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A particular refrigerant cools by evaporating liquefied CCl 2F 2. How many kg of the liquid must be evaporated to freeze a tray of water to ice (at zero degrees C)? The tray contains 525 grams water. Molar heat of fusion of ice = 6.01 kJ/mol. Molar heat of vaporization of CCl 2F 2 = 17.4 kJ/mole

Answers

Answer 1

Answer:

Answer : The mass of $CCl_2F_2$ evaporated must be, 1.217 kg

Explanation :

First we have to calculate the moles of water.

$\text{Moles of water}=\frac{\text{Mass of water}}{\text{Molar mass of water}}$

Molar mass of water = 18 g/mol

$\text{Moles of water}=(525g)/(18g/mol)=29.17mol$

Now we have to calculate the heat released.

Heat released = Moles of water × Molar heat of fusion of ice

Heat released = 29.17 mol × 6.01 kJ/mol

Heat released = 175.3 kJ

Now we have to calculate the moles of $CCl_2F_2$

Heat = Moles of $CCl_2F_2$ × Molar heat of vaporization of $CCl_2F_2$

175.3 kJ = Moles of $CCl_2F_2$ × 17.4 kJ/mol

Moles of $CCl_2F_2$ = 10.07 mol

Now we have to calculate the mass of $CCl_2F_2$

$\text{Mass of }CCl_2F_2=\text{Moles of }CCl_2F_2* \text{Molar mass of }CCl_2F_2$

Molar mass of $CCl_2F_2$ = 120.9 g/mol

$\text{Mass of }CCl_2F_2=10.07mol* 120.9g/mol=1217.463g=1.217kg$

Thus, the mass of $CCl_2F_2$ evaporated must be, 1.217 kg

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Salt, sugar, and snow are examples of ____________________ solids.
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Calculate ΔHrxn for the following reaction: C(s) + H2O(g) --> CO(g) + H2(g) Use the following reactions and given ΔH values: C (s) + O2 (g) → CO2 (g), ΔH = -393.5 kJ 2 CO (g) + O2 (g) → 2 CO2 (g), ΔH= -566.0 kJ 2 H2 (g) + O2 (g) → 2 H2O (g), ΔH= -483.6 kJ

Answers

Explanation:

Below is an attachment containing the solution to the question.

Assuming that the distances between the two ions are the same in all cases, which of the following ion pairs has the greatest electrostatic potential energy (i.e., largest in magnitude)? Please explain your answer.a.) Na+ - Cl- b.) Na+ - O-2. c.) Al+3 - O-2. d.) Mg+2-O-2 e.) Na- -Mg+2

Answers

Answer:

Correct option: C

Explanation:

As given in the question that distance between two ions are same in all cases hence r is same for all.

potential energy:

$P.E =(k* q_(1) * q_(2))/(r)$

therefore potential energy depend on the two charge muliplication

so higher the charge multiplication higer will be the potential energy.

magnitude of charge multiplication follow as:

a. 1

b. 2

c. 6

d. 4

e. 2

in option C it is higher

so correct option is C

Describe the relationship between predator and prey in a balanced ecosystem. Please help I'll give brainliest.

Answers

Answer:

predators are controlling the population of the species who are below them in the food pyramid . Also if the population of the preys decrease it will alternatively reduce the predator population .therefore the predator prey relationship balance an eco system.

Use molecular orbital theory to determine whether f22+ is paramagnetic or diamagnetic.

Answers

We have to know whether F₂²⁺ is paramagnetic or diamagnetic.

F₂²⁺ is paramagnetic.

If number of unpaired electron in any species is equal to zero, the species is diamagnetic and the species contains unpaired electrons, then the species is paramagnetic.

The magnetic property can be explained using molecular orbital theory.

Total number of electron present in F₂²⁺ is equal to 16 (i.e, 9+9-2). From the molecular orbital electronic configuration, number of electrons present in pi orbitals present is equal to 2.

So, F₂²⁺ is paramagnetic.

Answer : $F_2^(2+)$ is paramagnetic.

