Answer: Count only the electrons in the highest shell s and p orbitals when determining valence.
Explanation: I'm glad you asked this question. It is often not well explained. The term valence electrons is assigned to only the electrons in an element's highest energy level. These reside only in the s and p orbitals, and not the d or f, as I'll explain later. The s orbital can hold 2 electrons and the p can hold 6. Potassium, K, has an s orbital in its highest energy shell, 4. It contains only 1 electron, so it has a valency of 1.
Calcium, Ca, has 2 in its highest energy level: 4s^2, so it has a valency of 2. Moving to the right, the element scandium, Sc, add another electron, but it goes into the 3d orbital. 3d is in the 3rd energy shell, so it is not counted as a valence electron. Only after we move further right, to gallium, Ga, do we start adding electrons to the 4th energy level again - the 4p orbitals can accept up to 6 electrons. Ga has 3 valence electrons - 2 in the 4s and 1 in the 4p. Oxygen has 2 in the 2s and 4 in the 4p orbitals, for a total of 6. It is close to having a comple outer shell (2 in the 2s and 6 in the 2p). Just 2 more electrons would fill both the 2s and 2p orbitals for a total of 8 valence electrons, a stable configuration (the same configuration as thje stable gas Neon).
A building is found to be losing heat to the outside during the winter months. Which would be the best solution to correct this design problem?
increase amount of heating
increase surface area of walls
increase number of windows
increase thickness of insulation
no link or I will report
Answer:
increase thickness of insulation
Explanation:
don't increase amount of heating because that's difficult and not efficient.
don't increase surface area of walls because that makes heat be lost quicker.
don't increase windows because windows lose heat worse than walls.
increase thickness of insulation because it's the most effiecient and effective method of keeping heat.
What reaction would you expect chromium to have with water
Answer: It does not react with water, but reacts with most acids. It combines with oxygen at room temperature to form chromium oxide. Chromium oxide forms a thin layer on the surface of the metal, protecting it from further corrosion (rusting).
Explanation:
Please help. I need help with all 4
When Svante Arrhenius first proposed his acid base theory, he was a doctoral candidate. His professors thought his ideas were unfounded. Within a decade, the Arrhenius theory of acid base was widely accepted and praised within the scientific world. Arrhenius defined acids as compounds having an ionizable hydrogen and bases as compounds with ionizable hydroxides. Eventually scientists adopted a broader theory which includes more compounds to define acids and bases. The Bronsted-Lowry acid base theory defines an acid as a _______ and a base as a ______________.
Answer:
proton donar
proton acceptor
Explanation:
From the given information of the question, Arrhenius acid and base concept is explained, from which a better term to define an acid and base is defined, known as The Bronsted-Lowry acid base theory.
According to The Bronsted-Lowry acid base theory -
An acid is the species which can readily donate a proton, where as, a base is the species, which can readily accept a proton.
Hence, the correct answer is as follow -
proton donar
proton acceptor
Answer:
proton donar
proton acceptor
Explanation:
Image attached 50 points!
You know the number of moles of Mg that react: 6 moles.
You don't know (yet) how many moles of Mg₃N₂ are produced when 6 moles of Mg react.
The coefficients of each substance in the chemical equation tells us the molar ratio between the substances. The coefficient of Mg is 3, and the coefficient of Mg₃N₂ is 1 (coefficients of 1 are implied and omitted). So, for every 3 moles of Mg that react, 1 mole of Mg₃N₂ is produced.
We can use the proportion set up in the image to calculate the number of moles of Mg₃N₂ produced. In the first fraction, the green-boxed numerator should be our known number of moles of Mg, that is, 6 moles Mg. In the second fraction, we insert our molar ratio. Since we want the product of these two fractions to have the units "moles Mg₃N₂," the numerator in the second fraction should be 1 mole Mg₃N₂ and the denominator should be 3 moles Mg.
Our setup should look like this:
[tex]\frac{\textrm{6 moles Mg}}{1} \times \frac{\textrm{1 mole }\mathrm{Mg_3N_2}}{{\textrm{3 moles Mg}}} = \textrm{2 moles }\mathrm{Mg_3N_2}.[/tex]
Indeed, 2 moles of Mg₃N₂ are produced.
