Answer:
Gaps are produced in the light spectra that correspond to wavelengths of absorbed photons.
Explanation:
When electrons in atoms absorb energy, they move from a lower energy level to a higher energy level. With time, they revert to the their original energy state emitting a photon of light of appropriate wavelength.
The absorbed photons do not show up in the spectrum. They appear as dark lines in the spectrum. Hence, the absorption spectrum is the exact inverse of the emission spectrum. The dark lines in the spectrum indicates that the colors that ought to occupied those points there have been absorbed.
Find the Molarity of 6.25 grams of barium nitrate dissolved in 250 mL solution.
Answer:
0.0956 M
Explanation:
Step 1: Calculate the moles corresponding to 6.25 g of barium nitrate (solute)
The molar mass of barium nitrate is 261.34 g/mol.
6.25 g × 1 mol/261.34 g = 0.0239 mol
Step 2: Convert the volume of solution to liters
We will use the conversion factor 1 L = 1000 mL.
250 mL × 1 L/1000 mL = 0.250 L
Step 3: Calculate the molarity of the solution
The molarity is equal to the moles of solute divided by the liters of solution.
M = 0.0239 mol / 0.250 L = 0.0956 M
What must be true about two objects for conduction to take place?
The objects must be different temperatures and they must be in contact.
The objects must be the same temperature and they must be in contact
The objects must be different temperatures and they must be insulators.
O The objects must be the same temperature and they must be insulators.
Answer:
The objects must be different temperatures and they must be in contact.
Explanation:
For conduction to take place between two objects, they must be in contact with one another and at different temperatures.
Generally, heat transfer takes place over a gradient i.e. from a region of higher temperature to one with a low temperature. If two places or bodies have the same temperature, heat transfer will not take place. In conduction, the two bodies must be in contact with one another. The collision of molecules of one body transfers this kinetic energy to the other one in contact with it.Answer:
The objects must be different temperatures and they must be in contact.
Explanation:
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When an atom of oxygen forms an ion, what is the most likely charge for that ion?
a. -2
b. -8
C. +2
d. -6
Answer:
b option is the answer.
Answer:
-2
__________________________________________________________
How many electrons does Oxygen need:
We know that oxygen has an electric configuration of:
2 , 6 [8 electrons]
From the octet rule, we know that all elements try to get to the electronic configuration of the nearest noble gas
In the case of Oxygen, the nearest noble gas is Neon with the electronic configuration:
2 , 8 [10 electrons]
From the above, we can see that oxygen needs 2 more electrons in order to attain the nearest noble gas configuration
What will be the Charge on the ion?:
We know that electrons are negatively charged
Once oxygen gains 2 electrons to attain noble gas configuration, it will have 2 more electrons than it should have
So, the charge on the ion will be -2 since there are 2 extra electrons and both of the electrons contribute a negative charge
Hence, the charge is -2
what is the most likely arrangement of particles in a liquid?
O Farther apart and hire an
energy than those in a gas
O Farther apart and lower energy than those in a solid
O Closer together in lower and energy than those in gas
O Closer together and Lauren energy than those in a solid
Answer:
c. closer together and lower in energy than those in a gas.
Explanation:
In the different states of matter, the arrangement of particles and the kinectic energy that exists in the state of matter varies depending on which state the matter is in.
The particles of Solid are denser and closer than that of liquid. In solid state, the force of attraction between the particles are greater than the kinectic energy of the particles in a solid matter. Therefore, the particles in solid matter are closer together than those in liquid and gas. And also, the energy is lower in Solid matter than those in liquid and gas.
Liquid on the other hand, has denser particles that are closer together than those in gas. Also, liquid particles has lower energy than those in gas.
Particles in gas are more freer and farther apart from each other than the particle sin solid and gas. Also, particles in gas is greater than those in liquid and solid.
Therefore, the likely arrangement of particles in a liquid is that they are:
c. closer together and lower in energy than those in a gas.
Determine the total number of electrons in the d orbitals of an atom of tin, Sn (Z = 50).
