Matter is a slightly archaic word for something with mass, as in the conservation of matter (which must be paired with the conservation of energy to still hold true. Mass can be converted back and forth between energy, so therefore so can matter. Of course relativistic mass is conserved as it's a function of the energy of an object in that reference frame.
Solution. because the substances can't go back to their original form. like kool aid, when its mixed you cant separate the powder and the water again.
Answer:
0.0177 L of nitrogen will be produced
Explanation:
The decomposition reaction of sodium azide will be:

As per the balanced equation two moles of sodium azide will give three moles of nitrogen gas
The molecular weight of sodium azide = 65 g/mol
The mass of sodium azide used = 100 g
The moles of sodium azide used = 
so 1.54 moles of sodium azide will give =
mol
the volume will be calculated using ideal gas equation
PV=nRT
Where
P = Pressure = 1.00 atm
V = ?
n = moles = 2.31 mol
R = 0.0821 L atm / mol K
T = 25 °C = 298.15 K
Volume = 
5 electrons
Boron atomic number 5 has five electrons in its ground state.
Commonly Boron will lose 3 electrons leaving 2 electrons in its most common ionic form.
Explanation:
The atomic number gives the number of protons. Protons which have a positive charge are balanced by an equal number of electrons in a neutral atom.
Boron number 5 has five protons and therefore as a neutral atom also has five electrons.
Boron has an electron configuration of
1s22s22p1
The most stable electron configuration for Boron is
1s2
+ 3 charges. By losing three electrons Boron can achieve the stable electron structure of Helium
Brainliest? :D