<span>3 NO2 + H2O -------->. 2 HNO3. + NO
3(46g)------------------------> 2 ( 63g) HNO3
? kg-------------------------5.89 x10^3kg HNO3
Mass of NO2. = 5.89x10^3 x 138/ 2(63) = 6.45 x10^3 kg</span>
Answer is: MgF₂, magnesium fluoride.
Magnesium fluoride is salt, ionic compound, because magnesium is metal from 2. group of Periodic table of elements and has low ionisation energy and electronegativity, which means it easily lose valence electons, fluorine is nonmetal with greatest electronegativity, which meand it easily gain electron, so magnesium cation (Mg²⁺) and fluorine anion (F⁻) are formed.
There are 8.61 × 10²⁰ atoms in 0.290 g P₂O₅.
Step 1. Convert <em>grams of P₂O₅ to moles of P₂O₅</em>.

Step 2. Convert <em>moles of P₂O₅ to molecules of P₂O₅</em>.


Step 3. Convert <em>molecules of P₂O₅ to atoms</em>.
There are seven atoms in 1 mol P₂O₅.
∴ 
Answer:
A. releases a large amount of heat
Explanation:
A reaction is said to be spontaneous if it can proceed on its own without the addition of external energy. A spontaneous reaction is not determined by the length of time, because some spontaneous reactions are completed after a long period of time. They are exothermic in nature. An example is the conversion of graphite to carbon which takes a long period of time to complete. Spontaneous reactions are known to increase entropy in a system. Entropy is the rate of disorder in a system.
In the combustion of fire, energy is released to the surroundings as there is a decrease in energy. This is an example of a spontaneous reaction because it is an exothermic reaction, which causes an increase in entropy and a decrease in energy.
1 mol of Br = 79.9 g
15.7 g / 79.9 g = 0.196 moles of atoms