Answer:
2. Co(NO3)2 + H2
Explanation:
Hello,
In this case, we are evidencing a simple displacement reaction wherein the cobalt is able displace the hydrogen to produce cobalt (II) nitrate and gaseous hydrogen as a result of cobalt's higher activity:

Therefore, answer is 2. Co(NO3)2 + H2.
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Answer:
iron (Fe)
Explanation:
Since an atom is electrically neutral, so the atom has 26 electrons also. Ion has 24 electrons, so it has experienced loss of 2 electrons. So, charge on ion is +2. Also, the element with 26 protons (26 atomic number) is iron (Fe).
Answer:
Reflection
Explanation:
Because light is bouncing of the object
Answer;
- Oxygen
-Ancient cyanobacteria released oxygen, which assisted in creating the atmosphere as we know it today.
Explanation;
-The oxygen atmosphere that we depend on was generated by numerous cyanobacteria during the Archaean and Proterozoic Eras.
-Cyanobacteria are aquatic and photosynthetic, meaning they live in the water, and can manufacture their own food. During the process of photosynthesis, energy from sunlight is used together with carbon (iv) oxide and water to form organic molecules that serve as nutrients for the organisms and also oxygen gas is released to the atmosphere.