The reaction, Fe2O3 + 3CO------> 2Fe + 3CO2 is an oxidation-reduction reaction.
An oxidation-reduction reaction is a reaction in which there is a change in oxidation number from left to right in the reaction. This is because, a specie is oxidized and another specie is reduced.
In the reaction; Fe2O3 + 3CO------> 2Fe + 3CO2, we can see that the oxidation number of iron decreased from +3 on the left hand side to zero on the right hand side. The oxidation number of carbon was increased from + 2 to +4.
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Scientific Notation Is Basically The Shorthand For Writing Numbers. Scientists Use It When They Want To Write Numbers That Are Very Big Or Very Small.
Answer: an increase in the concentration of
in aqueous solutions and is capable of donating one or more 
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.
According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates protons and a base is defined as a substance which accepts protons.
According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.
Thus According to the Arrhenius concept, an acid is a substance that causes an increase in the concentration of
in aqueous solutions and is capable of donating one or more 
The density is one gram per mL, so 1.
The answer is salt water.
Salt water can conduct electricity or we can say that an electric current is conducted by salt water as salt water is a good conductor of electricity when salt that is sodium chloride or NaCl is dissolved in water , positively charged sodium (Na⁺) and negatively charged chlorine(Cl⁻) molecules are set apart by the water molecule so that they can float easily and freely. We can define the conductivity of a substance as the mobility or movement of ions. So as in water, sodium and chlorine are set apart and can move freely so it become a electrolyte that can conduct electricity.