To begin the experiment, 1. 65g of methane CH4 is burned in a bomb calorimeter containing 1000 grams of water. The initial temperature of water is 18. 98oC. The specific heat of water is 4. 184 J/g oC. The heat capacity of the calorimeter is 615 J/ oC. After the reaction the final temperature of the water is 36. 38oC.

5. The total heat absorbed by the water and the calorimeter can be by adding the heat calculated in steps 3 and 4. The amount of heat released by the reaction is equal to the amount of heat absorbed with the negative sign as this is an exothermic reaction. (2pts)
a. Using the formula ΔH = - (qcal + qwater ) , calculate the total heat of combustion. Show your work.
b. Convert heat of combustion (answer from part a) from joules to kilojoules. Show your work. 6. Evaluate the information contained in this calculation and complete the following sentence: (2pts) This calculation shows that burning _______ grams of methane [TAKES IN] / [GIVES OFF] energy (Choose one).

7. The molar mass of methane is 16. 04 g/mol. Calculate the number of moles of methane burned in the experiment. Show your work. (2pts)

8. What is the experimental molar heat of combustion in KJ/mol? Show your work. (2pts)

9. The accepted value for the heat of combustion of methane is -890 KJ/mol. Explain why the experimental data might differ from the theoretical value in 2-3 complete sentences. (2pts)

10. Given the formula: % error= |(theoretical value - experimental value)/theoretical value)| x 100 Calculate the percent error. Show your work. (2pts)​

According to the illustration, the factors that influence the gravitational attraction between two objects would be mass and distance. Option A.

The gravitational attraction between two objects is determined by two factors: their masses and the distance between them.

This is due to the inverse square law, which states that the force between two objects is proportional to the inverse square of the distance between them.

Therefore, the correct answer is mass and distance.

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Answer:it is A

Explanation:

No luminaires shall be installed for operation on supply circuits over 150 volts between conductors. Luminaires mounted in walls shall be installed with the top of the luminaire lens not less than 450 mm (18 in.)

In an electrical installation, what is a luminaire?

A luminaire, also known as a light fixture, is a complete lighting assembly that includes one or more lamps (light bulbs or tubes), a socket and other protective elements, wiring that links the lamp to a power source, and a reflector to help direct and spread the light.

The construction, installation, or inclusion of shades or guards on luminaires is required to prevent the exposure of combustible materials to temperatures above 90°C (194°F). Unswitched lamp holders must be used above materials that are very flammable.

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2.65 g KHP (molar mass=204.22 g/mol) was use to standardize a NaOH solution and the endpoint of titration was reached after 42.56 mL of NaOH was delivered. The molarity of the NaOH solution is 0.100 M.


To find the molarity of the NaOH solution, we need to use the balanced chemical equation for the reaction that occurred during the titration. This reaction is:
KHP + NaOH → NaKP + H2O
From the equation, we can see that 1 mole of NaOH reacts with 1 mole of KHP. Therefore, the number of moles of NaOH used in the titration can be calculated as:
moles NaOH = (42.56 mL)(1 L/1000 mL)(0.100 M) = 0.0004256 moles
Next, we can use the molar mass of KHP to calculate the number of moles of KHP used in the titration:
moles KHP = 2.65 g / 204.22 g/mol = 0.012979 moles
Since the reaction is a 1:1 stoichiometry, the number of moles of NaOH used is equal to the number of moles of KHP used. Therefore, we can set up an equation to find the molarity of the NaOH solution:
moles NaOH = moles KHP
0.0004256 moles = 0.012979 moles / x M
x = 0.100 M
Therefore, the molarity of the NaOH solution is 0.100 M.

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the Cl-Cl bond energy is a A. 1091 kJ/mol.

Chlorine trifluoride is prepared by reacting chlorine gas with fluorine gas.

The enthalpy change is -803 kJ/mol of chlorine reacted.

