Answer: Gold.
Explanation: Water, CO2, and table salt are compounds. They are composed of two or more separate elements; a mixture, where as gold is neither.
1) Left up: a chemical change. We can see new substance (red-blue) is formed from one blue and one red atom.
In chemical change new substances are formed, the atoms are rearranged and the reaction is followed by an energy change.
2) Left down: a chemical change. We can see new substance (red-blue) is formed from two blue and one red atoms.
3) MIddle: a physical change. There is no new substance. Bonds are not broken.
4) Right up: a chemical change. Bonds are broken.
5) Right down: a physical change. Change of state of matter.
Answer:
Ca₃(AsO₃)₂
Explanation:
Sodium arsenite, with the chemical formula Na₃AsO₃, is formed by the cation Na⁺ and the anion AsO₃³⁻. For the molecule to be neutral, 3 cations Na⁺ and 1 anion AsO₃³⁻ are required.
Calcium arsenite would be formed by the cation Ca²⁺ and the anion AsO₃³⁻. For the molecule to be neutral, we require 3 cations Ca²⁺ and 2 anions AsO₃³⁻. The resulting chemical formula is Ca₃(AsO₃)₂.
Answer:
Pb(s) ---> Pb+2 + 2e- is the anode
Cu+2(aq) + 2e- ---> Cu(s) is the cathode