1. Which of the following is true regarding the law of conservation of mass? A It dictates that the number of molecules on each side of a chemical equation must be the same. B It does not apply to chemical reactions. C It dictates that the number of atoms of each element must be the same on both sides of a chemical equation. D It states that the mass of the reactants must remain constant in order for a chemical reaction to proceed.

Answer :

Part (a) :  [tex]3H_2(g)+N_2(g)\rightarrow 2NH_3(g)[/tex]

Part (b) :  Theoretical yield of [tex]NH_3[/tex] = 440.96 g

Part (c) : Percentage yield of ammonia is 90.03 %

Mass of [tex]N_2[/tex] = 475 g

Molar mass of [tex]N_2[/tex] = 28 g/mole

Molar mass of [tex]NH_3[/tex] = 17 g/mole

Experimental yield of [tex]NH_3[/tex] = 397 g

Part (a) :The balanced chemical reaction will be:

[tex]3H_2(g)+N_2(g)\rightarrow 2NH_3(g)[/tex]

Part (b) :To calculate the moles of [tex]N_2[/tex]:

[tex]\text{Moles of }N_2=\frac{\text {Mass of }N_2}{\text{ Molecular mass of }N_2}=\frac{475g}{28g/mole}=16.96moles[/tex]

From the given balanced equation:

1 mole of [tex]N_2[/tex] gas produces 2 moles of [tex]NH_3[/tex]

16.96 moles of [tex]N_2[/tex] gas produces [tex]\frac{2}{1}\times 16.96=33.92[/tex] moles of [tex]NH_3[/tex]

Now we have to calculate the mass of [tex]NH_3[/tex]

[tex]\text{ Mass of }NH_3=\text {Moles of }NH_3\times \text{ Molar mass of }NH_3[/tex]

[tex]\text{ Mass of }NH_3=(33.92moles)\times (17g/mole)=440.96g[/tex]

Therefore, the theoretical yield of [tex]NH_3[/tex] gas = 440.96 g

Part (c) : Percentage yield :

[tex]\% \text{ yield of }NH_3=\frac{\text {Experimental yield of NH_3}}\text {Theoretical yield of }NH_3\times 100[/tex]

[tex]\% \text{ yield of }NH_3=\frac{397g}{440.96g}\times 100=90.03\%[/tex]

Therefore, the % yield of ammonia is 90.03 %

The correct answer is option C, that is, the turtles will no longer be found in Georgia.  

Due to the presence of protected dunes and temperate climate appropriate for nesting activities, the barrier island beaches of Georgia host an average of 1000 sea turtles nests in a year.  

However, the main danger to sea turtles in Georgia is the damage of their eggs and nests and offshore mortalities related to commercial longline fishing or shrimping activities. With the development going on in the coastal regions where the turtles thrive, a time will come when one will no longer witness any turtle along the coast of Georgia.  

Answer:

C

Explanation:

The turtles will no longer be found in Georgia.

I would have to say B. Linear

I hope this helps!

Cheers, July.

Answer : The correct option is, (B) Linear

Explanation :

Formula used  :

[tex]\text{Number of electrons}=\frac{1}{2}[V+N-C+A][/tex]

where,

V = number of valence electrons present in central atom

N = number of monovalent atoms bonded to central atom

C = charge of cation

A = charge of anion

Now we have to determine the hybridization of the [tex]BeH_2[/tex]  molecules.

[tex]\text{Number of electrons}=\frac{1}{2}\times [2+2]=2[/tex]

The number of electrons is 2 that means the hybridization will be [tex]sp[/tex] and the electronic geometry of the molecule will be linear.

The three-dimensional shape of the molecule with the Lewis structure are shown below.

I have done some research as well as asking some friends. This is what I came up with. Not sure if it is 100% correct.

step = time after death

1. Livor Mortis = 20-30 minutes

2. Eyes film (cloud) = 2 hours

3. Rigor Mortis begins = 4-6 hours

4. Empty small intestines = 12 hours

5. Bloating = 3-5 days

6. Decay

Forensic scientists determine the time of death initially by observing physical changes such as the heart stopping, greying of the skin, cell death, muscle relaxation, and the emptying of the bladder and bowels. The sequence of these events helps establish a timeline. Additional factors like insect activity, weather conditions, and the setting may further assist in making an accurate estimation.

