Describe the photoelectric effect and explain why it made modifications to the Rutherford model necessary.
Answer:
The emission of free carriers or electrons taking place when light falls into a substance is termed as the photoelectric effect. On the basis of the Rutherford model, the light of any energy should possess the tendency to cause the electrons to leave the atom and get emitted.
The energy obtained from the emitted electrons should be associated with the intensity of the light. However, the energy of the electron is in the real sense only associated with the energy of the light.
a family from minnesota turns off the heat and flies to florida for a winter holiday. when they come home, all of their water pipes have burst. what do you think happened?
The volume of solid ice is greater than the volume of water. In winter in the absence of heat water in the pipe freezes, as ice takes greater space to fit in than water, the pipe burst in winter in the absence of heating.
Freezing of water is an exothermic process (heat is released by the system into the surrounding) where as melting of ice is an endothermic process (heat is absorbed by the system from the surrounding). If the heat was on it would prevent ice formation in the pipes.
The water pipes burst due to the expansion of water in them.
Water behaves in an anomalous manner. While most substances expand when heated and contract when cooled, water begins to expand at 4°C.
As a result of this, solid water is less dense than liquid water because it has more volume than liquid water.
Since solid water has more volume compared to liquid water, the pipes may no longer be able to contain the expanding water which has turned to ice leading to the bursting of the water pipes.
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Hydrofluoric acid, hf(aq), cannot be stored in glass bottles because compounds called silicates in the glass are attacked by the hf(aq). sodium silicate (na2sio3), for example, reacts as shown below. na2sio3(s) + 8 hf(aq) h2sif6(aq) + 2 naf(aq) + 3 h2o(l) (a) how many moles of hf are needed to react with 0.340 mol of na2sio3?
2.72 moles of HF are needed to react with 0.340 mol of Na₂SiO₃ based on the balanced chemical equation.
To determine how many moles of HF are needed to react with 0.340 mol of Na₂SiO₃, we need to look at the balanced chemical equation:
Na₂SiO₃(s) + 8 HF(aq) -> H₂SiF₆(aq) + 2 NaF(aq) + 3 H₂O(l)
The balanced equation shows that 1 mole of Na₂SiO₃ reacts with 8 moles of HF. Therefore, to find the moles of HF needed for 0.340 mol of Na₂SiO₃, we use the ratio:
(0.340 mol Na₂SiO₃) * (8 mol HF / 1 mol Na₂SiO₃) = 2.72 mol HF
Therefore, 2.72 moles of HF are needed to react with 0.340 mol of Na₂SiO₃.
An acid's hydronium ion will donate its proton to a base's hydroxide ion, _________ both. a. acidifying b. alkalizing c. neutralizing
What is the net ionic equation of the reaction of mgs o 4 with sr(n o 3 ) 2?
Which of these statements is most likely correct about a weak nuclear force?
It binds electrons and protons
It binds protons and neutrons
it is an attractive force
It is a repulsive force
Answer: It binds protons and neutrons
Explanation: Nuclear forces are that kind of forces of attraction which binds the nucleons around the nucleus.
Nucleons are the particles present in the nucleus . Thus protons and neutrons are known as Nucleons.
Protons are positively charged particle and neutrons are neutral in nature and they both experience almost identical forces of attraction.
Calculate the mass (in ng) of 2.33 x 1020 atoms of oxygen.
Answer:
[tex]6.19*10}^{6}[/tex] g of Oxygen
Explanation:
In order to answer the question the Avogadro´s number is needed:
Avogadro´s number = [tex]6.022*10^{23}[/tex][tex]mol^{-1}[/tex]
Calculate the mass using the Avogadro´s number:
[tex]2.33*10^{20}atomsO*\frac{1molO}{6.022*10^{23}atomsO}*\frac{16gO}{1molO}*\frac{1*10^{9}g}{1g}=6.19*10}^{6}[/tex] g of Oxygen
What mass of iodine would react with 48 grams of magnesium to make magnesium iodide? Mg + I2 -> MgI2
Answer:508
Explanation:
I saw from another post or actually 507.8
What is the difference between electron configuration and valence electron configuration?