To calculate the Cl-Cl bond energy we have to know the energy in the Cl2 bond that is broken to create Cl atoms (x), as well as the energy released when a Cl atom forms a bond with another Cl atom (-803 kJ/mol).

We can say that the Cl2 bond energy is the opposite of the bond dissociation energy (BDE), thus the Cl2 bond energy is equal to +242 kJ/mol, and the Cl-Cl bond energy is +242 kJ/mol - (-803 kJ/mol), which is equal to 1045 kJ/mol.

Hence, the answer is a A. 1091 kJ/mol.

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A demand O2 delivery system utilizes a "pressure drop" mechanism to trigger oxygen flow.

In a demand oxygen delivery system, the flow of oxygen is triggered by a pressure drop that occurs when the user initiates inhalation. When the user takes a breath, the drop in pressure in the system activates the mechanism that releases oxygen.

This mechanism can be a valve or regulator that opens to allow oxygen to flow from the source to the user.

The pressure drop required to trigger the oxygen flow depends on the specific design of the system and can vary. Generally, the pressure drop is set at a level that ensures the user's inhalation effort is sufficient to activate the oxygen flow while maintaining a safe and reliable operation.

The pressure drop is typically calibrated and adjusted during the manufacturing process to meet the desired specifications and requirements of the system.

In summary, a demand oxygen delivery system relies on a pressure drop mechanism to initiate the flow of oxygen. This mechanism ensures that oxygen is released when the user inhales, providing them with the required oxygen supply.

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Answer:

Explanation:

Let us consider a stem to be a living material in this case:

An experiment that can be conducted to show that living materials contain water can be shown below:

An activity to show that stem conducts water and other substances is given below:

1) Take a glass and put some water in it.

2) Put a few drops of red ink in the water.

3) Cut the stem from the base of an herb plant.

4) Place the stem in the glass.

5) Results are observed, some parts of the stem become red and they indicate that water is being conducted through the stem.

Thus, we can say that through this activity that living material contains water. A stem is a part that connects the roots to the leaves, stores food, provides support, and holds the flowers, leaves, and buds.

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Answer:

Ionic bonds result from the transfer of electrons from one atom to another

Explanation:

In covalent bonds, atoms share electrons, whereas in ionic bonds atoms transfer electrons. The reaction components of covalent bonds are electrically neutral, whereas for ionic bonds they are both charged.Covalent bonds are formed between two non-metals, whereas ionic bonds are formed between a metal and non-metal.  

Answer:

Covalent bonds are defined as sharing of electrons, ionic bonds are the result of transferred electrons;

Covalent bonds form between non-metals (elements) and ionic bonds form between metal and non-metals (ions)

Answer:

20ml

Explanation:

using the formula;C1V1=C2V2

2.5×V1=0.2×250

2.5V1= 50

V1=50/2.5

V1=20L

Answer:

1 grams Cobalt(II) Sulfate = 0.006451787725861 mole using the molecular weight calculator and the molar mass of CoSO4.

Explanation:

The letter "d" corresponds to the emission of a violet photon since it falls within the wavelength range of 380-450 nm and the frequency range of 668-789 THz.

Wavelength is the distance between two consecutive peaks (crests) or troughs (valleys) of a wave. It is an important property of a wave, which is usually measured in meters, centimeters, or nanometers. Wavelength is related to the frequency of a wave, as it determines the amount of energy carried by the wave. It is an important factor in the study of sound and light, as the different wavelengths of light and sound have different properties. Wavelength is also used in communication technologies such as radio and TV, where it determines the range of frequencies available to transmit a signal.

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Answer:gravity

Explanation:

Answer:

the gravity speed up because the friction didn't speed up

From the formula unit of potassium carbonate, there are two potassium ions and one carbonate ion.

The term formula unit refers to the smallest unit in an ionic compound. It shows the ratio of the ions in the compound. For potassium carbonate, the formula unit is K2CO3.

From this formula unit, we can see that there are two potassium ions and one carbonate ion.

