Answers:
1) If the marble usually rolls right to the end of the box without bouncing off anything, this indicates that the size of the targets is appropriate for the marble.
2) Rutherford's data led him to conclude that atoms are mostly empty space, with a very small, very dense nucleus at the center. This data changed the model of the atom from a solid, indivisible sphere to a mostly empty space with a small, dense nucleus.
3) Bohr's model of the atom was an improvement on Rutherford's model. Bohr made the following changes:
proposed that electrons orbit the nucleus in discrete energy levelsexplained the stability of atoms by postulating that electrons can only occupy certain energy levelsproposed that when an electron jumps from one energy level to another, it emits or absorbs a photon with an energy equal to the difference in the energy levelsThese changes helped to explain the spectral lines of atoms and the stability of atoms.
of the following thermoplastics, the one most widely used for cable jackets is . select one: a. polyvinyl chloride b. polyethylene c. rubber d. crosslinked polyethylene
Polyvinyl chloride (PVC) is mostly used for cable jackets.
PVC cable jackets can withstand heat, sunlight, weathering, oils, acid, and physical abrasion, making them an excellent choice for outdoor cable jackets. It is a thermoplastic material.
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when a nucleus emits a positron, its atomic number group of answer choices decreases by 1. doesn't change. increases by 1.
When a nucleus emits a positron its atomic number decreases by 1
When a nucleus emits a beta particle means positron and its atomic number decreases by 1 and its mass number remain unchanged and a proton and electron combine to form a neutron and the mass number stay the same but the atomic number decreases by 1 and very few nuclides undergo this transformation and a proton in the parent nucleus decay into a neutron that remain in the daughter nucleus and the nucleus emit a neutrino and a positron and which is a positive particle like ordinary electron in mass but of opposite charge
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a 1.00 l solution contains 24.52 g of nitrous acid, hno2. what mass of sodium nitrite, nano2, should be added to it to make a buffer with a ph of 3.46? ka (hno2)
26.21g NaNO₂ is added to it to make a buffer with a pH of 3.46.
Describe buffer solution.A buffer solution's pH will not change when a small amount of an acid or an alkali is added.
A buffer solution that is acidic has a pH lower than 7, to put it simply. Acidic buffer solutions are usually made by mixing a weak acid with one of its salts, usually sodium salt.
A buffer solution with an alkaline pH exceeds 7. Alkaline buffer solutions are often made by mixing a weak base with one of its salts.
moles of HNO₂ = 24.52g HNO₂ ×[tex]\frac{1 mol HNO2}{47.013gHNO2}[/tex]
moles of HNO₂ = 0.33 moles HNO₂
pKa for HNO₂,
pKa = -log(Ka)
pKa = -log(4.0 × 10⁻⁴)
pKa = 3.39
Now, By using the Henderson-Hasselbach equation: determine the moles of NaNO₂.
Hence, both compounds (Weak base and acid) have same volume.
also use moles instead of concentrations:
pH = pKa + log ( [tex]\frac{moles NaNO2}{moles HNO2}[/tex])
moles of NaNO₂ = moles of HNO₂ × 10[tex]^{pH-pKa}[/tex]
moles of NaNO₂ = 0.33 moles × 10³°4⁶⁻³°³⁹
moles of NaNO₂ = 0.38 moles
moles of NaNO₂ to grams of NaNO₂,
= 0.38 × (68.99/1)
= 26.21g NaNO₂
amount of NaNO₂ is 26.21g.
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How many….
atoms of carbon on the reactant side? _____ on the product side? _____
atoms of hydrogen on the reactant side? _____ on the product side? _____
atoms of oxygen on the reactant side? _____ on the product side? _____
4. How many molecules of oxygen are on the reactant side? ____
5. How many molecules of water are on the product side? _____
6. Is this chemical equation balanced? (Y / N )
This is a balanced chemical reaction equation since the number of atoms of each of the elements is the same on both sides of the reaction equation.
What is a chemical reaction?We know that the term chemical reaction has to do with the kind of interaction that does occur between reactants and products. In this case, we have the reaction that exists between methane and oxygen. This is a combustion reaction.
There is one carbon atoms on the reactant side and one carbon atom on the products side. There are four hydrogen atoms of the reactants side and fur hydrogen atoms on the products side. There are four oxygen atoms on the reactants side and four oxygen atoms on the products side.
