Examkin

Physical Science

229 soru

Tüm türler229Çoktan seçmeli117Sayısal30Eşleştirme54Sıralama17Boşluk doldurma11
Soru 201Soru →

A neutral phosphorus atom contains 1515 protons and 1616 neutrons. If this atom gains 33 electrons to form a stable phosphide ion, what is the mass number of the resulting ion?

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Cevap: 31

Cevap

The mass number of the resulting phosphide ion is 3131.
The mass number (AA) is defined as the total number of protons and neutrons located in the nucleus (15+16=3115 + 16 = 31). When an atom gains or loses electrons, it forms an ion with an electric charge, but the contents of the nucleus remain unchanged.

Adım Adım Çözüm

1
Identify the components that determine the mass number of an atom or ion.
Mass number (AA) is calculated as the sum of protons (ZZ) and neutrons (NN).
Electrons have negligible mass relative to nucleons and reside outside the nucleus, so they are not included in the mass number.
2
Calculate the mass number using the given proton and neutron counts.
A=15+16=31A = 15 + 16 = 31
Adding 1515 protons and 1616 neutrons yields the total number of nucleons in the nucleus.
3
Evaluate the effect of gaining 33 electrons on the mass number.
The mass number remains 3131.
Gaining electrons changes only the net electric charge from 00 to −3-3, leaving the nucleus and mass number unaltered.

Anahtar Kavram

The mass number of an atom or ion is strictly the sum of its protons and neutrons (A=Z+NA = Z + N) and does not change during ionization.
Tahmini Süre:45s
Soru 202Soru →

Match each chemical species with its correct composition of protons, neutrons, and electrons.

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Öğeler

Neutral Carbon-12 atom (612C^{12}_{6}\text{C})
Sodium ion (1123Na+^{23}_{11}\text{Na}^{+})
Fluoride ion (919F−^{19}_{9}\text{F}^{-})
Neutral Neon-20 atom (1020Ne^{20}_{10}\text{Ne})

Eşleşmeler

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Cevap

Neutral Carbon-12 matches 6 protons, 6 neutrons, and 6 electrons; Sodium ion (+1) matches 11 protons, 12 neutrons, and 10 electrons; Fluoride ion (-1) matches 9 protons, 10 neutrons, and 10 electrons; Neutral Neon-20 matches 10 protons, 10 neutrons, and 10 electrons.
Each species is correctly matched by identifying protons from the atomic number (ZZ), computing neutrons by subtracting the atomic number from the mass number (A−ZA - Z), and adjusting the electron count according to the ionic charge (e−=Z−chargee^- = Z - \text{charge}).

Adım Adım Çözüm

1
Determine the number of protons from the atomic number (ZZ) for each species.
Carbon has 66 protons, Sodium has 1111 protons, Fluorine has 99 protons, and Neon has 1010 protons.
The atomic number uniquely defines the identity of an element and equals the total proton count.
2
Calculate the number of neutrons using Neutrons=Mass Number (A)−Atomic Number (Z)\text{Neutrons} = \text{Mass Number } (A) - \text{Atomic Number } (Z).
Carbon-12 has 12−6=612 - 6 = 6 neutrons; Sodium-23 has 23−11=1223 - 11 = 12 neutrons; Fluorine-19 has 19−9=1019 - 9 = 10 neutrons; Neon-20 has 20−10=1020 - 10 = 10 neutrons.
Mass number is the sum of protons and neutrons in the nucleus.
3
Determine the electron count based on net charge using Electrons=Protons−Charge\text{Electrons} = \text{Protons} - \text{Charge}.
Neutral Carbon has 66 electrons; Na+\text{Na}^{+} has 11−(+1)=1011 - (+1) = 10 electrons; F−\text{F}^{-} has 9−(−1)=109 - (-1) = 10 electrons; neutral Neon has 1010 electrons.
Cations lose electrons to form positive charges, anions gain electrons to form negative charges, and neutral atoms have equal numbers of protons and electrons.

Anahtar Kavram

Subatomic particle calculations in neutral atoms and isoelectronic ions
Tahmini Süre:1m 0s
Soru 203Soru →

A monochromatic beam of light travels through air and enters a transparent block of crown glass. As the light wave enters the optically denser glass medium, what happens to its speed, wavelength, and frequency?

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Cevap: Its speed decreases and its wavelength decreases, while its frequency remains constant.

Cevap

Its speed decreases and its wavelength decreases, while its frequency remains constant.
When light transitions from air into a medium with a higher refractive index such as glass, its propagation speed decreases (v=c/nv = c/n). The frequency of the oscillation is an intrinsic property established by the wave source and remains invariant at the interface. By the wave relationship v=fλv = f\lambda, a reduction in wave velocity at constant frequency results in a proportional reduction in wavelength.