Answer:
Explanation:
Sn (Z = 50 )
Electronic configuration = [Kr] 4d¹⁰5s²5p²
= 1s²2s²p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²5p²
So , total number of electrons in d orbital = 10 + 10 = 20 .
A flask of ammonia is connected to a flask of an unknown acid HX by a 1.68 m glass tube (where "X" represents a halogen). As the two gases diffuse down the tube, a white ring of NH4X forms 115 cm from the ammonia flask. Identify element X (Name or symbol).
Answer:
Explanation:
white ring of NH₄X is formed . Here X is Cl and
NH₄X is NH₄Cl ( ammonium chloride )
The reaction is as follows
NH₃ + HCl = NH₄Cl ( white fume )
The acid that reacts with ammonia has been Hydrochloric acid (HCl), and the element X in the acid has been Chlorine (Cl).
The ammonia has been the gas with the pungent smell. It has been the compound with the dihybrid element used for the production of various nitrogen compounds.
The reaction of Ammonia with acid results in the formation of ammonium ions. The ions on reacting with the basic part of the acid, form the salt and give the product.
The white ring with the reaction of ammonia has been formed of the ammonium chloride. Thus the acid that reacts with ammonia has been Hydrochloric acid (HCl), and the element X in the acid has been Chlorine (Cl).
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The half-life of the radioactive isotope Carbon-14 is about 5730 years.
a. What percentage of the original amount of Carbon-14 is left after 20,000 years?
b. If an old wooden tool is found in a cave and the amount of Carbon-14 present in it is estimated to be only 42% of the original amount, approximately how old is the tool?
c. Radiocarbon dating is not as easy as these exercises might lead you to believe. With the help of your classmates, research radiocarbon dating and discuss why our model is somewhat over-simplified.
Answer:
See explanation for details
Explanation:
a) Now from the data given, recall that;
N/No = (1/2)t/t1/2
Where,
N= amount of radioactive material remaining at time t
No= Amount of radioactive material originally present
t= time taken for N amount of radioactive material to remain
t1/2= half life of radioactive material
So,
N/No = (1/2)^20,000/5730
N/No = (1/2)^3.49
N/No = 0.089
Since the fraction N/No is the fraction remaining after t years, then;
Percentage of Carbon-14 left after 20,000 years = 0.089 * 100 = 8.9%
b) From;
0.693/t1/2 = 2.303/t log No/N
Given that N = 0.42 No
Hence;
0.693/5730 = 2.303/t log (No/0.42No)
1.21 * 10^-4 = 0.87/t
t= 0.87/1.21 * 10^-4
t = 7190 years
c) Radiocarbon dating is a method of obtaining the age of an object derived from plants or animals by comparing the Carbon-14 activity of living things with that of the sample under study. Due to contamination, the age of artifacts obtained by Carbon-14 dating may yield outlying figures.
Which term describes boron?
A. Metal
B. Metalloid
C. Noble Gas
D. Nonmetal
Answer:
Boron is Nonmetal
Explanation:
hope it's helped
A student determines that a 1.5 g mixture of CaCO3(s) and
NaHCO3(s) contains 0.010 mol of NaHCO3(s). Based on the student's
measurement, what is the mass percent of Na in the mixture?
We are given:
Mass of the mixture = 1.5 grams
Number of Moles of NaHCO₃ = 0.01 mole
Mass of 0.01 moles of NaHCO₃:
Mass = number of moles * Molar mass
Mass = 0.01 * 84
Mass = 0.84 grams
Mass% of Na in NaHCO₃:
Molar mass of NaHCO₃ = 84 grams/mol
Molar mass of Na = 23 grams / mol
Mass% = (Molar mass of Na / Molar mass of NaHCO₃) * 100
Mass% = (23/84) * 100
Mass% = 27%
Mass of Na in 0.01 moles:
Since the Mass% of Na is 27% and the total mass is 0.84 grams
So, we can say that 27% of 0.84 is the mass of Na
Mass of Na = 0.84 * 0.27
Mass of Na = 0.23 grams
Mass% of Na in the mixture:
Total mass of the mixture = 1.5 grams
Mass of Na in the mixture = 0.23 grams
Mass% of of Na in the Mixture = (Mass of Na / Mass of Mixture) * 100
Mass% of Na = (0.23 / 1.5) * 100
Mass% of Na = 15.3%
Therefore, we have 15.3% Na in the given mixture by mass
Coolant is added to car radiators to keep the water from becoming a gas and evaporating when the car gets hot. Which physical property of water is the coolant affecting in this case?