Explanation :

According to the molecular orbital theory, the general molecular orbital configuration will be,

$(\sigma_(1s)),(\sigma_(1s)^*),(\sigma_(2s)),(\sigma_(2s)^*),[(\pi_(2p_x))=(\pi_(2p_y))],(\sigma_(2p_z)),[(\pi_(2p_x)^*)=(\pi_(2p_y)^*)],(\sigma_(2p_z)^*)$

As there are 9 electrons present in fluorine.

The number of electrons present in $F_2^(2+)$ molecule = 2(9) - 2 = 16

The molecular orbital configuration of $F_2^(2+)$ molecule will be,

$(\sigma_(1s))^2,(\sigma_(1s)^*)^2,(\sigma_(2s))^2,(\sigma_(2s)^*)^2,(\sigma_(2p_z))^2,[(\pi_(2p_x))^2=(\pi_(2p_y))^2],[(\pi_(2p_x)^*)^1=(\pi_(2p_y)^*)^1],(\sigma_(2p_z)^*)^0$

Paramagnetic compounds : They have unpaired electrons.

Diamagnetic compounds : They have no unpaired electrons that means all are paired.

The number of unpaired electron in molecule is, 2. So, this is paramagnetic. That means, more the number of unpaired electrons, more paramagnetic.

Thus, is paramagnetic.

The heat capacity of chloroform (trichloromethane,CHCl3)in the range 240K to 330K is given
byCpm/(JK-1mol-1) = 91.47
+7.5x10-2(T/K). In a particular experiment,
1.0molCHCl3 is heated from 273K to 300K. Calculate the
changein molar entropy of the sample.

Answers

Answer : The change in molar entropy of the sample is 10.651 J/K.mol

Explanation :

To calculate the change in molar entropy we use the formula:

$\Delta S=n\int\limits^(T_f)_(T_i){(C_(p,m)dT)/(T)$

where,

$\Delta S$ = change in molar entropy

n = number of moles = 1.0 mol

$T_f$ = final temperature = 300 K

$T_i$ = initial temperature = 273 K

$C_(p,m)$ = heat capacity of chloroform = $91.47+7.5* 10^(-2)(T/K)$

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

$\Delta S=1.0\int\limits^(300)_(273){((91.47+7.5* 10^(-2)(T/K))dT)/(T)$

$\Delta S=1.0* [91.47\ln T+7.5* 10^(-2)T]^(300)_(273)$

$\Delta S=1.0* 91.47\ln ((T_f)/(T_i))+7.5* 10^(-2)(T_f-T_i)$

$\Delta S=1.0* 91.47\ln ((300)/(273))+7.5* 10^(-2)(300-273)$

$\Delta S=8.626+2.025$

$\Delta S=10.651J/K.mol$

Therefore, the change in molar entropy of the sample is 10.651 J/K.mol

A laboratory scientist wants to analyze the chlorogenic acid content of a 0.5 L sample. He uses an indicator solution and titrates with sodium hydroxide. He finds the equivalence point occurs when he's titrated 9.5 mL of 0.05 M sodium hydroxide. Approximately how much chlorogenic acid is in the sample? 475 umol ® 480 umol © 500 umol 510 umol

Answers

Answer:

There are approximately 475 umol of chlorogenic acid in the sample.

Explanation:

The first step is indentifying the chlorogenic acid structure. As it can be seen in the figure attached, this molecule is a carboxylic acid containing just one carboxyl group. This means, that chlorogenic acid is a monoprotic acid and it is only able to donate one proton per molecule or one mol of protons per one mol of molecules.

The second step is to balance the titration equation. Considering that sodium hydroxide will generate one mol of hydroxyl ions per mol of salt, we can simplify the equation:

H⁺ + OH ⁻ → H₂O

Therefore, we now know that for each mol of NaOH consumed 1 mol of chlorogenic acid is titrated.

Thus, the last step is calculation the amount of NaOH consumed during the tritation. We can use the following equation:

$C = (n)/(V)$

In which C is the concentration, n the amount of moles and V the volume.

$0,05 M = (n)/(0.0095 L)$

The result is that n = 475 umol.

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