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Answer:

It forms 2 single sigma bonds with 2 hydrogen atoms and double (1sigma and 1pi bonds with oxygen atoms. They are convalent

Answer:

No. of neutrons = 27 - 13 = 14

No. of protons = No. of electrons = 13

Hope it helps you

If the original cell density in a sample if 2.79 x 106 cfu/ml, \(10^{-1}\) mL or 0.1 mL. which sample volume should yield a countable plate.

To determine the sample volume that should yield a countable plate, we need to estimate the number of colonies that will grow on the plate. A countable plate is one that has between 30 and 300 colonies.

Assuming we want to use a standard Petri dish with a diameter of 90 mm, the surface area of the plate is:

\(Area = \pi * (diameter/2)^2 = 3.14 * (90/2)^2 = 6351 mm^2\)

To estimate the number of colonies that will grow on the plate, we need to dilute the original sample to a concentration that will yield between 30 and 300 colonies. A common dilution factor used in microbiology is \(10^{-6\), which means we will dilute the original sample by a factor of 1 million.

The calculation for dilution is:

\(C_1V_1 = C_2V_2\)

where \(C_1\) is the initial concentration, \(V_1\) is the initial volume, \(C_2\) is the final concentration, and \(V_2\) is the final volume.

Let's assume we want to plate 0.1 mL of the diluted sample on the plate. We can calculate the dilution factor as follows:

\(C_1V_1 = C_2V_2\)

\((2.79 * 10^6 \ cfu/mL) * V_1 = (2.79 *\ 10^6 \ cfu/mL) * 10^{-6} * 0.1 mL\\V_1 = 0.1 mL / 10^{-6} = 10^5 mL\)

This means we need to take 0.1 mL of the \(10^{-6\) diluted sample (which is equivalent to \(10^5\) times diluted) and plate it on the agar surface.

To check if this sample volume will yield a countable plate, we can estimate the number of colonies that will grow on the plate:

Number of colonies = (CFU/mL) × (plated volume) × (reciprocal of dilution factor)

Number of colonies = \((2.79 * 10^6 cfu/mL) * 0.1 mL * 10^6 = 279 colonies\)

This is within the range of 30 to 300 colonies, so a sample volume of 0.1 mL should yield a countable plate.

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Answer:

try c atom i hope this helps!! : )

Explanation:

Answer:

high kinetic

Explanation:

I just did it

Answer: the answer is high kinetic energy

Explanation:

The theoretical yield of Z for the given reaction would be 1.2 grams.

Given information:

Mol. weight of X (MW_X) = 250 g/mol

Mol. weight of Y (MW_Y) = 200 g/mol

Mol. weight of Z (MW_Z) = 300 g/mol

Mass of X used (m_X) = 375 mg

Mass of Y used (m_Y) = 400 mg

Convert mass of X and Y to grams for consistent units.

m_X = 375 mg = 375/1000 g = 0.375 g

m_Y = 400 mg = 400/1000 g = 0.4 g

The balanced chemical equation for the given reaction is: X + 2Y → Z

From the equation, we can see that the mole ratio of X to Z is 1:1, and the mole ratio of Y to Z is 2:1.

Comparing the mole ratios of X and Y to Z, we can calculate the theoretical yield of Z based on the limiting reactant.

If n_X/1 <= n_Y/2, then X is the limiting reactant.

If n_X/1 > n_Y/2, then Y is the limiting reactant.

If X is the limiting reactant:

n_Z = n_X

If Y is the limiting reactant:

n_Z = 2 * n_Y

Now, n_X = m_X / MW_X = 0.375 g / 250 g/mol = 0.0015 mol

n_Y = m_Y / MW_Y = 0.4 g / 200 g/mol = 0.002 mol

n_X/1 = 0.0015 mol/1 = 0.0015

n_Y/2 = 0.002 mol/2 = 0.001

Since n_X/1 > n_Y/2, Y is the limiting reactant.

n_Z = 2 * n_Y = 2 * 0.002 mol = 0.004 mol

m_Z_theoretical = n_Z * MW_Z = 0.004 mol * 300 g/mol = 1.2 g

So, the theoretical yield of Z for the given reaction would be 1.2 grams.

