Answer:
you never gave us the choices to go over. sorry
yes needs help......
Answer:
a and b
Explanation:
Some major contributions to the development of atomic theory are listed. Identify the scientist associated with each contribution. Not all names will be used, and some names will be used more than once. He discovered the electron. He discovered periodic changes in properties of elements when they are listed in order of their atomic weights. He experimented with the deflection of cathode rays by a magnetic field. He carried out experiments that measured the scattering of alpha particles by heavy atoms. His model of the hydrogen atom led to an accurate calculation of the wavelengths of light emitted by an excited hydrogen atom. He proposed the planetary model of the atom with most of the mass of the atom concentrated in a very small nucleus. He modified the planetary model of the atom by suggesting electrons could travel about the nucleus in only a few discrete stable orbits. Answer Bank
Answer:
He discovered the electron - J.J Thompson
He discovered periodic changes in properties of elements when they are listed in order of their atomic weights - Dimitri Mendeleev
He experimented with the deflection of cathode rays by a magnetic field - J.J Thompson
He carried out experiments that measured the scattering of alpha particles by heavy atoms - Ernest Rutherford
His model of the hydrogen atom led to an accurate calculation of the wavelengths of light emitted by an excited hydrogen atom - Neil Bohr
He proposed the planetary model of the atom with most of the mass of the atom concentrated in a very small nucleus - Ernest Rutherford
He modified the planetary model of the atom by suggesting electrons could travel about the nucleus in only a few discrete stable orbits - Neil Bohr
Explanation:
J.J Thompson discovered the electrons. He initially called them cathode rays and he also studied how they are deflected in magnetic fields and by so doing established that they are negatively charged particles.
Ernest Rutherford is renowned for his experiment using the thin gold foil and alpha particles to determine that atoms have a positively charged massive core called the nucleus. This led to the proposition of the planetary model of the atom.
Dimitri Mendeleev discovered periodic changes in properties of elements when they are listed in order of their atomic weights. This led to the discovery of the Mendeleev periodic table.
Neil Bohr model of the atom gave accurate explanation of the emission spectra of the hydrogen atom. His atomic model suggested that electrons could travel about the nucleus in only a few discrete stable orbits.
Answer:
He discovered the electron - J.J Thompson
He discovered periodic changes in properties of elements when they are listed in order of their atomic weights - Dimitri Mendeleev
He experimented with the deflection of cathode rays by a magnetic field - J.J Thompson
He carried out experiments that measured the scattering of alpha particles by heavy atoms - Ernest Rutherford
His model of the hydrogen atom led to an accurate calculation of the wavelengths of light emitted by an excited hydrogen atom - Neil Bohr
He proposed the planetary model of the atom with most of the mass of the atom concentrated in a very small nucleus - Ernest Rutherford
He modified the planetary model of the atom by suggesting electrons could travel about the nucleus in only a few discrete stable orbits - Neil Bohr
Explanation:
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Answer:
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Explanation:
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In a lab, silver nitrate,AgNO3, is dissolved in water until no solid is observed in the container. Then, a solution of sodium chloride, NaCl, is added to the container. When you combine these aqueous solutions, there is no noticeable change in temperature; however, a solid precipitates and there is a slight change of color. Which statements about the lab experiment involving silver nitrate and a sodium chloride solution are true?
Answer:
Formation of a solid indicates a chemical reaction occurred.
True
Explanation:
A chemical reaction is said to have occurred when a new substance(s) is (are) formed.
When we mix the sodium nitrate and sodium chloride, the following chemical reaction occurs;
2AgNO3(aq) + 2NaCl(aq) ------> 2AgCl(s) + 2NaNO3(aq)
The appearance of a solid shows that a chemical reaction has occurred and that NaCl really reacted chemically with AgNO3.
Consider the proposed structure of carbon dioxide. Determine whether the structure is correct and justify your decision. Select one: This structure is correct due to the total number of bonds and electrons. This structure is correct due to allowed exceptions to the octet rule for the involved atoms. This structure is incorrect due to the total number of electrons for the involved atoms. This structure is incorrect because the octet rule is not fulfilled for all the atoms.
The question is incomplete, the complete question is found in the image attached to this answer
Answer:
This structure is correct due to the total number of bonds and electrons.
Explanation:
We know that all atoms in a compound are expected to obey the octet rule and we use this rule to ascertain the correctness of any chemical structure.
The structure of carbon IV oxide drawn perfectly satisfies the octet rule for each atom. Each atom in the molecule has eight electrons around its valence shell.
