Answer:
Choices 2 and 4
Explanation:
HCL is formed witthe the elements Hydrogen and Chlorine. Whatever is on the left side of the equation must match up with the right side of the equation.
2. H + Cl --> HCl (we have one hydrogen and one chlorine)
4. 2HCl --> H2 + Cl2 (since the two is distributed to both the H and the Cl, H has 2 and Cl has two on the left side AND on the right side of the equation)
Answer:
C. Both observation 1 and observation 2.
Explanation:
The heliocentric model states that the Earth and planets revolve around the Sun at the center of the Solar System.
Observation 1 was answered by Nicolas Copernicus, father of the heliocentrism, in 1543. The reverse effect is an illusion created because the Earth revolves faster around the Sun than Mars.
And observation 2 also is explained by the model because the rotation of the earth made that the Stars be closer to it at different times of the year.
I hope this answer helps you.
4 and 1. I had this same test and those were it
Answer is: because weak acids do not dissociate completely.
The strength of an Arrhenius
acid determines percentage of ionization of acid and the number of H⁺ ions formed. <span>
Strong acids completely ionize in water and give large amount ofhydrogen ions (H</span>⁺), so we use only one arrow, because reaction goes in one direction and there no molecules of acid in solution.
For example hydrochloric acid: HCl(aq) → H⁺(aq) + Cl⁻(aq).
<span>
Weak acid partially ionize in water
and give only a few hydrogen ions (H</span>⁺), in the solution there molecules of acid and ions.
For example cyanide acid: HCN(aq) ⇄ H⁺(aq)
+ CN⁻(aq).
Answer:
The chlorine atom (or atoms) is covalently bonded by a shared pair of electrons to the other element.
Explanation: