Pedro wants to create a chemical reaction between oil and water. he adds oil to a beaker of water and notices that the liquids do not mix. he then shakes the beaker and the drops of oil become suspended through the water for a few moments before returning to their separate layers. did pedro succeed in creating a chemical change?
(a)-yes, because the oil was evenly suspended.
(b-)yes, because the solution was permanently changed.
(c)-no, because the oil only briefly mixed with the water. (
d)no, because no new substances were formed.

D

Explanation:

A chemical change occurs when new substances are formed for exemple

HCO3 --> H2O + CO2

This is a decomposition of the carbonic acid.

A) No, the oil been evenly suspended is a phisycal phenomenon

B) No, the solution changed when the beaker was shaked but returned to the initial state.

C) The oil will not react with water because of their polarity, the water is Polar and the oil is nonpolar

D) This one is correct, as there where no new substances formed, it no have a chemical change.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.