What is the number of valence electrons in a nitrogen atom in the ground state

Answer:

$0.0238

Explanation:

The energy you need to increase the temperature of water from 20°C to 100°C is obtained from:

Q = C×m×ΔT

Where Q is the energy, C is specific heat of water (4.184J/g°C), m is mass of water (2.00x10²g - Density of water 1g/mL), ΔT is change in temperature (100.0°C - 20.0°C)

Replacing:

Q = 4.184J/g°C × 2.00x10²g × 80.0°C

Q = 66944J = 66.944kJ

As you are assuming the energy of combustion will be just 50.0% to heat the water the energy you need is 66.944kJ × 2 = 133.888kJ

The combustion of methane is:

CH4(g) + 2O2(g) ⟶ CO2(g) + 2H2O(l) ΔH = −890.8kJ

That means 1 mole of methane produce 890.8kJ. As you need 133.888kJ, moles of methane are:

133.888kJ × (1 mol CH₄ / 890.8kJ) = 0.150 moles of CH₄.

Using PV = nRT, moles of 15.0ft³ (424.8L) at 20.0°C (293.15K) and 1.00atm:

1.00atmₓ424.8L = moles CH₄ₓ0.082atmL/molKₓ293.15K

17.67 = moles CH₄

As 17.67 moles of CH₄ cost $2.80, the cost of 0.150 moles of CH₄ is:

0.150 moles CH₄ ₓ ($2.80 / 17.67 moles) =

Answer:

C6H6<C7H15OH<C6H13OH<C2H5OH​

Explanation:

Organic substances are ordinarily nonpolar. This means that they do not dissolve in water. However, certain homologous series of organic compounds actually dissolve in water because they possess certain functional groups that effectively interact with water via hydrogen bonding.

A typical example of this is alcohol family. All members of this homologous series contain the -OH functional group. This group can effectively interact with water via hydrogen bonding, leading to the dissolution of low molecular weight alcohols in water.

Low molecular weight alcohols are miscible with water in all proportions. This implies that they are highly soluble in water. However, as the size of the alkyl moiety in the alcohol increases, the solubility of the alcohol in water decreases due to less effective interaction of the -OH group with water via hydrogen bonding. This explains the fact that C2H5OH​ is the most soluble alcohol in the list.

C6H6 is insoluble in water since it is purely a hydrocarbon with no -OH group capable of interaction with water via hydrogen bonding.

Answer:

Element and compounds are the pure substances but mixture is not a pure substance.

Explanation:

Element and compounds are the pure substances in which element comprise of only one atom while compound is formed by the chemical combination of more than one element in a fixed ratio by mass while mixture is also made up of more that one substances but they are combine physically not chemically. Elements, compounds, mixtures are very important because all the materials we used in our daily life are formed from elements, compounds and mixtures.

The major properties of matter are volume, mass, and shape.

All matter however too is made up of tiny particles known as atoms.

Other characteristics properties of matter which can be measured include object's density, color, length, malleability, melting point, hardness, odor, temperature, and others

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The property of matter should be volume, mass, and shape.

The following information should be considered:

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answer

1)maximise your software efficiency

2)Prevention against viruses and malware

3)Early detection of problematic issues

4)prevent data loss

5)Speed up your computer

Answer:

CaSO4

Explanation:

Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates.

Answer: 8 (feet)

Explanation:

24 inches = 2 feet

48 inches = 4 feet

12 inches = 1 foot

To find volume you do Base * Width * Height

2*4*1 = 8

Hope this helps!

The correct answer is  8 (feet).

How to calculate ?

Therefore, 2*4*1 = 8

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Answer:

The type of salt to be added to the water is not known from the question but no worries, I will try to give you the step by step procedure to answer any type of question similar to this.

To answer this question, we should know some facts.

1. the molar freezing point depression constant of water (Kf) = 1.86 K kg/mol

2. the molar mass of the salt if NaCl = 58.5 g/mol ; KCl = 74.5 g/mol

3. since the salt can dissociate if NaCl or KCl into two ions, the Van't Hoff factor ( i )= 2

Note that: the change in freezing point, molarity, deepression constant and van't Hoff factor are related by this formula;

                ΔTf = i Kf m

So lets take NaCl as the salt:

Molar mass = 58.5 g/mol

Van't Hoff factor = 2

1. calculate the number of moles

So we can calculate the molarity of the salt NaCl from the formula;

m = ΔTf / i Kf

m = 5 / 2 * 1.86

m = 5 / 3.72

m = 1.344 mol/kg

2. calculate the number of moles of the salt required

Next is to multiply the molarity by the mass of water. Density of water = 1kg/L

number of moles = 1.344 mol/kg * 1 Kg/L * 1 kg water

number of moles = 1.344 moles.

