Answer:
a) 
b) 
c) 
Explanation:
Hello,
In this case, in each reaction we must subtract the Gibbs free energy of formation the reactants to the Gibbs free energy of formation of the products considering each species stoichiometric coefficients. In such a way, the Gibbs free energy of formations are:

So we proceed as follows:
a)

b)

c)

Regards.
Answer:
Date Significance Soviet Union Mission
August 21, 1957 First intercontinental ballistic missile (ICBM) R-7 Semyorka
October 4, 1957 First artificial satellite First signals from space Sputnik 1
November 3, 1957 First dog in orbit (Laika) Sputnik 2
January 31, 1958 First US satellite, detection of Van Allen radiation belts
Explanation:
Answer:
184.113 g/mol
Explanation: The atomic mass of Mg is 24.3 amu. The atomic mass of bromine is 79.9. Therefore, the formula weight of MgBr2 equals 24.3 amu + (2 × 79.9 amu), or 184.1 amu. Because a substance's molar mass has the same numerical value as its formula weight, the molar mass of MgBr2 equals 184.1 g/mol.
A chemical reaction occurs when substances change. Photosynthesis is the process by which plants produce food.
1) A chemical reaction is a process by which substances can be changed into other substances. Hence, in a chemical reaction, new substances are formed.
2) Photosynthesis is the process by which plants produce food using carbon dioxide and water in the process of sunlight and chlorophyll. Glucose is produced during photosynthesis and the energy produced and stored as starch.
3) Valence electrons show the kind of bond that an atom can form. Reaction between two atoms that have many valence electrons is most likely covalent. An ionic bond is formed between an atom that has few valence electrons and an atom that has many valence electrons.
4) A carbohydrate is a compound that comprises of hydrogen and oxygen in a ratio of 2:1. The compound that is a carbohydrate is C3H6O3.
5) Rocks contain iron. Iron oxides form when cyanobacteria produce oxygen via photosynthesis.
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