Therefore,since CO2 has sixteen valence electrons, we can conclude that; this structure is correct due to the total number of bonds and electrons.
help! help! plz Why do two H atams combine to Form the molecule H2 while He remains monotonic?
How atoms interact with other atoms is largely dependant on the number of electrons on its outermost layer. The electrons on this layer are called valence electrons.
As you might know, atoms have their electrons arranged in layers/shells, starting at k, l m, n etc. Each layer has a maximum number of electrons it can accommodate, with the outermost one being the valence shell. The first layer (k) can accomodate 2 electrons, the second one (l) can accomodate 8, as can the third one (m) etc.
As a rule of thumb, most atoms don't like being alone. These atoms have a valence shell that isn't saturated. This is the case for hydrogen(1), with one free slot in its outter shell.
However, atoms like helium are a bit different. They are inert, and don't need to bond with other atoms. This is because their valence shell is saturated. In this case, helium saturated the k shell with 2 electrons. Helium in this form will not form bonds.
However, hydrogen is still out there looking for buddies. Hydrogen will bind with any other atom with a free electron. Being extremely common, it's likely that said atom will be another hydrogen.
However, another common example would be for 2 hydrogens to bond with one oxygen, forming h2O (oxygen can form 2 bonds)
Conclusion : helium is inert and will not interact with other atoms. Hydrogen is not, and thus needs to bond with other atoms.
ii) During burning, elements in the coal are
converted to compounds called ????
Answer:
Gasification refers to the conversion of coal to a mixture of gases, including carbon monoxide, hydrogen, methane, and other hydrocarbons, depending on the conditions involved.
The student measured 75.0 g of water into the beaker and lit the burner, the temperature of
the water went up by 8.9 °C. The specific heat capacity of water is 4.184 J/g.C.
Calculate the energy that entered the water.
help!!!
Answer:
d) 2792.8 J
Explanation:
Which mission is not going to explore outside of the solar system?
A. SAFIR
B. Europa Clipper
C. MIRI
D. Kepler
What is the main purpose of the curiosity rover ?
Answer:
What is the main purpose of the curiosity rover ?
Explanation:
Curiosity's mission is to determine whether the Red Planet ever was, or is, habitable to microbial life. The rover, which is about the size of a MINI Cooper, is equipped with 17 cameras and a robotic arm containing a suite of specialized laboratory-like tools and instruments.
Answer:
Curiosity's mission is to determine whether the Red Planet ever was, or is, habitable to microbial life. The rover, which is about the size of a MINI Cooper, is equipped with 17 cameras and a robotic arm containing a suite of specialized laboratory-like tools and instruments.
ASAP IM ON A TIMER Please select the word from the list that best fits the definition
is a cause of nonpoint-source pollution
a. non. point source pollution
b. boat and jet skis on a lake
c. point source pollution
d. sludge
e. trash dumping
f. Adopt. A. Beach
Answer:
a. non. point source pollution
Explanation:
also known as NPS pollution
I have the smallest atomic number of all the
elements that have electrons in three different
energy levels. Who am I?
The element with the smallest atomic number is hydrogen
What is atomic number?
A chemical element's atomic number is its position in the periodic system, which places the elements in ascending order of the number of protons in their nuclei. As a result, the atomic number is also determined by the number of protons, which is always equal to the number of electrons in a neutral atom.
The charge number of an atomic nucleus is the chemical element's atomic number, also known as nuclear charge number. This is the number of protons present in the nucleus of each atom of that element, or the proton number, for conventional nuclei. The atomic number of common chemical elements can be used to uniquely identify certain elements.
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One mole (mol) of nitrogen monoxide (NO) has a mass of 30.01 g. When
precisely 2 moles of NO(g) are produced in the following chemical reaction, 43
kcal of heat energy is "absorbed."
N2(g) + O2(g) → 2 NO(g), AH = +43 kcal
How much heat (in kJ) is exchanged when 152 g of NO(g) is produced?
Answer:
455.6 kJ.
Explanation:
Hello there!
In this case, according to the given reaction, we know that 2 moles of NO require 43 kcal of energy, thus, for the energy required by 150 g of NO we first need the moles, considering its molar mass (30.01 g/mol):
[tex]152g*\frac{1mol}{30.01g} =5.065mol[/tex]
Thus, we apply the following dimensional analysis to obtain the energy absorbed by 5.065 moles:
[tex]5.065mol*\frac{43kcal}{2mol} =108.9kcal[/tex]
Which kJ turns out:
[tex]108.9kcal*\frac{4.184kJ}{1kcal}\\\\455.6kJ[/tex]
Best regards!