There are two oxygen molecules on the reactants side and there are two water molecules on the products side. This is a balanced chemical reaction equation.
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Determine which base will work to deprotonate each compound in an acid/base extraction.
Bases that are useful for deprotonating compounds are:
NaHCO₃ or NaOH.
metal alkoxide
Sodium hydroxide
Benzene rings with carboxylic acids that are weak acids can be prepared using NaOH or NaHCO 3 due to the weakness of the carboxylic acid. deprotonated.
Metal alkoxides such as potassium tert-butoxide can be used to deprotonate benzene rings with three carbon chains attached to one carbon. Also, metal alkoxides are used because the benzene ring containing the hydroxyl group is a very weak acid.
A benzene ring with a hydroxyl group is a weak acid like a benzene ring with a carboxyl group, so it can be deprotonated with NaOH.
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what are halogens. B) what are transition elements.C) what are alkali metals .... please i need the awnser asap :)
Answer:
C.. Group I element they dissolve in water to form alkaline solution
B.. Element between group II and III and most of them form coloured compound
A... Group VII element they react with metals to form salts
what pairs would form covalent bonds?
Answer:
Covalent bonds usually occur between nonmetals.
Explanation:
what organic analytical technique is paired with the visible spectrum and cannot confirm a substances identity
The organic analytical technique that is paired with the visible spectrum and cannot confirm a substances identity is Spectrophotometry.
What is Spectrophotometry?
By measuring the intensity of light as a beam of light travels through a sample solution, a technique called spectrophotometry can determine how much light a chemical component absorbs. Every substance either absorbs or transmits light across a specific spectrum of wavelengths, according to the fundamental tenet. A known chemical substance's concentration can also be determined using this method. In several disciplines, including chemistry, physics, biochemistry, material and chemical engineering, and therapeutic applications, spectrophotometry is one of the most beneficial quantitative analysis techniques.For more informations on spectrophotometry follow
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thin-layer chromatography was performed and four spots were visualized on the glass slide. the substance with which rf value was least soluble in the stationary phase?
The spot with the lowest Rf value would be the most polar one and, thus, the one that is least soluble in the stationary phase.
Does more polarity indicate a higher or lower Rf value?
Calculating the Rf value is possible if you can see the spots. The identity and properties of the various compounds can be established using the Rf values. Since more polar compounds have a stronger affinity for the polar solid phase, they will have smaller Rf values.Rf values are typically higher for low polarity chemicals compared to higher polarity ones. Generally speaking, as polarity of a compound increases, so does its adsorptivity (i.e. the more polar the compound then the stronger it binds to the adsorbent).To learn more about Rf values, follow the link https://brainly.com/question/14393432
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State two ways that active transport is different from diffusion.
Answer: Active transport goes against the gradient causing it to use ATP (energy) unlike diffusion which uses passive. Two types of diffusion are simple diffusion and facilitated diffusion, whereas two types of active transport are primary and secondary active transport.
Explanation: Active energy uses more energy to function rather than diffusion which has multiple types causing it to be different from active transport. Hope this helps!!
4) Complete the notation configuration for Neon.
Answer:
Explanation:
[He]2s²2p⁶
an indium (in) atom has 49 electrons. electrons in which subshell of the indium atom ground state experience the lowest effective nuclear charge (z* or zeff)?
5p subshell of the indium atom ground state experience the lowest effective nuclear charge (Z or Zeff)
Atomic number of indium = 49
E.C of indium = [Kr]4d¹⁰5S²5p¹
The outer 3 electrons indicate that indium is a 3rd group element
In the ground state, the outer electrons of In are present in the 5s and 5p orbitals
So among 5s and 5p which will experience the lowest nuclear charge (Zeff)
The nuclear charge depends on the shape of the orbital
5s has spherical shape while 5p has DB shape
Among the spherical and DB shape, the second one experiences the lower nuclear charge.
So the answer is 5p subshell of the indium will experience the lowest effective nuclear charge (Z or Zeff)
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Many alcohols, including ethanol, are soluble in water.
Explain, with the aid of a diagram, why ethanol is soluble in water.
Include relevant dipoles and lone pairs.
