During diffusion substances move from the denser medium (meaning where there is more of the substance) to less dense medium (meaning where there is less of the substance).
How many moles of Pb are in 4.71 × 10^21 Pb atoms?
1 answer:
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Given that the mass of coffee in the cup = 140 g
Final temperature =
Initial temperature =
Let us assume the specific heat of coffee is equal to that of water = 4.184
Temperature change = T(final) - T(initial) = (20 - 75 )
=- 55
-Heat given out by coffee = heat absorbed by the surroundings
Heat released into the surroundings =-()
=
= 32,217 J
Answer: -
12.41 g
Explanation: -
Mass of CO₂ = 42 g
Molar mass of CO₂ = 12 x 1 + 16 x 2 = 44 g / mol
Number of moles of CO₂ =
= 0.9545 mol
The balanced chemical equation for this process is
2C₆H₆ + 15O₂ → 12CO₂ + 6H₂O
From the balanced chemical equation we see
12 mol of CO₂ is produced from 2 mol of C₆H₆
0.9545 mol of CO₂ is produced from
= 0.159 mol of C₆H₆
Molar mass of C₆H₆ = 12 x 6 + 1 x 6 =78 g /mol
Mass of C₆H₆ =Molar mass x Number of moles
= 78 g / mol x 0.159 mol
= 12.41 g