Answer:
The diagonal rule states that electrons fill orbitals in order of increasing "quantum number sum" (n + ℓ). When two orbitals share the same "quantum number sum", they will be filled in order of increasing n.
Explanation:The electrons in an atom fill up its atomic orbitals according to the Aufbau Principle; "Aufbau," in German, means "building up." The Aufbau Principle, which incorporates the Pauli Exclusion Principle and Hund's Rule prescribes a few simple rules to determine the order in which electrons fill atomic orbitals:
Electrons always fill orbitals of lower energy first. 1s is filled before 2s, and 2s before 2p.
The Pauli Exclusion Principle states no two electrons within a particular atom can have identical quantum numbers. In function, this principle means that if two electrons occupy the same orbital, they must have opposite spin.
Hund's Rule states that when an electron joins an atom and has to choose between two or more orbitals of the same energy, the electron will prefer to enter an empty orbital rather than one already occupied. As more electrons are added to the atom, these electrons tend to half-fill orbitals of the same energy before pairing with existing electrons to fill orbitals.
Valence Electrons:
The outermost orbital shell of an atom is called its valence shell, and the electrons in the valence shell are valence electrons. Valence electrons are the highest energy electrons in an atom and are therefore the most reactive. While inner electrons (those not in the valence shell) typically don't participate in chemical bonding and reactions, valence electrons can be gained, lost, or shared to form chemical bonds. For this reason, elements with the same number of valence electrons tend to have similar chemical properties, since they tend to gain, lose, or share valence electrons in the same way. The Periodic Table was designed with this feature in mind. Each element has a number of valence electrons equal to its group number on the Periodic Table.
If gas particles start colliding with the walls of their metallic container with increased force, what is their direct effect
higher gas pressure
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The balanced chemical equation, 2NO (g) + 5H2 (g) (Arrow pointing this way >>) 2NH3 (g) + 2H2O (g), can be expressed in words as:
Nitrogen dioxide gas plus hydrogen gas yields ammonia gas plus water
Nitrogen monoxide gas plus hydrogen gas yields ammonia gas plus water vapor
Nickel monoxide gas plus hydrogen gas yields nitrogen trihydride plus water
Nitrogen oxide gas plus hydrogen gas yields ammonia gas plus water vapor
I think it's either B, or D. I can't figure out which one it is though. Please help.
Answer:
B) Nitrogen monoxide gas plus hydrogen gas yields ammonia gas plus water vapor
Explanation:
The given reaction is:
[tex]2NO(g) + 5H_{2}(g)\rightarrow 2NH_{3}(g)+ 2H_{2}O(g)[/tex]
Here the chemical names of the reactants are:
NO = nitric oxide or nitrogen monoxide in gas phase
H2 = hydrogen gas
NH3 = ammonia in gas phase
H2O = water in gas phase i.e. vapor
Therefore the reaction can be expressed in words as:
Nitrogen monoxide gas plus hydrogen gas yields ammonia gas plus water vapor
Identify the phase in which the water molecules are closest together. identify the phase in which the water molecules are closest together. liquid gas solid dry ice
a solution with a higher concentration of hydroxide ions (oh-) than hydrogen ions (h+)
The solution with a higher concentration of hydroxide ions (oh-) than hydrogen ions (h+) are base solutions or solutions which are the basic option B is correct.
What is the base solution?A solution which is basic in nature in aqueous solution they contain more OH - ions concentration than that of H + ions concentration. that is they are, in aqueous solution with a pH greater than 7.
Basic solutions contain ions, with some conducted electricity, and it turn red litmus paper blue, and slippery while touching.
They are mostly used in the manufacturing of soaps, toothpaste, paper and rayon as they do not react with skin due to basic in nature.
Basic substances react to aqueous solutions by accepting or gaining of protons, giving away or releasing the electrons, or releasing and make free hydroxide ions.
Therefore, they are basic solutions. option B is correct
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The given question is incomplete therefore, the complete question is
a solution with a higher concentration of hydroxide ions (oh-) than hydrogen ions (h+)
A.acid
B. base
C.neutral
To how many significant figures can you report your measurement of the mass the nacl sample?
