Verona dissolves 20. grams of NaCl with water to make a 100 ml solution. What is the molarity of the solution? There are 1,000 mL in 1 L O a. 3.4 M O b.0.34 M O G.58 M O d. 20. M

Answers

Answer 1

Answer:

b.0.34 M

Explanation:

Given that:

Mass of NaCl = 20 grams

Molar mass of NaCl = 58.44 g/mol

The formula for the calculation of moles is shown below:

[tex]moles = \frac{Mass\ taken}{Molar\ mass}[/tex]

Thus,

[tex]Moles= \frac{20\ g}{58.44\ g/mol}[/tex]

[tex]Moles= 0.3422\ mol[/tex]

Given that volume = 100 mL

Also,

[tex]1\ mL=10^{-3}\ L[/tex]

So, Volume = 100 / 1000 L = 0.1 L

Considering:

[tex]Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}[/tex]

[tex]Molarity=\frac{0.3422}{0.1}[/tex]

Molarity = 0.34 M


Related Questions

We know that one mole of Oxygen gas contains two moles of O atoms (remember that O is a diatomic element in nature and is written O2). If we have a sample of O2 that contains 1.0000 x 10-20 mol, we will have (blank)
atoms of O in the sample.

Answers

Answer:

12.4 × 10∧3 atoms

Explanation:

Given data:

moles of oxygen molecule= 1.0000 x 10-20 mol

atoms =?

Solution:

32 g O2 = 1 mol = 6.02 × 10∧23

1.0000 x 10∧-20 mol × 6.02 × 10∧23 × 2 = 12.4 × 10∧3 atoms

how many grams of solid NaOH are required to prepare a 400ml of a 5N solution? show your work!

Answers

Answer: The mass of solid NaOH required is 80 g

Explanation:

Equivalent weight is calculated by dividing the molecular weight by n factor. The equation used is:

[tex]\text{Equivalent weight}=\frac{\text{Molecular weight}}{n}[/tex]

where,

n = acidity for bases = 1 (For NaOH)

Molar mass of NaOH = 40 g/mol

Putting values in above equation, we get:

[tex]\text{Equivalent weight}=\frac{40g/mol}{1eq/mol}=40g/eq[/tex]

Normality is defined as the umber of gram equivalents dissolved per liter of the solution.

Mathematically,

[tex]\text{Normality of solution}=\frac{\text{Number of gram equivalents} \times 1000}{\text{Volume of solution (in mL)}}[/tex]

Or,

[tex]\text{Normality of solution}=\frac{\text{Given mass}\times 1000}{\text{Equivalent mass}\times \text{Volume of solution (in mL)}}[/tex]         ......(1)

We are given:

Given mass of NaOH = ?

Equivalent mass of NaOH = 40 g/eq

Volume of solution = 400 mL

Normality of solution = 5 eq/L

Putting values in equation 1, we get:

[tex]5eq/L=\frac{\text{Mass of NaOH}\times 1000}{40g/eq\times 400mL}\\\\\text{Mass of NaOH}=80g[/tex]

Hence, the mass of solid NaOH required is 80 g

For the following reaction, calculate how many grams of each product are formed when 4.05 g of water is used.
2 H20 -----> 2 H2 + O2

Answers

Answer: The mass of hydrogen gas and nitrogen gas produced is 0.45 g and 3.15 g respectively.

Explanation:

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]      .....(1)

Given mass of water = 4.05 g

Molar mass of water = 18 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of water}=\frac{4.05g}{18g/mol}=0.225mol[/tex]

For the given chemical reaction:

[tex]2H_2O\rightarrow 2H_2+O_2[/tex]

For hydrogen:

By Stoichiometry of the reaction:

2 moles of water is producing 2 moles of hydrogen gas

So, 0.225 moles of water will produce = [tex]\frac{2}{2}\times 0.225=0.225mol[/tex] of hydrogen gas.

Now, calculating the mass of hydrogen gas by using equation 1, we get:

Moles of hydrogen gas = 0.225 mol

Molar mass of hydrogen gas = 2 g/mol

Putting values in equation 1, we get:

[tex]0.225mol=\frac{\text{Mass of hydrogen gas}}{2g/mol}\\\\\text{Mass of hydrogen gas}=0.45g[/tex]

For nitrogen:

By Stoichiometry of the reaction:

2 moles of water is producing 1 mole of nitrogen gas

So, 0.225 moles of water will produce = [tex]\frac{1}{2}\times 0.225=0.1125mol[/tex] of nitrogen gas.

Now, calculating the mass of nitrogen gas by using equation 1, we get:

Moles of nitrogen gas = 0.1125 mol

Molar mass of nitrogen gas = 28 g/mol

Putting values in equation 1, we get:

[tex]0.1125mol=\frac{\text{Mass of nitrogen gas}}{28g/mol}\\\\\text{Mass of nitrogen gas}=3.15g[/tex]

Hence, the mass of hydrogen gas and nitrogen gas produced is 0.45 g and 3.15 g respectively.

Write chemical formulas for compounds containing each of the following. One nitrogen atom for every three chlorine atoms.