Answer:
2 moles of Mg₃N₂ are produced.
Explanation:
If 21.6 g of NO and 13.8 g of O₂ are used to form NO₂, how many moles of excess reactant will be left over? 2 NO (g) + O₂ (g) → 2 NO₂ (g)
Answer: 0.071 moles of excess reactant [tex](O_2)[/tex] will be left over.
Explanation:
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]
a) moles of [tex]NO[/tex]
[tex]\text{Number of moles}=\frac{21.6g}{30.01g/mol}=0.720moles[/tex]
b) moles of [tex]O_2[/tex]
[tex]\text{Number of moles}=\frac{13.8g}{32g/mol}=0.431moles[/tex]
[tex]2NO(g)+O_2(g)\rightarrow 2NO_2(g)[/tex]
According to stoichiometry :
2 moles of [tex]NO[/tex] require 1 mole of [tex]O_2[/tex]
Thus 0.720 moles of [tex]NO[/tex] require=[tex]\frac{1}{2}\times 0.720=0.360moles[/tex] of [tex]O_2[/tex]
Thus [tex]NO[/tex] is the limiting reagent as it limits the formation of product and [tex]O_2[/tex] is the excess regaent.
moles of [tex]O_2[/tex] left = (0.431-0.360) = 0.071 moles
Which one is not a long-term environmental change?
Pollution
Swimming
Deforestation
Climate Change
Answer:
Swimming
Explanation:
Pollution is almost irreversible and takes forever to fix. deforestation leads to bad air quality and the erosion of the ground. climate change can melt polar caps or for instance freeze texas.
What is the role of the green substance chlorophyll in photosynthesis? (2 points)
Chlorophyll collects water from the ground.
Chlorophyll captures energy from the sun.
Chlorophyll captures carbon dioxide from the air.
Chlorophyll moves water up the stem to the leaves.
Answer:
captures energy from the sun
Explanation:
Answer:
☁️Chlorophyll captures energy from the sun. ☁️
If a lab requires you to use 1.25 mol oxygen gas in a chemical reaction, how many molecules of oxygen will you need?
Answer:
7.53*10²³ molecules of oxygen will you need.
Explanation:
Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) that can be found in the amount of one mole of said substance. Its value is 6.023*10²³ particles per mole. Avogadro's number applies to any substance.
You can then apply the following rule of three: if by definition of Avogadro's Number 1 mole of oxygen gas contains 6.023*10²³ molecules, 1.25 moles contains how many molecules?
[tex]amount of molecules=\frac{1.25 moles*6.023*10^{23}molecules }{1 mole}[/tex]
amount of molecules= 7.53*10²³
7.53*10²³ molecules of oxygen will you need.
When balancing chemical equations, it is okay to adjust
(3 points)
A.
coefficients.
B.
superscripts.
C.
subscripts.
D.
any of these.
Answer:
A
Explanation:
Thats the correct anwers
What do plants do that requires Energy?
Answer:
Photosynthesis
Explanation:
Photosynthesis uses energy from light to convert water and carbon dioxide molecules into glucose (sugar molecule) and oxygen. The oxygen is released, or “exhaled”, from leaves while the energy contained within glucose molecules is used throughout the plant for growth, flower formation, and fruit development.
infrared in __________controls
I will mark briniest to the one who is correct, also its fill in the blank I wasnt paying attention in school
Answer:
remote
Explanation:
i hope it helps
Which properties are characteristic of true solutions? (Select all that apply.)
The light beam is unaffected.
The particles are larger than 10 -8 cm.
The particles are dissolved.
The particles are suspended indefinitely.
Answer:
The correct answers are
Particles are dissolved
and light beam passes through invisibility
Explanation:
Odyssey
Consider the table below that summarizes the types of materials that can block the 3 different types of radiation. Based on the table, at which numbered spot in the table does each type of radiation belong. 1 = beta; 2 = alpha, 3 = gamma
Answer:
D. 1 = gamma; 2 = alpha, 3 = beta
Explanation:
I apologize if this answer is late, but I got answered the question right on my "Types of Radioactive Decay" quiz :)
Hope this is helpful for others! :D
Based on the table, the type of radiation belong from 1 is the gamma rays, from 2 is the aplha rays and from 3 is the beta rays.
