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4 years ago

A solution was prepared by dissolving 0.05000 mol of sucrose in 100.0 kg of water. Find

Chemistry

2 answers:

Licemer1 [7]4 years ago

8 0

Answer:

0.0005mol/kg

Explanation:

Molality = mole of solute/mass of solvent (kg)

From the question, we obtained the following data:

Mole of solute = 0.05mole

Mass of solvent = 100kg

Molality = 0.05/100

Molality = 0.0005mol/kg

The molality of the solution is 0.0005mol/kg

joja [24]4 years ago

8 0

Answer: 5x10-4 mole / kg

Explanation: Molality is expressed as number of moles per unit kilograms of solvent.

m = n / kg

= 0.05000 mole / 100.0 kg

= 0.0005 m or 5x10-4 mole / kg

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A chemist mixes 75.0 g of an unknown substance at 96.5°C with 1,150 g of water at 25.0°C. If the final temperature of the system

AleksAgata [21]

To do this problem it is necessary to take into account that the heat given by the unknown substance is equal to the heat absorbed by the water, but considering the correct sign:

$-m\cdot c_e\cdot \Delta T = m_w\cdot c_e_w\cdot \Delta T_w$

Clearing the specific heat of the unknown substance:

$c_e = \frac{m_w\cdot c_e_w\cdot \Delta T_w}{m\cdot \Delta T} = -\frac{1\ 150\ g\cdot 4.184\frac{J}{g\cdot ^\circ C}\cdot (37.1 - 25.0)^\circ C}{75\ g\cdot (37.1 - 96.5)^\circ C}$

$c_e = -\frac{1\ 150\ g\cdot 4.184\frac{J}{g\cdot ^\circ C}\cdot 12.1^\circ C}{75\ g\cdot (-59.4)^\circ C} = \bf 13.07\frac{J}{g\cdot ^\circ C}$

6 0

3 years ago

Calculate the freezing point of a solution that contains 8.0 g of sucrose (c12h22o11) in 100 g of h2o. kf for h2o = 1.86c/m

Sever21 [200]

Answer is: the freezing point of the solution of sucrose is -0.435°C.
m(H₂O) = 100 g ÷ 1000 g/kg = 0.1 kg.
m(C₁₂H₂₂O₁₁) = 8.0 g.
n(C₁₂H₂₂O₁₁) = m(C₁₂H₂₂O₁₁) ÷ M(C₁₂H₂₂O₁₁).
n(C₁₂H₂₂O₁₁) = 8.0 g ÷ 342.3 g/mol.
n(C₁₂H₂₂O₁₁) = 0.0233 mol.
b(solution) = n(C₁₂H₂₂O₁₁) ÷ m(H₂O).
b(solution) = 0.0233 mol ÷ 0.1 kg.
b(solution) = 0.233 m.
ΔT = b(solution) · Kf(H₂O).
ΔT = 0.233 m · 1.86°C/m.
ΔT = 0.435°C.
Tb = 0°C - 0.435°C = -0.435°C.

3 0

3 years ago

Which units can be used to measure length or distance? Check all that apply.

motikmotik

Answer:

Meter, kilometer & inch - used to measure length or distance.

8 0

3 years ago

A 2.50L sample of nitrogen gas at a temperature of 308K has a pressure of 1.15atm. What is the new volume of the gas if the pres

iris [78.8K]

Answer:

1.48L

Explanation:

From the question given, we obtained the following data:

V1 (initial volume) = 2.50L

T1 (initial temperature) = 308K

P1 (initial pressure) = 1.15atm

P2 (final pressure) = 1.80atm

T2 (final temperature) = 286K

V2 (final volume) =..?

Using the general gas equation P1V1/T1 = P2V2/T2, the final volume of the gas can obtain as follow:

P1V1/T1 = P2V2/T2

1.15 x 2.5/308 = 1.8 x V2/286

Cross multiply to express in linear form:

308 x 1.8 x V2 = 1.15 x 2.5 x 286

Divide both side by 308 x 1.8

V2 = (1.15 x 2.5 x 286)/(308 x 1.8)

V2 = 1.48L

Therefore, the new volume of the gas is 1.48L

7 0

3 years ago

Consider a solution that contains 60.0% r isomer and 40.0% s isomer. if the observed specific rotation of the mixture is –43.0°,

pychu [463]

The solution for this problem is:
Let x denote the specific rotation, R; andLet y denote the specific rotation, S = -x
Solution:60 x - 40 x/100 = - 43
20x = - 4300Divide both sides by 20The answer is:x = - 215 is the specific rotation of the pure r isomer.

5 0

3 years ago