2 liters may be 1.5 to 1.9 rounded up to 2 or 2.1 or 2.4 rounded down to 2.
2 - 1.5 = 0.5
percent error = (absolute error / quantity) * 100
percent error = 0.5/2 * 100% = 0.25 * 100% = 25%
Choice C. 25%.
I think it is Molar masses of compounds involved or Oxidation numbers, but you can choose one of them. Or you can think about the question carefully.
Answer:
A. 2.44g
B. Kd = 3.2
Explanation:
Concentration of benzoic acid = 50mL = 0.05L
Molecular weight = 122 g/mol
Moles of benzoic acid before the extraction = mass/molecular weight of Benzoic acid
= molar concentration * volume
Moles of benzoic acid before the extraction = 0.05 * 0.4
= 0.02moles of benzoic acid before extraction.
Mass of benzoic acid = 0.02 * 122
= 2.44 g
Partition coefficient, Kd is defined as the ratio of concentration of a substance in an organic medium to the concentration of the substance in the aqueous medium.
Since 1.22g of Benzoic acid was in Dicholoroethane, therefore (2.44 - 1.22)g of benzoic acid was in water.
Mass concentration of benzoic acid in water = mass of benzoic in water/volume of water
= 1.22/0.05
= 24.4 g/L
Mass concentration of benzoic acid in Dicholoroethane = mass of benzoic in Dicholoroethane/volume of Dicholoroethane
= 1.22/0.03
= 40.67g/L
Kd = [concentration]organic/[concentration]aqueous
= 40.66/24.4
= 1.67
If you start with the mass of a substance, divide it by its molar mass to find the number of moles of the substance. Then, multiply the number of moles by Avogadro's number, 6.022*10^23, which gives the number of particles per mole of a substance.
Example:
Find the number of atoms in 10 g of CO2.
The mass of a single mole of CO2 is 54 g/mol. You can get this value by adding up the molar masses of the atoms in CO2(12+16+16).
Then divide 10 g by 54 g/mol to get the number of moles of CO2 in 10 g, which is 0.19 mol.
Finally, multiply 0.19 by Avogadro's number to get 1.1*10^23 molecules of CO2.
Ultra violet is the correct Answer