C. Sulfur and oxygen (non metals) forms a covalent bond while the magnesium (a metal) will react with both non metals to form an ionic bond
Answer: 2948
Explanation:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant =
t = age of sample = ?
a = let initial amount of the reactant = 100
a - x = amount left after decay process = 
Thus the fossil is 2948 years old.
Answer: - 436.5 kJ.
Explanation:
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation.
The given chemical reaction is,

Now we have to determine the value of
for the following reaction i.e,

According to the Hess’s law, if we divide the reaction by half then the
will also get halved and on reversing the reaction , the sign of enthlapy changes.
So, the value
for the reaction will be:


Hence, the value of
for the reaction is -436.5 kJ.
Melting is an example of phase change
Answer:
NAD+, FAD.
Explanation:
The citric acid cycle is popularly known as the Kreb's cycle. The cycle involve the oxidation of acetyl-CoA to produce energy. The Kreb's cycle is a chemical process that produces produces two carbon dioxide molecules,NADH,FADH2 and one ATP.
When oxygen is depleted, the citric acid cycle stops, apart from oxygen NAD+ and FAD could be added to the system to restore citric acid cycle activity. NAD+ acts as an electron acceptor.
Citric acid cycle/Kreb's cycle is an aerobic process that occurs in the mitochondria and produces thirty-six(36) ATPs.