Carbon monoxide is a colorless, odorless, tasteless gas produced by burning gasoline, wood, propane, charcoal or other fuel. Improperly ventilated appliances and engines, particularly in a tightly sealed or enclosed space, may allow carbon monoxide to accumulate to dangerous levels.
Atomic number of gold,
= 79 means there are 79 electrons in per atom of gold.
Atomic mass of gold = 196.967 gm
0.990 oz of gold is given.
Now, converting 

So, 
Now, for determining the number of moles, the formula for number of moles is:

Substituting the values:

1 mole of 
So, for 0.1425 mole of 
Since 1 atom of gold has 79 electrons so,
Number of electrons = 
So, number of electrons in 0.990 oz of pure gold coin is
.
Answer
Fluorite
Explanation
Fluorine is a yellowish, poisonous, highly corrosive gas. It is the most chemically active nonmetallic element and is the most electronegative of all the elements. It is a member of Group 17 (the halogens ) of the periodic table .
Answer:
There is 5720 J of heat released.
Explanation:
Step 1: Data given
Molar mass of CH6N2 = 46.07 g/mol
The heat of combustion of methylhydrazine is −1.30 × 103 kJ/mol
Mass of methylhydrazine = 202.7 grams
Step 2: Calculate number of moles
Moles CH6N2 = mass of CH6N2 / Molar mass CH6N2
Moles CH6N2 = 202.7 grams / 46.07 g/mol
Moles CH6N2 = 4.4 moles
Step 3: Calculate heat released when 202.7 grams of CH6N2 is burned
q = 1300 J/mol * 4.4 moles
q = 5720 J
(Since there is heat released, ΔH = negative)
There is 5720 J released.