Answers

Answer:

NCL3

Explanation:

NCL3

- nitrogen trichloride.

The chemical formula for a compound containing one nitrogen atom for every three chlorine atoms is NCl₃.

The chemical formula NCl₃ represents a compound consisting of one nitrogen atom and three chlorine atoms. In this formula, "N" represents nitrogen, and "Cl" represents chlorine. The subscript "3" indicates that there are three chlorine atoms bonded to each nitrogen atom in the compound.

This arrangement reflects the stoichiometry of the compound, specifying the relative ratios of the elements. Chemical formulas provide a concise way to describe the composition of substances, allowing scientists to understand the types and quantities of atoms present in a compound.

NCl₃, nitrogen trichloride, is a covalent compound with notable chemical properties, and its formula encapsulates the balanced proportion of nitrogen and chlorine within its molecular structure.

To know more about nitrogen atom here

https://brainly.com/question/2396742

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At 14,000 ft elevation the air pressure drops to 0.59 atm. Assume you take a 1L sample of air at this altitude and compare it to 1 L of air taken at sea level. How much less O2 (in g) is available in 1 L of air at 14,000 ft (assume temperature of 298 K and that relative gas percentages are constant in both locations).

Answers

Answer:

There are 0.1125 g of O₂ less in 1 L of air at 14,000 ft than in 1 L of air at sea level.

Explanation:

To solve this problem we use the ideal gas law:

PV=nRT

Where P is pressure (in atm), V is volume (in L), n is the number of moles, T is temperature (in K), and R is a constant (0.082 atm·L·mol⁻¹·K⁻¹)

Now we calculate the number of moles of air in 1 L at sea level (this means with P=1atm):

1 atm * 1 L = n₁ * 0.082 atm·L·mol⁻¹·K⁻¹ * 298 K

n₁=0.04092 moles

Now we calculate n₂, the number of moles of air in L at an 14,000 ft elevation, this means with P = 0.59 atm:

0.59 atm * 1 L = n₂ * 0.082 atm·L·mol⁻¹·K⁻¹ * 298 K

n₂=0.02414 moles

In order to calculate the difference in O₂, we substract n₂ from n₁:

0.04092 mol - 0.02414 mol = 0.01678 mol

Keep in mind that these 0.01678 moles are of air, which means that we have to look up in literature the content of O₂ in air (20.95%), and then use the molecular weight to calculate the grams of O₂ in 20.95% of 0.01678 moles:

[tex]0.01678mol*\frac{20.95}{100} *32\frac{g}{mol} =0.1125 gO_{2}[/tex]

A student made an initial 1:5 dilution of protein lysate. Then 2mL of that was added to 8mL of water. Lastly, the student made a 1:20 dilution of the second tube. What is the final dilution of protein lysate.

Answers

Answer:

The final dilution is 1:400

Explanation:

Let's analyze what we are told: we have an initial 1:5 dilution of protein lysate. This means that the initial solution (stock solution) was diluted 5 times. Then, from this dilution the student prepared another dilution taking 2 mL of the first dilution in 8 mL of water. This is the same as saying we took 1 mL of first dilution in 4 mL of water (the ratio is the same), so we now have a second 1:4 dilution of the first dilution (1:5). Finally, the student made a third 1:20 dilution, this means that the second dilution was further diluted 20 times.

So, to calculate the final dilution of protein lysate, we have to multiply all the dilution factors of every dilution prepared: in this case we have a final dilution of 1:20, this means we have a factor dilution of 20. But it was previously diluted 4 times, so we have a factor dilution of 20×4 = 80. However, this dilution was also previously diluted 5 times, so the new dilution factor is 80 × 5 = 400

This means that the final dilution of the compound was diluted a total of 400 times compared to the initial concentration of stock solution.

One molecule of the spherically shaped, oxygen‑carrying protein in red blood cells, hemoglobin, has a diameter of 5.5 nm . What is this diameter in meters?

Answers

Answer:

[tex]5.5*10x^{-9}m[/tex]

Explanation:

As you have the diameter of the sphere in nanometers (nm), you need to use de conversion factor to find the diameter in meters (m):

First you should put the quantity that you want to convert with its respective units:

[tex]Diameter=5.5nm[/tex]

Then you put the conversion factor, always you should put the same unit that you want to convert in the denominator:

Diameter = [tex]5.5nm*\frac{1*10^{-9}m}{1nm}[/tex]

And finally, you should multiply and/or divide the quantities:

Diameter = [tex]5.5*10^{-9}m[/tex]

Define "Dispersed System", "Dispersion Medium", and "Dispersed Particles

Answers

Answer:

Dispersion system is a system in which certain particles are scattered in a continuous liquid or solid medium. The two phases present in this system are the dispersed particles and dispersion medium. These phases may or may not be present in the same state.

In a dispersion system, the particles that are dispersed are known as the dispersed particles and the medium in which the particles are dispersed is known as the dispersion medium.

