Calculate the standard enthalpy of reaction for the reaction 2Na(s) +2H2O(l) arrow2NaOH(aq) + H2(g) . Standard enthalpies of formation are -285.8kj/mol for H2O(l) and -470.11kj/mol for NaOH(aq).

Answer:

It contains most of the mass

Explanation:

that part A rigth

Answer:

A

Explanation:

Answer:

Explanation:

You have given the exact definition of what an atom is. It is the smallest entity that has all the same properties as a bunch of atoms put together.

D. A mountain range with folded layers of rock.

Intense compression can cause the rock layers to fold, creating a mountain range. This type of feature forms suddenly in the geological timescale, as a result of tectonic activity, and is known as a fold mountain.

The intense pressure causes the rock layers to buckle and deform, resulting in folds, faults, and other features. The Appalachian Mountains and the Rocky Mountains are examples of fold mountains in the United States.

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The shelf-life of the reconstituted ampicillin suspension remains unchanged at 16 days when stored at room temperature (25°C) compared to storing it in the refrigerator at 5°C.

To calculate the shelf-life of the reconstituted ampicillin suspension at room temperature, we'll assume that the degradation follows an Arrhenius relationship.

Shelf-life at 5°C (T₁) = 16 days

Temperature at 5°C (T₁) = 5°C

Temperature at room temperature (T₂) = 25°C

To find the shelf-life at room temperature, we can use the Arrhenius equation:

k₁ / k₂ = exp((Ea / R) * (1/T₂ - 1/T₁))

Since we don't have specific values for Ea and the reaction rate constants, we'll assume that they are the same for simplicity. Thus, we can write:

k₁ / k₂ = exp((Ea / R) * (1/25 - 1/5))

Simplifying the equation, we get:

exp((Ea / R) * (4/125)) = 1

To satisfy this equation, the exponential term must be zero, which implies:

(Ea / R) * (4/125) = 0

Solving for Ea, we find:

Ea = 0

Since Ea is zero, it means the reaction rate constants and degradation rates are the same at both temperatures. Therefore, the shelf-life at room temperature (25°C) is the same as the shelf-life at 5°C, which is 16 days.

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Answer: the statement issues are addressed by the people working together is true about activation.

Explanation:

Answer: 32.06 atomic mass units

Explanation:

Answer:

The particles need energy to overcome the attractions between them. As the liquid gets warmer more particles have sufficient energy to escape from the liquid. Eventually even particles in the middle of the liquid form bubbles of gas in the liquid.

The empirical formula of compound that contains 4. 03g of hydrogen per mole, 64. 14 g of sulfur per mole and 128 g of oxygen per mole is H₂SO₂.

given that :

mass of hydrogen = 4.03 g

mass of sulfur = 64.14 g

mass of oxygen = 128 g

moles of hydrogen = mass / molar mass

                                = 4.03 / 1

                                = 4mol

moles of sulfur = 64.14 / 32

                         = 2 mol

moles of oxygen = 128 / 32

                            = 4 mol

dividing by the smallest one , we get

mole of H = 2

mole of S = 1

mole of O = 2

The empirical formula = H₂SO₂

Thus,  the empirical formula of compound that contains 4. 03g of hydrogen per mole, 64. 14 g of sulfur per mole and 128 g of oxygen per mole is H₂SO₂.

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Internationally accepted system for measurement called as international system of units (SI)

The international system of unit (SI) is commonly known as the metric system and is the international standard for measurement and the international treaty of the meter was signed in Paris on may 20 1875 by seventeen countries including the united states and is now celebrated around the globe as world metrology day and long the dominant measurement system used in science

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Answer:

milliliter

Explanation:

Answer:

B milliliter

Explanation:

A current of 3.80 A would need to be applied for 0.24 hours to plate out 5.70 g of lead from a \(Pb(NO_3)_2\) solution.

