Electron configurations
Valence electrons are electrons used in forming bonds and are in the outer shell of an element.
The bond that occurs can be either an ionic bond or a covalent bond
Valence electron determination using electron configurations.
The main group elements usually have valence electron configurations in the s and p subshells
While the transition elements in the subshells (n-1) d
Further explanation
The location of the elemental groups in the periodic system is determined by the number of valence electrons filling the last sub-shell
The period of an element is determined from the valence shell (the biggest main quantum number (n) )
In an atom, there are levels of energy in the shell and subshell
This energy level is expressed in the form of electron configurations.
Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub-shells in the shell of an atom, namely s, p, d, and f. The maximum number of electrons for each subshell is
s: 2 electrons
p: 6 electrons
d: 10 electrons and
f: 14 electrons
Charging electrons in the subshell uses the following sequence:
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.
Calculate the mass of 100.0 mL of a substance whose density is 19.32 kg/L. Express your answer in kilograms using the correct number of significant figures. Do not enter your answer using scientific notation.
Answer:
1.932 kg
Explanation:
First we convert 100.0 mL to L:
100.0 mL / 1000 = 0.1000 LThen we calculate the mass of the substance, using the definition of density:
Density = mass / volumemass = density * volume19.32 kg/L * 0.1000 L = 1.932 kgAs the multiplication involves two numbers of 4 significant figures each, the answer needs to have 4 significants figures as well.
Tris has a molecular weight of 121 g/mol. How many grams of Tris would you need to make 100 mL of a 100 mM solution of Tris
Answer:
1.21 g of Tris
Explanation:
Our solution if made of a solute named Tris
Molecular weight of Tris is 121 g/mol
[Tris] = 100 mM
This is the concentration of solution:
(100 mmoles of Tris in 1 mL of solution) . 1000
Notice that mM = M . 1000 We convert from mM to M
100 mM . 1 M / 1000 mM = 0.1 M
M = molarity (moles of solute in 1 L of solution, or mmoles of solute in 1 mL of solution). Let's determine the mmoles of Tris
0.1 M = mmoles of Tris / 100 mL
mmoles of Tris = 100 mL . 0.1 M → 10 mmoles
We convert mmoles to moles → 10 mmol . 1mol / 1000mmoles = 0.010 mol
And now we determine the mass of solute, by molecular weight
0.010 mol . 121 g /mol = 1.21 g
. When is separation of substances necessary ?Name four methods used to separate solid substances ?
the one of 2 who send correct answer will get the brainliest and 40 points
OH- of a solution that has a pH of 8.57
Answer:
I think its -8.75
Explanation:
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Which organ produces the female hormone estrogen
Answer:
Ovary
Explanation:
ovaries produce the most estrogen in females.
. Suppose an infrared photon with a wavelength of 853 nm were combined with another infrared photon with a wavelength of 865 nm, what would be the wavelength of the new 'combined' photon, in nm
Answer:
Explanation:
Given the data in the question;
wavelength λ₁ = 853 nm = 853 × 10⁻⁹ m
wavelength λ₂ = 865 nm = 865 × 10⁻⁹ m
we determine the energy of each photons using the following expression;
[tex]E_{photon[/tex] = hc / λ
where h is Planck's constant ( 6.626 × 10⁻³⁴ J.s )
c is speed of light ( 3 × 10⁸ m/s )
For Photon with wavelength λ₁ = 853 × 10⁻⁹ m
[tex]E_{photon1[/tex] = hc / λ
we substitute
= ( ( 6.626 × 10⁻³⁴ J.s )( 3 × 10⁸ m/s ) ) / (853 × 10⁻⁹ m)
= 1.9878 × 10⁻²⁵ / 853 × 10⁻⁹
= 2.33 × 10⁻¹⁹ J
For Photon with wavelength λ₂ = 865 × 10⁻⁹ m
[tex]E_{photon2[/tex] = ( ( 6.626 × 10⁻³⁴ J.s )( 3 × 10⁸ m/s ) ) / (865 × 10⁻⁹ m)
= 1.9878 × 10⁻²⁵ / 865 × 10⁻⁹
= 2.298 × 10⁻¹⁹ J
We know that; energy of the combined photon will be equal to the sum of energies of the two photons.