When reporting the mass of the NaCl sample, consider the number of significant figures. The precision of the measurement equipment determines the appropriate number of significant figures to report.
Explanation:When reporting the measurement of the mass of the NaCl sample, you should consider the significant figures. Significant figures are the digits in a number that carry meaning and contribute to its precision. In general, you should report your measurement to the same number of significant figures as the least precise measurement involved in the calculation.
In the given question, there is no specific information provided about the NaCl sample and the precision of the measurement. Therefore, it is not possible to determine the accurate number of significant figures to report. However, it is important to determine the precision of the equipment used to measure the mass and report the measurement accordingly.
Is the ccl3– molecule polar or nonpolar? the molecule is nonpolar if the net molecular dipole moment is zero. the molecule is polar if the net molecular dipole moment is not zero?
Jon is completing a lab for his chemistry class, and Katarina is finishing a lab for her geology class. They investigated different topics, but they followed similar steps to complete their lab investigations. Even though they are studying different subjects, Jon and Katarina use the same method for completing a lab report because they are both
use the same materials in their lab experiments.
studying the same general content in both science courses
investigating the same scientific law in both courses
using scientific inquiry to conduct their experiments
Jon and Katarina use the same method for completing a lab report because they are both using scientific inquiry to conduct their experiments.
Explanation:Jon and Katarina use the same method for completing a lab report because they are both using scientific inquiry to conduct their experiments. The scientific method is a process that scientists follow to gather information, form hypotheses, test their hypotheses through experiments, and draw conclusions based on their results. It is a systematic and organized approach that can be applied to various scientific disciplines, including chemistry and geology.
How is the mass number of an isotope expressed in the name of an atom?
The mass number of an isotope is expressed in the name of an atom by placing it after the element's name, separated by a hyphen. For example, Carbon-12.
Explanation:The mass number of an isotope is represented in the name of an atom by placing it after the element's name, separated by a hyphen. For example, carbon with a mass number of 12 is represented as Carbon-12.
This mass number represents the total number of protons and neutrons in the nucleus of an atom. As isotopes of an element have the same number of protons, but different numbers of neutrons, the mass number differentiates one isotope from another. So, Carbon-12 and Carbon-14 are two isotopes of the Carbon element.
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What is the best definition of polar covalent bond?
Final answer:
A polar covalent bond is a type of covalent bond with unequal sharing of electrons due to a difference in electronegativity between the bonded atoms, leading to a partial negative and positive charge on the atoms.
Explanation:
The best definition of a polar covalent bond is a type of covalent bond in which the electrons are shared unequally between the bonded atoms. This disparity in sharing occurs because the atoms involved have different electronegativities - a measure of how strongly an atom attracts electrons in a bond.
When the difference in electronegativities between the two atoms falls between 0.4 and 1.7, the electrons are not shared equally, leading to a polar bond. One atom attracts the shared electrons more strongly, giving it a partial negative charge, while the other atom acquires a partial positive charge, creating a dipole.
In contrast, a nonpolar covalent bond occurs when the electronegativity difference is less than 0.4, resulting in equal sharing of electrons and no dipole. On the opposite end of the spectrum, if the difference in electronegativity is greater than 1.7, it may lead to an ionic bond, where electrons are transferred rather than shared.
A polar covalent bond is a type of covalent bond where the electrons are shared unequally between the bonded atoms.
This happens because the atoms involved have different electronegativities, meaning one atom attracts the shared electrons more strongly than the other. Typically, if the difference in electronegativity between the atoms is between 0.4 and 1.7, the bond is considered polar covalent.
Due to this unequal sharing, the molecule has regions with partial positive and partial negative charges, leading to an imbalance in electron distribution. These partial charges create a dipole moment within the molecule, making it polar.
Which physical property of water best allows solutes dissolved in it to be separated using simple distillation?
