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3 years ago

An air tight freezer measures 4 mx 5 m x 2.5 m high. With the door open, it fills with 22 °C air at 1 atm pressure.

Chemistry

1 answer:

____ [38]3 years ago

7 0

Answer:

(a) Density of the air = 1.204 kg/m3

(b) Pressure = 93772 Pa or 0.703 mmHg

Explanation:

(a) The density of the air at 22 deg C and 1 atm can be calculated using the Ideal Gas Law:

$\rho_{air}=\frac{P}{R*T}$

First, we change the units of P to Pa and T to deg K:

$P=1 atm * \frac{101,325Pa}{1atm}=101,325 Pa\\\\ T=22+273.15=293.15^{\circ}K$

Then we have

$\rho_{air}=\frac{P}{R*T}=\frac{101325Pa}{287.05 J/(kg*K)*293.15K} =1.204 \frac{kg}{m3}$

(b) To calculate the change in pressure, we use again the Ideal Gas law, expressed in another way:

$PV=nRT\\P/T=nR/V=constant\Rightarrow P_{1}/T_{1}=P_{2}/T_{2}\\\\P_{2}=P_{1}*\frac{T_{2}}{T_{1}}=101325Pa*\frac{7+273.15}{22+273.15}=101,325Pa*0.9254=93,772Pa\\\\P2=93,772 Pa*\frac{1mmHg}{133,322Pa}= 0.703 mmHg$

(c) To calculate the force needed to open we have to multiply the difference of pressure between the inside of the freezer and the outside and the surface of the door. We also take into account that Pa = N/m2.

$F=S_{door}*\Delta P=2m^{2} *(101325Pa - 93772Pa)=2m^{2} *7553N/m2=15106N$

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Evgen [1.6K]

Answer:

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Explanation:

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3 years ago

Even though so much energy is required to form a metal cation with a 2+ charge, the alkaline earth metals form halides with gene

nasty-shy [4]

The ∆Hrxn of the reaction is -394.5kJ/mol.

<h3>What is alkaline earth metal? </h3>

The alkaline earth metals are those elements which correspond to group 2 of the modern periodic table.

All elements of this group forms a cation of +2 charge.

The other elements of this group are:

Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium.

<h3>What is Halogen? </h3>

The Halogen elements are present in group 17 of the modern periodic table.

All elements of this groups forms anions of -1 charge.

The elements of this group are:

Fluorine, Chlorine, bromine, iodine, and astatine.

∆Hrxn = ∆H(bond broken) - ∆H(bond formed)

We have following data of bond energy in kJ/mol:

Mg—Mg = 738

Cl—Cl = -349

Mg—Cl = 783.5

Since, one mole of Mg react with one mole of Cl atom to form one mole of MgCl

∆Hrxn = 738-349-783.5

∆Hrxn = -394.5kJ/mol.

Thus, we concluded that the ∆Hrxn of the reaction is -394.5kJ/mol.

learn more about bond energy:

brainly.com/question/13526463

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3 0

2 years ago

In Lab 10 you make a stock solution of salicylic acid, and then four dilutions. The stock solution is made by diluting 5.00 ml o

Zigmanuir [339]

Answer:

Stock solution = 1.25 *10^-3 M

Dilution 1 = 5*10^-4 M

Dilution 2= 3.75 * 10^-4 M

Dilution 3 = 2.5 *10^-4 M

Dilution 4 = 1.25 *10^-4 M

Explanation:

<u>Step 1:</u> Data given

The stock solution is made by diluting 5.00 ml of 1.250 x 10-2 M salicylic acid in 50.00 mL of solution.

<u>Step 2</u>: Calculate the concentration of the stock solution:

M1*V1 = M2*V2

⇒ with M1 = the initial concentration = 1.250 *10^-2 M

⇒ with V1 = 5 mL = 5*10^-3 L

⇒ with M2 = TO BE DETERMINED

⇒ with V2 = 50 mL = 50 *10^-3 L

M2 = (M1*V1)/V2

M2 = (1.250 *10^-2 * 5*10^-3 L) / 50 *10^-3

M2 = 0.00125 M = 1.25 *10^-3 M

<u>Step 3:</u> Calculate dilution 1

M2 = (M1*V1)/V2

M2 = (1.25*10^-3 * 10 *10^-3)/(25*10^-3L)

M2 = 0.0005 M = 5*10^-4 M

<u>Step 4</u>: Calculate dilution 2

M2 = (M1*V1)/V2

M2 = (1.25*10^-3 * 10 * 7.5*10^-3)/(25*10^-3)

M2 = 0.000375 M = 3.75 * 10^-4 M

<u>Step 5:</u> Calculate dilution 3

M2 = (M1*V1)/V2

M2 = (1.25*10^-3 * 5*10^-3) /(25*10^-3)

M2 = 0.00025 M = 2.5 *10^-4 M

<u>Step 6</u>: Calculate dilution 4

M2 = (M1*V1)/V2

M2 = (1.25*10^-3 * 2.5*10^-3)/(25*10^-3)

M2 = 0.000125 M = 1.25 *10^-4 M

5 0

3 years ago

Which electron dot diagram represents H2?

Marizza181 [45]

Answer:

H:H

Explanation:

7 0

3 years ago

Can you please help me and can you show your work please

natali 33 [55]

Answer:

1. 25 moles water.

2. 41.2 grams of sodium hydroxide.

3. 0.25 grams of sugar.

4. 340.6 grams of ammonia.

5. 4.5x10²³ molecules of sulfur dioxide.

Explanation:

Hello!

In this case, since the mole-mass-particles relationships are studied by considering the Avogadro's number for the formula units and the molar mass for the mass of one mole of substance, we proceed as shown below:

1. Here, we use the Avogadro's number to obtain the moles in the given molecules of water:

$1.5x10^{25}molecules*\frac{1mol}{6.022x10^{23}molecules} =25 molH_2O$