Answer:
because ethanol is polar
Explanation:
polar dissolves in polar. Ethanol has a hydroxyl(-OH) functional group in it.
Due to the presence of a bond between electronegative atom oxygen and hydrogen, the O-H bond acquires polarity.
Hence, due to the presence of polarity in O-H bond, it forms a Hydrogen bond with water which is responsible for the responsibility of ethanol in water.
Balancing Chemical Equations and Identifying Types of Reactions Assignment.
10th grade Chemistry.
Answer:
how are you doing, please kindly help me with my homework
_____ are used for cell phone
communication.
Answer:
Radio Waves are used for cell phone communication.
calculate the pH of 10 g dm-3 HCL
The pH of 10 g dm -3 HCL is 3. The pH scale determines how acidic or basic water is. The range is 0 to 14, with 7 representing neutrality.
What is pH ?Acidity is indicated by pH values below 7, whereas baseness is shown by pH values above 7. In reality, pH is a measurement of the proportion of free hydrogen and hydroxyl ions in water.
Hydrogen potentials are what PH stands for. It speaks of how many hydrogen ions are present in a solution. This serves as a gauge for the acidity or alkalinity of a solution. On a pH scale, the pH value ranges from 0 to 14.
A solution's pH is a significant indicator of its chemical composition. The pH may affect how readily available nutrients are, how biological processes work, how bacteria behave, and how chemicals behave.
[ H⁺ ] = 10 − 3 M,
pH = − log [ 10 − 3 ],
pH = 3.
Thus, The pH of 10 g dm -3 HCL is 3.
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DART sent images from a camera to record its progress.
How were the collision and the results of the collision recorded?
DART sent images from a camera to record its progress. The collision and the results of the collision were recorded by the International Space Station.
What is DART?DART stands for Double Asteroid Redirection Test. The investigative team of the (DART) mission indicates that the spacecraft's kinetic contact with its target asteroid, Dimorphos, successfully changed the asteroid's orbit.
Asteroid is a small planet in our Solar System. Asteroids range in size and shape from 1-meter boulders to a dwarf planet almost 1000 kilometers in diameter; they are stony, metallic, or ice worlds with no atmosphere.
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equal volumes of equimolar solutions of ammonium iodide, nh4i, and lead (ii) acetate, pb(ch3coo)2, were combined and a precipitate forms.
Equal volumes of equimolar solutions of ammonium iodide, NH₄I, and lead (ii) acetate, Pb(CH₃COO)₂, were combined and a precipitate forms. The balanced equation is given as :
2NH₄I + , Pb(CH₃COO)₂ ----> PbI₂ + 2NH₄CH₃CO₂
The ammonium iodide, NH₄I react with lead (ii) acetate, Pb(CH₃COO)₂ to form lead(II)iodide and ammonium ethanoate. The balanced equation is given as follows :
2NH₄I + Pb(CH₃COO)₂ ----> PbI₂ + 2NH₄CH₃CO₂
ammonium lead (ii) acetate lead(II)iodide ammonium ethanoate
iodide
Thus, Equal volumes of equimolar solutions of ammonium iodide, NH₄I, and lead (ii) acetate, Pb(CH₃COO)₂, were combined and a precipitate forms. The balanced equation is given as :
2NH₄I + , Pb(CH₃COO)₂ ----> PbI₂ + 2NH₄CH₃CO₂
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calculate the number of moles of argon gas contained in a 4.00 l container at 1620. kpa and 25.0 oc. if the gas is helium instead of argon, will the answer change? explain 2.62 moles
The number of moles of argon gas in a 4L container at 1620KPa and 25C is 2.62 moles. This can be calculated by ideal gas equation. The number of moles will not change when the argon gas is replaced by helium gas.
What is an ideal gas equation?
The ideal gas equation states the relation between pressure, volume, number of moles and temperature. The pressure multiplied by volume is directly proportional to the number of moles multiplied to the temperature. The equation can be written as, PV = nRT.
According to the ideal gas equation,
PV = nRT
P is pressure, n is number of moles, T is temperature, V is volume.
n = 1620KPa x 4L / 8.314Jmol^-1K^-1 x 298K = 2.62 moles.
Therefore, according to ideal gas equation, 2.62 moles is the number of moles of the gas in 4L container with 1620KPa pressure and 25C temperature. The number of moles doesn't depend on the gas. So it doesn't change when argon gas is replaced with helium gas.
