Pure chlorine is an example of an element.
An element is a chemical substance that cannot be broken down into simpler components in a chemical reaction or by any chemical means, and is made up of atoms that all have the same number of protons. Pure chlorine is an example of an element because it contains only one kind of an atom. Chlorine is a toxic, green, gaseous chemical element. Chlorine is a halogen, has an atomic number of 17, symbol Cl and is found in group 17 in the periodic table. Chlorine is highly reactive and a strong oxidizing and disinfecting agent.
Answer:
21%
Explanation:
To remember this percentage, use the amount of land and water on earth, like this: 3 (land) x 7 (water) = 21
(note: oxygen does not change depending on land or water amount)
<span>C is the correct answer. Cats’ whiskers are touch receptors which help them sense things in the world through touch (tactile sensors). Therefore, trimming cats’ whiskers can be dangerous for the cat as it removes some of their senses until the whiskers grow back.</span>
Answer: C. The sign of the enthalpy of the reaction reverses.
Explanation: Enthalpy of a reaction is the net heat absorbed or released during a chemical reaction.It is represented by 
. It is negative for exothermic reactions in which heat is released and is positive for endothermic reactions in which heat is absorbed.
When a chemical reaction is reversed the heat of the reaction changes its sign.
The decomposition of calcium carbonate is an endothermic reaction as heat is required to break the bonds and thus energy is absorbed.
When the reaction is reversed, the reaction becomes exothermic as now bonds are getting formed and energy is released.
