45. most abundant metal in the earth's crust 46. first discovered in light coming from the sun
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The question incomplete , the complete question is:
A student dissolves of 18.0 g urea in 200.0 mL of a solvent with a density of 0.95 g/mL . The student notices that the volume of the solvent does not change when the urea dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to significant digits.
Answer:
The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.
Explanation:
Moles of urea =
Volume of the solution = 200.0 mL = 0.2 L (1 mL = 0.001 L)
Molarity of the urea solution ;
Mass of solvent = m
Volume of solvent = V = 200.0 mL
Density of the urea = d = 0.95 g/mL
(1 g = 0.001 kg)
Molality of the urea solution ;
The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.
Answer:
Explanation:
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In this case, since the percent water is computed by dividing the amount of water by the total mass of the hydrate; we infer we first need the molar mass of water and that of the hydrate as shown below:
Thus, the percent water is:
So we plug in to obtain:
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Answer:
Explanation:
The volume and amount of gas are constant, so we can use Gay-Lussac’s Law:
At constant volume, the pressure exerted by a gas is directly proportional to its temperature.
Data:
p₁ =5.7 atm; T₁ = 100.0 °C
p₂ = ?; T₂ = 20.0 °C
Calculations:
1. Convert the temperatures to kelvins
T₁ = (100.0 + 273.15) K = 373.15
T₂ = (20.0 + 273.15) K = 293.15
2. Calculate the new pressure