Density
Evaporation
Melting point
Surface tension
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Which property describes an acid but not a base?
dissociates into ions in solution
---------reacts with pure metals
tastes bitter
can change the color of plant-based dyes
I think it is the second choice but I'm unsure...
what must differ between the atom of two different element easy 10 POINTS
Answer:
protons in the atom
Explanation:
I took the test
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The molality of a solution that is made by dissolving a certain mass of benzene in 20.6 g of carbon tetrachloride is 0.529 m. How many moles of benzene were dissolved?
Answer:
0.0109 mol
Explanation:
Took the exam.
Which statement is true when considering color in a fiber?
the color is measured using an FTIR
the color depends upon the lighting source
the color is always a result of a pigment in all fibers
there are very few color dyes that can be used for fibers
none of the above are true
The true statement about color in a fiber is that the color depends upon the lighting source, because fibers absorb some wavelengths of light and reflect others. Different illumination can change the perceived color of the fiber.
Explanation:The statement 'the color depends upon the lighting source' is true when considering color in a fiber. The true color of an object, including fibers, is defined by its absorptive or reflective characteristics, which is how the object interacts with various wavelengths of light. When an object is illuminated by white light (a mixture of all visible wavelengths), it reflects some wavelengths while absorbing others; the reflected wavelengths determine the color we perceive. If illuminated by colored light, the object can appear a different color. For example, under pure red light, a blue object will appear black because it absorbs the red light. Furthermore, the color of fibers is not always a result of pigments as structural coloration also exists, and there is a wide variety of dyes that can be used for fibers, not just a few.
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In a particular redox reaction, clo2– is oxidized to clo4– and ag is reduced to ag. complete and balance the equation for this reaction in acidic solution. phases are optional.
We balance the given redox reaction using the half-reaction method. First, we write the half-reactions, balance atoms other than H and O, balance O by adding H2O, balance H by adding H+ ions, and ensure electrical neutrality by adding electrons. The result is the balanced reaction: 2Ag + clo2- + 2H2O → 2Ag + clo4- + 4H+.
Explanation:The task is to balance a redox reaction wherein clo2– is oxidized to clo4– and Ag is reduced to Ag in an acidic solution. We do this by employing a method known as the half-reaction method which involves the following steps:
First, write separate half-reactions for oxidation and reduction. In our case, clo2– gets oxidized to clo4–, so we write: clo2-→clo4-. As for reduction, there is no actual change in Ag. It remains Ag. Next, balance the atoms other than H and O. In our case, Cl is already balanced. Balance oxygen atoms by adding H2O. For every O atom required, add 1 H2O on the side lacking oxygen. So, we add 2 H2O molecules in our case to the left side: clo2- + 2H2O → clo4-. Balance the quantities of H by adding H+ ions. We have 4 H on the left side. So, we add 4H+ on the right side of the equation as such: clo2- + 2H2O → clo4- + 4H+. Ensure electrical neutrality by adding electrons. We add 4 electrons to the right side in our case to neutralize the 4H+ ions: clo2- + 2H2O → clo4- + 4H+ + 4e-. The complete balanced reaction is then: 2Ag + clo2- + 2H2O → 2Ag + clo4- + 4H+ . This properly represents the redox reaction taking place. Learn more about Balancing Redox Reactions here:https://brainly.com/question/32431557
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Calculate the energy of one photon of yellow light that has a wavelength of 589 nm
Write a balanced equation for the decomposition of tnt. assume that, upon explosion, tnt decomposes into n2(g),co2(g),h2o(g), and c(s):
The balanced chemical equation for the decomposition of TNT into nitrogen gas, water vapor, carbon dioxide, and solid carbon is: 2 C7H5N3O6(s) → 3 N2(g) + 5 H2O(g) + 7 CO(g) + 7C(s). This reaction is exothermic, meaning it releases energy.
Explanation:The decomposition of TNT (trinitrotoluene) can be represented by a balanced chemical equation that includes solid carbon (C) as one of the products, along with gaseous nitrogen (N2), carbon dioxide (CO2), and water vapor (H2O). The balanced equation is derived by ensuring that the number of atoms for each element is equal on both sides of the reaction. The balanced equation for TNT decomposition is:
2 C7H5N3O6(s) → 3 N2(g) + 5 H2O(g) + 7 CO(g) + 7C(s)
This reaction is exothermic, releasing energy upon explosion. However, it is important to note that the real decomposition of TNT can be more complex, and the products can vary depending on the conditions. For simplicity, this equation assumes that all the carbon is converted to solid carbon, not carbon monoxide or carbon dioxide which could also be formed.
