Answer:
A. Hydrogen and oxygen combines in a constant mole ratio in all the three water samples
B. Carbon and oxygen are combined in a constant mole ratio in all the three samples of carbon dioxide
C. All pure samples of a compound contain the same elements combined in the same proportion by mass
D. Since the same elements are always combining to form a certain compound, and the atoms of each element has its own mass, the atoms of each element combining to form the compound do so in a fixed proportion by mass.
Explanation:
A. molar mass of hydrogen = 1.0 g/mol; molar mass of oxygen = 16 g/mol
The molar ratio of elements in a compound gives the proportion each element is combined with the other by mass.
molar ratio of hydrogen to oxygen in the samples:
Sample 1: Hydrogen; 1.5/1 = 1.5: Oxygen; 12/16 = 0.75
molar ratio = 1.5/0.75 = 2 : 0.75./0.75 = 1
molar ratio = 2:1
Sample 2: Hydrogen; 2/1 = 2: Oxygen; 16/16 = 1
molar ratio = 2/1 = 2 : 1/1 = 1
molar ratio = 2:1
Sample 3: Hydrogen; 2.5/1 = 2.5: Oxygen; 20/16 = 1.25
molar ratio = 2.5/1.25 = 2 : 1.25/1.25 = 1
molar ratio = 2:1
Hydrogen and oxygen combines in a constant mole ratio in all the three water samples
B. molar mass of carbon = 12 g/mol; molar mass of oxygen = 16 g/mol
molar ratio of carbon to oxygen in the samples:
Sample 1: Carbon; 0.5/12 = 0.04 : Oxygen; 1.3/16 = 0.08
molar ratio = 0.04/0.04 = 1 : 0.08/0.04 = 2
molar ratio = 1:2
Sample 2: Carbon; 1.0/12 = 0.083 : Oxygen; 2.7/16 = 0.168
molar ratio = 0.083/0.083 = 1 : 0.168/0.083 = 2
molar ratio = 1:2
Sample 3: Carbon; 1.5/12 = 0.125 : Oxygen; 4.0/16 = 0.250
molar ratio = 0.125/0.125 = 1: 0.250/0.125 = 2
molar ratio = 1:2
Carbon and oxygen are combined in a constant mole ratio in all the three samples of carbon dioxide
C. All pure samples of a compound contain the same elements combined in the same proportion by mass
D. Since the same elements are always combining to form a certain compound, and the atoms of each element has its own mass, the atoms of each element combining to form the compound do so in a fixed proportion by mass.
