By studying fossils, scientists have learned that
A.
both animals and plants have changed over time.
B.
animals have changed over time, but plants have not.
C.
plants have changed over time, but animals have not.
D.
neither animals nor plants have changed over time.

Answer:

The compound has 187.5 g. of Carbon

Explanation:

If the 100% of the compound is 250 gr, then you can calculate the 75% of it by multiplying:

Amount of Carbon = (75%) 250 g.

75%= 0.75

250  (0.75)

= 187.5 g.

When the diffracting crystal is ammonium dihydrogen phosphate, the goniometer setting needed to observe the L1 (n=1) lines for Br at = 8.126 is 2 = 2 x 32.6° = 65.2°.

A goniometer is a tool that can be used to rotate an object to a specific position or measure an angle. The former description more accurately describes orthopedics. Goniometry is the art and science of determining the joint ranges in each plane of the joint.

Using Bragg's Law, we can determine the goniometer setting for seeing the L1 (n=1) lines for Br at = 8.126:

nλ = 2d sinθ

For the Lβ1 (n=1) lines for Br at λ = 8.126Å, we have:

n = 1

λ = 8.126Å

a) d = 4.404 for ethylenediamine d-tartrate.

When we apply the values to Bragg's Law, we obtain:

1 x 8.126Å = 2 x 4.404Å x sinθ

sinθ = (1 x 8.126Å) / (2 x 4.404Å) = 0.923

θ = sin(0.923) = 68.9°

b) d = 7.549 for ammonium dihydrogen phosphate. Å

When we apply the values to Bragg's Law, we obtain:

1 x 8.126Å = 2 x 7.549Å x sinθ

sinθ = (1 x 8.126Å) / (2 x 7.549Å) = 0.539

θ = sin(0.539) = 32.6°

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The mass of lead (IV) sulfite containing 7.25 x 10^23 sulfur atoms is 3.36 x 10^26 g.

What is Mass?

Mass is a fundamental physical property of matter that describes the amount of substance in an object or system. It is commonly measured in units of kilograms (kg) or grams (g). Mass is often confused with weight, but they are not the same thing. Weight is the force exerted on an object due to gravity, while mass is the amount of matter in the object.

To solve this problem, we need to first find the molar mass of lead (IV) sulfite (Pb(SO3)2), which contains one lead atom, two sulfur atoms, and six oxygen atoms per formula unit.

The molar mass of lead (IV) sulfite can be calculated as follows:

Pb(SO3)2: 1 x molar mass of Pb + 2 x molar mass of S + 6 x molar mass of O

= 1 x 207.2 g/mol + 2 x 32.1 g/mol + 6 x 16.0 g/mol

= 927.0 g/mol

Next, we can use the Avogadro's number to convert the given number of sulfur atoms to the corresponding number of moles of lead (IV) sulfite:

7.25 x 10^23 sulfur atoms x 1 mole Pb(SO3)2/2 moles S = 3.63 x 10^23 moles Pb(SO3)2

Finally, we can use the molar mass of lead (IV) sulfite to convert the number of moles to mass:

3.63 x 10^23 moles Pb(SO3)2 x 927.0 g/mol = 3.36 x 10^26 g

Therefore, the mass of lead (IV) sulfite containing 7.25 x 10^23 sulfur atoms is 3.36 x 10^26 g.

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The mass of water driven off during popping can be calculated by subtracting the mass of the popped corn and the dish from the mass of the dish and kernel before heating.

Heating is the process of increasing the temperature of a substance or object, typically using an external energy source such as heat, radiation, or electrical current. The heat energy is transferred to the object or substance, causing its particles to vibrate and move faster, which results in an increase in temperature. Heating is commonly used in a wide range of applications, including cooking, chemical reactions, industrial processes, and space heating.

Cooking is the process of preparing food by applying heat, typically using methods such as baking, roasting, grilling, frying, boiling, simmering, steaming, or microwaving. The aim of cooking is to make food more palatable and easier to digest, as well as to kill harmful bacteria and other microorganisms that may be present in raw food. Cooking can also enhance the nutritional value of some foods by making certain nutrients more bioavailable.