so
Energy of the combined photon = [tex]E_{photon1[/tex] + [tex]E_{photon2[/tex]
[tex]E_{combined[/tex] = 2.33 × 10⁻¹⁹ J + 2.298 × 10⁻¹⁹ J
[tex]E_{combined[/tex] = 4.628 × 10⁻¹⁹ J
so wavelength of the new combined photon will be;
[tex]E_{combined[/tex] = hc / λ[tex]_{combined[/tex]
[tex]E_{combined[/tex]λ[tex]_{combined[/tex] = hc
λ[tex]_{combined[/tex] = hc / [tex]E_{combined[/tex]
we substitute
λ[tex]_{combined[/tex] = ( ( 6.626 × 10⁻³⁴ J.s )( 3 × 10⁸ m/s ) ) / 4.628 × 10⁻¹⁹ J
= 1.9878 × 10⁻²⁵ / 4.628 × 10⁻¹⁹
= 4.2952 × 10⁻⁷ m
= ( 4.2952 × 10⁻⁷ × 10⁹ )nm
= 429.5 nm
Therefore, Wavelength of the new 'combined' photon is 429.5 nm
The mass of 1.63×10^21 silicon atoms
Answer:
I think it is 7.60 X 1
but if it's not srry
if every atom of an oxygen has 8 protons in its nucleus what is the atomic number of oxygen
Answer:
8
Explanation: # of protons = atomic #
Calculate the mass of 0.8 mol of KOH
Answer:
44.8g
Explanation:
molar mass of k= 39, O= 16, H= 1
molecular mass of KOH= 56g/mol
N=m/Mm
0.8=m/56
m= 0.8×56
m= 44.8g
Mass is "a measure of the amount of matter that an object contains".
What is matter?Matter is "any substance that has mass and takes up space by having volume".
The formula to calculate the molar mass is M = m/n
where M is molar mass
m is mass of substance in grams
n is no. of moles of a substance.
The molecular mass of KOH is 56.105 g/mol
molar mass of K= 39, O= 16, H= 1
M = m/n
0.8 = m/56.105
m = 0.8 x 56.105
m = 44.8g
Hence, the mass of 0.8 mol of KOH is 44.8g
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Question 1 of 10
Which of the following is a nonrenewable energy source?
O A. Geothermal
O B. Petroleum
C. Solar
O D. Hydroelectric
Petroleum is a nonrenewable energy source. Therefore, the correct option is option B.
What is nonrenewable energy source?The sources of non-renewable energy will deplete or not be renewed within our lifetimes, or perhaps within many, many lifetimes. Coal, oil, and natural gas are the main fossil fuels used as non-renewable energy sources. The primary component of fossil fuels is carbon.
The formation of fossil fuels, which took place between 360 and 300 million years ago, is referred to as the Carboniferous Era for this reason. The formation of all fossil fuels was identical. Prior to the dinosaurs, Earth used to have a different terrain thousands of thousands of years ago. It was entirely covered in swampy forests and broad, shallow oceans. Petroleum is a nonrenewable energy source.
Therefore, the correct option is option B.
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A 30.141 mg sample of a chemical known to contain only carbon, hydrogen, sulfur, and oxygen is put into a combustion analysis apparatus, yielding 53.694 mg of carbon dioxide and 21.980 mg of water. In another experiment, 30.199 mg of the compound is reacted with excess oxygen to produce 13.05 mg of sulfur dioxide. Add subscripts to the formula provided to correctly identify the empirical formula of this compound. Do not change the order of the elements empirical formula: CHSO
Answer:
The empirical formula of the chemical compound is C₆H₁₂SO₂
Explanation:
To determine the empirical formula, the mass of each element in the compound is first determined from their respective compounds formed after combustion analysis.
