Answer:
D. Gases were released to the atmosphere
Explanation:
In accordance to the law of conservation of mass, the total amount of reactants must equate the total amount of products at the end of the reaction because matter can not be lost or created. However, certain changes like gas evolution, formation of precipitate etc. indicates the occurrence of a chemical reaction.
In a chemical reaction, the total mass of the product(s) would be less than the total weight of the reactant(s) because GASES, which constituted part of the mass of the reaction, WERE RELEASED INTO THE ATMOSPHERE. However, if the mass of the gas released can be accounted for, the amount of reactants and products must balance.
The answer should be A.
Hope this helps :-)
POH of a 0.0072 M=-lg(0.0072) = 2.1426675
Answer:
A. 85.6 g
= 0.0856 kg.
B. 0.00027 mol/g
= 0.27 mol/kg.
C. 8.39 %
Explanation:
Given:
Molar concentration = 0.25 M
Molar weight of sucrose = 342.296 g/mol
Density of solution = 1.02 g/mL
Mass of water = 934.4 g.
Density in g/l = 1.020 g/ml * 1000ml/1 l
= 1020 g/l
Mass of solution in 1 l of solution = 1020 g
Mass of solution = mass of solvent + mass of solute
Mass of sucrose = 1020 - 934.4
= 85.6 g of sucrose in 1 l of solution.
A.
Density of sucrose = mass/volume
= molar mass/molar concentration
= 342.296 * 0.25
= 85.6 g/l
Number of moles = mass/molar mass
= 85.6/342.296
= 0.25 mol
B.
Molality = number of moles of solute/mass of solvent
= 0.25/934.4
= 0.00027 mol/g
C.
% mass of sucrose = mass of sucrose/total mass of solution * 100
= 85.6/1020 * 100
= 8.39 %
B. carbon because it's atomic number is 6