Adım Adım Çözüm

1
Determine the effect of the medium change on wave speed.
The speed of light decreases from c≈3.0×108 m/sc \approx 3.0 \times 10^8\text{ m/s} in air to approximately 2.0×108 m/s2.0 \times 10^8\text{ m/s} in crown glass (n≈1.52n \approx 1.52) based on v=cnv = \frac{c}{n}.
An increase in optical density (higher index of refraction) reduces the propagation speed of electromagnetic waves.
2
Determine the behavior of wave frequency across the medium boundary.
The frequency (ff) remains completely unchanged.
Wave frequency is set solely by the emitting source and is conserved across media boundaries because the number of wave cycles arriving per second must equal the number transmitted.
3
Apply the wave equation to determine the resulting change in wavelength.
The wavelength (λ\lambda) decreases proportionally with speed according to λ=vf\lambda = \frac{v}{f}.
With speed vv reduced and frequency ff constant, the spatial distance between consecutive crests must shorten.

Anahtar Kavram

Wave speed and wavelength changes during medium transition under constant frequency (v=fλv = f\lambda).
Tahmini Süre:45s
Soru 204Soru →

Electromagnetic waves span a wide range of frequencies, each exhibiting distinct physical properties and practical applications across technology and medicine. Match each type of electromagnetic radiation with its primary characteristic or practical use.

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Öğeler

Infrared Radiation
Ultraviolet Radiation
X-rays
Radio Waves

Eşleşmeler

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Cevap

Infrared Radiation matches thermal energy and thermal imaging; Ultraviolet Radiation matches vitamin D synthesis and sunburns; X-rays match skeletal medical imaging through soft tissue penetration; Radio Waves match broadcast transmissions and long-wavelength telecommunications.
Each type of electromagnetic radiation is characterized by distinct wavelength, frequency, and photon energy bands. Radio waves have the longest wavelengths and lowest energy, suitable for broadcasting; infrared radiation transfers thermal heat; ultraviolet radiation induces photochemical reactions in skin; and X-rays have sufficient penetration power to create shadow radiographs through soft tissue.

Adım Adım Çözüm

1
Identify the characteristic behavior and application of infrared radiation.
Infrared radiation is associated with molecular thermal vibration and heat emission, used in night-vision and thermal sensors.
Infrared photons are emitted by warm bodies and absorbed by matter as sensible heat.
2
Identify the biological effects and energy level of ultraviolet radiation.
Ultraviolet radiation carries higher photon energy than visible light, stimulating vitamin D synthesis in the skin but causing cellular damage leading to sunburns.
UV photon energy is sufficient to initiate chemical bond changes in biological tissue.
3
Identify the high-energy penetration characteristics of X-rays.
X-rays pass easily through soft tissues like muscle and skin but are blocked by dense bone structure.
High-frequency electromagnetic waves have high penetration power that is stopped predominantly by high-density matter.
4
Identify the fundamental wave traits of radio waves.
Radio waves possess the lowest frequencies and longest wavelengths, making them ideal for long-distance broadcast communication.
Long wavelengths diffract readily around terrain and experience low atmospheric absorption.

Anahtar Kavram

Electromagnetic Spectrum Characteristics and Applications
Tahmini Süre:1m 0s
Soru 205Soru →

An atom of potassium has a mass number of 3939 and contains 2020 neutrons in its nucleus. When this atom forms a stable potassium ion (K+K^+) by losing one electron, what is the total number of subatomic particles (protons, neutrons, and electrons) present in the ion?

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Cevap: 5757

Cevap

The potassium ion contains a total of 5757 subatomic particles.
The correct answer is 5757. The number of protons is found by subtracting the neutron count from the mass number (39−20=1939 - 20 = 19). Because the potassium ion carries a +1+1 charge (K+K^+), it has lost one electron, leaving 1818 electrons. Adding all subatomic constituents gives 19 protons+20 neutrons+18 electrons=57 total particles19\text{ protons} + 20\text{ neutrons} + 18\text{ electrons} = 57\text{ total particles}.

Adım Adım Çözüm

1
Calculate the number of protons in the potassium atom.
Protons = 39−20=1939 - 20 = 19
The mass number (AA) is the sum of protons (ZZ) and neutrons (NN), so Z=A−NZ = A - N.
2
Determine the number of electrons in the K+K^+ ion.
Electrons = 19−1=1819 - 1 = 18
A neutral potassium atom has 1919 electrons; forming a +1+1 cation requires losing 11 electron.
3
Sum the total number of protons, neutrons, and electrons.
Total particles = 19+20+18=5719 + 20 + 18 = 57
The question requests the combined count of all subatomic particles in the ion.

Anahtar Kavram

Subatomic particle calculations in atomic structure and ions
Tahmini Süre:1m 0s
Soru 206Soru →

An isotope of an alkaline earth metal located in Period 4 (Group 2) of the periodic table contains 2424 neutrons in its nucleus. What is the mass number of this neutral isotope?

