COMPARE AND CONTRAST
PROPANE AND HEXANE ...?

Lemon juice is classified as an acid because it contains citric acid and has a pH well below 7.

Lemon juice is an acid. This is because it contains citric acid, which is a compound found in citrus fruits such as lemons and limes. Acids have certain characteristics; they taste sour, can conduct electricity when dissolved in water, and react with metals to produce hydrogen gas. According to the Bronsted-Lowry theory, an acid is a proton donor. The pH scale is used to determine the acidity or basicity of a solution. A solution with a pH less than 7 is considered acidic. For example, in a laboratory setting when testing pH, wine, with a pH of approximately 3.0, is labeled as acidic, whereas pure water is neutral with a pH of 7 and milk of magnesia is basic with a pH of 10.5. Therefore, given that the pH of lemon juice is well below 7, we can conclusively identify it as an acidic substance.

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Answer:

A

Explanation:

Answer : The chemical symbol for the atom is Cu.

Explanation :

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

The atomic mass of lead (Pb) = 207.2 amu

The atomic mass of iron (Fe) = 55.9 amu

The atomic mass of europium (Eu) = 151.9 amu

The atomic mass of copper (Cu) = 63.5 amu

From this we conclude that the chemical symbol for the atom that has an average atomic mass of about 63.5 amu is copper (Cu).

Hence, the chemical symbol for the atom is Cu.

Carbon's ability to attract electrons is determined by its electronegativity, which is a measure of an atom's tendency to attract electrons towards itself in a chemical bond.

The ability of carbon to attract electrons is determined by its electronegativity. Electronegativity is a measure of an atom's tendency to attract electrons towards itself in a chemical bond. The more strongly an atom attracts electrons, the higher its electronegativity.

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Final answer:

People may use psychoactive drugs to escape an aversive state of consciousness or to seek pleasurable experiences. Consciousness can become a burden when individuals perceive themselves as not meeting their goals or being viewed negatively. Psychoactive substances can provide an escape or mimic natural states for therapeutic or recreational purposes.

Explanation:

The use of psychoactive substances can be motivated by a variety of factors. In some instances, consciousness can become burdensome or aversive, particularly when individuals are faced with the realization that they have not met their own goals or feel they are viewed negatively by others. In such cases, there may be a tendency to engage in behaviors that offer an escape from this state of consciousness. Psychoactive drugs can provide such an escape by altering one's perception and inducing different states of consciousness, allowing individuals to distance themselves from uncomfortable realities.

Moreover, some psychoactive drugs are used to mimic natural states of consciousness for therapeutic purposes. For example, sleeping pills are aimed at inducing drowsiness, and benzodiazepines are prescribed for relaxation. However, beyond medical use, people often seek recreational drugs to experience pleasurable states of consciousness or to escape the routine of normal consciousness.

The 80 ml solution has (.04)(80) ml of the medicine, or 3.3 ml of medicine.The pharmacist adds V ml of 7% solution, or .07V ml of medicine. The total amoune of medicine is (.07V + 3.2) mg. The total volume of solution is (V + 80) ml, so (.07V + 3.2) / (V + 80) = .05.

Solve for V.

V = 40 ml.

Answer:

All amino acids have a central carbon with four components attached to it. One of these components is called the R group.

Which statement best describes the R group?

The R group stabilizes the amino acid.

The R group is the same in all amino acids.

The R group helps the amino acid replicate.

The R group gives the amino acid unique characteristics.

Explanation:

Final answer:

The R-group, or side chain, is what gives each amino acid its unique characteristics by varying in size, polarity, and pH, thus affecting amino acid interactions and functions.

Explanation:

All amino acids have a central asymmetric carbon, also known as the α carbon, to which four different components are attached: an amino group (NH2), a carboxyl group (COOH), a hydrogen atom (H), and a variable R-group or side chain. The R-group is essential in determining the unique characteristics of each amino acid. With the exception of glycine, where the R-group is just a hydrogen atom, the R-groups vary among amino acids, affecting their size, polarity, and pH, which in turn dictate how the amino acids interact with each other and their environment.