Forensic scientists, specifically forensic anthropologists and forensic pathologists, determine the time of death by analyzing various changes that occur in the body after death. These changes occur in a specific sequence and at different rates, thereby providing a means to estimate the time of death. The sequence of changes are as follows:

In addition to these changes, forensic scientists also study other evidence such as insect activity, weather conditions and surroundings to calculate the postmortem interval or to validate their findings based on the body's changes.

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The incremental temperature change is 20°C or 50%.

Incremental temperature change is the change in the temperature of any substance when it is increased from its original temperature. Incremental temperature change is always measured as percentage increase in the rate of temperature.

Temperature is increased from 20°C to 40°C .

Thus incremental change in temperature,

  ΔT = Final temperature - Initial temperature

∴ ΔT = 40°C  -  20°C  =  20°C

Also percentage change in temperature ,

(ΔT / Final temperature) × 100 %

⇒ (20°C / 40°C) × 100 %

⇒ (1/2) × 100 %

∴ Percentage change = 50%

Thus incremental temperature change is 20°C or 50%

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 The enthalpy  of  combustion  of magnesium  is -601.3  kj/mol

calculation

  ΔH = cΔT

   C( heat capacity) =5,760 j/°c

    ΔT = 0.570°c

 ΔH = 5760 j/°c  x 0.570 °c = 3283.2 j

convert 3283.2 j into Kj

1 kj = 1000 j

 kj ?  =3283.2 j

 by cross multiplication

={ (3283.2  j  x 1 kj) / 1000 j}  =3.2832 kj

Find the  moles of Mg

moles = mass÷ molar mass  

from periodic table the molar mass   of Mg = 24.3 g/mol

= 0.1326 g÷ 24.3 g/mol =0.00546 moles

find ΔH in KJ/mol

 =  3.2832 kj/ 0.00546 moles = 601.3 Kj/mol

since  heat  is released during combustion the ΔH  is  = - 601.3 kj/mol

Hi!~~

Menthol, with chemical formula C10H20O, is a common compound used in medicine, often natural ones.

The safest way to check for the presence of menthol should be to use your hand. You would waft the substance's fumes toward your hands.

Answer:

Waft the substance's fumes toward you with your hand.

Explanation:

The simplest answer and the correct one is saturated. You can try this at home to see what it looks like. Take a  glass and fill it to the 1/2 full mark. Make sure the water is on the coolish side. Start putting measured amounts of salt in the water. Do this until you see salt on the bottom of the glass. The solution is now saturated.

Empty the glass. Put the same amount of water in the glass but make it much  warmer. Put the same amount of salt in the glass. It should not be saturated -- that is there should be no salt on the bottom.

So temperature determines saturation. But more important, you should get an idea of what saturation is.

The correct answer is reactants 2Na and 2H₂O and products 2NaOH and 1H₂.  

The given unbalanced chemical equation is:  

Na (s) + H2O (l) → NaOH (aq) + H₂ (g)

From the equation, it can be seen that there are three atoms of hydrogen on the products side, however, only two on the reactant's side. So, in order to balance the equation, one needs to multiply the sodium hydroxide by 2 to get a total of 4 atoms of hydrogen on the product's side.  

This will enable one to readily double the number of molecules of water to get 4 atoms of hydrogen on the reactants side, and then balance the atoms of sodium by multiplying the sodium metal by 2. The balanced equation obtained is:  

2Na (s) + 2H₂O (l) → 2NaOH (aq) + H₂ (g)

In the given chemical reaction, Reactants: 2Na and 2H₂O and Products: 2NaOH and 1H₂. Therefore, option D is correct.

In the balanced equation, the coefficients indicates the relative number of moles of each substance involved in the reaction. The balanced equation for the reaction between sodium (Na) and water (H₂O) to produce sodium hydroxide (NaOH) and hydrogen gas (H₂) is: 2Na + 2H₂O → 2NaOH + H₂

This balanced equation shows that 2 moles of sodium reacts with 2 moles of water to produce 2 moles of sodium hydroxide and 1 mole of hydrogen gas.