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Cevap: 44

Cevap

44
An element in Group 2 and Period 4 of the periodic table is calcium (Ca\text{Ca}), which has an atomic number of 2020. This means every calcium atom contains 2020 protons in its nucleus. The mass number of an isotope is the total number of protons and neutrons combined: 20 protons+24 neutrons=4420\text{ protons} + 24\text{ neutrons} = 44.

Adım Adım Çözüm

1
Determine the atomic number of the element using its periodic table position.
Atomic number is 2020 (contains 2020 protons).
The alkaline earth metal (Group 2) in Period 4 is calcium (Ca\text{Ca}), which has an atomic number of 2020.
2
Calculate the mass number by summing the number of protons and neutrons.
Mass number=20+24=44\text{Mass number} = 20 + 24 = 44.
The mass number (AA) is defined as the total count of nucleons (protons plus neutrons) in the nucleus.

Anahtar Kavram

Determining mass number from periodic table position and subatomic particle counts
Tahmini Süre:1m 0s
Soru 207Soru →

An observer at a construction site watches a worker strike a steel pipe with a hammer and hears the sound transmitted through the pipe before hearing it through the open air. Which of the following best explains why sound travels faster through solid steel than through air?

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Cevap: The closely packed particles and high elasticity of solids allow vibrational energy to transfer more rapidly between molecules.

Cevap

Sound travels faster through solid steel than through air because the closely packed particles and high elasticity of solids allow mechanical vibrational energy to transfer more rapidly between molecules.
Sound is a mechanical wave that propagates through the physical displacement and elastic restoration of medium particles. In solids like steel, atoms are tightly bonded in a crystal lattice with high elastic modulus, enabling compressions and rarefactions to transfer rapidly from particle to particle. In contrast, gas molecules in air are widely spaced and require longer travel times between collisions, resulting in a much lower propagation speed.

Adım Adım Çözüm

1
Identify the nature of sound waves and the medium requirement
Sound is a mechanical wave that propagates via sequential collisions and oscillations of particles in a physical medium.
Understanding that mechanical waves rely on intermolecular interactions is necessary to evaluate the effect of the medium on wave speed.
2
Compare particle arrangement and elasticity between solids and gases
Molecules in steel are closely bound with high elastic modulus, whereas air molecules are widely separated with low elasticity.
Greater medium elasticity and density of packing directly increase the speed of acoustic transmission (v=E/ρv = \sqrt{E/\rho}).
3
Relate medium properties to wave speed differences
Sound travels at roughly 5960 m/s5{}960\text{ m/s} in steel compared to approximately 343 m/s343\text{ m/s} in air.
The rapid transfer of kinetic energy between adjacent atoms in the solid explains why the sound arrives first through the steel pipe.

Anahtar Kavram

Mechanical sound wave propagation speed depends on the elasticity and atomic density of the transmitting medium, traveling fastest in solids, slower in liquids, and slowest in gases.
Tahmini Süre:1m 0s
Soru 208Soru →

A neutral atom has 22 electrons in its first energy level, 88 electrons in its second energy level, and 66 valence electrons in its third energy level. If the mass number of this atom is 3434, what is the total number of neutrons located in its nucleus?

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Cevap: 1818

Cevap

1818 neutrons
In a neutral atom, the total number of electrons equals the number of protons (atomic number, ZZ). Summing the electrons across all three energy levels (2+8+62 + 8 + 6) yields 1616 electrons, which means the nucleus contains 1616 protons. Because mass number (AA) is the sum of protons and neutrons (A=Z+NA = Z + N), the number of neutrons is found by subtracting the protons from the mass number: 34−16=1834 - 16 = 18.

Adım Adım Çözüm

1
Calculate the total number of electrons in the neutral atom by summing all energy levels.
2+8+6=162 + 8 + 6 = 16 electrons
The total electron count is the sum of electrons distributed across the inner shells and the valence shell.
2
Determine the atomic number (number of protons) from the electron count.
Atomic number (ZZ) = 1616 protons
In any neutral atom, the number of positively charged protons equals the number of negatively charged electrons.
3
Calculate the number of neutrons by subtracting the atomic number from the mass number.
Number of neutrons = 34−16=1834 - 16 = 18
Mass number (AA) equals protons (ZZ) plus neutrons (NN), so N=A−ZN = A - Z.

Anahtar Kavram

Subatomic particle relationships and electron configuration in neutral atoms
Tahmini Süre:1m 0s
Soru 209Soru →

The visible light spectrum consists of electromagnetic radiation spanning various wavelengths and frequencies. Arrange the following colors of visible light in order of increasing frequency, from lowest frequency to highest frequency.