Compute the following:

a. 0.034 x 4.13

b. (1.6 x 10-8 )/(7.25 x 10-8 )

c. 0.034 x 4.13

5) (1 pt) The density of titanium is 4.54 g/ml. What is the volume in liters of 2.63 kg of titanium?

3) (1 pts) How many milliseconds are there in 2.25 hours?

Answers

Answer:

a. 0.14042

b. 0.221

c. equal to a.

5) 0.579 L

3) 8.1e6 ms

Explanation:

Hello,

In the attached photo you'll find the numerical procedure to get the results.

Best regards.

Conversion of flow quantities by the continuity equation Water flows through a 3-inch, schedule 40 steel pipe (inside diameter- 3.068 inches) with an average velocity of 4 ft/s. Compute: (a) mass flow rate in lb/h, (b) volumetric flow rate in ft /h, and (c) mass velocity (mass flux) in lb/h-ft.

Answers

Answer:

a) m  = 2398256.64 Ib/hr

b) Q = 38433.6 ft^3/hr

c) J = = 898560 lb/h-ft2

Explanation:

a) To get the mass flow rate in lb/h we are going to use this formula:

m = ρνA

note: we have to change some units to reach to the final units

when m is the mass flow rate which we need to calculate

ρ is the density of water in lb/ft3 = 62.4 lbs/ft3 it is a constant numbers you can get it from anywhere

ν is the velocity of the water = 4 ft/s we need to change it to ft/h unit so  

when 1 ft/s = 3600 ft/hr (note : 3600 is a result of converting hr to sec 60min*60sec)

so  the velocity of the water = 4 ft/s * 3600 ft/hr= 14400 ft/hr

now , we need to get the area of the pipe in feet also when:

A = π*diameter * length

diameter = 3.068 inches

when 1 inch = 0.0833333333 feet so,

diameter in feet = 3.068 * 0.0833333333 =.300 0.2557ft

and length = 40 * 0.0833333333  = 3.333 ft

so the area of the pipe in feet^2 = 3.14*0.255*3.33 =2.669 ft^2

by substitution in the mass flow rate:

m = 62.4 lbs/ft3 * 14400 ft/hr *2.669 ft^2 = 2398256.64 Ib/hr

b) now to calculate volumetric flow rate in ft /h  we are going to use this formula:

Q = AV

when Q is  the volume flow rate

A is the cross-sectional area filled by water =2.669 ft^2

V is the average velocity of the water = 14400 ft/hr

so , by substitution:

Q = 2.669  ft^2* 14400 ft/hr= 38433.6 ft^3/hr

C) To calculate mass velocity (mass flux) in lb/h-ft  we are going to use this formula:

J = m / A

when J is the mass flux

and m is the mass flow rate which we calculated above = 2398256.64 Ib/hr

and A is the cross section area of the pipe which we calculated above and = 2.669 ft^2

so, by substitution:

J = 2398256.64 Ib/hr /  2.669 ft^2

 = 898560 lb/h-ft2

Which of the following describes what takes place
whensolutions of Pb(NO3)2 and
NH4Clare mixed? Detail the manner in which the
application of thesolubility rules reveal this answer.
A. Pb(NO3)2(aq)
+2NH4Cl(aq)-->NH4NO3(aq)
+PbCl2(s)
B. Pb2++2Cl- --> PbCl2(s)
C. Pb2+(aq) +
2NO3-(aq)+2NH+4(aq)
+2Cl-(aq)-->2NH+4(aq)
+2NO3-(aq) + PbCl2(s)
D. NH+4(aq) +
NO3-(aq)-->2NH4NO32NH4NO3(s)
E. No reaction occurs when the solutions aremixed.

Answers

Answer: The correct answer is Option B.

Explanation:

The chemical equation for the reaction of lead (II) nitrate and ammonium chloride follows:

[tex]Pb(NO_3)_2(aq.)+2NH_4Cl(aq.)\rightarrow PbCl_2(s)+2NH_4NO_3(aq.)[/tex]

Ionic form of the above equation follows:

[tex]Pb^{2+}(aq.)+2NO_3^-(aq.)+2NH_4^+(aq.)+Cl^-(aq.)\rightarrow PbCl_2(s)+2NH_4^+(aq.)+2NO_3^-(aq.)[/tex]

Net ionic equation of any reaction does not include any spectator ions.

Spectator ions are defined as the ions which does not get involved in a chemical equation. They are found on both the sides of the chemical reaction when it is present in ionic form.

As, ammonium and nitrate ions are present on both the sides of the reaction. Thus, it will not be present in the net ionic equation and are spectator ions.

The net ionic equation for the above reaction follows:

[tex]Pb^{2+}(aq.)+2Cl^-(aq.)\rightarrow PbCl_2(s)[/tex]

Solubility rules:

Chlorides of silver, mercury and lead are insoluble in water. So, they appear as a solid known as precipitate.Nitrates of most of the metals are soluble in water. So, they appear as ions in solution.

Hence, the correct answer is Option B.

Why is it important to compensate for pressure and temperature when an orifice is used to measure gas flow

Answers

Explanation:

Orifice meters require to compensate for pressure and temperature when one uses these meters to measure the steam or the gas flow in the pipes with the variable operating pressure as well as temperature conditions.

