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When a bottle is filled with water, the total mass of water and bottle is 120g. When it is filled with alcohol, the total mass of alcohol and bottle is 100g. What is the mass of alcohol in the bottle? What's the mass of the bottle? (ρ alcohol = 0.8 × 103kg / m3)
According to the meaning of the title, M0 + m water = 120g --- ①, M0 + m alcohol = 100g --- ②, from ① - ②, we can get m water - M alcohol = 20g, ρ water V - ρ alcohol v = 20g, then v = 20g, ρ water − ρ alcohol = 20g 1g / cm3 − 0.8g/cm3 = 20g, 0.2g/cm3 = 100cm3, m alcohol = ρ alcohol, v = 0.8g / cm3 × 100cm3 = 80g, M0 = 100g-m alcohol = 100g-80g = 20g
The weight of an empty bottle is 20g, the weight is 120g when it is filled with water, and the weight is 105g when it is filled with alcohol
Is this kind of alcohol pure? The density of alcohol is 0.8x10 cubic kg / m3
The mass of water is: 120-20 = 100g
The volume of water is: 100g / (1g. Cm ^ 3) = 100cm ^ 3 = V alcohol
The density of alcohol is: P1 = (105-20) / 100 = 0.85g/cm ^ 3
Because 0.85 > 0.8, this kind of alcohol is not pure alcohol
If the number of hydrogen atoms in ethanol is equal to that in water, the mass fraction of solute in ethanol solution is 0______ ．
According to the equal number of hydrogen atoms, the relationship between ethanol and water molecules is found out, and then the mass relationship is determined
In an ethanol aqueous solution, the total number of H atoms in the known solution solute is equal to the total number of H atoms in the solvent
Come back quickly
C2H5OH------6H-------3H2O
46 54
46/(46+54)*100%=46%
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