Advantages: No subcooling or phase separation phenomenon.
Disadvantages: Low thermal conductivity, flammable.
A solution is prepared by dissolving 25 g of glucose, C6H12O6 in 250 g of water. What is the percentage by mass of glucose in the solution?
answer: 14.77 g
what is the mass of chromium contained in 35.8 g (nh4)2cr2o7:
calculate the molecular mass of (nh4)2cr2o7
n: 2 x 14=28
h: 8 x 1=8
cr: 2 x 52=104
o: 7 x 16=112
by adding all these values, we conclude that the
molecular weight= 252 g/mol
convert the given mass to number of moles using the calculated molecular weight.
35.8 g/252 g/mol= 0.14 mol (nh4)2cr2o7
convert the calculate moles of the molecule to the no. of moles of cr present in the molecule.
0.14 mol molecule x (2mol cr/1 mole molecule)= 0.28 moles cr
convert the number of moles of cr to mass using atomic weight of cr=52 g/mol
0.28 mol cr x (52 g/1 mol cr)= 14.77 g cr/molecule
therefore, the mass of cr contained in 35.8 g (nh4)2cr2o7 is 14.77 g.
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