Normally chemists do not have online density measurement tool and thus to avoid complications, the chemists consider density as constant parameter.

In the steam or the gas flow measurement, density of steam or gas changes as the pressure and the temperature change. This significant  change in the density can affect accuracy of measured flow rate if the change is uncompensated and thus, this has to be fixed in order to avoid errors. Therefore, it is important to compensate for the pressure and the temperature when orifice is used to measure the steam or the gas flow.

2.4 Bromium has two naturally occurring isotopes: 79Br, with an atomic weight of 78.918 amu, and 81Br, with an atomic weight of 80.916 amu. If the average atomic weight for Br is 79.903 amu, calculate the fraction-of-occurrences of these two isotopes.

Answers

Answer:

49.3% 81Br and 50.7% 79Br or [tex]\frac{493}{1000}[/tex] 81Br and [tex]\frac{507}{1000}[/tex] 79BR

Step-by-step explanation:

To get the fraction-of-occurrences of the isotopes we must write the following equation. x is the isotopic abundance of 81Br, we can use 1 - x to get the isotopic abundance of 79Br.

(78.918)(1 - x) + (80.916)(x) = 79.903

78.918 - 78.918x + 80.916x = 79.903

1.998x = 0.985

x = 0.493

0.493 × 100 = 49.3% 81Br

100 - 49.3 = 50.7% 79Br

49.3% 81Br and 50.7% 79Br or [tex]\frac{493}{1000}[/tex] 81Br and [tex]\frac{507}{1000}[/tex] 79BR

Zinc reacts with hydrochloric acid according to the reaction equation shown. Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g) How many milliliters of 2.50 M HCl(aq) are required to react with 4.65 g of an ore containing 50.0% Zn(s) by mass? volume: mL

Answers

Answer:

Volume of HCl required = 28.4 mL

Explanation:

[tex]Zn(s) + 2HCl (aq) \rightarrow ZnCl_2(aq) + H_2(g)[/tex]

Mass of zinc ore = 4.65 g

% of zinc in zinc ore = 50 %

So, mass of zinc in zinc ore = 0.50 × 4.65 = 2.325 g

No. of moles of Zn = [tex]\frac{2.325}{65.40} = 0.0355\ mol[/tex]

So, as per the reaction coefficient,

1 mol of zinc reacts with 2 mol of HCl

0.0355 mol of zinc reacts with

                                    = 0.0355 × 2 = 0.071 mol of HCl

Molarity of HCl = 2.50 M

Volume of HCl = [tex]\frac{Moles}{Concentration}[/tex]

[tex]Volume\ of\ HCl = \frac{0.071}{2.50} = 0.0284\ L[/tex]

1 L = 1000 mL

0.0284 L = 1000 × 0.0284 = 28.4 mL

2. Sitting on a bench top are several samples: lithium metal (d = 0.53 g/mL), gold (d = 19.3 g/mL), aluminum (d = 2.70 g/mL), and lead (d = 11.3 g/mL). If all of the samples have the same mass, which one occupies the largest volume? Why?

Answers

Answer:

The sample of lithium occupies the largest volume.

Explanation:

Given the densities for the four elements, we have the expression [tex]d=\frac{m}{V}[/tex] that shows the relationship between mass and Volume to express the density of an element.

For each element we have:

[tex]d_{lithium}=\frac{m_{lithium}}{V_{lithium}}=0.53g/mL[/tex]

[tex]d_{gold}=\frac{m_{gold}}{V_{gold}}=19.3g/mL[/tex]

[tex]d_{aluminum}=\frac{m_{aluminum}}{V_{aluminum}}=2.70g/mL[/tex]

[tex]d_{lead}=\frac{m_{lead}}{V_{lead}}=11.3g/mL[/tex]

The problem says that all the samples have the same mass, so:

[tex]m_{lithium}=m_{gold}=m_{aluminum}=m_{lead}=m[/tex]

it means that m is a constant

Now, solving for the Volume in each element and with m as a constant, we have:

[tex]V_{lithium}=\frac{m}{d_{lithium}}[/tex]

[tex]V_{lithium}=\frac{1}{0.53\frac{g}{mL}} *m[/tex]

[tex]V_{lithium}=1.88\frac{mL}{g}*m[/tex]

[tex]V_{gold}=\frac{m}{d_{gold}}[/tex]

[tex]V_{gold}=\frac{1}{19.3\frac{g}{mL}} *m[/tex]

[tex]V_{gold}=5.18*10^{-2}\frac{mL}{g}*m[/tex]

[tex]V_{aluminum}=\frac{m}{d_{aluminum}}[/tex]

[tex]V_{aluminum}=\frac{1}{2.70\frac{g}{mL}} *m[/tex]

[tex]V_{aluminum}=3.70*10^{-1}\frac{mL}{g}*m[/tex]

[tex]V_{lead}=\frac{m}{d_{lead}}[/tex]

[tex]V_{lead}=\frac{1}{11.3\frac{g}{mL}} *m[/tex]

[tex]V_{lead}=8.85*10^{-2}\frac{mL}{g}*m[/tex]

If we assume m = 1g, we find that:

[tex]V_{lithium}=1.88mL[/tex]

[tex]V_{gold}=5.18*10^{-2}mL[/tex]

[tex]V_{aluminum}=3.70*10^{-1}mL[/tex]

[tex]V_{lead}=8.85*10^{-2}mL[/tex]

So we can see that the sample of lithium occupies the largest volume with 1.88mL

Note that m only can take positive values, so if you change the value of m, always will be the lithium which occupies the largest volume.