Answer:
Boiling point.
Heat is required to break the intermolecular forces of attraction between the particles. The role of coolant is to lowers the freezing point of water, and to increase the boiling point of water.
What is phase transition?Phase transition is a process in which transition takes place from one state to another of a medium on changing temperature or pressure. Phase transition is a physical process as there is no breaking of old bond and forming of new bonds takes place.
Coolant is added to car radiators to keep the water from becoming a gas and evaporating when the car gets hot. The role of coolant is to lowers the freezing point of water, and to increase the boiling point of water.
Therefore, the role of coolant is to lowers the freezing point of water, and to increase the boiling point of water.
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Which graph shows the pressure-temperature relationship for a gas at a fixed volume?
A. Graph D
B. Graph B
C. Graph A
D. Graph C
Answer:
The answer is
C. Graph A
Answer:
Graph A
Explanation:
:)
Heat energy is useful to us in all the following ways except:
Heat energy can be harnessed to warm homes.
Heat is converted to mechanical energy in engines to do work.
Heat energy can be used to melt materials and change their shape to create useful objects.
Heat energy is transferred to cooler objects to reduce the temperature of those objects.
Answer:
Heat energy is transferred to cooler objects to reduce the temperature of those objects.
Explanation:
The fourth option is not correct.
A correct way of writing it would be : " Heat energy is transferred from cooler objects to reduce the temperature of those objects.". When an object loses heat energy, its temperature reduces. Conversely, when an object receives heat energy, its temperature increases.
What are 2 ways that convection currents in the oceans distribute the sun's energy?
A: warm water is carried from the equator to the poles
B: living things swim in the cool and warm parts of the ocean
C: icebergs are carried from the poles to the equator
D: Nutrient-rich water is brought to the ocean surface
Answer:
When air in contact with the ocean is at a different temperature than the sea surface, heat transfer by conduction takes place. The ocean also absorbs and stores energy from the sun, and when precipitation falls, it releases heat energy into the atmosphere.
Hope it helps:)
Answer:
A and D
Explanation:
An element has the mass number 12 and atomic number 6. The number of neutron in it is?
A)6
B)10
C)4
D)8
Answer:
12-6=6
the answer is A)6
3. A calibration curve plotting E vs. pNi is used to measure the concentration of Ni2+ in solution at 25 °C using a solid Ni electrode. What is the slope of the calibration curve?
Answer: the slope of the calibration curve is - 0.0295
Explanation:
as things are not under standard conditions that is; 1M of each reactants at T = 25°C and P = 1 atm; therefore we will use the Nernst Equation.
E = a × pNi + b
a is the slope
pNi = -log [Ni²⁺] = log 1/[Ni²⁺]
therefore the Half reaction;
Ni²⁺ (aq) + 2e⁻ = Ni (s)
here; E = E₀ + RT/zF ln[Ni²⁺]
we know that;
gas constant R = (8.31 J/mol-K)
absolute temperature T =25°C = 298 K
number of moles of electrons transferred by the cell's reaction z = 2
F is Faraday constant, = 9.64853399(24)×10⁴ C mol−1
E₀ = b
RT/zF ln[Ni²⁺] = alog 1/[Ni²⁺]
Logx = Ln x / Ln 10 = Ln (x/2.3)
so
a = (RT/zF ln[Ni²⁺])/log 1/[Ni²⁺]
= (RT/zF ln[Ni²⁺]) / ((ln 1/[Ni²⁺]) / 2.3)
= (2.3RT/zF ln[Ni²⁺]) / (ln 1/[Ni²⁺])
= (2.3RT/zF ln[Ni²⁺]) / (-ln [Ni²⁺])
= -2.3RT/zF
so we substitute
= (-2.3 × 8.31 ×298 ) / (2 × 9.64853399(24) × 10⁴)
= - 0.0295
therefore the slope of the calibration curve is - 0.0295
How many moles of H2O2 are needed to react with 1.07 moles of N2H4?