3. calculate the mass of the salt.

numner of moles = mass / molar mass

mass = number of moles * molar mass

mass = 1.344 * 58.5

mass = 78.624 g of NaCl salt.

You can follow these steps to solve for the type of salt you are given in the question.

Answer:

142 grams

Explanation:

To find the molar mass of a molecule or compound, you simply need to add together the molar masses of all of the atoms that comprise it. Phosphorus has a molar mass of about 31, while oxygen has one of about 16, meaning that the molar mass of this molecule is:

2(31)+5(16)=62+80=142

Hope this helps!

Answer:

THE HEAT OF THIS REACTION PER MOLE OF SUCROSE IS 4868.75 KJ OF HEAT.

Explanation:

To answer this question:

First calculate the total heat given off by sucrose:

         Total energy/ heat = heat capacity * change in temperature

Heat capacity = 7.50 kJ/ °C

Change in temperature = 20.5 °C

Heat = 7.50 kJ * 20.5 °C

Heat = 153.75 kJ of heat.

Next is to calculate the heat of reaction per mole of the sucrose

Equation of the reaction:

               C12H22011 (s) + 12 O2 (g) ---------> 12 CO2 (g) + 11 H20(l)

Since 1 mole of sucrose will be the molar mass of sucrose, then we should calculate the molar mass of sucrose.

Molar mass of sucrose = ( 12* 12 + 1 * 22+ 16*11) g/mol

Molar mass = 342 g/mol of sucrose

Since 10.8 g of sucrose produces 153.75 kJ of heat, 342 g will produces how many joules of heat?

10.8 g of sucrose = 153.75 kJ of heat

342 g of sucrose = ( 342 * 153.75 kJ / 10.8)

= 52 582.5 kJ / 10.8

= 4868.75 kJ of heat

So therefore, 1 mole of sucrose will produce 4868.75 kJ of heat.

Answer:

The answer is 5.

Answer: The molecules in the thermometer's liquid spread apart.

Explanation:

Mercury is the only metal that remains liquid at room temperature. It has a high coefficient of expansion therefore the its level rises when exposed to a temperature range. It can detect a slight change in temperature. It has a high  boiling point.

When the thermometer is placed in the water to measure the temperature, the molecules of thermometer liquid that is mercury only will spread due to high coefficient of expansion. This can be seen as rise in temperature.

Answer:

B

Explanation:

Just did the test

Answer:

Explanation:

H₂CO₃(aq) + H₂O(l) ↔ H₃O⁺(aq) + HCO₃⁻(aq)

Let d be the degree of dissociation

.02( 1-d )                              .02d          .02d

Dissociation constant Ka₁ is given

4.3 x 10⁻⁷  = .02d x .02d / .02( 1-d )

= .004 d² / .02  ( neglecting d in denominator )

= .02 d²

d² = 215 x 10⁻⁷

d = 4.636 x 10⁻³

= .004636

concentration of H₃O⁺

= d x .02

= .004636 x .02

= 9.272 x 10⁻⁵

pH = - log [ H₃O⁺ ]

= - log ( 9.272 x 10⁻⁵ )

5 - log 9.272

= 5 - .967

= 4.033 .

Answer:

[tex]\Delta H=-11897J[/tex]

Explanation:

Hello,

In this case, it is widely known that for isochoric processes, the change in the enthalpy is computed by:

[tex]\Delta H=\Delta U+V\Delta P[/tex]

Whereas the change in the internal energy is computed by:

[tex]\Delta U=nCv\Delta T[/tex]

So we compute the initial and final temperatures for one mole of the ideal gas:

[tex]T_1= \frac{P_1V}{nR}=\frac{10.90atm*4.86L}{0.082*n}=\frac{646.02K }{n} \\\\T_2= \frac{P_2V}{nR}=\frac{1.24atm*4.86L}{0.082*n}=\frac{73.49K }{n}[/tex]

Next, the change in the internal energy, since the volume-constant specific heat could be assumed as ³/₂R:

[tex]\Delta U=1mol*\frac{3}{2} (8.314\frac{J}{mol*K} )*(73.49K-646.02K )=-7140J[/tex]

Then, the volume-pressure product in Joules:

[tex]V\Delta P=4.86L*\frac{1m^3}{1000L} *(1.24atm-10.90atm)*\frac{101325Pa}{1atm} \\\\V\Delta P=-4756.96J[/tex]

Finally, the change in the enthalpy for the process:

[tex]\Delta H=-7140J-4757J\\\\\Delta H=-11897J[/tex]

Best regards.