Air enters a diffuser witha velocity of 400 m/s, a pressure of 1 bar and temperature of 25 C. It exits with a temperature of 100 C. What is the exit velocity of the air? Assume there are no heat losses or change in potential energy Data:= 0.718 kJ/kg.°C. MW = 28.9 g/mol

Answers

Answer:

Exit velocity of air is 96.43 m/s.

Explanation:

Given that

[tex]V_1=400\ m/s[/tex]

[tex]T_1=25C[/tex]

[tex]T_2=100C[/tex]

For air

[tex]C_p=1.005\ KJ/kg.K[/tex]

Now from first law of thermodynamics for open system at steady state

[tex]h_1+\dfrac{V_1^2}{2000}+Q=h_2+\dfrac{V_2^2}{2000}+w[/tex]

For diffuser

[tex]h_1+\dfrac{V_1^2}{2000}=h_2+\dfrac{V_2^2}{2000}[/tex]

We know that

[tex]h=C_pT[/tex]

[tex]h_1+\dfrac{V_1^2}{2}=h_2+\dfrac{V_2^2}{2000}[/tex]

[tex]1.005\times 25+\dfrac{400^2}{2000}=1.005\times 100+\dfrac{V_2^2}{2}[/tex]

[tex]V_2=96.43\ m/s[/tex]

So the exit velocity of air is 96.43 m/s.

A certain insulation has a thermal conductivity of 0.2 W/m °C What thickness is necessary to effect a temperature drop of 400°C for a heat flux of 200 W/m2?

Answers

Answer:

It is necessary 1 meter of thickness.

Explanation:

You need to know the equation (P/A)=(k*T)/(L), where P/A is the heat flux, k is the thermal conductivity, T the temperature drop, and L the unknown thickness. So if rearrange the variables you will have that L = (k*T)/(P/A), and substituting the terms L = (0.2*400)/(200) = 1 meter

Final answer:

The necessary thickness of insulation to achieve a temperature drop of 400°C with a heat flux of 200 W/m^2, given a thermal conductivity of 0.2 W/m°C, is 0.4 meters.

Explanation:

The necessary thickness of insulation for a specific temperature drop and heat flux. By using the equation of thermal conduction Q = (kAΔT)/d, where Q is the heat flux, k is the thermal conductivity, A is the area, ΔT is the temperature difference, and d is the thickness, we can solve for the thickness d.

To start, we know that k (thermal conductivity) is 0.2 W/m°C, the temperature drop ΔT is 400°C, and the heat flux Q is 200 W/m^2. Plugging these values into the equation gives us d = (kAΔT)/Q. Since the area A is not specified, it will cancel out in this case, allowing us to solve for d directly. Rearranging the equation yields d = (kΔT)/Q, which equals (0.2 W/m°C * 400°C)/200 W/m^2, resulting in d = 0.4 m. Therefore, the thickness required for this insulation is 0.4 meters.

Write 0.00000009345 in Engineering Notation with 3 significant figures

Answers

Answer:

[tex]93.43\times 10^{-9}[/tex]

Explanation:

Scientific notation is the way of writing numbers which are either large or small. The number is written in the scientific notation when the number is between 1 and 10 and then multiplied by the power of 10. Engineering notation is the same version of the scientific notation but the number can be between 1 and 1000 and in this exponent of the ten is divisible by three.

For example, [tex]1000^2[/tex] is to be written as [tex]10^6[/tex] in engineering notation.

The given number:

0.00000009345 can be written as [tex]93.425\times 10^{-9}[/tex]

Answer upto 4 significant digits = [tex]93.43\times 10^{-9}[/tex]

How many atoms are found in 4.20 g of Magnesium?

Answers

Answer:

There are 1.041×10²³ atoms in 4.20g of Magnesium.

Explanation:

To find the amount of atoms in 4.20 g of Magnesium we need de molar mass of Mg: 24.305 g/mol

According to Avogadro number there are 6.022×10²³ particles in 1 mol, so the number of atoms of Mg is:

[tex]4.20 g Mg*\frac{1 molMg}{24.305gMg} *\frac{6.022*10^{23}atoms }{1 mol Mg} = 1.041*10^{23}atoms Mg[/tex]

Answer: The number of atoms found in given amount of magnesium is [tex]1.042\times 10^{23}[/tex]

Explanation:

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

Given mass of magnesium = 4.20 g

Molar mass of magnesium = 24.31 g/mol

Putting values in above equation, we get:

[tex]\text{Moles of magnesium}=\frac{4.20g}{24.31g/mol}=0.173mol[/tex]

According to mole concept:

1 mole of an element contains [tex]6.022\times 10^{23}[/tex] number of atoms

So, 0.173 moles of an element contains = [tex]0.173\times 6.022\times 10^{23}=1.042\times 10^{23}[/tex] number of atoms

Hence, the number of atoms found in given amount of magnesium is [tex]1.042\times 10^{23}[/tex]

When 0.491 grams of a protein were dissolved in 44 mL of benzene at 24.4 degrees C, the osmotic pressure was found to be 50.9 torr. Calculate the molar mass of the protein.