Answer:
2.14 moles of H₂O₂ are required
Explanation:
Given data:
Number of moles of H₂O₂ required = ?
Number of moles of N₂H₄ available = 1.07 mol
Solution:
Chemical equation:
N₂H₄ + 2H₂O₂ → N₂ + 4H₂O
now we will compare the moles of H₂O₂ and N₂H₄
N₂H₄ : H₂O₂
1 : 2
1.07 : 2×1.07 = 2.14 mol
A chemist heats 34.10 g of nickel to 77.17 °C, then places the metal sample in the cup of water shown in the interactive.
Calculate the final temperature of the water. The specific heat of nickel is 0.444 J/g °C and the specific heat of water is
4.184 J/g °C.
Answer:
[tex]T_{eq}=27.97\°C[/tex]
Explanation:
Hello.
In this case, for equilibrium temperature problems, it is said that the heat balance allows us to notice how the hot substance heats up the cold substance until they reach the equilibrium temperature which is a temperature that remains constant upon time. Thus, since here the hot substance is the nickel and water gains that released heat by the nickel we can write:
[tex]Q_{Zn}=-Q_{water}[/tex]
Which can be written in terms of temperatures, masses and specific heats:
[tex]m_{Zn}C_{Zn}(T_{eq}-T_{Zn})=-m_{water}C_{water}(T_{eq}-T_{water})[/tex]
Thus, solving for the equilibrium temperature we write:
[tex]T_{eq}=\frac{m_{Zn}C_{Zn}T_{Zn}+m_{water}C_{water}T_{water}}{m_{Zn}C_{Zn}+m_{water}C_{water}}[/tex]
Now, plugging in the known data, considering the mass of water 64.00-4.00=60.00 g and its initial temperature, 25.00°C, we obtain:
[tex]T_{eq}=\frac{34.10g*0.444\frac{J}{g\°C}* 77.17\°C+60.0g*4.184\frac{J}{g\°C}*25.00\°C}{34.10g*0.444\frac{J}{g\°C}+60.0g*4.184\frac{J}{g\°C}}\\\\T_{eq}=27.97\°C[/tex]
Best regards!
The final temperature of water is required.
The final temperature of water is [tex]27.97^{\circ}\text{C}[/tex].
T = Equilibrium temperature
[tex]T_n[/tex] = Temperature of nickel = [tex](77.17^{\circ}\text{C}+273.15)\ \text{K}[/tex]
[tex]T_w[/tex] = Temperature of water = [tex](25^{\circ}\text{C}+273.15)\ \text{K}[/tex]
[tex]c_n[/tex] = Specific heat of nickel = [tex]0.444\ \text{J/g}^{\circ}\text{C}[/tex]
[tex]c_w[/tex] = Specific heat of water = [tex]4.184\ \text{J/g}^{\circ}\text{C}[/tex]
[tex]m_n[/tex] = Mass of nickel = 34.1 g
[tex]m_w[/tex] = Mass of water = 60 g
The heat balance of the system is given by
[tex]m_wc_w(T-T_w)=m_nc_n(T_n-T)\\\Rightarrow m_wc_wT-m_wc_wT_w=m_nc_nT_n-m_nc_nT\\\Rightarrow T=\dfrac{m_nc_nT_n+m_wc_wT_w}{m_wc_w+m_nc_n}\\\Rightarrow T=\dfrac{34.1\times 0.444\times 350.32+60\times 4.184\times 298.15}{60\times 4.184+34.1\times 0.444}\\\Rightarrow T=301.12\ \text{K}=301.12-273.15\\\Rightarrow T=27.97^{\circ}\text{C}[/tex]
The final temperature of water is [tex]27.97^{\circ}\text{C}[/tex].