The change in enthalpy is 70.42J

Data;

The change of enthalpy is calculated as

[tex]\delta H = \delta V + \delta nRT\\\delta n = 0\\\delta H = \delta U \\[/tex]

The volume change is negligible

The change in enthalpy here is equal to change in internal energy over ΔE

[tex]\delta H = \delta U = nCv\delta T\\\delta H = \frac{3}{2}(nR\delta T)\\\delta H = \frac{3}{2}\{\delta PV)\\ \delta H = \frac{3}{2}[(10.90-1.24)*4.86] \\\delta H = 70.42J[/tex]

The change in enthalpy is 70.42J

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Answer:

Ozone has dipole moments because its molecular chemical structure is no linear.

Explanation:

This molecular form refers to the geometry of said gas, which is potentially toxic and dangerous.

This non-linear geometric shape is what makes it have dipolarity.

Answer:0.30 m KI ---- A. Highest boiling point

0.19 m Mg(CH3COO)2 ---- B. Second highest boiling point

0.53 m Glucose(nonelectrolyte) ---- Third highest boiling point-C

0.13 m FeCl3---- Lowest boiling point-D

Explanation:

Using the  boilng point elevation formula

ΔTb=m* kb *i

where m= molality

kb= elevated boiling point constant( here kb values will be same for all soluton)

i= vant hoff factor = number of ions present in a solution

Using the  number of ions and molarity present in a solution as a collagative property, since kb is constant, we can determine which of the species has the highest boiling point.

1.) 0.13 m FeCl3= Fe³⁻  + Cl⁻

        i=4

ΔTb=m* kb* i= molarity x number of ionsx Kb= 0.13 x 4= 0.52kb

2) 0.19 m Mg(CH3COO)2 = Mg²⁺ + CH₃COO⁻

i= 3

ΔTb=m* kb* i= molarity x number of ions= 0.19 x 3= 0.57kb

3. 0.30 m KI = K⁺  + I⁻

i= 2

ΔTb=m *kb *= imolarity x number of ions xKb= 0.30x 2= 0.60kb

4. 0.53 m Glucose(nonelectrolyte) =

i= 1 for nonelectroytes

ΔTb=m* kb* i = molarity x number of ionsx Kb= 0.53 x 1= 0.53Kb

therefore,

0.30 m KI ---- A. Highest boiling point

0.19 m Mg(CH3COO)2 ---- B. Second highest boiling point

0.53 m Glucose(nonelectrolyte) ---- Third highest boiling point

0.13 m FeCl3---- Lowest boiling point

Answer:

True

Explanation:

A real image can be projected or seen on a screen but a virtual image cannot because a real image is formed when light rays coming from an object actually meet at a point after refraction through a lens while a virtual image is formed when light rays coming from an object only appear to meet at a point when produced ...

Hope this helps you, and Good luck!

Answer:

The functional class(es) of this compound is(are):

Explanation:

3450 cm-1 is indicative of OH stretching

1725 cm-1 is indicative of carbonyl group C=O

1100cm-1 shows carbon is bonded to electronegative element e.g C-O

Further information on molecular formula is required for proper structural elucidation

Answer:

219.15 grams

Explanation:

What is the mass of 3.75 moles of NaCI? ( Na= 22.99g/mol, CI= 35.45 g/mol)

Mole of Na = 22.99g

Mole of Cl = 35.45g

For NaCl we have ratio of 1:1, so we have 1 Na for every Cl

So we just add the two together to get the molar mass of NaCl which is

22.99 + 35.45 = 58.44g/mol

And we know we have 3.75 moles of NaCl so we multiply that by the molar mass of NaCl to get our answer

3.75 x 58.44 = 219.15grams

Answer:

mL * L²

Explanation:

The question in t his problem is to calculate the units of the final answer.

The units in the numerator is mol, ml and L.

The unit in the denominator is mol/L

This leads us to;

Numerator / Denominator =  mol * mL * L / (mol / L )

The final units is mL * L²

Answer:

Explanation:

The covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements, such as hydrogen H, oxygen O and chlorine Cl. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas.

The covalent bond between two atoms can be polar or nonpolar. If the atoms are equal, the bond will be nonpolar (since no atom attracts electrons more strongly). But, if the atoms are different, the bond will be polarized towards the most electronegative atom, because it will be the atom that attracts the electron pair with more force. Then it will be polar.

It can occur in a molecule that the bonds are polar and the molecule is nonpolar. This occurs because of the geometry of the molecule, which causes them to cancel the different equal polar bonds of the molecule.

In carbon tetrachloride the bonds are polar, but the tetrahedral geometry of the molecule causes all four dipoles to cancel out and the molecule to be apolar.

The carbon tetrachloride s CCL4 is a carbon molecule and four chloride molecule's. The carbon tetrachloride is a nonpolar, as the dipole movement of the molecules ae evenly spaced around the central carbon atom.

Hence the carbon tetrachloride happens to be a nonpolar molecular.

Learn more about the in terms of charge distribution, why a molecule.

