The answer is C. an endothermic reaction. The endothermic reaction means this reaction will absorb energy and exothermic reaction means this reaction will release energy.
Answer: metal and carbonate
Explanation:
According to Arrhenius concept, a base is defined as a substance which donates hydroxide ions 
when dissolved in water and an acid is defined as a substance which donates hydrogen ions 
in water.
An acid is represented as :
1. When metal is treated with an acid such as 
, if the metal is more reactive than hydrogen displaces hydrogen from its salt solution and thus produce zinc chloride and hydrogen gas.
2. When carbonates are treated with acid, double displacement takes place ad carbon dioxide is released as a gas.
<span>the element that requires the least amount of energy to remove the outer-most electron from a gaseous atom in the ground state is s</span><span>odium</span>
It's the mitochondrion. It it the powerhouse of the cell and deals mainly with energy.
Materials with ionic bonds tend to be more easily scratched.