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Why are group IA elements called alkali metals??
Answer:
All forms of hydroxides
Explanation:
The metals in Group IA (Li, Na, K, Rb, Cs, and Fr) are called alkali metals because they all form hydroxides (such as NaOH) that were once known as alkalies. The electron configurations of the alkali metals are characterized by a single valence electron.
Which statement correctly describes how hydrolysis causes chemical weathering? (1 point)
O Water reacts with minerals in rocks to produce carbonic acid, weakening the rock.
O Water reacts with carbon dioxide to produce clay, weakening the rock.
O Water reacts with minerals in rocks to produce clay, weakening the rock.
O Water reacts with carbon dioxide to produce carbonic acid, weakening the rock.
The term chemical weathering is said to occur when water reacts with carbon dioxide to produce carbonic acid, weakening the rock.
What is weathering?The term weathering has to do with the breaking down of the rock. Now we know that rocks are defined as the solid part of the earth's crust. We can find the rocks either at the surface or under the earth.
The process of the breakdown of the rocks can be initiated by many processes and one of the processes is by the break down of the rock by the hydrolysis of the minerals that can be found in the rock. This owes to the formation of acid in the rocks.
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How many chromium atoms are
present in one formula unit of
sodium chromate?
Na2CrO4
A. 2 atoms
B.7 atoms
C. 1 atoms
D. 4 atoms
Only 1 atom of chromium is present in one formula unit of sodium chromate (option C).
What is a chemical compound?A chemical compound is a substance formed by the union of two or more chemical elements in a fixed ratio, the union being a chemical bond.
A chemical formula, which is a notation indicating the number of atoms of each element present in a compound, shows the type and number of atoms of elements in a compound.
According to this question, a chemical compound named sodium chromate (Na₂CrO₄) is given. This chemical formula shows that only one atom of chromium is present in the compound.
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Answer:
D. 4 atoms
Explanation:
what is the estimated effective nuclear charge, zeff, experienced by an electron in a 3p orbital of a chlorine atom?
The estimated nuclear charge on an electron in a 30 orbital of chlorine atom is 6.1
The charge that the outermost valence electrons of any many-electron atom experience is known as the effective nuclear charge. This is done by taking into account how many shielding electrons there are surrounding the nucleus. Rule of Slater: The effective nuclear charge that an electron in a multi-electron atom experiences is measured using this method. This rule states that the screening effect of the other electrons in the atom causes the actual nuclear charge an electron experiences to be smaller than the actual nuclear charge. An atom's distribution of electrons within its atomic orbitals is known as its electronic configuration.
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true or false-an oxygen molecule (o2) has eight times as much mass as a hydrogen molecule (h2). for equal masses of oxygen and hydrogen at the same volume and the same temperature, the oxygen sample will exert more pressure than the hydrogen sample.
The oxygen molecule is 16 times heavier than the hydrogen molecule. So, the answer is false. The molar mass of gases decide the mass of the gases.
What is molar mass?
Molar mass is the mass of the substance divided by the number of moles of that substance. The SI unit of molar mass is Kg/mol. It is an intensive property. It is the mass of the substance in 1 mole of that substance.
The molar mass of hydrogen molecule (H2) is 2 g/mol. The molar mass of oxygen molecule (O2) is 32 g/mol. The oxygen molecule is heavier than hydrogen molecule.
Therefore the oxygen molecule has a molar mass of 32 g/mol which is 16 times more than the molar mass of hydrogen molecule which is 2 g/mol. The answer is false.
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Diana measured 233 mL for the volume of the object. The actual volume of the object was 241 mL. What is the percent error of Diana’s results?
Answer:
3.32%
Explanation:
To calculate the percent error, you need to use the following equation:
| measured value - actual value |
Percent Error = -------------------------------------------------- x 100%
actual value
In this equation, the measured value is the amount generated after running an experiment. The actual value is the amount generated solely through calculations.