Mass of element = mass of compound × molar mass of element / molar mass of compound
Carbon: 53.694 g x (12g/mol / 44.0 g/mol) = 14.643 mg of C in 30.141 mg sample Hydrogen: 21.980 mg x ( 2.00 / 18.00) = 2.442 mg of H in 30.141 mg sample
Sulfur: 13.05 mg x (32.00/ 64.00) = 6.525 mg of S in 30.199 mg in sample
The percentage mass composition of the elements in the compound is then determined:
Carbon: 14.643 mg / 30.141 mg = 48.58%
Hydrogen: 2.442 mg / 30.141 mg = 8.10%
Sulfur: 6.525 mg / 30.199 mg = 21.60 %
Oxygen: 100% - (48.58% + 8.10% +21.60%) = 21.72%
Number of moles of each element is then determined:
Number of moles = percentage mass/molar mass
Carbon: 48.58/12 = 4.07
Hydrogen: 8.10/1 = 8.10
Sulfur: 21.60/32 = 0.68
Oxygen: 21.72/16 = 1.36
Dividing with the smallest amount to obtain a whole number mole ratio
Carbon: 4.07 ÷ 0.68 = 6
Hydrogen: 8.10 ÷ 0.68 = 12
Sulfur: 0.68 ÷ 0.68 = 1
Oxygen: 1.36 ÷ 0.68 = 2
Therefore, the empirical formula of the chemical compound is C₆H₁₂SO₂
Climate models show that human climate forcing is causing the loss of mountain and tidewater glaciers. Briefly explain why glaciers are an important aspect of human survival.
Answer:
A glacier is a large mass of snow and ice that has accumulated over many years and is present year-round. In the United States, glaciers can be found in the Rocky Mountains, the Sierra Nevada, the Cascades, and throughout Alaska. A glacier flows naturally like a river, only much more slowly. At higher elevations, glaciers accumulate snow, which eventually becomes compressed into ice. At lower elevations, the “river” of ice naturally loses mass because of melting and ice breaking off and floating away (iceberg calving) if the glacier ends in a lake or the ocean. When melting and calving are exactly balanced by new snow accumulation, a glacier is in equilibrium and its mass will neither increase nor decrease.
In many areas, glaciers provide communities and ecosystems with a reliable source of streamflow and drinking water, particularly in times of extended drought and late in the summer, when seasonal snowpack has melted away. Freshwater runoff from glaciers also influences ocean ecosystems. Glaciers are important as an indicator of climate change because physical changes in glaciers whether they are growing or shrinking, advancing or receding provide visible evidence of changes in temperature and precipitation. If glaciers lose more ice than they can accumulate through new snowfall, they ultimately add more water to the oceans, leading to a rise in sea level (see the Sea Level indicator). The same kinds of changes occur on a much larger scale within the giant ice sheets that cover Greenland and Antarctica, potentially leading to even bigger implications for sea level. Small glaciers tend to respond more quickly to climate change than the giant ice sheets. Altogether, the world’s small glaciers are adding roughly the same amount of water to the oceans per year as the ice sheets of Greenland and Antarctica combined. During the last two decades, they added more water overall to the oceans than the ice sheets did.
Explanation:
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Because they offer a variety of essential functions, including as controlling river flows and water supply, safeguarding coastal areas from floods, and preserving biodiversity, glaciers are a crucial component of human survival.
What is the source of the freshwater ?First, many people throughout the world rely heavily on glaciers as a supply of freshwater. When glaciers melt, they release water that has been stored and is subsequently utilised for agriculture, drinking water, and other things.
In dry areas with limited access to other freshwater sources, this water is very crucial. As a natural reservoir, glaciers may also hold a lot of water during the winter and release it gradually throughout the summer. This helps to control river flows and avoid flooding.
Second, glaciers contribute significantly to the global climate.system of climate. Large volumes of carbon dioxide and other greenhouse gases are released as glaciers melt, which can contribute to global warming. Glaciers may also reflect sunlight, which aids in cooling the surroundings around them.
High-altitude places, where glaciers can help regulate temperatures and avert catastrophic weather occurrences, are particularly crucial for this cooling impact. Last but not least, glaciers are crucial for the preservation of biodiversity. Numerous types of plants, animals, and microorganisms find a special niche in glaciers. These species may be disrupted by glacier melting, which might result in the extinction of entire ecosystems. The environment and the communities who rely on it may be significantly impacted by this.
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Identify the true statement(s). There may be one answer or more than one answer.FADH2 is a reducing agent. FADH2 is an oxidizing agent. NADH is an oxidizing agent. NADPH is a reducing agent. FAD is an oxidizing agent.
Answer:
FADH2 is a reducing agent.
FAD is an oxidizing agent.
Explanation:
The full form of FAD is flavin adenine dinucleotide. It is mainly a redox-active coenzyme which is associated with the different proteins and is involved with the enzymatic reactions in the metabolism.
FAD is obtained by donating or accepting electrons.
In the citric acid cycle,
succinate + FAD → fumarate + [tex]$FADH_2$[/tex]
Thus we see that FAD is an oxidizing agent while [tex]$FADH_2$[/tex] is a reducing agent.
Which of the following describes a spectrum?
A. A measurement of the energy associated with an electron
transition
B. A piece of glass that causes light to be divided into different
colors
C. A range of wavelengths or frequencies of electromagnetic
radiation
D. A list of the quantum numbers assigned to a particular electron
Answer: The Answer would be C
Explanation: A spectrum is a Range of Wavelengths and Frequencies of Electromagnetic Radition.
The statement that describe spectrum is a range of wavelengths or frequencies of electromagnetic radiation.
What is Spectrum?Spectrum arrangement or electromagnetic radiations base on their wavelength and frequency which can be visible light, ultraviolet, and infrared light. An instrument that is use for visual observation of spectra is called a spectroscope.
Therefore, The statement that describe spectrum is a range of wavelengths or frequencies of electromagnetic
radiation.
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A car starts out when the air temperature is 298 K and the absolute (total) air pressure in the tires is 500 kPa. After driving a while, the temperature of the air in the tires increases to 315 K. What is the pressure in the tires at that point, assuming their volume does not change
Answer: The pressure in the tires at that point is 528.52 kPa.
Explanation:
Given: [tex]T_{1}[/tex] = 500 K, [tex]P_{1}[/tex] = 500 kPa
[tex]T_{2}[/tex] = 315 K, [tex]P_{2}[/tex] = ?
According to Gay-Lussac's law, at constant volume the pressure of a gas is directly proportional to temperature.
Formula used to calculate the pressure is as follows.
[tex]\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{2}}\\\frac{500 kPa}{298 K} = \frac{P_{2}}{315 K}\\P_{2} = 528.52 kPa[/tex]
Thus, we can conclude that the pressure in the tires at that point is 528.52 kPa.
Which part of the atom does gamma radiation depend on?
nucleus
protons
energy levels
electrons
Answer:Gamma radiation is the product of radioactive atoms. Depending upon the ratio of neutrons to protons within its nucleus, an isotope of a particular element may be stable or unstable.
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Calculate the volume occupied
at s.t.p by 6.89
gas [H = 10, N = 14
Answer:
9.07 L
Explanation:
Calculate the volume occupied at s.t.p by 6.89 g of NH₃ gas [H = 1.0, N = 14.0].
Step 1: Given and required data
Mass of NH₃ (m): 6.89 gMolar mass of NH₃ (M): 17.0 g/molStep 2: Calculate the moles (n) of NH₃
We will use the following epxression.
n = m / M
n = 6.89 g / (17.0 g/mol) = 0.405 mol
Step 3: Calculate the volume occupied by 0.405 moles of NH₃ at STP
At STP, 1 mole of NH₃ occupies 22.4 L (assuming ideal behavior).
0.405 mol × 22.4 L/1 mol = 9.07 L
Which compound is an isomer of CH3CH2OH?
A) CH3OCH3
B) CH3COOH
C) CH3COCH3
D) CH3CH2CH3
help please hurry lots of points
suggest a likely pH for a reasonable concentrated solution of hydrogen atatide in water
Answer:
It can be said that a reasonable concentration of HAt in water would be 0
Explanation:Hydrogen astatide is a chemical compound with the chemical formula HAt, consisting of an astatine atom covalently bonded to a hydrogen atom.
This chemical compound can dissolve in water to form hydroastatic acid, which exhibits properties very similar to the other four binary acids, and is in fact the strongest among them. So we can safely say that a reasonable concentration of HAt in water would be 0. However, it is limited in use due to its ready decomposition into elemental hydrogen and astatine.
whic process does not occur in the organelle illustrated above?
Answer:
it isnt possible to answer this without you providing the "organelle illustrated above".
Explanation:
please provide the "organelle illustrated above".
1.
When 0.990g of Na3PO4.12H20 reacts with excess BaCl2.2H20 how many
moles of Ba3(PO4)2are produced?
The balanced reaction is
(Na3PO4)12H2O + 9(BaCl2)2H2O → 6Ba3(PO4)2 + 36NaCl + 10H2O
molar mass of (Na3PO4)12H2O = 380 g/mol
given mass of (Na3PO4)12H2O = 0.990 g
moles of (Na3PO4)12H2O = given mass/molar mass
moles of (Na3PO4)12H2O = 0.990/380= 0.0026 mole
one mole of (Na3PO4)12H2O forms 6 mole of Ba3(PO4)2
0.0026 mole of (Na3PO4)12H2O forms 0.0026×6 =
0.0156 mole of Ba3(PO4)2
mass of 0.0156 moles of Ba3(PO4)2 is = 0.0156 × 601.9 g = 9.40 gram
How does percolation filter water?
Answer:
Explanation:
Percolation is a natural process in which surface water is gradually filtered through the soil into aquifers. When groundwater is depleted, recycled water can be introduced into aquifers by letting it gradually filter through the soil When you hear the word “percolation,” making coffee probably comes to mind.
Which type of molecule is shown below?
A. Cyclic alkene
B. Alkene
C. Alkyne
D. Cyclic alkane
Answer:
D. Cyclic alkane
Explanation: there is no double or triple bond
The type of molecule that is shown below in the picture is a cyclic alkane. The correct option is D.
What is the cyclic alkane?This is the compound that contain hydrogen and carbon bond. They are mono cyclic saturated hydrocarbons.
These are the atoms that replace the hydrogen atom in an organic compound.
Thus, the correct option is D. Cyclic alkane.
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an atom has atomic number 13 and atomic mass number of 24. Write electronic configuration using the Bohr's model
Answer:
Explanation:
element is aluminium
shells K L M N
electrons 2 8 3
how many grams of NaCl are in 1.25 x 10^24 molecules of NaCl
Answer:
Mole = number of molecules divided by the avogadro's constant.
Molar mass of NaCI =23 + 35.5 =58.5g/mol
Mass= moles multipled by molar mass of NaCI
M
Josh decided his glass of iced tea needed to be sweeter. He found two types of sugar he could use in the kitchen. There was a bowl of loose crystals of sugar and a bowl of sugar cubes. Which one will dissolve faster in the iced tea
Answer:
Therefore, it can be said that sugar molecules whether in crystal or cube form do not dissolve in ice tea.
Explanation:
Sugar molecules easily dissolve in warm or hot tea. However, in iced tea sugar does not dissolve it does not matter whether you use sugar cubes or sugar crystals.
This happens because of the entropy. The entropy of warm water is high as it has fast-moving molecules, whereas the entropy of ice water is negligible. hence, sugar molecules do not dissolve in ice tea.
Therefore, it can be said that sugar molecules whether in crystal or cube form do not dissolve in ice tea.
what is the name of the functional group of pentanoic acid
Answer:
organic acid
Explanation:
Answer:
Hey mate.....
Explanation:
This is ur answer.....
Alkyl carboxylic acid
Valeric acid (pentanoic acid) is a straight-chain alkyl carboxylic acid with a very unpleasant odor. It is found naturally in the perennial flowering plant valerian (Valeriana officinalis), from which it gets its name.
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5. There is no water cycle where it is cold.
O true
O false
Answer:
False
Explanation:
There is a water cycle wherever there is water. If it is cold, the water cycle will just be very slow.
What is the volume of a brick with a Length of 5cm, height of 1cm, and a
width of 2cm. *
O 8cm
O 10cm
15cm
O 12cm
all answer are cubed. I just couldn't add the cube symbol to the answer choices
Answer:
The answer is 10cm^3
Explanation:
5x1x2=10
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