Therefore, the correct description of the R-group is that it gives the amino acid unique characteristics; the R-group is not involved in replication, nor is it the same in all amino acids, nor does it solely stabilize the amino acid.

Final answer:

Hybrid cars do get better gas mileage in many cases, but it depends on various factors, so the answer is 'b) Sometime'. Factors like cold weather and individual needs can influence the suitability and efficiency of hybrid vehicles.

Explanation:

Hybrid cars sometimes get better gas mileage than cars with standard engines. The correct answer to the question is b) Sometime. Hybrids are designed to be more fuel efficient, offering better mileage per gallon of gas in many circumstances because they can utilize electric propulsion. However, the efficiency of a hybrid car can vary depending on driving conditions, the model of the car, and how the vehicle is driven.

During exceptionally cold weather, for example, all vehicles, including hybrids, might experience a decrease in fuel efficiency. Additionally, hybrid cars might not always be the best choice for everyone based on factors such as upfront costs, acceleration needs, or seating capacity requirements.

An example of an element with an electron distribution ending in s2p1 is Boron (B) situated in Period 2 of the Periodic Table. However, there isn't an element with an electron distribution ending in s2d2 as 'd' orbitals start filling from the 3rd energy level and in a sequence after 'p' orbitals.

In the field of Chemistry, the electron distribution of an element refers to how the electrons are arranged in various energy levels around the nucleus of an atom. Electron distributions are typically written as series of numbers and letters, each of which indicate the energy level, type of orbital, and number of electrons in that orbital, respectively.

For an element with an electron distribution ending in s2p1, we look in the second period of the Periodic Table. An example of such element is Boron (B). It has the electron configuration of 1s2 2s2 2p1.

As for an element with an electron distribution ending in s2d2, we cannot find one because 'd' orbitals begin filling only from the 3rd energy level or Period 4 of the Periodic Table and after 's' orbital is fully occupied by 2 electrons, it's followed by 'p' orbital and then 'd'. So, there is no suitable element with an electron configuration ending in s2d2.

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The answer is C 2,1,1,2

Final answer:

The most useful characteristic to classify igneous rocks as intrusive or extrusive is the texture, specifically the size of the mineral grains, with larger grains indicating slow cooling and an intrusive nature, and smaller grains indicating fast cooling and an extrusive origin.

Explanation:

To classify igneous rocks as either intrusive or extrusive, the most useful characteristic of the samples would be the texture, particularly the size of the mineral grains. Intrusive, or plutonic, rocks form from magma that cools slowly inside the Earth, resulting in larger mineral grains that can often be identified without magnification. In contrast, extrusive, or volcanic, rocks form from lava that cools quickly on the Earth's surface, producing smaller grains that are harder to identify without magnification.

Considering the composition, rocks like diorite are coarse-grained and thus would be classified as intrusive. A rock with similar composition but fine grain size, like andesite, would be considered extrusive. When observing igneous rocks, you could use this information alongside a classification chart of igneous rocks based on mineral content, as suggested in Figures 2.11 and 2.12 provided in the course material.

Additionally, by comparing the physical characteristics of the samples to those listed in a Rock and Mineral Guide, you will be able to confirm whether your findings regarding whether the rock is mafic, felsic, intermediate, or ultramafic are accurate and whether the texture of the rock indicates an intrusive or extrusive origin.

The most useful characteristic to classify igneous rocks as either intrusive or extrusive is the size of the mineral grains.

Igneous rocks are classified based on how they were formed. Intrusive igneous rocks, also known as plutonic rocks, form when magma cools and solidifies slowly beneath Earth's surface. This slow cooling process allows large mineral grains to form, resulting in a coarse-grained or phaneritic texture. Examples of intrusive igneous rocks include granite and gabbro.

Extrusive igneous rocks, on the other hand, form when lava cools and solidifies rapidly at or near Earth's surface. The rapid cooling does not allow enough time for large mineral grains to form, resulting in a fine-grained or aphanitic texture, or sometimes a glassy texture if the cooling is extremely rapid. Examples of extrusive igneous rocks include basalt and rhyolite.