A solution is prepared by dissolving 15.0 g of nh3 in 250.0 g of water. the density of the resulting solution is 0.974 g/ml. the molarity of nh3 in the solution is ________ m.
To solve this problem, first we assume the volume is purely additive. The density of the mixture can then be calculated by the summation of mass fraction of each component divided by its individual density:
1 / ρ mixture = (x NH3 / ρ NH3) + (x H2O / ρ H2O) ---> 1
Calculating for mass fraction of NH3:
x NH3 = 15 g / (15 g + 250 g)
x NH3 = 0.0566
Therefore the mass fraction of water is:
x H2O = 1 – x NH3 = 1 – 0.0566
x H2O = 0.9434
Assuming that the density of water is 1 g / mL and substituting the known values back to equation 1:
1 / 0.974 g / mL = [0.0566 / (ρ NH3)] + [0.9434 / (1 g / mL)]
ρ NH3 = 0.680 g / mL
Given the density of NH3, now we can calculate for the volume of NH3:
V NH3 = 15 g / 0.680 g / mL
V NH3 = 22.07 mL
The number of moles NH3 is: (molar mass NH3 is 17.03 g / mol)
n NH3 = 15 g / 17.03 g / mol
n NH3 = 0.881 mol
Therefore the molarity of NH3 in the solution is:
Molarity = 0.881 mol / [(22.07 mL + 250 mL) * (1L / 1000 mL)
M = 3.238 mol/L = 3.24 M
To find the molarity of the NH3 solution, divide the moles of NH3 by the volume of the solution in liters.
Explanation:To find the molarity of the NH3 solution, we need to first calculate the moles of NH3. We can do this by dividing the mass of NH3 (15.0 g) by its molar mass (17.03 g/mol) to get 0.881 mol. Next, we need to calculate the volume of the solution. Because density is mass divided by volume, we can rearrange the equation to solve for volume, which is mass divided by density. Substituting in the given values, we get 250.0 g / 0.974 g/ml = 256.62 ml. Since 1 ml is equal to 0.001 L, the volume of the solution is 0.25662 L. Finally, we can calculate the molarity by dividing the number of moles of solute (NH3) by the volume of the solution in liters. Substituting the values, we get 0.881 mol / 0.25662 L = 3.43 M.
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Based on its location on the periodic table, which element would be most likely to form a negative ion?
A. Aluminum (Al)
B. Copper (Cu)
C. Sodium (Na)
D. Fluorine (F)
The correct answer among the choices would be:
D. Fluorine (F)
Among all the elements, fluorine is the most electronegative element. Electronegativity refers to the measure of tendency of an electron to be attracted to that element. Since Fluorine is very electronegative, it can easily absorb the electrons of other elements. Since it sucks up electron, this gives Fluorine an excess electron thus making it a negative ion F-.
Answer: Bromine (Br)
Explanation:
If 1 calorie = 4.18 kj, how many kj of energy can be released by an apple containing 125 Cal?
Answer:
522.2kJ
Explanation:
Hello,
In this case, based on the given conversion data, we apply the following proportional factor to obtain the corresponding energy in kJ:
[tex]125cal*\frac{4.18kJ}{1cal}=522.2kJ[/tex]
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Two isotopes of the same element will have the same _____ but a different ____. mass number, atomic number. atomic number, mass number. atomic mass, mass number. mass number, atomic mass.
Answer: The correct answer is atomic number, mass number.
Explanation:
Isotopes are defined as the chemical species which have same number of protons but differ in the number of neutrons.
It can also be said that they are the chemical species of the same element which have same atomic number but have different mass number.
For Example: [tex]_6^{12}\textrm{C}\text{ and }_6^{14}\textrm{C}[/tex] are the isotopes of carbon element, which have same atomic number but different mass number.
Hence, the correct answer is atomic number, mass number.