What are radiations?During the radioactive decay process, some amount of energy is released in the form of particles and that radiations will known as alpha rays, beta rays and gamma rays.
Gamma ray are mare energetic rays and will shielded by only lead and thick concrete materials.Beta rays are less energetic than gamma rays and will shielded by lead, cloth, paper, wood, aluminium foil and thick concrete materials.Aplha rays have very less amount of energy in it and it will be shielded by all above mention materials.Hence 1 is the gamma rays, 2 is the aplha rays and 3 is the beta rays.
To know more about radiations, visit the below link:
https://brainly.com/question/13909492
some plz help me make mnemonic to helpme remember the oder of the planets
Answer:
My - Mercury
Very- Venus
Excited- Earth
Mother- Mars
Just- Jupiter
Served- Saturn
Us- Uranus
Nachos- Neptune
Explanation:
Mark me Brainliest?
Answer:
My very encouraging made just us nachos
Explanation:
My stands for Mercury
Very stands for venus
Encouraging- Earth
made- Mars
just- Jupiter
Us- Uranus
Nachos- Neptune
A. What do the four quantum numbers describe about an electron? (1 point)
B. Match each quantum number with what it defines about an electron's position
or energy. (2 points)
A. The first quantum number, n
B. The second quantum number, /
C. The third quantum number, m
D. The fourth quantum number, ms
___ Defines the electron's orbital
___ Defines the electron's energy level
___ Defines the electron's spin
___ Defines the electron's sublevel
Answer: Part A / The four quantum numbers tell you the location and energy of an electron.
Part B / _C_ Defines the electron's orbital
_A_ Defines the electron's energy level
_D_ Defines the electron's spin
_B_ Defines the electron's sublevel
Which is the highest pressure?
a. 1.2 atm
b. 101 Pa
c. 101 kPa
d. 748 torr
Calcium Carbonate decomposes at 1200°C to form carbon dioxide and
calcium oxide. If 25 L of carbon dioxide are collected at 1200°C, what will
the volume of this gas be after it cools to 25°C?
This is a Charles' Law problem: V1/T1 = V2/T2. As the temperature of a fixed mass of gas decreases at a constant pressure, the volume of the gas should also decrease proportionally.
To use Charles' Law, the temperature must be in Kelvin (x °C = x + 273.15 K). We want to solve Charles' Law for V2, which we can obtain by rearranging the equation into V2 = V1T2/T1. Given V1 = 25 L, T1 = 1200 °C (1473.15 K), and T2 = 25 °C (298.15 K):
V2 = (25 L)(298.15 K)/(1473.15 K) = 5.1 L.
The volume of this gas will be "5.1 L".
Given:
[tex]V_1 = 25 \ L[/tex][tex]T_1 = (1200+ 273 )K[/tex][tex]= 1473 \ K[/tex]
[tex]T_2 = (25+ 273)K[/tex][tex]= 298 \ K[/tex]
As we know,
→ [tex]\frac{V_1}{V_2} = \frac{T_1}{T_2}[/tex]
By substituting the values, we get
→ [tex]\frac{25 \ L}{V_2} = \frac{1473 \ K}{293 \ K}[/tex]
→ [tex]V_2 = \frac{25\times 298}{1473} \ L[/tex]
→ [tex]= 5.1 \ L[/tex]
Learn more:
https://brainly.com/question/21437107
1. What is the molarity of an HCl solution if 50.0 mL of it is neutralized in a titration by
40.0 mL of 0.400 M NaOH? (0.32)
Answer:
C1 * V1 = C2 * V2
Explanation:
Where ‘C’ and ‘V’ refer to concentration and volume, ‘1’ and ‘2’ to solution 1 and 2 respectively. So, if ‘1’ refers to the HCl solution, we want to solve this equation for C1.
V1 = (C2*V2)/C1 = (0.4 * 50)/40 = 0.5 M
Please answer the question for BRAINLIEST
Answer:
The Drip, The Gucci, The Swag, and The OG
Explanation:
Which situation has given to a trait that could be passed on to offspring ?
Answer:
Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents.
