Answer:
A) 4P + 5O₂ → 2P₂O₅
Explanation:
A) 4P + 5O₂ → 2P₂O₅
This equation is balanced. There are four phosphorus and ten oxygen atoms are on both side of equation.
B) 5P + 4O₂ → 2P₄O₅
This equation is not balanced. There are five phosphorus and eight oxygen atoms on left, eight phosphorus ten oxygen on right side of equation.
C) 2P + O₂ → P₂O₅
This equation is not balanced. There are two phosphorus, two oxygen atoms on left and two phosphorus five oxygen on right side of equation.
D) 4P + 2O₂ → 2P₄O₅
This equation is not balanced. There are four phosphorus, four oxygen atoms on left and eight phosphorus ten oxygen on right side of equation.
Atomic mass is usually defined by the total number of protons, neutrons and electrons in a single atom. You can measure it by spectrometry.
First, calculate the mass of sodium in g with the help of molar mass and number of moles.
Number of moles =
(1)
Molar mass of sodium =
Substitute the given value of number of moles and molar mass of sodium in formula (1)
(1)
(1)
mass of sodium in g = 
Now, according to conversion factor, 1 g = 1000 mg
So,
of sodium =
=
of sodium
Thus, mass of sodium in mg =
Wdym mole like the animal or something else ?
Using PV = nRT, we can calculate the moles of the sample.
874 mmHg = 116,524 Pa
n = PV/RT
n = 116,524 x 294 x 10⁻⁶ / 8.314 x (140 + 273)
n = 9.98 x 10⁻³ mol
moles = mass / Mr
Mr = 0.271/9.98 x 10⁻³
Mr = 27.2
Mass of empirical formula = 14
Repeat units = 27.2 / 14 ≈ 2
Formula of substance:
C₂H₄
Combustion equation:
C₂H₄ + 3O₂ → 2CO₂ + 2H₂O
1 mole produces 2 moles of CO₂, so 3 moles will produce 6 moles CO₂