Answers

Answer:

4057.85 g/mol

Explanation:

Hello, the numerical procedure is shown in the attached file.

- In this case, since we don't have the density of the protein, we must assume that the volume of the solution is solely given by the benzene's volume, in order to obtain the moles of the solute (protein).

-Van't Hoff factor is assumed to be one.

Best regards.

Final answer:

To calculate the molar mass of the protein, use the formula M = (RT) / (V * P), where M is the molar mass, R is the ideal gas constant, T is the temperature, V is the volume, and P is the osmotic pressure.

Explanation:

To calculate the molar mass of the protein, we can use the formula:

M = (RT) / (V * P)

Where M is the molar mass, R is the ideal gas constant (0.0821 L.atm/mol.K), T is the temperature in Kelvin (24.4 + 273 = 297.4 K), V is the volume in liters (44 mL / 1000 = 0.044 L), and P is the osmotic pressure in atm (50.9 torr / 760 = 0.067 atm).

Substituting the values into the formula:

M = (0.0821 * 297.4) / (0.044 * 0.067) = 25567.14 g/mol

Therefore, the molar mass of the protein is approximately 25567.14 g/mol.

Why was 1,2 dichlorobenzene used as the solvent for the diels alder reaction we performed in the lab?

Because it smells good since it is aromatic

Because it is easy to remove from the product since it is quite volatile

Because it can kill some bacteria in the reactants since it is toxic

because the co elimination part of the reaction needs high temp and a high boiling point solvent such as 1,2 dichlorobenzene bp 179C has to be used

Answers

Answer:

1,2 dichlorobenzene was used as the solvent for the diels alder reaction: because the co elimination part of the reaction needs high temp and a high boiling point solvent such as 1,2 dichlorobenzene

Explanation:

Diels-Alder Reaction is a useful synthetic tool to prepare cyclohexane rings. It is a process, which occurs in a single step that consists of a cyclic redistribution of its electrons. The two reagents are bond together through a cyclic transition state in which the two new C-C bonds are formed at the same time. For this to occur, most of the time, it is necessary a high temperature and high-pressure conditions. Since 1,2 dichlorobenzene has a boiling point of 180ºC is a good solvent for this type of reactions.

The density of air under ordinary conditions at 25°C is 1.19 g/L. How many kilograms of air are in a room that measures 10.0 ft × 11.0 ft and has an 10.0 ft ceiling? 1 in = 2.54 cm (exactly); 1 L = 103 cm3.

Answers

Answer: The mass of air present in the room is 37.068 kg

Explanation :  Given,

Length of the room = 10.0 ft

Breadth of the room = 11.0 ft

Height of the room = 10.0 ft

To calculate the volume of the room by using the formula of volume of cuboid, we use the equation:

[tex]V=lbh[/tex]

where,

V = volume of the room

l = length of the room

b = breadth of the room

h = height of of the room

Putting values in above equation, we get:

[tex]V=10.0ft\times 11.0ft\times 10.0ft=1100ft^3=31148.53L[/tex]

Conversion used : [tex]1ft^3=28.3168L[/tex]

Now we have to calculate the mass of air in the room.

[tex]Density=\frac{Mass}{Volume}[/tex]

[tex]1.19g/L=\frac{Mass}{31148.53L}[/tex]

[tex]Mass=37066.7507g=37.068kg[/tex]

Conversion used : (1 kg = 1000 g)

Therefore, the mass of air present in the room is 37.068 kg

Answer: There are 37 kg of air in the room.

Explanation:

To calculate the volume of cuboid (room), we use the equation:

[tex]V=lbh[/tex]

where,

V = volume of cuboid

l = length of room = 11 ft

b = breadth of room =  10 ft

h = height of room= 10 ft

Putting values in above equation, we get:

[tex]V=10\times 11\times 10=1100ft^3=1100\times 28.3L=31130L[/tex]  (Conversion factor: [tex]1ft^3=28.3L[/tex]

To calculate mass of a substance, we use the equation:

[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]

We are given:

Density of air = 1.19 g/L

Volume of air = volume of room =  31130 L

Putting values in above equation, we get:

[tex]1.19g/L=\frac{\text{Mass of air}}{31130L}\\\\\text{Mass of air}=37000g=37.0kg[/tex]    (1kg=1000g)

Hence, the mass of air is 37 kg.

