A.
Begin numbering at the end closest to the first branch, not the farthest.
Answer:
C₂H₅O₂
Explanation:
From the question given above, the following data were obtained:
Mass of compound = 0.25 g
Mass of CO₂ = 0.3664 g
Mass of H₂O = 0.15 g
Empirical formula =?
Next, we shall determine the mass of carbon, hydrogen and oxygen present in the compound. This can be obtained as follow:
For Carbon (C):
Mass of CO₂ = 0.3664 g
Molar mass of CO₂ = 12 + (2×16) = 44 g/mol
Mass of C = 12/44 × 0.3664
Mass of C = 0.1
For Hydrogen (H):
Mass of H₂O = 0.15 g
Molar mass of H₂O = (2×1) + 16 = 18 g/mol
Mass of H = 2/18 × 0.15
Mass of H = 0.02 g
For Oxygen (O):
Mass of C = 0.1 g
Mass of H = 0.02 g
Mass of compound = 0.25 g
Mass of O =?
Mass of O = (Mass of compound) – (Mass of C + Mass of H)
Mass of O = 0.25 – (0.1 + 0.02)
Mass of O = 0.25 –0.12
Mass of O = 0.13 g
Finally, we shall determine the empirical formula for the compound. This can be obtained as follow:
C = 0.1
H = 0.02
O = 0.13
Divide by their molar mass
C = 0.1 / 12 = 0.0083
H = 0.02 / 1 = 0.02
O = 0.13 / 16 = 0.0081
Divide by the smallest
C = 0.0083 / 0.0081 = 1
H = 0.02 / 0.0081 = 2.47
O = 0.008 / 0.008 = 1
Multiply by 2 to express in whole number
C = 1 × 2 = 2
H = 2.47 × 2 = 5
O = 1 × 2 = 2
Thus, the empirical formula for the compound is C₂H₅O₂
Weathering is the process of breaking large rocks and boulders into much smaller ones. Weathering can be brought about by wind and water mostly. Sometimes even biological forces account for some types of weathering.
Answer:
The fourth one down
Explanation:
It is the only setup in which the units of "cm" and "in" cancel correctly and give the desired units of "ft."
The second one down has the correct units but the wrong conversion factor for converting centimetres to inches.
Answer:
He
Explanation:
A molecule is the smallest physical unit of a substance that can exist independently, consisting of 2 or more atoms chemically combined
He is one atom of Helium
