Answer:
The answer is B. A river is a body of water, therefore, there will always be some water running over the rock.
From the periodic table:
molecular mass of carbon = 12 grams
molecular mass of fluorine = 18.99 grams
molecular mass of chlorine = 35.5 grams
Therefore:
one mole of CF2Cl2 = 12 + 2(18.99) + 2(35.5) = 120.98 grams
Therefore, we can use cross multiplication to find the number of moles in 79.34 grams as follows:
mass = (79.34 x 1) / 120.98 = 0.6558 moles
Now, one mole contains 6.022 x 10^23 molecules, therefore:
number of molecules in 0.65548 moles = 0.6558 x 6.022 x 10^23
= 3.949 x 10^23 molecules
Answer:
i) 16 mL of ethanol
ii) maximum amount recoverable = 15.52 g; percentage recovery = 97%
iii) maximum amount recoverable = 15.1 g
percentage recovery = 94.4%
Explanation:
Solubility = mass/volume
i) mass of ethanol recovered per mL of ethanol when cooled from 78 °C to 0 °C = 0.13 - 0.03 = 0.10 g
Therefore 1.60 g of Y will require a minimum of 1.60 x 1 mL/0.10 g = 16 mL of ethanol
ii) maximum amount of Y that can be recovered is given as :
mass of Y left in solution after recrystallization, x is obtained
0.03 g/mL = x g/16 mL
x = 0.48 g
maximum amount recoverable = 16 - 0.48 = 15.52 g
percentage recovery = (15.52/16) x 100 % = 97%
iii) if 30 mL of ethanol were used:
mass of Y left in solution after recrystallization, x is obtained;
0.03 g/mL = x g/30 mL
x = 0.03 x 30 = 0.9 g
maximum amount recoverable = 16 - 0.9 = 15.1 g
percentage recovery = (15.1/16) x 100% = 94.4%
<span>kinetic energy and gravity. Hope this helps! Good luck!</span>
An organ in the human or animal body that secretes particular chemical substances for use in the body or for discharge into the surroundings.