An AM radio station broadcasts at 1030 kHz , and its FM partner broadcasts at 98.5 MHz .

partA;Calculate the energy of the photons emitted by the AM radio station.

partB;Calculate the energy of the photons emitted by the FM radio station.

partC;Compare the energy of the photons emitted by the AM radio station with the energy of the photons emitted by the FM radio station.

Answers

Final answer:

The energy of the photons emitted by the AM and FM radio stations can be calculated using Planck's equation (E = hf). The calculated energies show that the FM radio station's photons have higher energy than the AM radio station's photons.

Explanation:

To calculate the energy of the photons emitted by radio stations, we use the formula:

E = hf, where E is the energy, h is Planck's constant (6.62607015 × 10⁻³⁴ Js) and f is the frequency.

(For the sake of this calculation, we are going to convert the frequency from kHz and MHz to Hz.)

The AM radio station broadcasts at 1030 kHz, which is equal to 1.03×10⁶ Hz. Substitute the values into the formula: E = (6.62607015 × 10⁻³⁴ Js) × (1.03 × 10⁶ Hz) = 6.825 × 10⁻²⁸ joules.The FM radio station broadcasts at 98.5 MHz, which is equal to 98.5×10^6 Hz. Substitute the values into the formula: E = (6.62607015 × 10⁻³⁴ Js) × (98.5 × 10⁶ Hz) = 6.527 × 10⁻²⁶ joules.

Comparing these energy values, it's clear that the FM radio station's emitted photons have a higher energy than the AM radio station's photons, due to its higher frequency.

Learn more about Energy of Photons here:

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ObIel WiLll unt COl.. USSMS A certain chemical reaction releases 31.2 kJ/g of heat for each gram of reactant consumed. How can you calculate what mass of reactant will produce 1080. J of heat? Set the math up. But don't do any of it. Just leave your answer as a math expression. Also, be sure your answer includes all the correct unit symbols. mass X ? Explanation Check ducabon ARghtsserved T of Ue Phacy The I'm esc

Answers

Answer:

The expression to calculate the mass of the reactant is [tex]m = \frac{1.080kJ}{31.2kJ/g}[/tex]

Explanation:

The amount of heat released is equal to the amount of heat released per gram of reactant times the mass of the reactant. To keep to coherence between units we need to transform 1,080 J to kJ. We do so with proportions:

[tex]1,080J.\frac{1kJ}{10^{3}J } =1.080kJ[/tex]

Then,

[tex]1.080kJ=31.2\frac{kJ}{g} .m\\m = \frac{1.080kJ}{31.2kJ/g}[/tex]

Answer:

1. The expression is: [tex]m=\frac{E}{\Delta _rH}[/tex]

2. The computed mass is: [tex]m=0.0346g[/tex]

Explanation:

Hello,

In this case, we know the so called enthalpy of reaction whose symbol and value is shown below:

[tex]\Delta _rH=31.2\frac{kJ}{g}[/tex]

In addition, we know that the energy released by the involved reactant is:

[tex]E=1080 J[/tex]

Therefore, the expression to compute the required mass, based on the given units is:

[tex]m=\frac{E}{\Delta _rH}[/tex]

Finally, the computed mass turns out:

[tex]m=\frac{1080J*\frac{1kJ}{1000J} }{31.2\frac{kJ}{g}} \\m=0.0346g[/tex]

Best regards.

in which of these substances is significant hydrogen bonding possible: methylene chloride (CH2Cl2), phosphine (PH3), chloramine (NH2Cl), acetone (CH3COCH3) ?

Answers

Answer:

Significant hydrogen bonding is possible in [tex]NH_{2}Cl[/tex]

Explanation:

Hydrogen bonding takes place between an electronegative atom (O, N and F) and a H atom attached to those electronegative atoms.Lewis structure reveals that H atom attached to N in [tex]NH_{2}Cl[/tex].In all other compounds no such H atom is present attached to O or N or F.Hence significant hydrogen bonding is possible only in [tex]NH_{2}Cl[/tex]Lewis structures are given below.

The only substance from above in which significant hydrogen bonding possible is chloramine ( NH2Cl )

What are organic compounds?

Organic compounds are substances which contain carbon and hydrogen. Some few groups of organic compounds include:

AlkanesAlkenesAlkynesAlkanolsAlkanalsAlkanonesKetonesAmines

So therefore, the only substance from above in which significant hydrogen bonding possible is chloramine ( NH2Cl )

Learn more about organic compounds:

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A sample of helium gas has a volume of 1.50 L at 159 K and 5.00 atm. When the gas is compressed to 0.200 L at 50.0 atm, the temperature increases markedly. What is the final temperature? Enter your answer in the provided box. K

Answers

Answer:

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Explanation:

The given data is as follows.

     [tex]V_{1}[/tex] = 1.50 L,    [tex]T_{1}[/tex] = 159 K,

      [tex]P_{1}[/tex] = 5.00 atm,   [tex]V_{2}[/tex] = 0.2 L,

       [tex]T_{2}[/tex] = ?,       [tex]P_{2}[/tex] = 50.0 atm  

And, according to ideal gas equation,  

               [tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}[/tex]

Hence, putting the given values into the above formula to calculate the value of final temperature as follows.          

