Answer:
At the burner temp. and pressure, 18.85 litres of air is needed to completely combust each gram of propane
Explanation:
The combustion stoichiometry is as follows:
C₃H₈ + 5O₂ = 4 H₂O + 3CO₂ The molecular weights (g/mol) are:
MW 44 5x32 4x18 3x44
So each gram of propane is 1/44 = 0.02272 mol propane
and will need 5 x 0.02272 = 0.1136 mol oxygen
At 0.21 mol fraction oxygen in air, 0.1136 / 0.21 = 0.54 mol air is needed to burn the propane.
At the low pressure in the burner we can use the Ideal Gas Law
PV=nRT, or V = nRT/P
P = 1.1 x 101325 Pa = 111457 Pa
T = 195°C + 273 = 468 K
R = 8.314
and we calculated n = number of moles air = 0.54 mol
So V m³ = 0.54 x 8.314 x 468 / 111457 = 0.0188 m³ = 18.85 litres air.
Monosaccharides are the simplest carbohydrates. Although glucose and fructose have the same molecular formula they have different structures or the atoms are arranged differently from each other and this is evident in the way they react, behave and in their properties.
Answer:
ΔG = -61.5 kJ/mol (<u>Spontaneous process</u>)
Explanation:
2 NO (g) + O₂ (g) ⇄ 2NO₂ (g)
Let's apply the thermodynamic formula to calculate the ΔG
ΔG = ΔG° + R .T . lnQ
We don't know if the gases are at equilibrium, that's why we apply Q (reaction quotient)
ΔG = - 69 kJ/mol + 8.31x10⁻³ kJ/K.mol . 298K . ln Q
How can we know Q? By the partial pressures (Qp)
P NO = 0.450atm
PO₂ = 0.1 atm
PNO₂ = 0.650 atm
Qp = [NO₂]² / [NO]² . [O₂]
Qp = 0.650² / 0.450² . 0.1 = 20.86
ΔG = - 69 kJ/mol + 8.31x10⁻³ kJ/K.mol . 298K . ln 20.86
ΔG = -61.5 kJ/mol (<u>Spontaneous process</u>)
Answer:
Atoms are composed of a central nucleus which is surrounded by orbiting <u>Electrons</u>.
Explanation:
The word Atom is derived from atomos meaning indivisible particle. An atom is a very small sized particle and its size is approximately 100 picometers.
Atoms are composed of a Nucleus which contains protons and neutrons and the nucleus is surrounded by orbiting electrons. Also, the nucleus is positively charged due to +ve protons and the electrons revolving around nucleus are -vely charged making overall atom neutral in nature.
Atoms react with another atoms due to the presence of valence electrons present in the valence shell of an atom. The valence electrons would make a covalent bond by mutually sharing the electrons or it may form an ionic bond by gaining and loosing valence electron.
