Answer:
Explanation:
A physical change occurs when only the physical properties change. They are generally reversible and no new substances are formed.
However, in a chemical change, the chemical structures and properties change, plus new substances are formed.
Let's analyze each answer choice.
1. Change in state of matter
The state of matter is a physical property, so this is a physical change.
2. Precipitate was formed
A precipitate is a solid formed in a liquid solution. This is a new substance and a chemical change.
3. Unexpected change in odor.
A change in odor is a sign of chemical change.
4. Formation of bubbles
Bubbles signify the formation of gas or a new substance.
So, the best answer choice is <u>A. change in state of matter</u>
Answer:
C- convection (convectional current)
Explanation:
Convection occurs in fluids e.g gases and liquids. It is the prices by which heat energy is transferred in a fluid by the actually movement of the heated fluid.
It is also called convectional current when the term current is used in the question.
Answer:
The whole molecule is polar because Sulfur has lone pairs but Carbon doesn't. Lone pairs count more toward polarity, shifting dipole toward S.
Explanation:
Even though carbon and sulfur have identical values of electronegativities, the molecule, 
is polar because of the presence of the lone pairs on the sulfur atom.
The C-S bond is not polar because the both the atoms have electronegatiivty. <u>But S has lone pairs which can attract the bond pairs of the bond between the S and H and thus acquires slightly negative charge and H acquires slightly positive charge.</u>
An organism that breathes with its lungs, lays eggs and has feathers is a bird!
Answer:
The reaction in this experiment is termed an iodine clock reaction, because it is the molecular iodine (I2) that undergoes the sudden concentration change. When the iodine concentration increases, it reacts with the starch in the solution to form a complex, turning it a deep blue-black color.