 [tex]\frac{5.0 atm \times 1.50 L}{159 K} = \frac{5 atm \times 0.2 L}{T_{2}}[/tex]

            [tex]T_{2}[/tex] = 21.27 K

Thus, we can conclude that the final temperature is 21.27 K .

When a compound is dissolved in hot ethanol during a recrystallization, what is changing on a molecular level? The intermolecular forces between the solute and solvent The covalent bonds of the solute The compound slowly melts into the hot solvent The covalent bonds between the solute and solvent

Answers

Answer:

The intermolecular forces between the solute and solvent.

Explanation:

When you are heating a solvent, the intermolecular forces are reduced because the distances between molecules are large. Thus, in a solution where solvent is hot the intermolecular forces between solute and solvent are lower than those solutions where solvent is in room temperature.

The covalent bonds do not change because this mean a chemical reaction that doesn't occur in a solution.

Usually solid solutes melts in a higher temperature than boiling point in solvents. Thus, a compound normally doesn't melt in a hot solvent.

I hope it helps!

Final answer:

When a compound is dissolved in hot ethanol during recrystallization, the intermolecular forces between the solute and solvent are changing on a molecular level. The process of solution formation involves the formation of new intermolecular forces between the solute and solvent molecules, allowing the compound to dissolve in the solvent.

Explanation:

Intermolecular forces are attractive or repulsive forces between molecules. They include London dispersion forces, dipole-dipole interactions, and hydrogen bonding. These forces influence physical properties like boiling points and solubility in molecular substances. The intermolecular forces between the solute and solvent are changing on a molecular level when a compound is dissolved in hot ethanol during recrystallization.

When the compound is dissolved in the hot solvent, the solute-solvent interactions which is also known as solvatio then naturally takes place. In addition to this, these interactions involve the formation of new intermolecular forces between the solute and solvent molecules, which are nearly as strong as the intermolecular forces within the solute and solvent alone. This favorable solution formation process allows the compound to dissolve in the solvent.

A weak acid. What is the pH of a 0.1 M solution of acetic acid (pKa = 4.75)?
(Hint: Let x be the concentration of H+ ions released from acetic acid when it dissociates. The solutions to a quadratic equation of the form ax^2 + bx + c = 0 are x = (-b +- squareroot (b^2- 4ac)/2a.

Answers

Answer:

pH of acetic acid solution is 2.88

Explanation:

[tex]pK_{a}=4.75[/tex]

or, [tex]-log(K_{a})=4.75[/tex]

or, [tex]K_{a}=10^{-4.75}=1.78\times 10^{-5}[/tex]

We have to construct an ICE table to determine concentration of [tex]H^{+}[/tex] and corresponding pH. Initial concentration of acetic acid is 0.1 M.

[tex]CH_{3}COOH\rightleftharpoons CH_{3}COO^{-}+H^{+}[/tex]

I(M):  0.1                            0                    0

C(M): -x                              +x                 +x

E(M): 0.1-x                         x                    x

So, [tex]\frac{[CH_{3}COO^{-}][H^{+}]}{[CH_{3}COOH]}=K_{a}[/tex]

or, [tex]\frac{x^{2}}{0.1-x}=1.78\times 10^{-5}[/tex]

or, [tex]x^{2}+(1.78\times 10^{-5}\times x)-(1.78\times 10^{-6})=0[/tex]

So, [tex]x=\frac{-(1.78\times 10^{-5})+\sqrt{(1.78\times 10^{-5})^{2}+(4\times 1\times 1.78\times 10^{-6})}}{2\times 1}[/tex](M)

so, [tex]x=1.33\times 10^{-3}M[/tex]

Hence [tex]pH=-log[H^{+}]=-log(1.33\times 10^{-3})=2.88[/tex]

What type of chemical bond would form between an atom of carbon (C) and an atom of nitrogen (N). Explain specifically why this type of bond would form.

Answers

Answer:

Due to the low difference of electronegativity in carbon and nitrogen, these will form a covalent bond, and this covalent union of C-N is one of the most common bonds in the organic chemistry and biological systems. This type of bonds can be found in amines, amides, imines, etc. Also, a single atom of C and a single atom of N can form a cyanide, that is a triple covalent bond between the atoms.

What percentage of the mass of a carbon-12 atom is
contributedby its electrons? Given the mass of an electron is
(1/1836)amu.

Answers

Answer:

% of mass of electrons in C = 0.0272

Explanation:

Atomic no. of carbon = 6

So, no. of electron = 6

Mass of an electron = [tex]\frac{1}{1836} amu[/tex]

Mass of 6 electrons = [tex]6 \times \frac{1}{1836} = 0.003268 amu[/tex]

Mass of C = 12.0107 u

% of mass of electrons in C = [tex]\frac{Mass\ of\ all\ electrons}{Mass\ of\ C}\times 100[/tex]

% of mass of electrons in C = [tex]\frac{0.003268}{12.0107}\times 100=0.0272 \%[/tex]

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