Q = I × t

moles Pb = (5.70 g)/(331.2 g/mol) = 0.0172 mol

Q = 2 × F × moles Pb

Q = 2 × 96,485 C/mol e- × 0.0172 mol = 3,320 C

t = Q/I = 3,320 C / 3.80 A = 874 seconds

Finally, we convert the time to hours:

t = 874 s / (60 s/min × 60 min/h) = 0.24 hours

A solution typically refers to a homogeneous mixture of two or more substances that are uniformly dispersed throughout each other. The substance that is present in the largest quantity is known as the solvent, while the other substances present in smaller quantities are known as solutes.

Solutions play a crucial role in many areas of physics, including chemistry, material science, and engineering. They can be used to study the properties and behavior of substances, as well as to design and develop new materials with specific properties. The behavior of solutions is governed by several physical laws and principles, including thermodynamics, kinetics, and colloidal chemistry. These laws help us understand phenomena such as osmosis, diffusion, and solubility.

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Answer: B

Explanation: molarity = concentration c= n/V = 0.5 mol/ 0.05 l = 10 mol/l

The molarity of  a solution is the number of moles of its solute divided by volume in liters. The molarity of the 50 ml solution containing 0.5 moles of potassium fluoride is 10 M or 10 molar.

Molarity is a common term used to express the concentration of a solution. It is the ratio of number of moles of solute particles to the volume of solution in liters. Hence, its unit is mol/L or molar.

The molarity of a solution is a colligative quantity as well as temperature dependent.

Given,

no.of moles of potassium fluoride salt in water = 0.5 moles.

volume of solution = 50 ml

1 L = 1000 ml

then 50 ml = 0.05 L.

Molarity = no.of moles of solute/ volume of solution in L

M = 0.5 moles/ 0.05 L

   = 10 M.

Therefore, the molarity of the given solution is 10 molar.

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Cartridge brass an fcc substitutional solid solution of zinc (Zn) in copper (Cu) is a single-phase alloy.

The FCC stands for face centered cubic lattice. An alloy is defined as a metal that is made up of two or more chemical elements, at least one of which is a metal, and where the atoms are intermixed through metallurgical processing. The atoms of the different elements in an alloy are commonly separated by a few atomic diameters, which distinguishes them from a mixture of metals in which the chemical properties of each component remain unchanged.

There are two types of alloys: single-phase alloys and two-phase alloys. When all of the atoms in an alloy are in the same phase, it is known as a single-phase alloy. In a single-phase alloy, the atoms are uniformly distributed throughout the sample. The material is considered to be homogeneous, or the same throughout, because all of the atoms are in the same phase.

On the other hand, when an alloy contains two different phases, it is known as a two-phase alloy. The constituents are in different phases. In such cases, the phases can either be entirely separated from one another or dispersed. To summarize, cartridge brass is a single-phase alloy because it is an FCC substitutional solid solution of zinc in copper.

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If the lab is cold at 15°C, the melting point of acetic acid will be lower than that temperature and we will find it as a solid. Acetic acid has a melting point of 16.6°C, which means that it will remain in a solid state at 15°C.

However, if we increase the temperature, the acetic acid will eventually melt and become a liquid. It's important to note that the melting point of a substance can vary depending on the conditions, such as pressure or purity. Therefore, it's essential to control the temperature and other factors when determining the melting point of a substance accurately.
If the lab is cold at 15°C, the melting point of acetic acid, which is around 16.6°C, will be higher than that temperature. As a result, you will find acetic acid in its solid form, known as a crystalline solid, under these conditions.

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Answer:

This is a balanced equation because the same types of atoms and the same numbers of each atom are present on both sides of the equation. 8 S atoms are found on both sides of the equation, and 48 F atoms are found on both sides of the equation. S8 and 24F2 are the reactants; 8SF6 is the product. This is a combination reaction because two substances (S8 and 24F2) undergo a chemical union to form a more complex substance (8SF6).

S8+24F2→8SF6

Explanation:

Answer:

5.77x10^-7 m or 577 nm (nanometers)

Explanation:

The wavelength, λ, and frequency, ν, of light are described by the equation:

c = λν

where c is the speed of light.  

c = 3.0x10^8 m/s

v = 5.2x10^14

λ = c/v

λ = (3.0x10^8 m/s)/(5.2x10^14) = 5.77x10^-7 m

since 1 m = 10^9nm, we can express this as 577 nm (nanometers)

577 nm.  This is in the yellow light span of wavelengths.