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Final answer:

Copper wire is used in electrical wiring because its metallic bonding aids with conductivity of the material.

Explanation:

The metallic bonding between the atoms aids with the conductivity of the material.

Copper wire is used in electrical wiring because it has high electrical conductivity. Metallic bonding is responsible for the free flow of electrons in copper, allowing it to conduct electricity efficiently. This property makes copper an ideal material for conducting electric current in various appliances.

The quick answer is B

3 moles

A mole has an alternate definition of 6.02 * 10^23 particles or atoms (in this case) that make it up.

A is possible, but it is not the question.

C is possible, but it is not the question.

I've never directly seen D before. It is used with gases (indirectly).

In order to find the mass (in grams) of an element, you just need to multiply the no. of moles given by the atomic mass of the element, which can be found in a periodic table.

mass of 15.0 moles of N= 15.0 x 14.0 = 210g

mass of 5.0 moles of Zn= 5.0 x 65.4 = 327g

mass of 20.0 moles of H= 20.0 x 1.0 = 20g

mass of 1.0 moles of Pb= 1.0 x 207.2 = 207.2g

Therefore, since 327g is the greatest mass out of the 4 options, the answer is 5.0 moles of Zn.

Answer:

Start and end times; distance run.  

Step-by-step explanation:

Average speed = distance/time.

Kaila should record the distance run, the time she started, and the time she ended her run.

The difference between the start and end times gives the time for the run.

If she inserts her numbers into the formula, she will get her average running speed.  

Kaila should record the distance she runs and the time it takes to cover that distance to calculate her average running speed using the formula: Average Speed = Distance / Time.

To calculate her average running speed, Kaila should record the distance she runs and the time it takes to cover that distance. The formula for average speed is given by:

Average Speed = Distance / Time

For example, if Kaila runs 400 meters and it takes her 60 seconds to do so, her average speed would be:

Average Speed = 400 meters / 60 seconds = 6.67 meters per second

By consistently recording the distances and times for each of her runs, Kaila can calculate her average speed for each session and track her progress over time.

Answer: The angle between the carbon-chlorine bonds in phosgene will be 120°

Explanation: Formula used to calculate the hybridization:

[tex]{\text{Number of electron pairs}} =\frac{1}{2}[V+N-C+A][/tex]

where,

V = number of valence electrons present in central atom i.e. carbon = 4

N = number of monovalent atoms bonded to central atom = 2

C = charge of cation = 0

A = charge of anion = 0

For [tex]COCl_2[/tex]

[tex]{\text{Number of electron pairs}} =\frac{1}{2}[4+2-0+0]=3[/tex]

The number of electron pairs are 3 which means that the hybridization will be [tex]sp^2[/tex] and the electronic geometry of the given molecule will be trigonal planar.

The bond angle in this electronic geometry is 120°

The structure of phosgene is attached below.

The angle between the Carbon-Chlorine bonds in the Phosgene molecule (COCl₂) is generally 120 degrees due to the sp² hybridization of the Carbon Atom

The phosgene molecule (COCl₂) has a planar shape, with the oxygen atom in the center, bonded to the carbon atom, and the chlorine atoms bonded to either side of the carbon atom. This creates a molecule with a structure in the shape of the letter 'V'. The angle between the carbon-chlorine bonds in the phosgene molecule is typically 120 degrees. This is due to the fact that the carbon atom in the center is sp² hybridized, meaning it has three regions of electron density spread out in a plane, forming angles of 120 degrees with each other.

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As a comet approaches the Sun, it starts to heat up. The ice transforms directly from a solid to a vapor, releasing the dust particles embedded inside. Sunlight and the stream of charged particles flowing from the Sun – the solar wind – sweeps the evaporated material and dust back in a long tail.

Answer:

Comets are composed of ice, dust and frozen gases. The core of the comet is known as nucleus which is formed of rocks and frozen gases. Coma is the atmosphere of the comet. As the comet enters the inner solar system, the coma expands due to sublimation of frozen gases. As it nears the sun, the coma extends backwards and forms a long tail. It extends backwards due to the solar wind. The charged particles from the sun take away the evaporated material and dust of the comet backwards forming tail.