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Cevap

The correct order from lowest frequency to highest frequency is Red light, Yellow light, Blue light, and Violet light.
Electromagnetic waves in the visible spectrum have frequencies that are inversely related to their wavelengths. Red light has the longest wavelength (around 700 nm700\text{ nm}) and thus the lowest frequency. As wavelength decreases across the spectrum toward violet (around 400 nm400\text{ nm}), wave frequency increases progressively from yellow to blue to violet.

Adım Adım Çözüm

1
Recall the fundamental wave relationship connecting wave speed, frequency, and wavelength.
Since all electromagnetic waves travel at the same speed in a vacuum (c=fλc = f\lambda), frequency is inversely proportional to wavelength (f=c/λf = c / \lambda).
This relationship demonstrates that colors with the longest wavelengths have the lowest frequencies, while colors with the shortest wavelengths have the highest frequencies.
2
Determine the relative wavelengths and frequencies of the given visible light colors using the standard spectral sequence.
From longest to shortest wavelength, the visible spectrum follows the sequence: Red →\rightarrow Orange →\rightarrow Yellow →\rightarrow Green →\rightarrow Blue →\rightarrow Indigo →\rightarrow Violet.
Mapping the colors to this sequence directly determines their relative positions regarding frequency.
3
Arrange the specified colors in order of increasing frequency.
The sequence from lowest frequency (longest wavelength) to highest frequency (shortest wavelength) is Red light →\rightarrow Yellow light →\rightarrow Blue light →\rightarrow Violet light.
This orders the items accurately according to the specified physical criteria.

Anahtar Kavram

Visible Light Spectrum and Wave Frequency
Tahmini Süre:1m 0s
Soru 210Soru →

In physical science and mechanics, fundamental physical principles govern how forces determine the motion of bodies and systems. Match each physical law to its precise operational description.

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Öğeler

Newton's First Law of Motion
Newton's Second Law of Motion
Newton's Third Law of Motion
Law of Conservation of Linear Momentum

Eşleşmeler

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Cevap

Newton's First Law matches constant velocity under zero net external force; Newton's Second Law matches acceleration directly proportional to net force and inversely proportional to mass; Newton's Third Law matches simultaneous equal and opposite forces exerted between two interacting bodies; the Law of Conservation of Linear Momentum matches constant total vector momentum in an isolated system.
Each law corresponds to its specific physical definition: Newton's First Law governs the inertia of objects when net force is zero; Newton's Second Law relates net force to mass and acceleration; Newton's Third Law defines equal and opposite interaction pairs acting on two distinct bodies; and the Law of Conservation of Linear Momentum dictates that total momentum remains constant in an isolated system without external forces.

Adım Adım Çözüm

1
Analyze the conditions for inertia and equilibrium governed by Newton's First Law.
Identify that a body in motion at constant velocity or at rest requires zero net external force to maintain that state.
Inertia represents the natural resistance of any physical body to a change in its state of velocity.
2
Determine the quantitative formulation linking net force, mass, and acceleration for Newton's Second Law.
Match the law to the relation a=Fnetma = \frac{F_{\text{net}}}{m}, representing acceleration produced by an unbalanced force.
Newton's Second Law provides the fundamental equation of dynamics relating force inputs to kinematic acceleration.
3
Examine the nature of action-reaction force pairs acting across interacting objects for Newton's Third Law.
Match the law to simultaneous, equal-magnitude, opposite-direction forces acting on separate bodies.
Action-reaction pairs act on different objects and therefore cannot cancel each other out to prevent individual body acceleration.
4
Evaluate the state of total vector momentum in a closed physical system for Conservation of Linear Momentum.
Match the law to the constancy of total vector momentum when external net forces are absent.
In the absence of external net forces, the time derivative of total system momentum is zero.

Anahtar Kavram

Fundamental Newtonian mechanics principles and conservation laws governing forces, acceleration, inertia, and momentum.
Soru 211Soru →

Match each physical or chemical process involving matter on the left with its correct scientific classification and underlying property on the right.

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Öğeler

Sublimation of solid carbon dioxide (dry ice) at room temperature
Rise of liquid mercury inside a calibrated thermometer column
Gradual formation of a green patina on an outdoor copper surface
Fractional distillation separating hydrocarbon components from crude oil

Eşleşmeler

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Cevap

The sublimation of dry ice matches the endothermic phase transition; mercury rising in a thermometer matches the physical change driven by thermal expansion; patina formation on copper matches the chemical oxidation change; and fractional distillation matches the physical separation exploiting boiling points.
Each item is matched by determining whether the process alters the chemical identity of the substance or merely its physical state and dimensions. Sublimation of carbon dioxide is a physical phase change; mercury expansion is physical thermal expansion; fractional distillation uses boiling point differences for physical separation; and patina on copper is chemical oxidation forming new chemical compounds.

