Avogadro number
How many oxygen atoms are there in 0.20 mol of ethanoic acid, CH3COOH?
2.41 × 1023
What is the molar mass of Al2(SO4)3?
342.15 g/mol
What is the mass percent of nitrogen in ammonium nitrate NH4NO3?
35%
what is the correct result for the following calculation: 58.25/2.5?
23
What is the total number atoms 1.0 mol of ethanoic acid, CH3COOH?
4.82×1024
What is the molar mass of CuSO4*5H2O?
249.68 g/mol
Determine the empiric formula of a compound containing 40.0% carbon, 6.7% hydrogen, and the rest - oxygen
CH2O
The mass of an empty crucible is 5.50±0.01g
The mass of the crucible with NaCl salt is 7.75±0.01g.
What is the mass (including uncertainty) of the salt?
2.25 ± 0.02g
What is the total number of ions in 2.0 mol of Mg(OH)2?
3.61 × 1024
What is the mass of 3 moles of water?
54.06g
The empiric formula of a compound was found to be CH. The molar mass of the compound is 78.11g. What is the molecular formula of the compound?
C6H6
In an experiment, the molar mass of CO2 was measured to be 45.70 g/mole.
What is the % error of the experiment?
4%
What is the number of molecules in 90 g water?
3.01× 1024
What amount (in moles) is present in 2.0 g of sodium hydroxide, NaOH?
0.05 mole
What is the empirical formula of a compound containing 50% by mass of element X (Ar = 20) and 50% by mass of element Y (Ar = 25)?
X5Y4
Students measured the temperature increase as result of a chemical reaction. Calculate the average increase in temperature (℃) including the uncertainty of the following measurements: 21.0±0.2, 21.8±0.2, 19.4±0.2, 20.2±0.2, 21.6±0.2
21±1
What is the number of carbon atoms in 23 g of ethanol C2H5OH (Mr=46)
6.02x1023
What is the molar mass of a compound if 0.2 moles have a mass of 12 g?
60 g/mol
0.30g of an organic compound containing C,H and O on combustion yields 0.44g CO2 and 0.18g H2O. If one mol of compound weighs 60, then molecular formula of the compound is:
C2H4O2
Concentration can be calculated as mass per volume: g/cm3. What is the concentration (in g/cm3), including absolute uncertainty of a solution made of:
10.0±2% g sugar dissolved in 50.0±2% cm3 water?
0.200±0.008 g/cm3