Answer: The given statement is false.

Explanation:

In gases, the molecules are held by weak Vander waal forces. Hence, they have high kinetic energy due to which they move rapidly from one place to another leading to more number of collisions.

Hence, gases are able to expand more rapidly as compared to liquids.

Therefore, gases will expand to fill their container.

Whereas in liquids, the molecules are held by more strong intermolecular forces of attraction as compared to gases. Due to which they are not able to move much more freely.

Hence, liquids do not expand to fill their container.

Thus, we can conclude that the statement gases and liquids will both expand to fill their container, is false.

True, Gases and liquids both expand to fill their containers,

The statement that gases and liquids will both expand to fill their container is true. Gases, such as air, are composed mostly of empty space with molecules moving freely and constantly, causing a quantity of gas to expand to fill the entire container it's placed in, taking on the shape and volume of the container. Liquids, on the other hand, will also assume the shape of the part of the container they occupy, but have a definite volume and are not compressible like gases. This is also reflected in the fact that gases can be significantly compressed and have larger coefficients of volume expansion compared to liquids and solids, allowing them to expand and contract rapidly with temperature changes.

Final answer:

The earliest ideas about atoms were speculative and lacked scientific evidence, while the later work of scientists involved experimentation and observation.

Explanation:

The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers, Leucippus and Democritus, who argued that all matter was composed of small, finite particles called atoms. They thought of atoms as moving particles that differed in shape and size and could join together. However, these early ideas about atoms were philosophical and were not backed by experimental evidence or scientific methods.

In contrast, the later work of scientists such as John Dalton, Amadeo Avogadro, and Dmitri Mendeleev involved rigorous experimentation and observation. Dalton introduced the concept of atomic theory, which proposed that atoms are indivisible and combine in specific ratios to form compounds. Avogadro's work on the relationship between the number of particles and the volume of gases contributed to the development of Avogadro's law. Mendeleev's periodic table of elements provided a systematic organization of elements based on their atomic properties.

Overall, while the earliest ideas about atoms were speculative and lacked scientific evidence, the later work of scientists involved experimentation and observation, leading to the development of atomic theories and our current understanding of atoms.

Final answer:

The earliest ideas about atoms by ancient philosophers were speculative and not based on experimentation. Later scientific work incorporated experimentation and more sophisticated tools, leading to a deeper understanding and concrete evidence of atomic structure, including the nuclear model, subatomic particles, and the periodic table.

Explanation:

The development of the earliest idea about atoms by ancient Greek philosophers such as Leucippus and Democritus was based on philosophical reasoning rather than empirical evidence, as they theorized matter to be made up of indivisible particles they called atomos. Centuries later, scientists like John Dalton, Amadeo Avogadro, Dmitri Mendeleev, and Ernest Rutherford built upon these early ideas, developing a more sophisticated understanding of atoms through systematic experimentation and observation. Their work made use of developing technologies to confirm the existence of atoms, leading to discoveries such as the nuclear model of the atom and the periodic table.

The early Greek concept held that matter could not be subdivided infinitely and proposed atoms as the smallest units, different in shape and size, and always in motion. Later scientific work, however, provided concrete evidence and expanded on these notions by finding atoms could indeed be split, revealing subatomic structures, conducting experiments to confirm their theories, and establishing a comprehensive organization of elements based on atomic weight and properties.

The solubility of substances in water can be predicted using solubility rules: NaNO3 is soluble, AgBr and Ag2CO3 are insoluble, NH4OH and NH4Br are soluble, BaSO4, Pb(OH)2, and PbCO3 are insoluble.

To predict the solubility of the following substances in water we need to consider general solubility rules:

Final answer:

Solubility in water can be predicted using solubility rules. NaNO3 and NH4OH (or NH3 in water) are soluble, while AgBr, Ag2CO3, BaSO4, Pb(OH)2, and PbCO3 are generally insoluble.

Explanation:

To predict the solubility of substances in water, we refer to solubility rules and know that:

Compounds containing the nitrate ion (NO3-) such as NaNO3 are generally soluble.

Halides, except those of silver, mercury, and lead, are typically soluble, which means AgBr would be insoluble.

