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3 years ago

How much heat (kj) is required to convert 3.12 moles of liquid benzene at 75.1Â°c to gaseous benzene at 115.1Â°c?

1 answer:

3 0

The total energy includes sensible heat to raise the temperature from 75.1°C to the boiling point. It also includes the latent heat to convert the liquid to gas. Then, it also includes sensible heat from he boiling point to 115.1°C. The equation is:

Energy = nCp,liquid(T,bp - T₁) + nΔH + nCp,gas(T₂ - T,bp)
where
n is the number of moles
T,bp is the boiling point of benzene at 80.1°C
Cp,liquid = 134.8 J/mol·°C
Cp,gas = 82.44 J/mol·°C
ΔH = 87.1 J/mol

Energy = (3.12 moles)(134.8 J/mol·°C)(80.1°C - 75.1°C) + (3.12 moles)(87.1 J/mol) + (3.12 moles)(82.44 J/mol·°C)(115.1°C - 80.1°C)
Energy = 11,377.08 J

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3 years ago

What is the freezing point of an aqueous solution that has 25.00 g of calcium iodide dissolved in 1250 g of water?

ozzi

Answer:

- 0.380ºC

Explanation:

The lowering of the freezing point of a solvent is a colligative property ruled by the formula:

$\Delta T_f=K_f\times m\times i$

Where:

ΔTf is the lowering of the freezing point

Kf is the molal freezing constant of the solvent: 1.86 °C/m

m is the molality of the solution

i is the van't Hoff factor: the number of particles (ions) per unit of ionic compound.

a) molality, m

m = number of moles of solute/ kg of solvent

number of moles of CaI₂ = mass in grams/ molar mass

number of moles of CaI₂ = 25.00g / 293.887 g/mol = 0.0850667mol

m = 0.0850667mol/1.25 kg = 0.068053m

b) i

Each unit of CaI₂, ideally, dissociates into 1 Ca⁺ ion and 2 I⁻ ions. Thus, i = 1 + 2 = 3

c) Freezing point lowering

ΔTf = 1.86 °C/m × 0.068053m × 3 = 0.3797ºC ≈ 0.380ºC

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6 0

3 years ago

A bowling ball (mass = 7.2 kg, radius = 0.10 m) and a billiard

evablogger [386]

Answer:

Maximum gravitational Force: $F_{gmax} = 1,026*10^{-08} N$

Explanation:

The maximum gravitational force is achieved when the center of gravity are the closer they can be. For the spheres the center of gravity is at the center of it, so the closer this two centers of gravity can be is:

bowling ball radius + billiard ball radius = 0,128 m

The general equation for the magnitude of gravitational force is:

$F_{gmax} = G \frac{M*m}{r_{min}^{2} }$

Solving for:

$G = 6,67*10^{-11} \frac{Nm^{2}}{kg^{2}}$

$M = 7,2 kg$

$m = 0,35 kg$

$r_{min} = 0,128 m$

The result is:

$F_{gmax} = 1,026*10^{-08} N$

3 0

3 years ago

A sample of sulfurous acid (H2SO3) has a mass of 1.31 g.

lakkis [162]

Answer:

a) 2 (H+) ions

b) 1 (SO3²-) ions

c) 1.36 × 10^-22 grams.

Explanation:

According to this question, sulfurous acid has a chemical formula; H2SO3. It is made up of hydrogen and sulfite ion. Hydrogen ion (H+) is the cation while sulfite ion (SO32-) is the anion.

Based on the chemical formula, there are 2 moles of hydrogen ions that reacts with 1 mole of sulfite ion as follows:

2H+ + SO3²- → H2SO3

Hence;

- there are 2 hydrogen ions (2H+) present in H2SO3.

- there is 1 sulfite ion (SO3²-) present in H2SO3.

c) The mass of one formula unit of H2SO3 is calculated thus:

= 1.008 (2) + 32.065 + 15.999(3)

= 2.016 + 32.065 + 47.997

= 82.08 a.m.u

Since, 1 gram is = 6.02 x 10^23 a.m.u

82.08 a.m.u = 82.08/6.02 × 10^-23

= 13.6 × 10^-23

= 1.36 × 10^-22 grams.

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2 years ago

Maize, man, Goat, is an example of a food chain true or false

Lina20 [59]

Answer:

False

Explanation:

The correnct chain is labeled Maize, Goat, Man.

8 0

3 years ago