The correct answer as to which observation most likely indicates that only a chemical change has taken place would that the change cannot be reversed.
When it comes to changes in a system, it can either be:
- physical change
- chemical change
When a substance undergoes a physical change, the original version of the substance can be recovered. In other words, physical changes can be reversible.
When a substance undergoes a chemical change, the original version cannot be recovered because an entirely new product would have been formed. In other words, chemical changes are irreversible.
Thus, once a change becomes irreversible, such a change is said to be a chemical change.
More on chemical change can be found here: brainly.com/question/1161517
First, draw the 2-hexene. Th is is a molecule of six carbons with a double bond in the second carbon:
CH3 - CH = CH2 - CH2 - CH2 - CH3
Secong, put one Br on the second carbon and one Br on the third carbon:
CH3 - CBr = CBr - CH2 - CH2 - CH3
Third, cis means that the two Br are placed in opposed positions, this is drawn with one Br up and the other down. So, you need to represent the position of the Br in the space:
H Br H H H
| | | | |
H - C - C = C - C - C - C - H
| | | | |
H Br H H H
The important fact to realize is that the two Br are in opposed sides of the molecule.
Answer: C)Anion, it would gain 2 electrons to satisfy the octet rule.
Explanation:
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.
The electrons are filled according to Afbau's rule in order of increasing energies and thus the electronic configuration of oxygen with 8 electrons is

The cation is formed by loss of electrons and anions are formed by gain of electrons.
In order to complete its octet and get stable, it gains 2 electrons and thus would form an anion.

Answer:
The answer to your question is Q = 18702.5 J
Explanation:
Data
mass of water = m = 447 g
Cp = 4.184 J/g°C
Temperature 1 = T1 = 25°C
Temperature 2 = T2 = 35°C
Heat = Q = ? Joules
Process
1.- Write the formula to calculate heat
Q = mCp(T2 - T1)
2.- Substitution
Q = (447)(4.184)(35 - 25)
3.- Simplification
Q = (447)(4.184)(10)
4.- Result
Q = 18702.5 J