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Answer:

b because the detective ate coffee all day

The metals loses electrons forming cations while on the other hand, the non-metals gains the electrons forming anions.

Covalent bonding is a type of bonding linking two non-metallic atoms which are distinguished by the sharing of pairs of electrons joining atoms and other covalent bonds. An ionic bond is the force of appeal that holds together positive and negative ions. It forms when atoms of a metallic element loses electrons to atoms of a nonmetallic element. Ionic bonds form only allying metals and nonmetals. When two nonmetals bond, they share pairs of electrons in a covalent bond and both gets stability.

So w can conclude that A covalent bond is formed between two non-metals. The sharing of electron pairs takes place between their atoms and a covalent bond is formed.

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To prepare the pH 4.00 buffer solution, you should mix approximately 61.35 mL of the 0.100 M benzoic acid solution with 38.65 mL of the 0.240 M sodium benzoate solution.The ratio of benzoic acid to sodium benzoate in the buffer solution using the Henderson-Hasselbalch equation.

To prepare a pH 4.00 buffer solution using benzoic acid and sodium benzoate, we need to calculate the appropriate volumes of the 0.100 M benzoic acid and 0.240 M sodium benzoate solutions.

First, we need to determine the ratio of benzoic acid to sodium benzoate in the buffer solution. The Henderson-Hasselbalch equation can help us with this calculation:

pH = pKa + log([A-]/[HA])

Given that the pH is 4.00 and pKa is 4.20, we can rearrange the equation:

log([A-]/[HA]) = pH - pKa

log([A-]/[HA]) = 4.00 - 4.20

log([A-]/[HA]) = -0.20

Next, we take the antilog of -0.20 to find the ratio of [A-] to [HA]:

[A-]/[HA] = antilog(-0.20)

[A-]/[HA] = 0.63

The ratio of [A-] to [HA] is 0.63.

Now, let's calculate the volumes of each solution needed. Let's assume x represents the volume (in mL) of the 0.100 M benzoic acid solution and y represents the volume (in mL) of the 0.240 M sodium benzoate solution.

Since the total volume is 100.0 mL, we have the equation: x + y = 100

Considering the ratio of [A-] to [HA] as 0.63, we can write the equation: y/x = 0.63

Solving these two equations simultaneously will give us the volumes of each solution:

x + y = 100

y/x = 0.63

By substituting y = 0.63x from the second equation into the first equation, we get:

x + 0.63x = 100

1.63x = 100

x = 61.35 mL (rounded to two decimal places)

Substituting this value back into the equation x + y = 100, we find:

61.35 + y = 100

y = 38.65 mL (rounded to two decimal places)

Therefore, to prepare the pH 4.00 buffer solution, you should mix approximately 61.35 mL of the 0.100 M benzoic acid solution with 38.65 mL of the 0.240 M sodium benzoate solution.

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Answer:

D. the starting subtances

:)

Answer: D. The starting substances !!

Explanation:

Answer:

Water-> Brine-> Kerosene

Explanation:

Answer:

Brine, water, kerosine

Explanation:

Brine is the densest.

Kerosine Is less dense than water.

Answer: write the solubility equilibrium and the solubility-product constant expression for the slightly soluble salt CaF2 CaF2 (s) <---> Ca2+ (aq) + 2F- (aq) Ksp=[Ca2+][F-]2.

Explanation:

Answer:

HF and CH3OH

Explanation:

Hydrogen bonding is a special strong dipole-dipole interaction.