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Answer:

  98.9%

Explanation:

2 moles of I₂ are required for each mole of Mg, so the reaction is limited by the available I₂. The 3.56 moles of I₂ should react with 1.78 moles of Mg to produce 1.78 moles of MgI₂. Instead, we get 1.76 moles of MgI₂.

The yield is 1.76/1.78 × 100% ≈ 98.876%

The yield is 98.9% of the quantity expected based on available reactants.

Answer:

Keq= [(Cl2) (H2)] / (HCl)^2

Explanation:

Equilibrium Constant, Keq, is written as products/reactants.

So it's going to be Keq= [(Cl2) (H2)] / (HCl)^2

Answer:

85.34g of NH3

Explanation:

Step 1:

The balanced equation for the reaction. This is given below:

N2 + 3H2 —> 2NH3

Step 2:

Determination of the number of moles of NH3 produced by the reaction of 2.51 moles of N2. This is illustrated below:

From the balanced equation above,

1 mole of N2 reacted to produce 2 moles of NH3.

Therefore, 2.51 moles of N2 will react to produce = (2.51 x 2)/1 = 5.02 moles of NH3.

Therefore, 5.02 moles of NH3 is produced from the reaction.

Step 3:

Conversion of 5.02 moles of NH3 to grams. This is illustrated below:

Molar mass of NH3 = 14 + (3x1) = 17g/mol

Number of mole of NH3 = 5.02 moles

Mass of NH3 =..?

Mass = mole x molar Mass

Mass of NH3 = 5.02 x 17

Mass of NH3 = 85.34g

Therefore, 85.34g of NH3 is produced.

Answer:

ΔH = - 44.0kJ

Explanation:

H2O(l)→H2O(g), ΔH =44.0kJ

In the reaction above, liquid water changes to gaseous water. This occurs through a process known as boiling. This process requires heat, hence the ΔH  is positive.

If he reaction is reversed, we have;

H2O(g)→H2O(l)

In this reaction, gaseous water changes to liquid water. This process is known as condensation. The water vapor loses heat in this reaction. Hence ΔH would be negative but still  have the same value.

Answer:

This isotope of fluorine has 9 protons, 9 electrons and 10 neutrons.

Explanation:

Answer:

8.09x10⁻⁵M of Fe³⁺

Explanation:

Using Lambert-Beer law, the absorbance of a sample is proportional to its concentration.

In the problem, the Fe³⁺ is reacting with KSCN to produce Fe(SCN)₃ -The red complex-

The concentration of Fe³⁺ in the reference sample is:

4.80x10⁻⁴M Fe³⁺ × (5.0mL / 50.0mL) = 4.80x10⁻⁵M Fe³⁺

Because reference sample was diluted from 5.0mL to 50.0mL.

That means a solution of  4.80x10⁻⁵M Fe³⁺ gives an absorbance of 0.512

Now, as the sample of the lake gives an absorbance of 0.345, its concentration is:

0.345 × (4.80x10⁻⁵M Fe³⁺ / 0.512) = 3.23x10⁻⁵M.  

As the solution was diluted from 20.0mL to 50.0mL, the concentration of Fe³⁺ in Jordan lake is:

3.23x10⁻⁵M Fe³⁺ × (50.0mL / 20.0mL) = 8.09x10⁻⁵M of Fe³⁺

The concentration of  Fe³⁺ in Jordan Lake is = 8.09* 10⁻⁵ M  

According to Lambert-Beer law ;The rate of absorbance of a sample is directly proportional to concentration of the sample

The reaction that produces a red complex

Fe³⁺ + KScN ----> Fe ( SCN )₃  ( red complex )

First step:  Determine the Concentration of  Fe³⁺ in  reference sample

= 4.80x10⁻⁴ *  ( 5.0 / 50.0 ) = 4.80 * 10⁻⁵M  

reference sample was diluted from 5.0 mL to 50.0 mL

∴ Concentration of 4.80 * 10⁻⁵M  has an absorbance = 0.512

Given that Lake sample absorbance = 0.345

Next step : Determine the concentration of the lake sample

Concentration of lake sample :

= absorbance of lake sample * ( conc of reference sample / absorbance )

= 0.345 *  (  4.80* 10⁻⁵ / 0.512  )  = 3.23* 10⁻⁵M.

Final step : Determine the concentration of Fe³⁺ in Jordan  lake

=  3.23 * 10⁻⁵ *  ( 50.0mL / 20.0mL) = 8.09* 10⁻⁵ M  

Note :  Solution  was diluted from 20.0 mL to 50.0 mL

Hence we can conclude that The concentration of  Fe³⁺ in Jordan Lake is = 8.09* 10⁻⁵ M  .

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Answer:

Explanation:

ratio of  moles of N and O in molecule =

N / O = 2.17 / 4.35

1/2

empirical formula = NO₂