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How do you know about a substance if you know its temperature
A. How heavy the substance is
B. How large or small the particles of the substance are
C. How hot or cold the substance is
D. How many particles are in the substance
Answer:
How hot or cold the substance is
Explanation:
You can do a lot with just the temperature of a substance. Chemists can use this to identify the substance because of the temperature at which it melts. They can then find out how long it took to melt, which can also help.
Answer:c how hot or cold
Explanation:
A quantity of water vapor at 100°C is condensed to liquid water at the same temperature. In the process, 180,414.08 joules of heat are released. What is the quantity of water that is condensed?
Answer:
0.08kg
Explanation:
Given parameters:
Temperature of water = 100°C
Quantity of heat released = 180414.08J
Unknown:
Quantity of water condensed = ?
Solution:
This is simple phase change process without any attendant change in temperature.
To solve this problem, use the formula below;
H = mL
H is the heat released
m is mass
L is the latent heat of condensation of water = 2260 kJ/kg
Insert the parameters and solve;
180,414.08 = m x 22.6 x 10⁵ J/kg
m = [tex]\frac{180414.08}{2260000}[/tex] = 0.08kg
A 9.439 mol sample of oxygen gas is maintained in a 0.8200 L container at 304.4 K. What is the pressure in atm calculated using the van der Waals' equation for O2 gas under these conditions
Answer:
[tex]P=273.1atm[/tex]
Explanation:
Hello!
In this case, since the Van der Waals' equation is used in order to analyze a gas slightly deviated from the ideal condition and is defined as:
[tex]P=\frac{RT}{v_m-b}-\frac{a}{v_m^2}[/tex]
Whereas a and b for oxygen are 0.0318 L/mol and 1.36 atm*L²/mol² respectively and represent the effective volume and the eventual interactions among the gas molecules. Moreover, the molar volume, vm, is:
[tex]v_m=\frac{0.8200L}{9.439mol}=0.08687L/mol[/tex]
Thus, the required pressure turns out:
[tex]P=\frac{0.082\frac{atm*L}{mol*K}*304.4K}{0.08687L/mol-0.0318L/mol}-\frac{1.36\frac{atm*L^2}{mol^2} }{(0.08687L/mol)^2}\\\\P=453.3atm-180.2atm\\\\P=273.1atm[/tex]
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A 1.9450 g sample containing only Na2CO3 (F.M. 105.99) and NaHCO3 (F.M. 84.01) is titrated with 35.31 mL of 0.8724 M HCl. Calculate the percentage sodium carbonate and sodium bicarbonate.
Answer:
1.0979g of Na2CO3
0.8471g of NaHCO3
Explanation:
NaHCO3 and Na2CO3 reacts with HCl as follows:
NaHCO3 + HCl → NaCl + H2O + CO2
Na2CO3 + 2HCl → 2NaCl + H2O + CO2
Moles of HCl required were:
0.03531L * (0.8724mol / L) = 0.03080 moles of HCl
With this information we can write 2 equations:
1.9450g = X + Y (1)
X is the mass of NaHCO3 and Y is mass of Na2CO3
Also we can write:
0.03080 moles = X/84 + 2Y/106 (2)
Where 84 is molar mass of NaHCO3 and 106 is molar mass of Na2CO3, 2 is due the reaction (2 moles of HCl react per mole of Na2CO3)
Replacing (1) in (2):
0.03080 moles = (1.9450-Y)/84 + 2Y/106
0.03080 = 0.023155 - Y/84 + Y/53
0.007645 = 0.00696316Y
Y = 1.0979g of Na2CO3
And mass of NaHCO3 =
1.9450g - 1.0979g =
0.8471g of NaHCO3
Select the correct answer.
