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3 years ago

Calculate the freezing point of a solution 1.25 g benzene (C6H6) in 125 g of chloroform (CHCl3).

Chemistry

1 answer:

posledela3 years ago

3 0

Answer:

The freezing point for the solution is -64.09°C

Explanation:

This problem can be solved, by the freezing point depression. This colligative problem shows, that the freezing point of a solution is lower than the freezing point of pure solvent.

ΔT = Kf. m

ΔT = T° freezing pure solvent - T° freezing solution

Kf = Cryscopic constant, for chloroform is 4.68

T°freezing pure solvent = -63.5°C

m is mol/kg of solvent → molality

Let's determine the moles of benzene

1.25 g / 78 g/mol = 0.0160 mol

Let's convert the mass of solvent to kg

125 g . 1kg / 1000 g = 0.125 kg

m = 0.0160 mol / 0.125 kg → 0.128 m

Let's go to the formula to replace the data

-63.5°C - T° freezing solution = 4.68 °C/m . 0.128 m

T° freezing solution = - (4.68 °C/m . 0.128 m + 63.5°C)

T° freezing solution = - 64.09°C

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Determine how many liters of hydrogen adjusted to STP there are in a 50.0 liter steel cylinder if the pressure inside is 100.0 a

Dvinal [7]

Answer : The volume of hydrogen gas at STP is 4550 L.

Explanation :

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.

The combined gas equation is,

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1$ = initial pressure of gas = 100.0 atm

$P_2$ = final pressure of gas at STP = 1 atm

$V_1$ = initial volume of gas = 50.0 L

$V_2$ = final volume of gas at STP = ?

$T_1$ = initial temperature of gas = $27.0^oC=273+27.0=300K$

$T_2$ = final temperature of gas at STP = $0^oC=273+0=273K$

Now put all the given values in the above equation, we get:

$\frac{100.0atm\times 50.0L}{300K}=\frac{1atm\times V_2}{273K}$

$V_2=4550L$

Therefore, the volume of hydrogen gas at STP is 4550 L.

3 0

3 years ago

How does a greenhouse keep radiant energy from escaping?

Rina8888 [55]

Greenhouse effect is the process of trapping sun radiation in the earth surface, so as to make the planet warm. It is a natural phenomenon in which sun rays that enters the earth surface are re-radiated into the earth surface causing the heat trap in the earth.
In similar manner, green house also trap radiation inside the glass house. The sun rays once reach inside the glass house, strike on plants and objects and reflected back. For entire radiation to escape from the green house, the heat flow between the two points must be proportional to the temperature difference and thermal conductivity. The glass of which the green house are made up, have low thermal conductivity. So, temperature must rise inside glass house so to maintain the heat flow rate of incoming and outgoing radiation.
The green house glass are insulated and they trap the infrared emitted by the objects inside the green house from escaping outside. Since the infrared have longer wave lengths, it is released slowly.

Also, the thermal energy inside the glass house are transferred by convection process. But the glass walls and roof act as insulator, keeping the radiant energy from escaping outside the green house.<span />

7 0

3 years ago

20 points! Help ASP! Your answer must be explained!

Mariana [72]

<span>b.mixtures are made up of more than one component</span>

5 0

3 years ago

Read 2 more answers

In what state of matter do molecules bounce off one another rapidly and freely

lions [1.4K]

I think its gas i forgot

6 0

3 years ago

A volume of 90.0 mL of aqueous potassium hydroxide (KOH) was titrated against a standard solution of sulfuric acid (H2SO4). What

Gemiola [76]

Answer:

The answer to your question: 0.7 M

Explanation:

Data

V of KOH = 90 ml

[KOH] = ?

V H2SO4 = 21.2 ml

[H2SO4] = 1.5 M

2KOH(aq) + H₂SO₄(aq) → K₂SO₄(aq) + 2H₂O(l)

Molarity = moles / volume

moles of H₂SO₄ = (1.5) (21.2)

= 31.8

2 moles of KOH -------------- 1 mol of H₂SO₄

x -------------- 31.8 mol of H₂SO₄

x = (31.8)(2) / 1

x = 63.8 moles of KOH

Molarity = 63.8 / 90

= 0.7 M

7 0

3 years ago