For hydrogen bonding to occur there must be:

1. An H atom bonded covalently to a N, O, or F atom. This bond between H and N, O, or F describes the particular hydrogen as an "H bond donor"- a necessary part of a hydrogen bond

2. An O, F, or N atom with one or more lone pairs. The presence of lone pairs on any of these atoms makes these atoms "H bond acceptors"- the second component of intermolecular hydrogen bonding

So, to start draw the lewis structure of each atom. Assuming this question is asking if it is possible for the atom to hydrogen bond with itself, we can already eliminate CH3CH3  and H2S due to their lack of an N, O ,or F atom.

Descriptions of each lewis structure:

HF: H contributes 1 electron and F contributes 7, H can only be single bonded to another atom, so the F atom has three lone pairs

CH3OH: 4+ (4H*1) + 6 = 14 electrons, H cannot be the central atom so the C and O atom must be in the center. The C atom has three single bonds with 3 H atoms and one single bond with the O atom, completing the octet. The O atom has a single bond with the last H atom and two lone pairs.

The presence of lone pairs in both HF (on the F atom) and CH3OH (on the O atom) creates the possibility for H bond acceptors.

Therefore, hydrogen bonding is an important intermolecular force in HF and CH3OH

The three lone pairs on fluorine act as H bond acceptors and H covalently bonded to F creates an H bond donor

The two lone pairs on oxygen act as H bond acceptors and the H covalently bonded to the O acts as an H bond donor

The hydrogen bonding is an important intermolecular force in the following compound: HF (hydrogen fluoride) and CH₃OH (methanol).

Hydrogen bonding occurs when there is a significant electronegativity difference between hydrogen and a highly electronegative atom, such as fluorine, oxygen, or nitrogen. In HF, hydrogen is bonded to fluorine, a highly electronegative atom, resulting in hydrogen bonding. In CH₃OH, hydrogen is bonded to oxygen, another highly electronegative atom, which also results in hydrogen bonding.

CH₃CH₃ (ethane) and H₂S (hydrogen sulfide) do not exhibit hydrogen bonding as their intermolecular forces because the electronegativity difference between their atoms is not significant enough to result in hydrogen bonding.

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Answer:

Number of moles of oxygen = 0.037  mol

Explanation:

Given data:

Total pressure = 98.5 KPa

Partial pressure of nitrogen = 22.0 KPa

Partial pressure of argon = 50.0 KPa

Volume = 3.5 L

Temperature = 25°C (25+273= 298K)

Number of moles of oxygen = ?

Solution:

Total pressure = P(N₂) + P(O₂) + P(Ar)

98.5 KPa = 22.0 KPa +P(O₂) + 50.0 KPa

98.5 KPa = 72.0 KPa +P(O₂)

P(O₂)  = 98.5 KPa - 72.0 KPa

P(O₂)  = 26.5 KPa

KPa to atm:

26.5 KPa/ 101 = 0.262 atm

Number of moles of oxygen:

PV = nRT

n = PV/RT

n = 0.262 atm × 3.5 L / 0.0821 atm.L/mol.K  × 298 K

n = 0.917atm.L /24.47atm.L/ mol

n = 0.037  mol

Answer: true

Explanation:

Ocean salinity will vary with evaporation as well as with freezing and thawing. this statement is true.

Salinity, commonly known as saline water (also see soil salinity), is the degree of saltiness or the quantity of salt dispersed throughout a body of water. The standard units of measurement are grammes of salt per litre (g/L) or grammes per kilogramme (g/kg; the latter one is dimensionless therefore equal to ).

Salinity is a thermodynamic condition variable that, along with pressure and temperature, controls physical properties like the density also heat capacity of the water. Salinity plays a significant role in defining numerous facets of the chemical composition of natural waters as well as the biological processes within them. Ocean salinity will vary with evaporation as well as with freezing and thawing. this statement is true.

Therefore, ocean salinity will vary with evaporation as well as with freezing and thawing. this statement is true.

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Answer:

its either A or B most likley A if im wrong then im sorry.

Explanation:

have a wonderfull day

Answer:

protons

Explanation:

The number of protons in the nucleus determines which element an atom is, while the number of electrons surrounding the nucleus determines which kind of reactions the atom will undergo.