Measured Value = 233 mL
Actual Value = 241 mL
| 233 mL - 241 mL |
Percent Error = -------------------------------- x 100%
241 mL
8 mL
Percent Error = ----------------- x 100%
241 mL
Percent Error = 0.0332 x 100% = 3.32%
12) A solution of acetic acid, HC2H3O2, on a laboratory shelf was of undetermined concentration. If the pH of the solution was found to be 2.68, what was the concentration of the acetic acid? (Ka = 1.7 x 10-5)
HC2H3O2 (aq) + H2O(l) C2H3O2-(aq) + H3O+(aq)
The concentration of acetic acid in the solution is 0.257 M.
What is the concentration of acetic acid in the solution?The concentration of acetic acid in the solution is determined from the Henderson- Hasselbalch equation as follows:
pH = pKₐ + log ([A⁻]/[HA])where;
pKa = - log(Ka) of acetic acid[A⁻] = concentration of acetate[HA] = concentration of acetic acidpKa = - log(1.7 * 10⁻⁵)
pKa = 4.77
Equation of reaction: HC₂H₃O₂ (aq) + H₂O(l) --> C₂H₃O₂⁻ (aq) + H₃O⁺ (aq)
From the equation of reaction; [A⁻] = [H₃O⁺]
[H₃O⁺] = antilog -(pH)
[H₃O⁺] = antilog (-2.68)
[H₃O⁺] = 0.002
[A⁻] = 0.002
[HA] = [A⁻] / antilog of (pH - pKa)
[HA] = [A⁻] / antilog (2.68 - 4.77)
[HA] = 0.002 / 0.00812
[HA] = 0.257 M
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15. The figure shows a reaction. What type of reaction is shown?
a. Synthesis
b. Decomposition
CSingle replacement
d. Double replacement
e. Combustion
Cl cu cl —> Cu+ClCl
a 355-ml can of soda pop contains 41 g of sucrose (c12h22o11). what is the molarity of the solution with respect to sucrose?
A 355-ml can of soda pop contains 41 g of sucrose the molarity of the solution with respect to sucrose is 0.337 M
Given that 41g of sucrose
Number of moles = amount in g/ molar mass
Number of moles= 41 g / 342.2965 g/mol
Number of moles= 0.12 moles Sucrose
Volume = 355 ml or 0.355 L
Thus,
Molarity = 0.12 moles / 0.355 L
Molarity= 0.337 M
The term "molarity of the solution" refers to how many moles of solute there are in a liter of solution. M served as its symbol. The ratio of moles of solutes per liter of solution is known as the molarity of any solution. The following formula captures it.
Molarity (M) = moles of solute/liter of solution
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when temperature and pressure are held constant, volumes can be used in gas-phase reaction stoichiometry because
Because of Avogardo Hypothesis, volumes can be used in gas phase reaction stoichiometry at constant temperature and pressure.
Avogadro's Law (also known as Avogadro's Hypothesis or Avogadro's Principle) is an experimental gas law that relates the volume of gas to the amount of gaseous matter present.
Avogadro's law states that "equal volumes of all gases at the same temperature and pressure have the same number of molecules". At constant temperature and pressure, (mol) of a gas is directly proportional.
For example, if two ideal gases, hydrogen and nitrogen, are mixed in equal amounts, they contain the same amount of molecules. This only happens if they are kept at the same pressure and temperature. This shows the ideal behavior of gases.
Let's look at this law mathematically: the overall law can be written as
V is directly proportional to n
or V = nK , K (a constant)
Amount of gas; “n” is the gaseous substance measured in moles. "k" is a constant defined for a specific pressure and temperature.
Comparing the same gas under different conditions, the law is : V₁/ n₁=V₂/ n₂
The equation shows that the number of moles of gas increases in proportion to the increase in gas volume. Therefore, the total number of atoms or molecules present in a given volume of gas is completely independent of the molar mass or size of the gas.
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q12 (1pts) which one of the following molecules has an atom with an incomplete octet? a) nf3 b) h2o c) ascl3 d) geh4 e) bf3
The following molecules has an atom with an incomplete octet is BF₃.
the following molecules given as follows :
a) NF₃ - it follow the octet rule. all the atom present have there octet complete. the molecule is stable;
b) H2O - all the have complete octet.
c) AsCl₃ - all the atoms have 8 electron in valence shell and follow octet rule.
d) GeH₄ - thos molecule also follow the octet rule
e) BF₃ - not follow the octet and have incomplete octet. Boron atom have in complete octet.
thus, The following molecules has an atom with an incomplete octet is BF₃.
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