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Answer:2.5 g CuSO4⋅5H2O.

Explanation:

You're dealing with copper(II) sulfate pentahydrate,

CuSO

4

⋅

5

H

2

O

, an ionic compound that contains water of crystallization in its structure.

More specifically, you have five moles of water of crystallization for every one mole of anhydrous copper(II) sulfate. This means that you're going to have to account for the mass of this water of crystallization in your calculations.

Now, you need your target solution to have a molarity of

0.10 M

and a volume of

100. mL

. Since molarity is defined as moles of solute per liter of solution, you can say that the target solution must contain

Answer:

sound waves

Explanation:

hope this helps

Answer: There are 3019.2 atoms of iron.

Answer:

Explanation:

Iron is a ductile, malleable, silver-white metallic element, scarcely known in a pure condition, but much used in its crude or impure carbon-containing forms for making tools, implements, machinery, etc. Symbol: Fe; atomic weight: 55.847; atomic number: 26; specific gravity 7.86 at 20°C.

1 mol contains [tex]=6.02\times10^{23}[/tex] particles, whether it be atoms, ions, molecules or whatever (Avogadro's number).

So you just divide:

[tex]\frac{2.96\times10^{20}}{6.02\times10^{23}}[/tex] = = 4.9169435215947 × 10^-4

Taking into account the definition of dilution, if chemist must dilute 93.1 mL of 7.79 of uM aqueous mercury (I) chloride solution until the concentration falls to 3.00 uM, the final volume is 0.24175 L.

Dilution is a procedure by which the concentration of a solution is lowered, usually with the addition of a diluent.

In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume of the solution increases.

A dilution is mathematically expressed as:

Ci×Vi = Cf×Vf

where

In this case, you know:

Replacing in the definition of dilution:

7.79 uM× 93.1 mL= 3 uM× Vf

Solving:

(7.79 uM× 93.1 mL)÷ 3 uM= Vf

241.75 mL= 0.24175 L = Vf (being 1000 mL= 1 L)

In summary, the final volume is 0.24175 L.

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Alkenes are described as being unsaturated hydrocarbons because they contain at least one carbon-carbon double bond, which is not completely saturated with hydrogen atoms.

Atoms are the basic building blocks of all matter, and are the smallest particles known to exist. Atoms are made up of protons, neutrons and electrons. Protons are positively charged particles located in the nucleus of the atom, while neutrons are neutral particles also located in the nucleus. Electrons are negatively charged particles that orbit the nucleus.

a) Alkenes are described as being unsaturated hydrocarbons because they contain at least one carbon-carbon double bond, which is not completely saturated with hydrogen atoms. The presence of the double bond creates a greater degree of unsaturation than single-bonded hydrocarbons, allowing them to form more chemical bonds and react with other molecules.

b) A carbon-carbon double bond forms when two carbon atoms share two pairs of electrons. The double bond is formed by overlapping the two sp2 hybrid orbitals on each carbon atom.

c) The reaction between ethene and hydrogen bromide (HBr) is an example of an electrophilic addition reaction. In this reaction, HBr acts as an electrophile, meaning it is attracted to the electrons in the double bond of the ethene molecule. The electrons from the double bond are shared between the two atoms in the HBr molecule, forming a covalent bond. This process is known as nucleophilic attack.

The reaction mechanism is shown below:

Step 1: Electrophilic attack of the hydrogen atoms of HBr to the electrons in the double bond of the ethene molecule.

HBr + Ethene → H-Br + Carbocation

Step 2: Nucleophilic attack of a bromide ion on the carbocation, forming a new covalent bond.

Br− + Carbocation → H-Br + Bromoethane

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Answer:

Transcribed Image Text: Rank the following substances in order of increasing acid strength. (1 as least and 4 as most in acid strength) ✓ H₂Se ✓ HBr HI ✓ AsH3 Expert Solution

Explanation:

HOPE IT HELPS!!

The major organic product of an SN2 substitution reaction is an alkene, which may be either in retention or inversion of configuration relative to the original substrate.

