change in which there is rearrangement of atoms and thus new substance is formed. There may or may not be a change in physical state. The change can only be reversed using chemical methods.
Thus when iron and sulfur are heated in a test tube, the chemical change occurs and thus lead to formation of new substances which could not be separated using magnet.
Answer:
Momentum of first train car will reduce
Explanation:
When the moving care collides with the stationary car, it will increase the momentum of the stationary car. However, its own momentum will reduce.
It is so because the speed of the first train car will reduce after collision due to loss of energy in the collision while the stationary car may gain some momentum due to rise in velocity from zero (velocity at stationary position).
Its leading to contaminated drinking water.
Answer: Mass Of CFC that needs to evaporate for the freezing of water = 328.24 g
Explanation: Heat gained by the CFC = Heat lost by water
Heat lost by water = Heat required to take water's temperature to 0°c + Heat required to freeze water at 0°c
Heat required to take water's temperature from 33°c to 0°c = mCΔT
m = 201g, C = 4.18 J/(gK), ΔT = 33
mCΔT = 201 × 4.18 × 33 = 27725.94 J
Heat required to freeze water at 0°c = mL
m = 201g, L = 334 J/g
mL = 201 × 334 = 67134 J
Heat gained by CFC to vaporize = mH = 27725.94 + 67134 = 94859.94 J
H = 289 J/g, m = ?
m × 289 = 94859.9
m = 328.24 g
QED!!