Based on your understanding of color's relationship to wavelength, identify the approximate wavelength of light (nm) emitted by strontium when it was burned in Part C. (No quantitative data was collected for this; you are giving an approximate value only, based on what you observed.) Explain your reasoning in full, making sure to cite specific data and observations to support your answer.
Answer:
The flame colour of strontium is red. Red has a wavelength of around 620 to 750 nm.
Explanation:
Visible light is part of the electromagnetic spectrum. The electromagnetic waves are composed of electric and magnetic fields.
The visible spectrum is composed of seven different wavelengths that corresponds to different colours. When a metallic element is exposed flame, one of these colours is observed. This is commonly called the flame test.
The flame colour of strontium is red. Red has a wavelength of around 620 to 750 nm.
The approximate wavelength of light (nm) emitted by strontium when it was burned is red, where red has a wavelength of round 620-750 nm.
Wavelength of light emitted by strontiumGenerally, Visible mild is phase of the electromagnetic spectrum. the electromagnetic waves are composed of electric powered and magnetic fields. When a metal factor is uncovered flame, one of they seven colors of visible spectrum is seen.
The flame shade of strontium is red, where red has a wavelength of round 620-750 nm.
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what is the steps you need to determine the molar mass of unknown solute
the formula is heard and difficult to solve
double displacement reaction - write the balanced conventional, total ionic and net ionic equations:
Ca I2 (aq) + K2 C2 O4 (aq) >
Answer:
See explanation.
Explanation:
Hello!
In this case, these three equations show how the molecule behaves in terms aqueous and solid species; thus, we first write balanced conventional equation:
[tex]Ca I_2 (aq) + K_2 C_2 O_4 (aq)\rightarrow CaC_2O_4(s)+2KI(aq)[/tex]
Whereas the solid product is CaC₂O₄ based off its low solubility. Next, we ionize the aqueous species to obtain the total ionic equation:
[tex]Ca^{2+} +2I^- + 2K^+ +(C_2 O_4)^{2-} \rightarrow CaC_2O_4(s)+2I^- + 2K^+[/tex]
Finally, we cancel out potassium and iodide ions as they are the spectator ions due to their presence at both reactants and products in order to obtain the net ionic equation:
[tex]Ca^{2+} (aq) +(C_2 O_4)^{2-}(aq) \rightarrow CaC_2O_4(s)[/tex]
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someone help. trying to past this test but keep failing on this question.
Atoms may emit light energy when____
a. protons move to a higher energy level
b. protons move to a lower energy level
c. electrons move to a higher energy level
d. electrons move to a lower energy level
Answer:
When electrons move to a lower energy level.
Explanation:
100 POINTS PLEASE ANSWER!
Read the following chemical equation.
Fe + O2 → Fe2O3
Which of the following fractions can be used for the mole ratio to determine the mass of Fe from a known mass of Fe2O3?
four over two
three over two
two over three
two over four
Answer:
Answer would be 4/2
Explanation:
A is the best answer choice because it was between A and D but 2 is not the denominator so it couldnt be D
Fe + O2 → Fe2O3 four over two fractions can be used for the mole ratio to determine the mass of Fe from a known mass of Fe2O3. Therefore, option A is correct.
What do you mean by mole ratio ?The mole ratio is a conversion factor that is derived from the coefficients of the compounds in a balanced equation. As a result, the mole ratio is used to convert between quantities of compounds in a chemical reaction.
Using the atomic masses, convert the mass of each element to moles of each element. Divide the number of moles of each element by the smallest number of moles to find the ratio or moles of each element.
Four over two is the best answer choice because it was between A and D, but 2 is not the denominator, so it couldn't be D.
Thus, four over two fractions can be used for the mole ratio to determine the mass of Fe from a known mass of Fe2O3, option A is correct.
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Which of the following describes a competitive relationship?
a.Owl and field mouse
b. Oak tree and pine tree
c.Spider and fly
d.Shark and remora fish
НЗРО4 +
KOH ->
Н2О +
KЗРО4
Answer:
I am assuming you want it balanced?
НЗРО4 +
3KOH ->
3Н2О +
KЗРО4
Explanation:
Determine the energy change in the following reaction. This reaction is considered ...
C6H12 + O2
CO2 + H2O + heat
energy absorbed is equal to the energy released
endothermic
O isothermic
O exothermic
Answer:isothermic
Explanation:
Answer:
Energy abosorbed = Energy released.
