Answer:
A. Exposure to air has caused the iron-bearing minerals in the granite to oxidize.
Explanation:
The main cause of granite rust is a metal substance that remains in it's contact over a long period of time. As a result of a moist or wet environment, . a geologist discovers a piece of granite that has a coating of soft, crumbling rust.
Exposure to air has caused the iron-bearing minerals in the granite to oxidize.
Option A. is correct.
<span>disproportionation is a type of redox reaction in which an element can undergo both oxidation and reduction.
Let's take a look at the choices:
First we have the oxide ion. Oxide ion has a charge of -2 which is the lowest charge that an oxygen atom can have. Therefore, an oxide ion cannot be further reduced, so this choice is not correct.
Next we have the peroxide ion. The oxygen has a charge of -1 which means it can be further reduced. So, this choice is acceptable
Last but not least, we have the superoxide ion. The oxygen has a charge of -1/2 which means it can be further reduced. So, this choice is also acceptable.
Based on this, we have two accepted choices which are b and c.</span>
Causes movement in the heart
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.
Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom.
The term isotope is formed from the Greek roots isos ("equal") and topos ("place"), meaning "the same place".