Explanation:
Plss markk me Brainlyist
Scientists create models for all of the following reasons, EXCEPT
A - because a model can represent objects too large to comprehend
B - because a model can help to communicate their ideas
C - because a model is the only way to conduct an experiment
D - because a model is the only way to represent objects too small to see
PLEASE HELP!!!!
Which bond would be the least polar?
1) H-Br (hydrogen-bromine)
2) H-F (hydrogen-fluorine)
3) H-H (hydrogen-hydrogen)
4) H-O (hydrogen-oxygen)
Answer:
[tex]\boxed {\boxed {\sf 3. \ H-H}}[/tex]
Explanation:
To determine the polarity of a bond, we use the electronegativities of the individual atoms. The greater the difference, the more polar the bond.
1. H-Br
Hydrogen: 2.2 Bromine: 3.03.0-2.2=0.8
2. H-F
Hydrogen: 2.2 Fluorine: 4.04.0-2.2=1.8
3. H-H
Hydrogen: 2.22.2-2.2=0.0
4. H-O
Hydrogen: 2.2Oxygen: 3.43.4-2.2=1.2
As we can see, the lowest difference is in hydrogen hydrogen at 0.0. You may also recognize that because they are 2 atoms of the same element, the electronegativity is the same for both, so it will equal 0. Since the electronegativity is 0, this is a nonpolar bond.
In your own words, describe the difference between Thermal Energy and Heat.
Answer:
Heat is the flow of thermal energy between two objects of different temperature whereas the thermal energy tells about how much is the transfer of energy due to temperature difference between two bodies. Hence thermal energy in transit gives heat
Name the following base: NaOH
Answer:
Arrhenius Base
Explanation:
"NaOH is an Arrhenius base because it dissociates in water to give the hydroxide (OH-) and sodium (Na+) ions. An Arrhenius acid is therefore any substance that ionizes when it dissolves in water to give the H+, or hydrogen, ion. ... Acids provide the H+ ion; bases provide the OH- ion; and these ions combine to form water."
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Hope I Helped, Feel free to ask any questions to clarify :)
Have a great day!
More Love, More Peace, Less Hate.
-Aadi x
WILL MARK BRAINLEST
Use this image of a greenhouse to help explain how the Earth gets heated through the greenhouse effect.
Answer/Explanation:
The greenhouse effect is a natural process that warms the Earth's surface. When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases.
Earth's surface warms up in the sunlight. At night, Earth's surface cools, releasing heat back into the air. But some of the heat is trapped by the greenhouse gases in the atmosphere. That's what keeps our Earth a warm and cozy 58 degrees Fahrenheit (14 degrees Celsius), on average.
A steel bottle contains nitrogen gas at STP. What is the final pressure if the temperature is changed to 155°C?
Answer:
Option D
Explanation:
As we know at
PV = nRT
at STP,
Pressure is 1 atm and temperature is 273 K
[tex]\frac{P_2}{P_1} = \frac{T_2}{T_1} \\P_2 = 1*(428 )/273\\P_2 = 1.567[/tex]
Hence, option D is correct
How many moles of carbon atoms is 7.72 x 10 ^24 atoms of carbon? Round to 2 decimal places
Answer:
12.82 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{7.72 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 12.8 239[/tex]
We have the final answer as
12.82 molesHope this helps you
CH3(ch2)2C(ch3)3 IUPAC name please?
Answer:
Explanation:
The name is of the compound is 3,3,4,4-tetramethylhexane.
If 4.00 moles of gasoline are burned, what volume of oxygen is needed if the pressure is 0.953 atm, and the temperature is 35.0°C?
Answer:
1325 L
Explanation:
For this excersise we assume gasoline as an octane.
The combustion is:
2C₈H₁₈ + 25 O₂ → 16 CO₂ + 18H₂O
2 moles of octane react to 25 moles of oxygen, according to stoichiometry.
If we have 4 moles of gasoline, we need (4 . 25)/2 = 50 moles of oxygen.
We can apply the Ideal Gases Law to solve this.
We convert T° to Absolute Value
35°C + 273 = 308K
P . V = n . R . T
V = (n . R . T) / P → (50 mol . 0.082 mol.K/L.atm . 308K) / 0.953 atm
Volume = 1325 L