If the pH at one-half the first and second equivalence points of a dibasic acid is 4.20 and 7.34, respectively. The values for pKa1 and pKa2 will be 4.20 and 7.34. Ka1 and Ka2 will be ≈ 6.31 x 10^(-5), and ≈ 2.07 x 10^(-8) respectively.

To find the values of pKa1 and pKa2, we need to understand the relationship between pH and pKa in a titration curve. At one-half the equivalence point, the concentrations of the acid and its conjugate base are equal, resulting in a pH equal to the pKa of the corresponding dissociation.

Given:

pH at one-half the first equivalence point (pKa1) = 4.20

pH at one-half the second equivalence point (pKa2) = 7.34

From the information provided, we can determine the values for pKa1 and pKa2.

pKa1 = pH at one-half the first equivalence point

pKa1 = 4.20

pKa2 = pH at one-half the second equivalence point

pKa2 = 7.34

To calculate Ka1 and Ka2, we use the relationship:

Ka = 10^(-pKa)

Ka1 = 10^(-pKa1)

Ka1 = 10^(-4.20)

Ka2 = 10^(-pKa2)

Ka2 = 10^(-7.34)

Calculating the values:

Ka1 ≈ 6.31 x 10^(-5)

Ka2 ≈ 2.07 x 10^(-8)

To summarize:

pKa1 = 4.20, pKa2 = 7.34

Ka1 ≈ 6.31 x 10^(-5), Ka2 ≈ 2.07 x 10^(-8)

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Answer:

Explanation:

Energy needed = mass * temperature difference * specific heat

= 4.37 * (27.5-25) * 0.24

= 4.37 * 2.5 * 0.24

= 2.622J

Answer:

Explanation:

warm up 2.5C

mass 4.37

specific heat 0.24

energy = 2.5*4.37*0.24

= 2.6J

The structural formula for the following compound is

 CH3       CH3

  |           |

  C           C

  |           |

CH2---CH2---CH---CH2---CH3

    |           |

    CH3       CH3

To draw the structural formula for 4-isobutyl-1,1-dimethylcyclohexane, we need to understand the position and arrangement of the different substituents on the cyclohexane ring.

Starting with the cyclohexane ring, it consists of six carbon atoms arranged in a ring structure. We number the carbon atoms from 1 to 6, ensuring that the substituents are given the lowest possible numbers. In this case, we have a methyl group at position 1 and an isobutyl group at position 4.

At position 1 of the cyclohexane ring, we have a methyl group (CH3). This means that there is a single carbon atom attached to the first carbon of the ring, along with three hydrogen atoms.

At position 4 of the cyclohexane ring, we have an isobutyl group. The isobutyl group consists of four carbon atoms, with the central carbon attached to the fourth carbon of the cyclohexane ring. The isobutyl group has the following structure: (CH3)2CHCH2.

Additionally, the name of the compound specifies that there are two dimethyl groups, indicating that two additional methyl groups (CH3) are attached to the cyclohexane ring.

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Answer:

slaked lime - Ca(OH)2

Ca(OH)2 + CO2 ----> CaCO3(solid) + H2O

X is CO2

Answer:

2

Explanation:

Answer:

there primary food source will still be the same

Explanation:

they will still ear mice but coyotesmay eat Humans if they are close because once they see humans they think they will be killed its there protectiong

Answer:

D. It will increase because coyotes are the competition.

Explanation:

Because Competition is When 2 organisms fight for the same thing, and sense rattlesnakes are the other competition they will increase because coyotes are being killed.

Answer:

This is what I think it is, correct me if I'm wrong. Answer is stated below:

Explanation:

Destructive Interference

Two waves combine to form a wave with a smaller amplitude than either the original wave. Destructive interference can occur when the crest of one wave overlaps the trough of another wave. If the crest has a larger amplitude than the trough of the other wave, a part of it remains.

