Answer: 10.2 grams
Explanation:
The balanced chemical reaction is :
According to the ideal gas equation:
P = Pressure of the gas = 740 torr = 0.97 atm (760torr=1atm)
V= Volume of the gas = 12.0 L
T= Temperature of the gas = 19°C = 292 K 
R= Gas constant = 0.0821 atmL/K mol
n= moles of gas
According to stoichiometry:
2 moles of hydrogen are generated by = 1 mole of 
Thus 0.48 moles of hydrogen are generated by =
moles of
Mass of 
Thus 10.2 grams of are needed to generate 12.0 L of hydrogen gas if the pressure of hydrogen is 740. torr at 19°C
The mass number of an atom is basically the total number of protons and neutrons.
First, we use avogadro's number to convert atoms into moles. Then, relate the number of moles from elemental to the compound. Lastly, we use conditions at STP to calculate the volume. We do as follows:
<span>9.86 x 10²⁸ O-atoms ( 1 mol / 6.022x10^23 atoms O) ( 1 mol N2O2 / 2 mol O ) ( 22.4 L / 1 mol ) = 1833809.37 L needed</span>
Chemical properties is when a material undergoes a chemical change or reaction like a nail rusting and a physical change can be observed without changing the material like temperature, color, texture, odor,etc.