Thus ISOTHERMIC
which properties represent a non metal ( there are more than one answer )
a. malleable
b. dull
c. poor conductors
d. brittle
e. ductile
Answer:
B.) Dull
C.) Poor conductors
D.) Brittle
Everything in the universe that we can detect is either matter or ___________.
Answer:
Everything in the universe that we can detect is either matter or energy.
Everything in the universe that we can detect is either matter or energy.
What is energy?Energy exists in the capacity of a physical system to do work. The common symbol for energy exists in the uppercase letter E. The standard unit stands for the joule, symbolized by J. One joule (1 J) exists as the energy resulting from the equivalent of one newton (1 N) of force operating over one meter (1 m) of displacement.
A matter is referred as a substance having a certain mass and can take up a certain volume in the space. For example pen, pencil, toothbrush, water, milk are matters as well as car, bus, bicycle is also a matter. So matter is considered as a living thing and a non-living thing.
Energy, is the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms.
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The mass fractions of a mixture of gases are 15 percent nitrogen, 5 percent helium, 60 percent methane, and 20 percent ethane with a total mixture molecular weight of 16.12 kg/kmole. Determine the mole fraction of each constituent, the partial pressure of each constituent when the mixture pressure is 1200 kPa and the apparent specific heats of the mixture when the mixture is at room temperature
Answer:
See explanation
Explanation:
Number of moles of each gas is
Nitrogen = 15/28 = 0.536 kmoles
Helium = 5/4 = 1.25 kmoles
Methane = 60/16 = 3.75 kmoles
Ethane = 20/30 = 0.67 kmoles
Total number of moles = 0.536 kmoles + 1.25 kmoles + 3.75 kmoles + 0.67 kmoles = 6.206 kmoles
Mole fraction of each gas;
Nitrogen = 0.536 kmoles/6.206 kmoles = 0.086
Helium = 1.25 kmoles/6.206 kmoles = 0.201
Methane = 3.75 kmoles/6.206 kmoles =0.604
Ethane = 0.67 kmoles/6.206 kmoles =0.108
Partial pressure of each gas;
Nitrogen = 0.086 * 1200 kPa = 103.2 kPa
Helium = 0.201 * 1200 kPa = 241.2 kPa
Methane = 0.604 * 1200 kPa = 724.8 kPa
Ethane = 0.108 * 1200 kPa = 129.6 kPa
Apparent specific heat at constant pressure;
Cp = (0.15 * 1.039) + (0.05 * 5.1926) + ( 0.6 * 2.2537) + (0.2 * 1.7662)
Cp = 2.12 KJ Kg-1 K-1
Cv = Cp- Ru/M
Cv= 2.12 - 8.314/16.12 = 1.604 KJ Kg-1 K-1
Which of the following is an educated guess?
O Inference
O Observation
O Hypothesis
O Quantitative
Five kilograms of liquid carbon tetrachloride undergo a mechanically reversible, isobaric change of state at 1 bar during which the temperature changes from 0∘C to 20∘C0 ∘ C to 20 ∘ C Determine ΔVt,W,Q,ΔHt, and ΔUt.ΔV t ,W,Q,ΔH t , and ΔU t . The properties for liquid carbon tetrachloride at 1 bar and 0∘C0 ∘ C may be assumed independent of temperature: β=1.2×10−3K−1,CP=0.84kJ⋅kg−1⋅K−1, and rho=1590kg⋅m−3β=1.2×10 −3 K −1 ,C P =0.84kJ⋅kg −1 ⋅K −1 , and rho=1590kg⋅m −3
Answer:
Explanation:
From the information given:
Mass of carbon tetrachloride = 5 kg
Pressure = 1 bar
The given density for carbon tetrachloride = 1590 kg/m³
The specific heat of carbon tetrachloride = 0.84 kJ/kg K
From the composition, the initial volume of carbon tetrachloride will be:[tex]= \dfrac{5 \ kg }{1590 \ kg/m^3}[/tex]
= 0.0031 m³
Suppose [tex]\beta[/tex] is independent of temperature while pressure is constant;
Then:
The change in volume can be expressed as:
[tex]\int ^{V_2}_{V_1} \dfrac{dV}{V} =\int ^{T_2}_{T_1} \beta dT[/tex]
[tex]In ( \dfrac{V_2}{V_1}) = \beta (T_2-T_1)[/tex]
[tex]V_2 = V_1 \times exp (\beta (T_2-T_1))[/tex]
[tex]V_2 = 0.0031 \ m^3 \times exp (1.2 \times 10^{-3} \times 20)[/tex]
[tex]V_2 = 0.003175 \ m^3[/tex]
However; the workdone = -PdV
[tex]W = -1.01 \times 10^5 \ Pa \times ( 0.003175 m^3 - 0.0031 \ m^3)[/tex]
W = - 7.6 J
The heat energy Q = Δ h
[tex]Q = mC_p(T_2-T_1)[/tex]
[tex]Q = 5 kg \times 0.84 \ kJ/kg^0 C \times 20[/tex]
Q = 84 kJ
The internal energy is calculated by using the 1st law of thermodynamics; which can be expressed as;
ΔU = ΔQ + W
ΔU = 84 kJ + ( -7.6 × 10⁻³ kJ)
ΔU = 83.992 kJ
Which statement is true about the speed of light? (2 points)
Light travels relatively slowly.