Adım Adım Çözüm

1
Analyze the sublimation of dry ice
Dry ice transitions from solid to gaseous carbon dioxide (CO2CO_2) without altering molecular composition, which represents a direct solid-to-gas physical phase change.
Phase transitions alter physical state through energy transfer (latent heat) without forming or breaking intramolecular chemical bonds.
2
Analyze the rise of liquid mercury in a thermometer
Liquid mercury expands predictably when heated, which is an application of thermal expansion (an intensive physical property).
Volume changes resulting from temperature fluctuations do not transform the elemental identity of mercury.
3
Analyze the development of copper patina
Copper metal reacts chemically with atmospheric gases (oxygen, water vapor, sulfur/carbon compounds) to synthesize copper carbonate or copper sulfate.
The production of new substances with distinct chemical formulas and properties constitutes a chemical change.
4
Analyze fractional distillation of crude oil
Crude oil is heated so that hydrocarbons vaporize and condense at their respective characteristic boiling point thresholds.
Boiling point is an intensive physical property used to separate physical mixtures without chemical transformation.

Anahtar Kavram

Distinguishing between physical properties and changes (phase transitions, thermal expansion, separation by boiling point) versus chemical changes (oxidation and compound formation).
Soru 212Soru →

In aerospace manufacturing, a protective oxide layer forms when solid aluminum reacts with atmospheric oxygen gas according to the unbalanced chemical equation:

‾Al+3O2→2Al2O3\underline{\quad}\text{Al} + 3\text{O}_2 \rightarrow 2\text{Al}_2\text{O}_3

To satisfy the Law of Conservation of Mass, what coefficient must be placed in front of Al\text{Al} to properly balance this chemical equation?

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Cevap: 44

Cevap

The coefficient required in front of Al\text{Al} is 44.
In the chemical equation, the product side shows two formula units of aluminum oxide (2Al2O32\text{Al}_2\text{O}_3). Multiplying the leading coefficient of 22 by the subscript of 22 for aluminum gives 2×2=42 \times 2 = 4 aluminum atoms in the products. Conserving matter requires exactly 44 aluminum atoms on the reactant side, producing the balanced equation 4Al+3O2→2Al2O34\text{Al} + 3\text{O}_2 \rightarrow 2\text{Al}_2\text{O}_3.

Adım Adım Çözüm

1
Count the total number of aluminum atoms on the product side of the equation.
The product side contains 2Al2O32\text{Al}_2\text{O}_3, which has 2×2=42 \times 2 = 4 aluminum atoms.
According to the Law of Conservation of Mass, the number of atoms of each element must remain constant throughout a chemical reaction.
2
Determine the coefficient needed for aluminum on the reactant side to balance the four product aluminum atoms.
Since aluminum appears as an individual atom Al\text{Al}, a coefficient of 44 provides 4×1=44 \times 1 = 4 aluminum atoms.
Assigning a coefficient of 44 balances the equation completely: 4Al+3O2→2Al2O34\text{Al} + 3\text{O}_2 \rightarrow 2\text{Al}_2\text{O}_3, with 4 aluminum atoms and 6 oxygen atoms on each side.

Anahtar Kavram

Balancing chemical equations by applying the Law of Conservation of Mass to ensure equal numbers of each atomic species among reactants and products.
Tahmini Süre:1m 0s
Soru 213Soru →

In an industrial metal recovery process, solid aluminum reacts with an aqueous solution of copper(II) sulfate according to the unbalanced chemical equation:

Al(s)+CuSO4(aq)→Al2(SO4)3(aq)+Cu(s)\text{Al}(s) + \text{CuSO}_4(aq) \rightarrow \text{Al}_2(\text{SO}_4)_3(aq) + \text{Cu}(s)

When this equation is completely balanced using the smallest possible whole-number coefficients, what is the sum of all the stoichiometric coefficients?

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Cevap: 99

Cevap

The sum of all stoichiometric coefficients in the balanced equation is 99.
Balancing the equation requires 22 aluminum atoms and 33 copper(II) sulfate units to react to form 11 unit of aluminum sulfate and 33 copper atoms: 2Al(s)+3CuSO4(aq)→1Al2(SO4)3(aq)+3Cu(s)2\text{Al}(s) + 3\text{CuSO}_4(aq) \rightarrow 1\text{Al}_2(\text{SO}_4)_3(aq) + 3\text{Cu}(s). Summing all four stoichiometric coefficients gives 2+3+1+3=92 + 3 + 1 + 3 = 9.

