Answer : (a) 
is a decomposition reaction.
Explanation :
(a) is a decomposition reaction.
- Decomposition reaction : It is a type of chemical reaction in which a single compound decomposes into two or more compounds.
(b) 
is a displacement reaction.
- Displacement reaction : It is a type of reaction in which a most reactive element displaces the least reactive element in a compound.
(c) 
is a combination reaction.
- Combination reaction : It is a type of reaction where two or more compounds combine to form a single compound.
(d) 
is a combustion reaction.
- Combustion reaction : It is a type of reaction where a hydrocarbon react with the oxygen to produced carbon dioxide and water.
Therefore, option (a) is a decomposition reaction.
Cobalt-59 is the only stable isotope of this transition metal. • Mass of proton = 1.00783 amu1.00783 amu
<h3>What is isotope ?</h3>
Isotopes are two or more atom types that share the same atomic number (number of protons in their nuclei), location in the periodic table, and chemical element but have distinct nucleon numbers (mass numbers) as a result of having a different number of neutrons in their nuclei. Although the chemical properties of each isotope of a given element are nearly identical, they differ in their atomic weights and physical characteristics.
The name "isotope" refers to the fact that different isotopes of a single element occupy the same location on the periodic table. The term "isotope" is derived from the Greek words isos ("equal") and topos ("place"), which together indicate "the same place." In 1913, Scottish physician and author Margaret Todd suggested the term to British chemist Frederick Soddy.
To learn more about isotope from the given link:
brainly.com/question/364529
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Answer:
1.3 kg
Explanation:
Mass of ocean water = mass of NaCl × (mass of ocean water/mass NaCl).
The % NaCl tells us there are 3.5 g NaCl/100 g ocean water or 100 g ocean water/3.5 g NaCl.
Mass of ocean water = 46.8 × (100/3.5)
Mass of ocean water = 46.8 × 28.6
Mass of ocean water = 1300 g = 1.3 kg
<em>Note</em>: The answer can have only <em>two significant figures</em> because that is all you gave for the percentage of NaCl.