Answer:

i guess the answer is..true

the ozone in troposphere protects the earth from ultra violet waves that may cause global warming

To determine whether a hot or cold pack is effective, safe, and easy to use, several criteria can be considered: effectiveness, safety, and ease of use.

1. Effectiveness: The effectiveness of a hot or cold pack is evaluated based on its ability to relieve pain and reduce inflammation. An effective pack should provide the desired level of relief without causing any adverse effects or complications.

2. Safety: Safety is paramount when using any therapeutic tool. A hot or cold pack should not cause harm to the user. This means it should be designed in a way that prevents burns, bruises, or abrasions to the skin. Proper temperature control is essential to ensure the pack is not too hot or too cold. Sufficient padding should be provided to prevent direct contact with the skin.

3. Ease of use: A hot or cold pack should be user-friendly. It should be easy to handle and should not be overly bulky or heavy. Clear and concise instructions for use should be provided, and the pack should be easy to clean and store. Portability is also important so that the pack can be conveniently carried around.

For a hot or cold pack to be considered effective, safe, and easy to use, it should provide relief from pain and inflammation without causing harm. The pack should have appropriate temperature control and sufficient padding to protect the skin. It should be user-friendly, with clear instructions, easy handling, and convenient portability. Additionally, the pack should be easy to clean and store. By considering these criteria, one can determine whether a hot or cold pack meets the requirements for effective, safe, and easy pain management.

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First, we write the reaction and balance it:

HNO2 (aq) + NH3 (aq) = NH4+ + NO2- (Balanced)

Data:

50 mL of 0.2 M HNO2

50 mL of 0.2 M NH3

In total, we have 100 mL, therefore, this solution between HNO2 and NH3 will be diluted in half. I mean: The concentration of HNO2 and NH3 will be 0.10 M

HNO2 (aq) + NH3 (aq) = NH4+ + NO2-

Initial 0.10 M 0.10 M 0 0

reacts -x -x +x +x

Equilibrium 0.10-x 0.10-x +x +x

Now, we write Kc:

Values of x:

For 1) x = 0.0999

For 2)x = 0.1001

We choose number 1) x = 0.0999

Number 2 gives us a value higher than the initial values of concentration

Therefore, concentration in equilibrium of NH3 = 0.10-x =0.10 - 0.0999 = 0.00010M

Answer: A. 0.00010M

Answer:

This is a single replacement reaction because I replaces Br.

Answer: This reaction can'toccur

Explanation

Iodine can't displace Bromine from its compound been less reactive than Br

The vertebrae in the human spinal column are classified as irregular bones. Option B is correct.

Irregular bones have complex shapes that do not fit into other bone classification categories. The vertebrae are irregular because they have a unique structure and shape that allows them to interlock and articulate with each other to form the spinal column.

The spinal column is divided into different regions, including the cervical, thoracic, lumbar, sacral, and coccygeal regions, and each region has a distinct number of vertebrae with specific characteristics. The vertebrae consist of a body, vertebral arch, and various processes for muscle and ligament attachment.

The spinal cord runs through a central canal in the vertebral arch, and nerves branch out between the vertebrae to various parts of the body. Overall, the irregular shape of the vertebrae is critical for providing flexibility, support, and protection to the spinal cord and the body. Option B is correct.

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The flame  test colors of metal ions are based on atomic emission spectra,  the atom move from a lower energy level to a higher energy level. that's why  metal ions produce the color.

A quantum mechanical system or particle that is bound(that is, confined spatially) can only take on certain discrete values of energy, called energy levels.

When an atom absorbs radiation of a certain wavelength, the electrons contained in the atom move from a lower energy level to a higher energy level. Such a process is called absorption. When this excited electron returns to the ground state, it loses energy, especially color, depending on the frequency of the absorbed radiation. Such a process is called emission. Atoms have different energy levels, so levels closer to the nucleus have less energy than levels further away from the nucleus. That is, an electron moves from a lower energy level to a higher energy level by reaching a certain energy, and after being excited, emits light and returns from a higher energy level to a lower energy level.

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Answer:

Explanation:

The relative formular mass for Lithium Chloride is 42.5 This is the sum of the relative atomic masses of Lithium-7 and chlorine-35.5.