Compounds with the ammonium ion (NH4+) like NH4OH (ammonium hydroxide, which is actually NH3 in water) are soluble.

Most compounds containing the carbonate ion (CO3 2-) are insoluble, so Ag2CO3 is likely insoluble.

As with NH4OH, NH4Br contains the ammonium ion, hence it is soluble.

Sulfates are generally soluble but there are exceptions like barium sulfate, thus BaSO4 is insoluble.

Hydroxides are usually insoluble except for those of alkali metals and a few others, indicating that Pb(OH)2 will be insoluble in water.

Lead carbonate, PbCO3, would follow the solubility trend of carbonates and be considered insoluble.

In a reaction to produce sulfuric acid with a theoretical yield of 300.g and an actual yield of 280.g, the percent yield is 93.33%.

Percent Yield Calculation:

The answer is:

-Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.

-and Cellular respiration is the process of breaking down food such as glucose into carbon dioxide and oxygen. During the process, cellular respiration also releases energy in the form of ATP (adenosine triphosphate) for use by all energy consuming activities of the cell. It is found in the simultaneous process of Glycolysis and Kreb’s cycle. Glycolysis is the breakdown of glucose to two pyruvic acids. These two pyruvic acids will be used for the production of carbon dioxide and water in Krebs cycle.

Answer:

The correct answer is; 'The carbon sample would have three times the mass of the helium sample'.

Explanation:

Number of moles of carbon = 3.0 moles

Mass of 3 moles of carbon ,m= [tex]3 moles\times 12 g/mol = 36 g[/tex]

Number of moles of helium = 3.0 moles

Mass of 3 moles of helium,m' = [tex]3 moles\times 4 g/mol = 12 g[/tex]

Grams of carbon do we have more than grams of helium:

Mass of carbon > Mass of helium

[tex]\frac{m}{m'}=\frac{36 g}{12 g}=3[/tex]

m =  3m'

The carbon sample would have three times the mass of the helium sample

Answer:

B. salt water

Explanation:

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Answer:

1) pH = 4.51

2) pH = 4.87.

3) pH = 12.32

Explanation:

1) the Ka of propanoic acid is 1.34 X 10⁻⁵

Therefore pKa = 4.87

When we add 5 mL of 0.300 M NaOH the moles of base added is

moles = molarity X volume

moles = 0.300 X 5mL = 1.5 mmoles

moles of acid present = molarity X volume = 0.165 X 30.0 = 4.95 mmoles

on addition of 1.5 mmoles of base the moles of acid neutralized = 1.5mmole

This will result in formation of salt of the acid

the moles of salt formed = 1.5 mmoles

the moles of acid left = 4.95 - 1.5 = 3.45 mmol

this acid and its salt mixture results in formation of a buffer

the pH of buffer is calculated as:

pH = pKa + log [salt] / [acid]

pH = 4.87 + log [1.5/3.45] = 4.51

2) at half equivalence point the moles of acid becomes equal to moles of salt formed thus the pH of solution will become equal to the pKa of acid

pH = 4.87.

3) the moles of based added due to addition of 20.0 mL = molarity X volume

moles = 0.300 X 20 = 6mmol

This will completely neutralize the acid (4.95 mmol)

after neutralization the moles of base left = 6-4.95 = 1.05 mmol

Total volume of solution  = volume of acid + volume of base =30+20=50

concentration of hydroxide ion (due to excess base) = [tex]\frac{mmoles}{volume(mL)}[/tex]

[OH⁻]=0.021

pOH = -log[OH⁻]=1.68

pH = 14-pOH = 12.32

The titration results in the neutralization reaction with the addition of acid to the base. The pH with the addition of 5 ml of the base is 4.51. The pH at half equivalence is 4.87. The pH with 20 mL base is 12.32.

The pH can be defined as the concentration of hydrogen ions in the solution.