Distance in space is measured using the speed of light.
Time in space is measured using the speed of light.
The speed of light is unknown
Answer:
2nd option is the correct answer of this question
Answer:
yes it is b
Explanation:
A 6.165 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 10.27 grams of CO2 and 3.363 grams of H2O are produced. In a separate experiment, the molecular weight is found to be 132.1 amu. Determine the empirical formula and the molecular formula of the organic compound.
Answer:
Explanation:
mass of carbon in 10.27 g of CO₂ = 12 x 10.27 / 44 = 2.80 g
mass of hydrogen ( H ) in 3.363 g of H₂O = 2 x 3.363 / 18
= .373 g
These masses would have come from the sample of 6.165 g .
Rest of 6.165 g of sample is oxygen .
So oxygen in the sample = 6.165 - ( 2.8 + .373 ) = 2.992 g
Ratio of C , H , O in the sample
2.8 : .373 : 2.992
C: H : O : : 2.8 : .373 : 2.992
Ratio of moles
C: H : O : : 2.8/12 : .373/1 : 2.992 / 16
C: H : O : : .2333 : .373 : .187
C: H : O : : .2333/.187 : .373/.187 : .187/.187
C: H : O : : 1.247 : 1.99 : 1
C: H : O : : 5 : 8 : 4 ( after multiplying by 4 )
Hence empirical formula
C₅H₈O₄
Molecular formula ( C₅H₈O₄ )n
n ( 5 x 12 + 8 x 1 + 4 x 16 ) = 132
n x ( 60 + 8 + 64 ) = 132
n = 1
Molecular formula = C₅H₈O₄.
Butane gas reacts with oxygen gas to give carbon dioxide gas and water vapor (gas). If you mix butane and oxygen in the correct stoichiometric ratio, and if the total pressure of the mixture is 392 mmHg, what is the pressure (in mmHg) of water vapor after the reaction has completed (temperature and volume do not change).
Answer:
118.776 mmHg
Explanation:
The equation of the reaction is;
C4H10(g) + 13/2 O2(g) ------> 4CO2(g) + 5H20(g)
Now the mole ratio according to the balanced reaction equation is;
1 : 6.5 : 4 : 5
Hence, the total number of moles present = 1 + 6.5 + 4 + 5 = 16.5 moles
Mole fraction of water vapour = 5/16.5 = 0.303
We also know that;
Partial pressure= mole fraction * total pressure
Partial pressure of H20(g) = 0.303 * 392 mmHg = 118.776 mmHg
The pressure (in mmHg) of water vapor is 118.78 mmHg
Balanced equation for the reaction
Butane reacts with oxygen according to the following equation
2C₄H₁₀ + 13O₂ —> 8CO₂ + 10H₂O
How to determine the mole fraction of water Mole of butane = 2 moles Mole of oxygen = 13 molesCarbon (IV) oxide = 8 moles Mole of water = 10 moles Total moles = 2 + 13 + 8 + 10 = 33 moles Mole fraction of water =?Mole fraction = mole / total mole
Mole fraction of water = 10 / 33
Mole fraction of water = 0.303
How to determine the partial pressure of waterMole fraction of water = 0.303Total pressure = 392 mmHgPartial pressure of water =?Partial pressure = mole fraction × total pressure
Partial pressure of water = 0.303 × 392
Partial pressure of water = 118.78 mmHg
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Intermolecular forces exist between what?
Answer:
Intramolecular forces are the forces that hold atoms together within a molecule. Intermolecular forces are forces that exist between molecules.
Explanation: