Answer:
I don’t mnow
Explanation:
What is the energy of an electron in a Li+ ion when an electron moves from n = 2 to n =3?
HELP PLEASEEEEEE ASAP
A condition in which bones become weak and brittle.
The body constantly absorbs and replaces bone tissue. With osteoporosis, new bone creation doesn't keep up with old bone removal.
thus 2) is correct.
a disease in which bone tissue becomes breakable and thin.
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Which equation represents a double replacement reaction? A) 2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g) B) 2Al(s) + 3Cl2(g) - 2AlCl3(s) C) 2AlCl3(s) + 2Al(s) + 3Cl2(g) D) AlCl3(aq) + 3KOH(aq) - Al(OH)3(s) + 3KCl(aq)
Answer:
D) AlCl₃(aq) + 3 KOH(aq) → Al(OH)₃(s) + 3 KCl(aq)
Explanation:
Which equation represents a double replacement reaction?
A) 2 Al(s) + 6 HCl(aq) → 2 AlCl₃(aq) + 3 H₂(g)
No, this is a single replacement reaction, in which Al replaces H in its acid.
B) 2 Al(s) + 3 Cl₂(g) → 2 AlCl₃(s)
No, this is a synthesis reaction, in which two simple substances combine to form a compound.
C) 2 AlCl₃(s) → 2 Al(s) + 3 Cl₂(g)
No, this is a decomposition reaction, in which a compound decomposes into simple substances.
D) AlCl₃(aq) + 3 KOH(aq) → Al(OH)₃(s) + 3 KCl(aq)
Yes, this is a double replacement reaction, in which both reactants exchange their cations and anions.
There is a bottle of KCl solution: the volume is 35 mL; its molarity is 3.0 M.
After diluting it into final volume 200 mL, what is the molarity (in M) now?
Answer:
0.525 M
Explanation:
As the problem deals with a dilution process, we can use the following formula:
C₁V₁=C₂V₂Where subscript 1 stands for initial concentration and volume, while 2 stands for the final conditions. Meaning that in this case:
C₁ = 3.0 MV₁ = 35 mLC₂ = ?V₂ = 200 mLWe input the data given by the problem:
3.0 M * 35 mL = C₂ * 200 mLAnd solve for C₂:
C₂ = 0.525 MThink
about the physical properties used to identify elements as either metal,non-metals, or metalloids. Write
Imagine that you are asked to classify a group of elements as either metal, non-metals, or metalloids.
Explain how you would use their physical properties to accomplish this task.
Be sure to –Address the prompt, provide support, and conclude your thoughts. Write legibly and concisely.
Answer:
The elements can be classified as metals, nonmetals, or metalloids. ... Elements are further classified into metals, non-metals, and metalloids based on their properties, ... when they undergo chemical reactions They normally do not accept ... Most metal oxides are basic oxides and dissolve in water to form .
Explanation:
1.
Why are kilometers not a good unit of measurement in space?
T.
2.
What distance measurement unit is used for objects within our solar system?
astronomical
units
3.
How many kilometers are in one astronomical unit?
4.
What distance measurement unit is used for objects outside of our solar
system?
_light
year!
5.
How many kilometers are in one light-year? I
How far away is the nearest star to Earth other than our Sun?
6.
7.
How far away is the center of the Milky Way Galaxy from Earth?
8.
What is the diameter of the Milky Way Galaxy?
A wave travels at 22 m/s and has a wavelength of 11 m. What is its frequency
The answer is 2Hz
To calculate frequency, divide the number of times the event occurs by the length of time.
Gram for gram, fats in food have much more chemical energy than sugar. One component of fat is stearic acid, C18H36O2. When a sample of 1.02 g of stearic acid was burned completely in a bomb calorimeter, the temperature of the calorimeter rose by 4.26oC. The heat capacity of the calorimeter was 9.43 kJ/oC. Calculate the molar heat of combustion of stearic acid in kilojoules per mole.
Answer:
[tex]\mathbf{-1.12 \times 10^4 \ kJ/mol}[/tex]
Explanation:
Given that:
mass (m) of the sample = 1.02 g
number of moles of stearic acid [tex]=\dfrac{mass}{molar mass}[/tex]
[tex]= \dfrac{1.02 \ g}{284.49 \ g/mol} \\ \\ = 0.000358 \ moles[/tex]
The change in temp. [tex]\Delta T = 4.26^0 \ C[/tex]
heat capacity of the calorimeter (c) = 9.43 kJ/° C
Thus, heat due to reaction = cΔT
= 9.43 kJ/° C × 4.26° C
= 40.17 kJ
The heat in kJ/mol = [tex]\dfrac{40.17 \ kJ}{0.00358 \ mol}[/tex]
= 11204.23 kJ/mol
= 1.12 × 10⁴ kJ/mol
As a result of the reaction is exothermic, the heat reaction of the combustion is:
[tex]\mathbf{-1.12 \times 10^4 \ kJ/mol}[/tex]
how many molecules are in 4.08 moles of CCL4
Q3: Match the column A with Column B and write answer in Column C
Answer:
ok
Explanation:
1d
2c
3b
4a
Define a salt bridge. Question 6 options: A pathway between the cathode and anode in which ions are oxidized. A pathway by which counterions can flow between the half-cells without the solutions in the half-cell totally mixing. A pathway in which no ions flow. A pathway between the cathode and anode in which ions are reduced. A pathway, composed of salt water, that ions pass through.
Answer:
A pathway by which counterions can flow between the half-cells without the solutions in the half-cell totally mixing.
Explanation:
In a voltaic cell, oxidation occurs at the anode and reduction occurs at the cathode.
Hence, there is a build up of positive ions at the anode and a build up of negative ions at the cathode. This tends to disrupt the electrical neutrality of the half cells.
Hence, there is a need for negative ions in the salt bridge to flow towards the anode and positive ions in the salt bridge to flow towards the cathode in order to maintain the electrical neutrality of the cells.
Hence, a salt bridge provides a pathway by which counterions can flow between the half-cells without the solutions in the half-cell totally mixing.
Why are half-reactions used in redox reactions?
Answer:
Because a redox reaction holds for both oxidation and reduction.
One half equation is of oxidation and the other is of reduction.
When these two half equations are combined, we get an overall equation of the redox reaction.
The atomic musses of N (99. 64 percent) and 1N (0.36 percent) are 14.00307 amu and 15.0001 amu, respectively. Calculate the average atomic mass of nitrogen. The percentages in parentheses denote the relative abundances C01?
Answer:
14.01 amu
Explanation:
Step 1: Given data
Isotope Atomic mass (am) Abundance (ab)
¹⁴N 14.00307 amu 99.64% (0.9964)
¹⁵N 15.0001 amu 0.36% (0.0036)
Step 2: Calculate the average atomic mass (aam) of nitrogen
We will use the following expression.
aam = ∑ am × ab
aam = 14.00307 amu × 0.9964 + 15.0001 amu × 0.0036 = 14.01 amu
the color of an object that absorbs all colors except red
Answer:
The color black absorbs most colors, while white reflects most colors.
What volume would 75.0g of oxygen gas occupy
Answer:
Explanation: It is already known that 1 mole of the gas( or 32g of O2) is equivalent to 22.4 Litres of the oxygen gas. So, 8g is equivalent to = (22.4/32) × 8 = 5.6 L of the gas.
What would
happen to the
vultures if the
gazelle
decreased?
Answer: If the gazelle population starts to decrease this could lead to some vultures not having enough food to eat
Explanation: This explains the obvious outcome of what would happen.
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Which resources are unevenly distributed throughout Earth?
Select all that apply.
oil
soil
iron
oxygen
Answer:
Some natural resources like sunlight and wind are found everywhere, but other natural resources are unevenly distributed. Resources like oil, coal, and natural gas are only found where conditions were favorable to grow and preserve large quantities of animal or plant matter.
Explanation:
Iodine shines like metals but is not metal what is its basis
Answer:
Iodine is a non-metal, but it is lustrous (lustrous is the property of metal) in nature.
Psychology is the study of the human brain. A psychoanalyst is a person who
analyzes people's minds. What does the prefix psycho-mean?
A. Related to the brain
B. Related to studying
C. Related to science
D. Related to analysis
is pyramidal molecular geometry?
A. N2
B. H2O
C. NH3
D. CCL4
Answer:
[tex]\color{Blue}\huge\boxed{Question} [/tex]
Is pyramidal molecular geometry?[tex]\color{Blue}\huge\boxed{Answer} [/tex]
B.H2OGiven the following balanced chemical equation:
2C2H10 + 902 +4CO2 + 10H2O
How many moles of C2H10 are needed to completely react with 6.15
moles of oxygen?
O 1.37 mol
2 mol
0277 mol
Explanation:
[tex]6.15 \: mol \: oxygen \: \times \frac{2 \: mol \: c2h10}{9 \: mol \: oxygen} = 1.37 \: moles \: of \: c2h10 \: needed [/tex]
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3.
The color of the powdered form of a mineral is called
O fracture
O cleavage
O luster
O streak
Answer:
D. Streak.
Explanation:
A mineral, in simple terms, can be defined as a solid inorganic substance that occurs in a pure form with a specific crystal structure. A mineral is identified based on its physical properties which include luster, color, streak, crystal shape, etc.
The color of the powdered form of a mineral is called a streak. A streak is a useful property in distinguishing sulfide and oxide minerals. To check the color of a mineral, it is rubbed against the surface of a ceramic streak plate or a piece of unglazed ceramic. In its finely powdered form, a mineral is easy to identify.
Therefore, option D is correct.
a freshwater stream flows into the ocean as shown in the diagram which statement correctly describes how the stream affects these salinity of the ocean
A- salinity increases because the stream adds salt to the ocean.
B- salinity decreases because the stream adds freshwater to the ocean
C- salinity increases because of stream adds freshwater to the ocean
D- salinity Remains the Same because the stream adds freshwater to the ocean
What is the cation in KF?
Answer:
K, or Potassium
Explanation:
explain what is ment by solvent front
Answer:
In paper chromatography, the wet moving edge of the solvent that progresses along the surface where the separation of the mixture is occurring.
Explanation:
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Ali says the climate of a town is rainy because it is raining outside today. Is she correct? In one or two sentences, explain why Ali is or is not correct about the climate of the town.
Answer:
Ali is incorrect.
Explanation:
Ali is wrong because the climate is a study of the weather pattern over a long period of time. You cannot look outside one day and determine the climate because the climate is long-term.
She could say the weather is rainy, because that is short term, but not the climate.
How are cells organized?
A: Organs
B: Organelles
C: Tissues
Answer:
tissues,organs, organelles
What is a renewable resource on Earth?
minerals
coal
wind
petroleum
Answer:
Wind
Explanation:
Wind turbines make energy by the movement of the natural force on earth called 'wind' and renewable resources are resources that can be made from natural and environment-safe objects or things (e.g. Water, Geothermal Heat, The Sun, and Wind)
For each process, predict the sign on the entropy change and write a sentence or two to explain how to make this prediction without completing any mathematics. a.A solid melts. b.A vapor is converted into a solid. CH 117 Recitation Name: _________________________________ ~ 196 ~ c.A liquid freezes. d.A solid sublimes e.A vapor condenses to a liquid. f.A liquid boils. g.Dissolving a tablespoon of salt in water. h.Combustion of gasoline.
Answer: a. A solid melts: [tex]\Delta S=+ve[/tex]
b. a vapor is converted to solid: [tex]\Delta S=-ve[/tex]
c. a liquid freezes: [tex]\Delta S=-ve[/tex]
d. A solid sublimes: [tex]\Delta S=+ve[/tex]
e. a vapor condenses to liquid : [tex]\Delta S=-ve[/tex]
f. a liquid boils: [tex]\Delta S=+ve[/tex]
g. dissolving a tablespoon of salt in water: [tex]\Delta S=+ve[/tex]
h. combustion of gasoline: [tex]\Delta S=+ve[/tex]
Explanation:
Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy change is negative and vice versa.
a. A solid melts: The solid is converting to liquid, thus the randomness is increasing as the molecules are moving away and the intermolecular forces are getting weaker. Thus the entropy change [tex](\Delta S)[/tex] is positive.
b. a vapor is converted to solid: The gas is converting to solid, thus the randomness is decreasing as the molecules are moving close and the intermolecular forces are getting stronger Thus the entropy change [tex](\Delta S)[/tex] is negative.
c. a liquid freezes: The liquid is converting to solid, thus the randomness is decreasing as the molecules are moving close and the intermolecular forces are getting stronger. Thus the entropy change [tex](\Delta S)[/tex] is negative.
d. A solid sublimes: The solid is converting to gas, thus the randomness is increasing as the molecules are moving away and the intermolecular forces are getting weaker. Thus the entropy change [tex](\Delta S)[/tex] is positive.
e. a vapor condenses to liquid : The gas is converting to liquid, thus the randomness is decreasing as the molecules are moving close and the intermolecular forces are getting stronger. Thus the entropy change [tex](\Delta S)[/tex] is negative.
f. a liquid boils: The liquid is converting to gas, thus the randomness is increasing as the molecules are moving away and the intermolecular forces are getting weaker. Thus the entropy change [tex](\Delta S)[/tex] is positive.
g. dissolving a tablespoon of salt in water: The solid is converting to ions , thus the randomness is increasing as the ions can move freely. Thus the entropy change [tex](\Delta S)[/tex] is positive.
h. combustion of gasoline: The liquid is converting to gas, thus the randomness is increasing as the molecules are moving away and the intermolecular forces are getting weaker. Thus the entropy change [tex](\Delta S)[/tex] is positive.
What transition energy corresponds to an absorption line at 502 nm?
A. 4.56 x 10-19
B. 1.76 10-19
C. 2.53 x 10-19
D. 3.96 10-19 J
Answer:
D 3.96 10-19J
Explanation:
I took the test