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1
Count the number of each type of atom/polyatomic ion in the unbalanced equation.
Reactants: 1 Al1\text{ Al}, 1 Cu1\text{ Cu}, 1 SO42−1\text{ SO}_4^{2-}. Products: 2 Al2\text{ Al}, 1 Cu1\text{ Cu}, 3 SO42−3\text{ SO}_4^{2-}.
Establishing initial quantities identifies which species violate the Law of Conservation of Mass.
2
Balance the polyatomic sulfate groups by placing a coefficient of 33 before CuSO4\text{CuSO}_4.
Al+3CuSO4→Al2(SO4)3+Cu\text{Al} + 3\text{CuSO}_4 \rightarrow \text{Al}_2(\text{SO}_4)_3 + \text{Cu}
Treating polyatomic ions as single units when they remain intact simplifies balancing.
3
Balance the aluminum and copper atoms by adding coefficients of 22 to Al\text{Al} and 33 to Cu\text{Cu}.
2Al+3CuSO4→1Al2(SO4)3+3Cu2\text{Al} + 3\text{CuSO}_4 \rightarrow 1\text{Al}_2(\text{SO}_4)_3 + 3\text{Cu}
Ensures equal numbers of each elemental atom on both the reactant and product sides.
4
Sum all lowest whole-number coefficients, including the implicit coefficient of 11.
2+3+1+3=92 + 3 + 1 + 3 = 9
Calculates the total coefficient sum requested in the problem.

Anahtar Kavram

Balancing chemical equations according to the Law of Conservation of Mass using lowest whole-number stoichiometric coefficients.
Tahmini Süre:1m 15s
Soru 214Soru →

A sample of mineral oil has a density of 0.8 g/cm30.8\text{ g/cm}^3 and a volume of 50 cm350\text{ cm}^3. What is the mass of the oil sample in grams?

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Cevap: 40

Cevap

40 g
The mass of a substance is determined by multiplying its density by its volume: Mass=Density×Volume=0.8 g/cm3×50 cm3=40 g\text{Mass} = \text{Density} \times \text{Volume} = 0.8\text{ g/cm}^3 \times 50\text{ cm}^3 = 40\text{ g}.

Adım Adım Çözüm

1
State the formula for calculating mass from density and volume
Mass=Density×Volume\text{Mass} = \text{Density} \times \text{Volume}
Density represents mass per unit volume (Density=MassVolume\text{Density} = \frac{\text{Mass}}{\text{Volume}}); rearranging this relationship isolates mass.
2
Substitute the given values into the equation and compute the result
Mass=0.8 g/cm3×50 cm3=40 g\text{Mass} = 0.8\text{ g/cm}^3 \times 50\text{ cm}^3 = 40\text{ g}
Multiplying the density (0.8 g/cm30.8\text{ g/cm}^3) by the total volume (50 cm350\text{ cm}^3) yields the total mass in grams.

Anahtar Kavram

The relationship between mass, volume, and density as physical properties of matter
Tahmini Süre:45s
Soru 215Soru →

A submersible drainage pump is used to clear water from a flooded basement. The pump lifts 200 kg200\text{ kg} of water to a street-level drain located 5 meters5\text{ meters} above the basement floor. If the pump operates at a constant useful power output of 500 W500\text{ W} and the acceleration due to gravity is 10 m/s210\text{ m/s}^2, how many seconds does it take to complete the lift?

Cevabı ve açıklamayı göster

Cevap: 20 seconds20\text{ seconds}

Cevap

20 seconds20\text{ seconds}
Lifting an object at constant speed requires an upward force equal to its weight: F=mg=200 kg×10 m/s2=2000 NF = mg = 200\text{ kg} \times 10\text{ m/s}^2 = 2{}000\text{ N}. The work performed over a vertical height of 5 m5\text{ m} is W=Fd=2000 N×5 m=10000 JW = Fd = 2{}000\text{ N} \times 5\text{ m} = 10{}000\text{ J}. Since power represents the rate of work (P=WtP = \frac{W}{t}), the time required is t=WP=10000 J500 W=20 secondst = \frac{W}{P} = \frac{10{}000\text{ J}}{500\text{ W}} = 20\text{ seconds}.

Adım Adım Çözüm

1
Calculate the downward gravitational force (weight) acting on the water
F=m⋅g=200 kg×10 m/s2=2000 NF = m \cdot g = 200\text{ kg} \times 10\text{ m/s}^2 = 2{}000\text{ N}
Lifting the water requires applying an upward force equal to its weight.
2
Calculate the total work done (gain in gravitational potential energy)
W=F⋅d=2000 N×5 m=10000 JW = F \cdot d = 2{}000\text{ N} \times 5\text{ m} = 10{}000\text{ J}
Work is the product of the upward force and the vertical displacement.
3
Calculate the time required using the definition of power (P=WtP = \frac{W}{t})
t=WP=10000 J500 W=20 secondst = \frac{W}{P} = \frac{10{}000\text{ J}}{500\text{ W}} = 20\text{ seconds}
Power is the rate at which work is performed over time.

Anahtar Kavram

Work is calculated as force times distance (W=Fd=mghW = Fd = mgh), and power is the rate of doing work (P=WtP = \frac{W}{t}), which allows solving for time as t=WPt = \frac{W}{P}.