Assuming total mass to be 100 g

Mass of C = 52.93 g

=> Moles of C = [tex]52.93 g *\frac{1 mol}{12gC} =4.41 mol C[/tex]

Mass of H = 5.92 g

=> Moles of H=[tex]5.92g*\frac{1mol}{1.01g}=5.86molH[/tex]

Mass of N = 41.15 g

=>Moles of N=[tex]41.15g*\frac{1 mol}{14 g}=2.94mol N[/tex]

Simplest mole ratio of the atoms in the compound:

[tex]C_{\frac{4.41mol}{2.94mol} } H_{\frac{5.86mol}{2.94mol} }N_{\frac{2.94mol}{2.94mol} } =C_{1.5}H_{2}N_{1} or(C_{1.5}H_{2}N_{1})_{2}=>C_{3}H_{4}N_{2}[/tex]

Empirical formula mass=[tex](3*12)+(4*1.01)+(2*14)=68.04g[/tex]

Multiple n = [tex]\frac{204.2}{68.04}=3[/tex]

Molecular formula= [tex](Empirical formula)_{n} =(C_{3}H_{4}N_{2})_{3}=C_{9}H_{12}N_{6}[/tex]

Final answer:

The empirical formula of triethylenemelamine is determined to be C₃H₄N₂ based on the given percentage composition. By comparing the molecular mass of triethylenemelamine to the mass of the empirical formula unit, the molecular formula is found to be C₆H₈N₄.

Explanation:

To determine the empirical formula and molecular formula of triethylenemelamine based on its percent composition (52.93% carbon, 5.92% hydrogen, 41.15% nitrogen) and molecular mass (204.2 g/mol), follow these steps:

Calculate the moles of each element based on 100 g of the compound.
For Carbon: (52.93 g / 12.01 g/mol) = 4.41 moles
For Hydrogen: (5.92 g / 1.008 g/mol) = 5.87 moles
For Nitrogen: (41.15 g / 14.01 g/mol) = 2.94 moles

Determine the simplest whole number ratio of the elements by dividing by the smallest number of moles, which in this case is 2.94 moles (N). This gives:
C: 4.41 / 2.94 ≈ 1.5
H: 5.87 / 2.94 ≈ 2
N: 2.94 / 2.94 = 1

Since the ratio needs to be in whole numbers, multiply each by 2 to get C₃H₄N₂ as the empirical formula.

To find the molecular formula, divide the molecular mass of triethylenemelamine (204.2 g/mol) by the mass of the empirical formula unit (C₃H₄N₂ = 3(12.01) + 4(1.008) + 2(14.01) ≈ 84.1 g/mol), getting approximately 2.43. Since molecular formulas must be whole numbers, this indicates the empirical formula must be multiplied by 2, giving C₆H₈N₄ as the molecular formula of triethylenemelamine.

your element would be calcium

Answer:

C₆H₁₂O₆ < NaCl ≈ CH₃OH < MgCl₂

Step-by-step explanation:

The formula for osmotic pressure (Π) is

Π = icRT

If T is constant,

Π = kic

C₆H₁₂O₆:

Π = k × 1 × 1 = k

MgCl₂:

Π = k × 3 × 1 = 3k

CH₃OH:

Π = k × 1 × 2 = 2k

NaCl:

Π = k  × 2 × 1 = 2k

The order of osmotic pressures is  

C₆H₁₂O₆ < NaCl ≈ CH₃OH < MgCl₂

MgCl₂ > NaCl = CH₃OH > C₆H₁₂O₆ or MgCl₂ > CH₃OH = NaCl > C₆H₁₂O₆.

Given:

Question:

Rank the solutions according to their respective osmotic pressures in decreasing order assuming the complete dissociation of ionic compounds.

The Process:

The osmotic pressure of a nonelectrolyte solution is calculated as follows:

[tex]\boxed{ \ \pi = MRT \ }[/tex]

The osmotic pressure of an electrolyte solution is calculated as follows:

[tex]\boxed{ \ \pi = MRTi \ }[/tex]  

The van't Hoff factor is i = 1 + (n - 1)α, with  

In our problem, assuming the complete dissociation of ionic compounds results in α = 100% and i = n.

