The atomic mass on the periodic table represents the sum of number of protons and number of neutrons.
Atomic mass = Number of protons + number of neutrons
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Answer:The first method to determine the chemical composition of a substance in space was using light. By determining red shift in the observed spectrum of light they could determine the elements they were observing
Explanation:
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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