Alternatif Yöntem

Use the gravitational potential energy equation directly: ΔPE=mgh=200 kg×10 m/s2×5 m=10000 J\Delta PE = mgh = 200\text{ kg} \times 10\text{ m/s}^2 \times 5\text{ m} = 10{}000\text{ J}. Then apply t=ΔPEP=10000 J500 W=20 secondst = \frac{\Delta PE}{P} = \frac{10{}000\text{ J}}{500\text{ W}} = 20\text{ seconds}.
Tahmini Süre:1m 0s
Soru 216Soru →

Elements in the periodic table are organized into families based on their shared subatomic properties, valence electron arrangements, and chemical reactivity. Match each chemical family on the left with its defining valence electron configuration and ionization behavior on the right.

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Öğeler

Alkali Metals (Group 1)
Alkaline Earth Metals (Group 2)
Halogens (Group 17)
Noble Gases (Group 18)

Eşleşmeler

Cevabı ve açıklamayı göster

Cevap

Alkali Metals pair with the single valence electron (ns1ns^1) forming +1+1 cations; Alkaline Earth Metals pair with two valence electrons (ns2ns^2) forming +2+2 cations; Halogens pair with seven valence electrons (ns2np5ns^2 np^5) forming −1-1 anions; Noble Gases pair with the filled valence octet (ns2np6ns^2 np^6) displaying high ionization energy and chemical inertness.
Each periodic family possesses a distinct valence electron configuration that dictates its chemical reactivity and ionic charges. Group 1 alkali metals possess one outer ss electron which they lose to form +1+1 cations. Group 2 alkaline earth metals possess two outer ss electrons and form +2+2 cations. Group 17 halogens possess seven valence electrons and gain one electron to form −1-1 anions. Group 18 noble gases have full outer electron shells, rendering them inert with exceptionally high ionization energies.

Adım Adım Çözüm

1
Analyze the valence configuration and ion formation of Group 1 (Alkali Metals).
Group 1 elements have 11 valence electron in the outermost ss-orbital (ns1ns^1), leading to low first ionization energy and +1+1 cation formation.
Matching requires identifying the subatomic electron configuration unique to Group 1.
2
Analyze the valence configuration and ion formation of Group 2 (Alkaline Earth Metals).
Group 2 elements have 22 valence electrons in the outermost ss-orbital (ns2ns^2), forming +2+2 cations.
Differentiating Group 2 from Group 1 based on the number of valence electrons lost.
3
Analyze the valence configuration and ion formation of Group 17 (Halogens).
Group 17 nonmetals have 77 valence electrons (ns2np5ns^2 np^5), requiring one electron to complete an octet and forming −1-1 anions.
Halogens seek to achieve a noble gas configuration by gaining one electron.
4
Analyze the valence configuration and chemical properties of Group 18 (Noble Gases).
Group 18 elements possess complete valence shells (ns2np6ns^2 np^6), making them chemically unreactive with very high ionization energies.
Filled valence shells confer maximal stability and chemical inertness.

Anahtar Kavram

Periodic table family trends, valence electron configurations, and resulting ionic behavior.
Tahmini Süre:1m 30s
Soru 217Soru →

A scientist suspends two metal blocks of equal mass, Block X and Block Y, by thin insulating threads inside a completely evacuated vacuum chamber. The chamber walls are maintained at 0°C, and both blocks are initially at 100°C. Block X has a matte black surface and a low specific heat capacity. Block Y has a highly polished, shiny surface and a high specific heat capacity. Which of the following correctly identifies the exclusive mechanism of heat transfer from the blocks to the chamber walls, and which block will reach 0°C first?

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Cevap: Radiation; Block X will reach 0°C first.

Cevap

Radiation is the exclusive heat transfer mechanism, and Block X will reach 0°C first.
In a vacuum, there is no physical matter to transfer heat, meaning conduction and convection are impossible; therefore, radiation is the only method of heat transfer. Block X will cool faster for two compounding reasons: its matte black surface makes it a significantly better emitter of thermal radiation than the polished Block Y, and its lower specific heat capacity means it requires less total thermal energy loss to drop its temperature.

Adım Adım Çözüm

1
Determine the mechanism of heat transfer.
The mechanism must be radiation.
The chamber is a completely evacuated vacuum. Conduction and convection require matter (particles) to transfer heat, leaving radiation as the only possible method.
2
Analyze the effect of the surface finishes on the cooling rate.
Block X emits thermal energy faster than Block Y.
Matte black surfaces (Block X) are excellent emitters of thermal radiation, whereas highly polished surfaces (Block Y) are poor emitters that reflect radiation internally.
3
Analyze the effect of specific heat capacity on the cooling rate.
Block X requires less energy loss to drop in temperature.
A low specific heat capacity means a substance requires less heat transfer to change its temperature. Therefore, Block X's temperature drops more rapidly for a given amount of heat lost.
4
Combine findings to determine which block cools first.
Block X will reach 0°C first.
Block X is losing heat at a faster rate (due to its emissive surface) AND requires less heat loss to drop its temperature (due to its low specific heat capacity). These factors compound to make it cool much faster than Block Y.

