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
For multiple covalent bonds to form in molecules, the molecules must contain carbon nitrogen or oxygen.
<u>Explanation:</u>
- Think about carbon dioxide (CO2). If every oxygen atom imparts one electron to the carbon molecule, there will be 6 electrons in carbon particle and 7 electrons in every oxygen atom. This doesn't give the carbon atom as a total octet.
- Sometimes more than one set of electrons is shared between two atoms. In carbon dioxide, a second electron from every oxygen atom is likewise imparted with the central carbon atom, and the carbon particle imparts one more electron with every oxygen atom.
- Two sets of electrons shared between two atoms make a double bond between the atoms. A few particles contain triple bonds, covalent bonds in which three sets of electrons are shared by two atoms.
Explanation:
The species with a positive charge over it, which means lack of electrons are called cations. Whereas the species with negative over it, meaning it has an excess of electrons with it are called anions.
From the list given the cations are
H+, Ba2+, Hg2+, Li+, Ca2+ and Fe2+
Whereas anions from the list are
O-2, Br-5, F-, S-2.
A Combination of cation and anions make an ionic compound in which cation is written first and then anion.
I think this one is the organelles.
