The % yield of Hf is 91. 8%
calculation
% yield = actual mass/ theoretical mass x100
actual mass = 2.85 Kg
calculate the theoretical mass
by first write the equation for reaction
CaF2 +H2SO4 → 2HF + CaSO4
find the moles of CaF2 used
moles = mass/molar mass
mass = 6.05Kg = 6.05 x1000 =6050 Kg
molar mass of CaF2 = 40 + (19 x2) = 78 g/mol
moles= 6050/ 78 = 77.6 moles
by use of mole ratio between CaF2 to HF which is 1:2 the moles of HF is therefore = 77.6 x2 =155.2 moles of Hf
find the theoretical mass of HF = moles x molar mass ( 1 +19=20g/mol)
= 155.2 moles x 20 g/mol = 3104 grams = 3104 /1000 = 3.104 Kg
The % yield is therefore = 2.85 Kg/ 3.104 Kg x100 = 91.8%
Answer:
1st paragraph:
1.compound 2.physical 3.elements 4.water 5. gas 6.white 7. season 8.ratio 9.formula 10.elements 11.atoms 12.subscript 13.one
2nd paragraph
1.stable 2.many/reactive 3.eight 4.helium 5.seven 6.outer 7.one 8.level 9. compounds 10.reactive 11. seven 12. Eight 13.lose 14.gain 15. Share 16.compounds 17. atoms
Explanation:
I just did the 1st page. Gimme a min and I'll do the second.
Answer:
Chemists study matter and the chemical reactions between substances
Explanation:
<span>A. smog
B. Use a large amount of water
C. increased temperatures
D. poisoning wildlife
The correct answer is D) poising wildlife. Burning fossil fuels and pesticide from farming have the effect of releasing toxic elements in nature, thus the consequences of poisoning wildlife. The fossil fuels released CO2 and other particulates that threats the respiration system of most animals, while the pesticide that animals ingest or breath can have different effects on the wildlife, depending on the type of pesticide.
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