Which letter represents the wavelength of the wave?
c
ОА а
OB. b
ОС, с
OD d
Answer:
it is the letter D
Explanation:
Considering the definition of wavelength, the correct answer is option D. You can see that "d" represents the distance between two consecutive highs, and then the wave repeats. In this way the definition of wavelength is fulfilled.
Definition of wavelengthIn a periodic wave, that is, for the type of wave that repeats with exactly the same shape every given time interval, the wavelength is the physical distance between two points from which the wave repeats.
That is, the wavelength is its spatial period, that is, the distance at which the waveform repeats itself. Normally, two consecutive points that have the same phase are considered: two maximums, two minimums, two zero crossings (in the same direction).
In summary, the wavelength is the actual distance that a disturbance can travel in a given time interval, the quas between two consecutive maxima with respect to the physical property of the wave.
Letter that represent the wavelength of the waveConsidering the definition of wavelength, the correct answer is option D. You can see that "d" represents the distance between two consecutive highs, and then the wave repeats. In this way the definition of wavelength is fulfilled.
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What is the primary cause of diffusion? some substances can dissolve in solvents heat added to a substance random internal motion of atoms and molecules attraction of opposite atomic charges
Answer:
random internal motion of atoms and molecule
Explanation:
The primary cause of diffusion is the random internal motion of atoms and molecules.
Randomness of atoms and molecules results in diffusion.
Diffusion is the movement of particles from a region of high concentration to that of lower concentration. Substances often tend to spread out over the concentration gradient. Therefore, they have this propensity to be randomized.Answer:
random internal of motion of atoms and molecules
Explanation:
took assignment on odyssey ware
A solution was prepared by mixing 20.00 mL of 0.100 M and 120.00 mL of 0.200 M. Calculate the molarity of the final solution of nitric acid.
Answer:
0.186M
Explanation:
First, we need to obtain the moles of nitric acid that are given for each solution. Then, we need to divide these moles in total volume (120mL + 20mL = 140mL = 0.140L) to obtain molarity:
Moles Nitric acid:
0.0200L * (0.100mol / L) = 0.00200 moles
0.120L * (0.200mol / L)= 0.02400 moles
Total moles: 0.02400moles + 0.00200moles = 0.026 moles of nitric acid
Molarity: 0.026 moles / 0.140L
0.186MHow many milliliters of an aqueous solution of 0.227 M sodium carbonate is needed to obtain 3.55 grams of the salt?
Answer:
147.6 mL .
Explanation:
sodium carbonate , Na₂CO₃
Molecular weight = 106
3.55 gm of sodium carbonate = 3.55 / 106
= .0335 moles
Let the volume of litre required = V
V litre of .227 M solution will contain
V x .227 moles of sodium carbonate . So
V x .227 = .0335
V = .1476 L
= 147.6 mL .
2. How many orbitals are in the following sublevels?
a. ls
b. 5s
c. 4d
d. 4f
e. 7s
f. 3p
How does heat energy help change shape of metals?
Metals releases heat energy to be able to be shaped.
Heat energy provides more pressure that allows metals to bend.
Heat energy allows metal to become more malleable.
Metals require a lot of heat energy to be destroyed.
Answer: 3
Explanation:
It speed up the molecules to get them to bent and move instead of staying solid
Answer:
c
Explanation:
When enough heat energy is transferred to a metal, the molecules vibrate quickly enough so that the solid metal starts to change shape.
What happens as a roller-coaster car rises up the first hill of its track?
A.
is potential energy increases.
B. Its kinetic energy increases.
O C. Its potential energy decreases.
D. Both its kinetic and potential energy decrease.
SUBMIT
Testbank, Question 098 In the reaction between an alkyne and Na metal in liquid ammonia, the role of Na is as a(n) ___________.
a. catalyst
b. electrophile
c. Brønsted base
d. reducing agent
e. Bronsted acid
Answer:
d. reducing agent
Explanation:
Na acts as a reducing agent. A reducing agent is a substance whose function is to reduce or donate electrons to another, and by doing so it becomes oxidized. We can see the mechanism of the reaction in the image attached below.
does living organism capable of both process
Yes because it can produce unlike nonliving organism