The reaction you are asking about is an SN2 substitution reaction, in which a nucleophile (Nu) displaces a leaving group (LG) from a molecule with an alkyl halide substrate. The major organic product of this reaction will be an alkene, which has the same carbon chain as the alkyl halide substrate. Depending on the relative configuration of the substrate, the alkene product may be the same as the original substrate (retention) or have its configuration inverted (inversion). If stereochemistry is relevant to the question, then it should be specified in the answer.

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The mass of the gas in the preceding problem is 30.1 g.

To find the molar mass or molecular weight of the gas, we'll use the Ideal Gas Law, which is given as: PV = nRT where, P = pressure of the gas V = volume of the gas n = number of moles of the gas R = ideal gas constant T = temperature of the gas We can rewrite the Ideal Gas Law as: M = (mRT) / (PV) where, M = molar mass or molecular weight of the gas m = mass of the gas R = ideal gas constant T = temperature of the gas P = pressure of the gas V = volume of the gas Substituting the given values in the above formula, we get: M = (30.1 g x 0.0821 L atm mol-1 K-1 x 273 K) / (1 atm x 0.228 L)≈ 29.1 g/mol Hence, the molar mass or molecular weight of the gas is approximately 29.1 g/mol.

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The enthalpy change of the reaction is 7,227 kJ/mol and the reaction is endothermic.

To calculate the enthalpy change of the reaction using bond enthalpies, we need to find the total energy required to break the bonds in the reactants and the energy released when new bonds are formed in the products.

The enthalpy change of the reaction can be calculated as follows:

Reactants:

1 mole of C2H6O requires breaking 2 C-H bonds and 1 C-O bond.

3 moles of O2 requires breaking 3 O=O bonds.

Products:

2 moles of CO2 releases forming 4 C=O bonds.

3 moles of H2O releases forming 6 O-H bonds.

The bond enthalpies for the relevant bonds are:

The enthalpy change for the reaction is:

(2 × 745 kJ/mol) + (3 × 6 × 467 kJ/mol) - (2 × 413 kJ/mol) - (1 × 358 kJ/mol) - (3 × 495 kJ/mol) = 7,227 kJ/mol

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Answer: Approximately 267.5 Kelvin

Explanation:

To find the temperature of a sample of neon with an rms speed of 500.0 m/s, we can use the following formula that relates the root mean square (rms) speed of gas molecules to their temperature:

v_rms = sqrt((3kT) / m)

where v_rms is the rms speed of the gas molecules, k is the Boltzmann constant, T is the temperature in Kelvin, and m is the mass of a single gas molecule.

For neon, the mass of a single molecule is approximately 20.18 atomic mass units (u), which is equivalent to 3.35 x 10^-26 kg.

Substituting the given values into the formula, we get:

500.0 m/s = sqrt((3kT) / (3.35 x 10^-26 kg))

Solving for T, we get:

T = (m / (3k)) * v_rms^2

T = (3.35 x 10^-26 kg / (3 * 1.38 x 10^-23 J/K)) * (500.0 m/s)^2

T ≈ 267.5 K

Therefore, the temperature of the neon sample with an rms speed of 500.0 m/s is approximately 267.5 Kelvin.

To produce ammonia (NH₃) from thin air, the reactants required are N₂ and H₂. So the correct option is b).

Ammonia is one of the most abundantly produced inorganic chemicals. In 2016, there are a number of large ammonia plants around the world that produced a total of 144 million tons of nitrogen (equivalent to 175 million tons of ammonia). That number will rise to 235 million tonnes of ammonia in 2021. China produced 31.9% of its global production, followed by Russia at 8.7%, India at 7.5% and the United States at 7.1%. More than 80% of the ammonia produced is used as fertilizer for agricultural crops.

Today, most ammonia is produced on a large scale using the Haber process, with capacities of up to 3,300 tons per day. Gases N₂ and H₂ are reacted at a pressure of 200 bar. A typical modern ammonia production plant first converts natural gas, LPG, or petroleum gas into gaseous hydrogen. The process of producing hydrogen from hydrocarbons is known as steam reforming. Hydrogen then combines with nitrogen to produce ammonia by the Haber-Bosch process.

One way to produce green ammonia is to use hydrogen from the electrolysis of water and nitrogen separated from air. These are fed into the Haber Process (aka Haber-Bosch), all of which produce sustainable power.

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Answer:

0.8 L

Explanation:

The volume of the stock solution needed to make 2.0 L of 0.20M MgSO4 is 0.8 L.

Answer:

50 ml

Explanation:

n = moles

c = concentration

v = volume

n = c × v

HCl + NaOH --> NaCl + H2O

HCl:

50 ml = 50 cm³ = 0.05 dm³

n = 0.05 × 0.1

n = 0.005

Ratio of HCl to NaOH:

HCl : NaOH

Based on reaction equation:

1 : 1

0.005 : x

x = 0.005

NaOH:

0.005 = 0.1 × v

v = 0.05

0.05 dm³ = 50 cm³ = 50 ml

In geologic strontium isotopic analysis by ICP-MS, the use of a collision cell with CH3F helps reduce isobaric interference between 87Rb+ and 87Sr+.

The ability to quantify each element's distinct isotopes makes ICP-MS useful for laboratories looking to compare the ratio of two isotopes of an element or one particular isotope.

Only a few elements cannot be measured by ICP-MS: F and Ne (which cannot be ionized in an argon plasma), Ar, N, and O (which are present at high levels in the plasma and air), and H and He (which are below the mass range of the mass spectrometer).

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This lone pair makes the molecule polar. H2O also has a dipole moment due to the bent structure and the electronegativity difference between hydrogen and oxygen. Therefore, the correct answer is option d. None of the above.

The molecule that does not have a dipole moment is CO2. A dipole moment is a measurement of the separation of two opposite electrical charges in a molecule. The molecule is polar when there is a dipole moment. CO2 is a linear molecule that consists of two polar C-O bonds that are arranged in a straight line. However, the two dipole moments are opposite and equal, which means that they cancel each other out. Thus, the molecule is not polar, and there is no dipole moment for CO2. On the other hand, both NH3 and H2O have a dipole moment. NH3 has a trigonal pyramidal structure that has a lone pair of electrons on the nitrogen atom.

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Answer:

1) b. Caesium

2) b. Indium

The distillation temperature would be > 80 degrees. The composition of the few drops of the distillate would be: 40℅ benzene and 60℅

Distillation is a technique used to separate the components of a combination made up of two liquids that mix well. The liquid mixture is boiled, evaporated, condensed, and isolated using this technique.

The boiling point of a liquid is the temperature at which the vapor pressure of the liquid, a pure compound, or a combination equals 1 atm.

We are aware that pure benzene has a boiling point of 80 oC.

Pure toluene has a boiling point of 106 oC.

As benzene has a lower boiling point than toluene, it distills first. Thus, the distillation temperature is greater than 80 oC.

The mixture contains 40 percent benzene and 60 percent toluene by percentage.

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This claim is untrue. A developmental mismatch between the maturation of various brain systems, particularly the prefrontal cortex, and the limbic system, is a hallmark of the teenage brain.

The limbic system, which is engaged in emotion regulation and reward processing, develops earlier than the prefrontal cortex, which is in charge of impulse control, decision-making, and other executive processes.

Teenagers may therefore be more likely to participate in a dangerous activity and seek out unique experiences, but they may also have trouble controlling their impulses and making reasoned decisions.

The development of the brain is a complicated and ongoing process, and individual variations in neural maturation and life events can also have an impact on teenage behavior and decision-making.

However, there is no typical pattern of adolescent behavior or brain function due to individual variances and ongoing brain development.

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Answer:

We can use the equation for the dissociation of a weak acid:

HA + H2O ⇌ H3O+ + A-

The equilibrium constant expression (Ka) is:

Ka = [H3O+][A-]/[HA]

We are given the initial concentration of the acid (0.49 M) and the concentration of the acid at equilibrium (0.36 M). We can use the concentration change to determine the concentration of H3O+ and A- at equilibrium.

Let x be the concentration of H3O+ and A- at equilibrium. Then, at equilibrium, the concentration of HA is (0.49 - x).

We know that the equilibrium concentration of HA is 0.36 M, so we can set up the following equation:

0.36 = 0.49 - x

Solving for x, we get:

x = 0.49 - 0.36 = 0.13 M

Now we can plug in the equilibrium concentrations into the Ka expression:

Ka = [H3O+][A-]/[HA] = (0.13)(0.13)/(0.36) = 0.0481

Rounding to two significant figures, Ka for this acid is 0.048.

The equilibrium constant of an acid's dissociation reaction is known as the acid dissociation constant, or Ka. The strength of an acid in a solution is numerically represented by this equilibrium constant. Here the value of Ka is 0.0481.

The difference between strong and weak acids is determined by the acid dissociation constant (Ka). As Ka rises, the acid dissociates more. Therefore, strong acids must dissociate more in water. On the other hand, a weak acid has a lower propensity to ionise and release a hydrogen ion, resulting in a less acidic solution.

Here the dissociation constant Ka = [H₃O⁺][A⁻]/[HA]

Let x be the concentration of H₃O⁺ and A⁻ at equilibrium. Then, at equilibrium, the concentration of HA is (0.49 - x). We know that the equilibrium concentration of HA is 0.36 M, so we can set up the following equation:

0.36 = 0.49 - x

Solving for x, we get:

x = 0.49 - 0.36 = 0.13 M

Now we can plug in the equilibrium concentrations into the Ka expression:

Ka = [H₃O⁺][A⁻]/[HA] = (0.13)(0.13)/(0.36) = 0.0481

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Under specific temperature and pressure conditions, a gas acts as an ideal gas. Particularly, the optimal conditions for the petrol' behaviour are low pressure and high temperature.

An ideal gas is a hypothetical gas made up of numerous tiny particles moving randomly all the time. Intermolecular forces, molecular size, and volume are all presumptions that apply to ideal gases. Additionally, it is presummated that they collide in completely elastic collisions in which there is no kinetic energy loss. The ideal gas law, PV=nRT, which has P as the pressure, V as the volume, n as the number of moles, R as the gas constant, and T as the temperature, can be used to describe the behaviour of an ideal gas. This law offers a helpful model for how many actual gases behave when exposed to situations like high temperatures and low pressures.

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Answer: 9084355.951 L  if need in correct sig figs answer is

9.08 X 10^6 L

Explanation:

Ideal gas law  PV=nRT  = V=nrt/P

R= 62.44

n=0.511

T= 513

P= 555

V= 0.511 X 62.44 X 513 / 555

DNA synthesis requires a source of energy, which is provided by ATP. This source of energy is required to drive the formation of the phosphodiester bonds between nucleotides.

Solution contains DNA polymerase and the Mg salts of dATP; dGTP: dCTP; and TTP. When added l0 aliquots of the solution, DNA synthesis occurs in the following DNA molecule. The double-stranded linear molecule of IOOD nucleotide pairs with I free 3 ~OH group at each end would lead to DNA synthesis.

The reasons why the DNA molecule you selected would lead to DNA synthesis are given below:

DNA polymerase enzymes add nucleotides only to a 3-OH end of a pre-existing nucleic acid strand, extending the 3' end of the newly forming strand in a 5' to 3' direction. DNA synthesis proceeds only in a 5' to 3' direction. Double-stranded DNA is required for the formation of new double-stranded DNA. When DNA polymerase is bound to a single-stranded template, it will extend a complementary strand in a 5' to 3' direction. Both strands of the double-stranded DNA molecule serve as templates for DNA synthesis because they have the available template strand. Primer with a free 3' OH group is required to begin the synthesis of a new DNA strand.

DNA polymerase adds nucleotides to the 3' OH group of the primer. DNA synthesis requires a source of energy, which is provided by ATP. This source of energy is required to drive the formation of the phosphodiester bonds between nucleotides.

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At has a higher initial ionisation energy than Br, while Br has a bigger atomic radius. Se has a bigger atomic radius than Br, and Br has a higher initial ionisation energy than Se.

The most loosely bound electron is further from the nucleus and thus easier to remove in bigger atoms. Hence, the ionisation energy should decrease as size (atomic radius) increases.

This is because the outer electrons aren't bound as strongly because they are farther from the nucleus.

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