The moles of acid in the solution is:

[tex]\rm Moles=Molarity\;\times\;Volume(L)[/tex]

[tex]\rm Moles\;propionic \;acid=0.165\;\times\;0.03\;L\\Moles\;propionic\;acid=4.95\;mmoles[/tex]

The moles of base, KOH in 5 mL will be:

[tex]\rm Moles\;KOH=0.3\;M\;\times\;0.0005\;L\\Moles\;KOH=1.5\;mmoles[/tex]

The moles of acid left after neutralization is:

[tex]\rm Moles\;acid\;left=4.95-1.15\;mmoles\\Moles\;acid\;left=3.45\;mmoles[/tex]

The pH of the solution can be given as:

[tex]\rm pH =pKa+log\dfrac{salt}{acid}\\ pH=4.87+log\dfrac{1.5}{3.45}\\pH=4.51[/tex]

The pH at half equivalence point will be equivalent to the pKa, as the moles of salt is equivalent to the moles of acid.

Thus, the pH at the half equivalence point is 4.87.

The moles of base added is:

[tex]\rm Moles\;KOH=0.3\;M\;\times\;0.02\;L\\Moles\;KOH=6\;mmol[/tex]

The acid will be completely neutralized with the formation of 4.95 mmol of salt. The base left in the reaction will be:

[tex]\rm Moles\;KOH\;left=6\;mmol-4.95\;mmol\\Moles\;KOH\;left=1.05\;mmol[/tex]

The final volume of the solution will be 50 mL. The molarity of the KOH in the solution will be:

[tex]\rm Molariy\;OH^-=\dfrac{mmoles}{volume}\\ Molarity\;OH^-=\dfrac{1.05}{50} \\Molarity\;OH^-=0.021[/tex]

The pOH of the solution is given as:

[tex]\rm pOH=-log[OH^-]\\pOH=-log(0.021)\\pOH=1.68[/tex]

The pH of the solution will be:

[tex]\rm pH=14-pOH\\pH=14-1.68\\pH=12.32[/tex]

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Final answer:

A radioactive sample emits the most decay particles at the start of its decay process, decreasing as per its half-life. This knowledge is crucial for safety and effective use of radioactive materials in biomedical applications and understanding radiation exposure risks.

Explanation:

A radioactive sample emits the largest number of decay particles at the beginning of its decay process, when it has the largest number of undecayed nuclei available for decay. This number decreases over time as the sample undergoes radioactive decay, conforming to its half-life, which is the time taken for half of the sample's atoms to decay. This concept is essential in understanding the safety protocols for handling radioactive materials, as well as their applications in various fields such as biomedical physics, where radioactive materials are used in diagnostic and therapeutic procedures.

In biomedical physics applications, understanding the decay process is important for determining the optimal time for imaging or treatment when using a substance that decays into a different nuclide, which itself decays. The time when the population of the daughter nuclide B is largest is crucial for making sure the procedure is most effective. For instance, in treatments involving the radioactive isotope I-131, the gamma rays emitted are detected because they penetrate the body and can be measured externally, providing valuable diagnostic information without causing excessive damage to tissues.

In comparing the radiation exposure of different radioactive substances, we take into account their half-life and decay products. For example, Fred holding a substance with a half-life of 1000 years receives a vastly smaller dose in a second than Ginger holding a substance with a half-life of one minute, due to the larger number of decays (and consequently, radiations) occurring in Ginger's sample over the same period of time.

Answer:

    ATP =  Adenine + Ribose sugar + Triphosphates

Explanation:

Adenosine tri phosphate is made up of adenine , ribose sugar and three phosphate which is soluble in water and has a high energy content. Energy is produced by breaking bonds between phosphates.

Then answer is =  Base+Sugar+Three phosphates.

Answer: Option (C) is the correct answer.

Explanation:

Atoms which have high difference in electronegativity will be more polar in nature.

This is because more electronegative atom will attract the electrons more towards itself. And, this causes development of a partial negative charge on the electronrgative and a partial positive charge will develop on the atom from which electrons have been withdrawn.

For example, N-H will be polar in nature because of the difference in electronegativity of N and H.

Whereas Al-Si, S-Cl, and C-N are all non-metals with not much difference in electronegativity.

Thus, we can conclude that N-H pair of atoms has the greatest polarity.