From the information above, each type of solution can be prepared as follows:

Now we compare the amount of osmotic pressure from each solution.

From the above results, it can be observed that 2 M CH₃OH and 1 M NaCl have the same osmotic pressure.

Thus, the rank of the solutions according to their respective osmotic pressures in decreasing orders is MgCl₂ > NaCl = CH₃OH > C₆H₁₂O₆ or MgCl₂ > CH₃OH = NaCl > C₆H₁₂O₆.

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Notes:

The answer is 9 please rate 5 ⭐️ if it was helpful.

For which of the following conversions does the value of the conversion factor depend upon the formula of the substance?

The answer is C

The answer is: C) mass of any substance to moles.

To converte mass to amount of substances, mass must be divided by molar mass (n = m ÷ M).

Molar mass M represent the mass of a substance divided by the amount of substance. If the formula is not correct, amount of substance is not correct.

For example, calculate molar mass of iron(II) chloride:

Atomic mass of iron is 55.8 g/mol.

Atomic mass of chlorine is 35.5 g/mol.

If compound is FeCl, molar mass would be 55,8 g/mol + 35,5 g/mol = 91,3 g/mlo, that is not correct.

If compound is FeCl₂, malar mass of compound would be:

55,8 g/mol + 2·35,5 g/mol = 126,8 g/mol, that is correct.

Answer:

The correct answer is option A.

Explanation:

Schrodinger proposed the mechanic model of atom in which he defined the location of electrons inside an atom by electron cloud in 3-d space. And in order to locate them he introduced the concept of quantum numbers.

Where as photons are the discrete  packet or bundle of energy related to electromagnetic radiations.

Answer:

q = -39.8 kJ

Step-by-step explanation:

CH₃OH(g) ⇌ CH₃OH(l); ΔH(cond) = -35.2 kJ·mol⁻¹

(1) Calculate the moles of methanol

n = 36.2 × 1/32.04

n = 1.130 mol

=====

(2) Calculate the heat evolved

q = nΔH(cond)

q = 1.130 × (-35.2)

q = -39.8 kJ

432 inches

Each project is 9 feet, and she is making 4 projects, so multiply 9 by 4 to find the number of feet needed. You should get 36. Each foot is equal to 12 inches, so multiply 36 by 12 to get 432 inches.

Answer: 432 inches

Explanation:

Given : length of ribbon needed by Shannon for an art project = 9 feet

As we know : 1 feet = 12 inches

9 feet =[tex]\frac{12}{1}\times 9=108inches[/tex]

Thus if for 1 project , length of ribbon required is = 108 inches

For 4 projects , length of ribbon required is =[tex]\frac{108}{1}\times 4=432inches[/tex]

Thus 432 inches of ribbon should she buy if she is making 4 projects.

Answer: Option (C) is the correct answer.

Explanation:

When the volume of a container is decreased and same number of gas molecules are present inside the container at the same temperature then it means that more number of gas molecules are spread per unit volume.

As earlier when the volume of container was more then the molecules were widely spread inside the container but on decreasing the volume of container, molecules come closer to each other and hence there will be increase in molecules per unit volume.  

Answer:

It is C

Explanation:

Acids produce H+ ions in solution.

Since it produces ions in solution and ions can carry current.

Hence acids can conduct electricity as it produces ions in solution.

Strong acids dissociate completly and produce more ions (than weaker acids which do not dissociate completly) so strong acids are better conductors of electricity.

The answer is B as isotopes are different versions of the same chemical element containing the same amount of protons and electrons but different amounts of neutrons.

The given reaction is C₅H₉O + O₂ → CO₂ + H₂O

On balancing the equation we get:  

20 C₅H₉O + 90 O₂ → 100 CO₂ + 9 H₂O

This is a single replacement type of reaction. A single replacement reaction, also called a single-displacement reaction, refers to a kind of chemical reaction where an element reacts with a compound and occupies the place of another element in that compound.