Reaction:
Magnesium is a stronger reducing agent than copper and is thus able to reduce copper(II) oxide.
Products of the reaction: Magnesium oxide and metallic copper.
Answer:
The correct answer would be - c. A solid was added to water and the mixture was stirred until the solid was no longer visible
Explanation:
Photostabalizing is the process where a solid change its color in the presence of ultraviolet light, it is a chemical change, so the first option would not be the correct answer.
when two liquid or aqueous solutions are mixed together and form a solid substance, this reaction is known as precipitation and it is a chemical reaction too.
When a solid is placed in a liquid and after stirring it makes the solid vanish is a physical change known as dissolving character.
Thus, the correct answer is option C.
C. single replacement. A single replacement is represented by this formula : AB + C = AC + B
Answer:
The decreasing order of bond length in the carbon - carbon bonds will be:
Explanation:
Bond length is defined as average distance between two nuclei of bonded atoms in a molecule.Bond length is inversely proportional to the number of bonds present between two atoms.
...[1]
Bond energy is defied as amount of energy required to break apart the bond of 1 mole of molecule into their individual atom. Bond energy is directly proportional to the number of bonds present between two atoms.
..[2]
From [1] and [2]:
hybridized
hybridized
hybridized
Extent of overlapping of orbitals in these hybridization;
Higher the overlapping of orbital more closer will be both atoms to each other and shorter will be the bond lenght.
So, the decreasing order of bond length in the carbon - carbon bonds will be:
There are two kinds of forces, or attractions, that operate in a molecule—intramolecularand intermolecular. Let's try to understand this difference through the following example.

Figure of towels sewn and Velcroed representing bonds between hydrogen and chlorine atoms
We have six towels—three are purple in color, labeled hydrogen and three are pink in color, labeled chlorine. We are given a sewing needle and black thread to sew one hydrogen towel to one chlorine towel. After sewing, we now have three pairs of towels: hydrogen sewed to chlorine. The next step is to attach these three pairs of towels to each other. For this we use Velcro as shown above.
So, the result of this exercise is that we have six towels attached to each other through thread and Velcro. Now if I ask you to pull this assembly from both ends, what do you think will happen? The Velcro junctions will fall apart while the sewed junctions will stay as is. The attachment created by Velcro is much weaker than the attachment created by the thread that we used to sew the pairs of towels together. A slight force applied to either end of the towels can easily bring apart the Velcro junctions without tearing apart the sewed junctions.
Exactly the same situation exists in molecules. Just imagine the towels to be real atoms, such as hydrogen and chlorine. These two atoms are bound to each other through a polar covalent bond—analogous to the thread. Each hydrogen chloride molecule in turn is bonded to the neighboring hydrogen chloride molecule through a dipole-dipole attraction—analogous to Velcro. We’ll talk about dipole-dipole interactions in detail a bit later. The polar covalent bond is much stronger in strength than the dipole-dipole interaction. The former is termed an intramolecular attraction while the latter is termed an intermolecular attraction.