Anahtar Kavram

Heat Transfer in a Vacuum and Thermal Properties
Soru 218Soru →

An industrial robotic manipulator in an assembly plant applies a steady vertical force of 400 N400\text{ N} to lift a structural bracket through a height of 3 meters3\text{ meters}. If the manipulator delivers a constant power output of 150 W150\text{ W} throughout the movement, how much time does the manipulator take to complete the lift?

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Cevap: 8 seconds8\text{ seconds}

Cevap

The robotic manipulator takes 8 seconds8\text{ seconds} to complete the lift.
The correct answer is found by first determining the mechanical work performed and then dividing by the power output. The work done lifting the bracket is W=F×d=400 N×3 m=1200 JW = F \times d = 400\text{ N} \times 3\text{ m} = 1{}200\text{ J}. Since power is the rate of work done (P=WtP = \frac{W}{t}), the time required is t=WP=1200 J150 W=8 secondst = \frac{W}{P} = \frac{1{}200\text{ J}}{150\text{ W}} = 8\text{ seconds}.

Adım Adım Çözüm

1
Calculate the total mechanical work done to lift the bracket.
W=Force×Distance=400 N×3 m=1200 JW = \text{Force} \times \text{Distance} = 400\text{ N} \times 3\text{ m} = 1{}200\text{ J}
Work is defined as force multiplied by the distance over which that force is applied in the direction of motion.
2
Calculate the time elapsed using the power relationship.
t=WP=1200 J150 W=8 secondst = \frac{W}{P} = \frac{1{}200\text{ J}}{150\text{ W}} = 8\text{ seconds}
Power represents the rate of doing work (P=WtP = \frac{W}{t}), which rearranges to t=WPt = \frac{W}{P}.

Anahtar Kavram

Relationship between mechanical work, force, distance, and power
Tahmini Süre:1m 0s
Soru 219Soru →

A sound wave generated in air enters a pool of water, where its propagation speed increases by a factor of four. How are the frequency and wavelength of the sound wave affected upon entering the water?

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Cevap: The frequency remains unchanged, while the wavelength quadruples.

Cevap

The frequency remains unchanged, while the wavelength quadruples.
When any wave crosses the boundary between two media, its frequency is conserved because frequency is determined solely by the source vibration. According to the wave equation v=fλv = f\lambda, if wave speed increases by a factor of 4 while frequency remains constant, the wavelength must also increase by a factor of 4 to maintain the equality.

Adım Adım Çözüm

1
Identify the behavior of wave frequency across a boundary.
The frequency (ff) remains constant because it depends exclusively on the oscillating source.
When a wave transitions from one medium into another, particles at the boundary oscillate in synchronization with the incident wave, preserving frequency.
2
Apply the universal wave equation relating speed, frequency, and wavelength.
v=fλv = f\lambda, which rearranges to λ=vf\lambda = \frac{v}{f}.
This formula defines the relationship between the physical parameters of any wave.
3
Calculate the proportional change in wavelength when speed increases by a factor of 4.
Since vwater=4vairv_{\text{water}} = 4v_{\text{air}} and ff is constant, λwater=4vairf=4λair\lambda_{\text{water}} = \frac{4v_{\text{air}}}{f} = 4\lambda_{\text{air}}.
Wavelength is directly proportional to wave speed when frequency is constant.

Anahtar Kavram

Wave boundary behavior and the wave equation (v=fλv = f\lambda)
Tahmini Süre:1m 0s
Soru 220Soru →

A camper uses a small portable propane stove to prepare a meal. Which of the following occurrences during this process is an example of a chemical change?

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Cevap: Propane gas burning at the burner to produce heat, carbon dioxide, and water vapor

Cevap

Propane gas burning at the burner to produce heat, carbon dioxide, and water vapor
Combustion of propane is a chemical change because propane molecules react chemically with atmospheric oxygen to break and reform chemical bonds, creating entirely new substances: carbon dioxide and water vapor.

Adım Adım Çözüm

1
Distinguish between physical and chemical changes.
A physical change alters only the form or state of a substance without forming new chemical bonds or substances. A chemical change rearranges atoms to create one or more new substances with different properties.
Classification requires identifying whether the molecular composition is preserved or altered.
2
Evaluate each occurrence in the scenario.
Vaporizing propane, melting ice, and boiling water are all phase transitions (physical changes). Burning propane (combustion) reacts propane with oxygen to produce new substances (carbon dioxide and water).
Only combustion results in the formation of new chemical substances.

Anahtar Kavram

Distinction between physical changes (phase changes) and chemical changes (reactions)
Tahmini Süre:45s
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