Answer:
A
Explanation:
The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell. When atoms have fewer than eight electrons, they tend to react and form more stable compounds. When discussing the octet rule, we do not consider d or f electrons. Only the s and p electrons are involved in the octet rule, making it useful for the main group elements (elements not in the transition metal or inner-transition metal blocks); an octet in these atoms corresponds to an electron configurations ending with s2p6 .
Answer:
it's A
The octet rule is a chemical rule of thumb that reflects the theory that main group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.
The octet rule states that atoms tend to form compounds in ways that give them eight valence electrons and thus the electron configuration of a noble gas. An exception to an octet of electrons is in the case of the first noble gas, helium, which only has two valence electrons.
Explanation:
please mark me as brainliest thank
1. Air contains mostly nitrogen (78%) and oxygen (21%). It also contains other gases, including carbon dioxide and helium, and various pollutants (both gases and solids). Write a brief explanation about why air is a mixture, whether it is homogeneous or heterogeneous, and how it can be separated into its components.
Answer:
It also contains other gases, including carbon dioxide and helium, and various pollutants (both gases and solids).
how many moles do you have in 37.3 g of Co(CrO4)3
Answer:
0.0917 mol Co(CrO₄)₃
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisExplanation:
Step 1: Define
37.3 g Co(CrO₄)₃
Step 2: Identify Conversions
Molar Mass of Co - 58.93 g/mol
Molar Mass of Cr - 52.00 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of Co(CrO₄)₃ - 58.93 + 3(52.00) + 12(16.00) = 406.93 g/mol
Step 3: Convert
[tex]37.3 \ g \ Co(CrO_4)_3(\frac{1 \ mol \ Co(CrO_4)_3}{406.93 \ g \ Co(CrO_4)_3} )[/tex] = 0.091662 mol Co(CrO₄)₃
Step 4: Check
We are given 3 sig figs. Follow sig fig rules and round.
0.091662 mol Co(CrO₄)₃ ≈ 0.0917 mol Co(CrO₄)₃
what are the 10 properties of metals
Explanation:
Lustrous (shiny)
Good conductors of heat and electricity.
High melting point.
High density (heavy for their size)
Malleable (can be hammered)
Ductile (can be drawn into wires)
Usually solid at room temperature (an exception is mercury)
Opaque as a thin sheet (can't see through metals)
Help needed ASAP
= Select all that apply
Natural selection _____.
[] is random
[] cannot work if beneficial traits are not hereditary
[] is often called survival of the fittest
[] favors organism well adapted to the environment
Natural selection cannot work if beneficial traits are not hereditary
Answer:
favors organisms well adapted to the environment
cannot work if beneficial traits are not hereditary
is often called survival of the fittest
Explanation:
NOT
is random
happens by chance
1)how many red blood cells could you line up across the grain of sand?
2) How many red blood cells could you line up across the diameter of a penny (0.02 m)?
Please I need helpppppp
Answer:
The correct answer is -
1. 1 grain of sand = 244 red blood cells.
2. 1 penny = 2439
Explanation:
A normal red blood cell has a normal disk diameter of 6.2 - 8.2 micron or micrometer is way small than a grain of sand which ranges in diameter from 0.0625 mm (or 1⁄16 mm) to 2 mm. The size of the diameter of a penny is given 0.02 m.
Let take the highest value of them:
RBC = 8.2 micrometer
The grain of sand = 2 mm
Penny = 0.02 m
we know:
1 meter = 10e+6 or 100000 micron
1 millimeter = 1000 micron
then, the grain of sand = 2* 1000 = 2000
so, the 1 grain sand = 2000/8.2
= 244
Similarly,
Penny = 0.02*100000= 20000
= 2439
Thus, the correct answer is =
1. 1 grain of sand = 244 red blood cells.
2. 1 penny = 2439
A student places four identical cells into four different liquids. Over time which cell will look the smallest WXY or Z
Answer: W
Explanation:
The cell in liquid W will look the smallest out of the four because of Osmosis.
Osmosis is a process by which water molecules move from an area of relatively higher concentration of water to an area with a relatively lower concentration through a selectively permeable membrane(cell membrane).
With W being saltier than the cell, water molecules will move from the cell to liquid W to balance the concentrations inside and outside the cell which will lead to the cell in W being smaller.
What is the likely origin of the two moons orbiting Mars?
Answer:
....? What-
Explanation:
my grades are as the following;
86.7%
82.1%
77.7%
88.3%
69.2%
what is my gpa im having trouble trying to find out
Answer:
try a calulator online just go to g.oogle and type in gpa calculator
Multiple choice
I genuinely have no idea-- but I don't think it's the first one or the last.
I think it may be the third one but I'm not too sure.
Answer:
The correct option is;
By first reversing Reaction 2 and then adding the enthalpy of Reaction 1 and the enthalpy of reaction 2
Explanation:
The given reactions are;
1) C₂H₂ (g) + 2H₂ (g) → C₂H₆ (g) [tex]{}[/tex] ΔH = -75 kcal
2) C₂H₄ (g) + H₂ (g) → C₂H₆ (g) [tex]{}[/tex] ΔH = -33 kcal
3) C₂H₂ (g) + H₂ (g) → C₂H₄ (g) [tex]{}[/tex] ΔH = ?
By reversing reaction (2) and subtracting the reactants from the products we then have followed by adding the enthalpy of reaction 1 to the value of the enthalpy of the (reversed) reaction 2, we have;
C₂H₂ (g) + 2H₂ (g) → C₂H₆ (g) [tex]{}[/tex] ΔH = -75 kcal
C₂H₆ (g) → C₂H₄ (g) + H₂ (g) [tex]{}[/tex] ΔH = 33kcal
Adding, and cancelling out the italicized terms which are repeated in the product and reactants, we get
C₂H₂ (g) + H₂ (g) → C₂H₄ (g) [tex]{}[/tex] ΔH = -75 kcal + 33 kcal = -42 kcal
Therefore, the correct option is "by first reversing Reaction 2 and then adding the enthalpy of Reaction 1 and the enthalpy of reaction 2"
Ciao, adios, I'm done (I'm done)
Ciao, adios, I'm done
Done (I'm done)
Ciao, adios, I'm done
And now you take her out in your fancy car
And make out in the rain
And when she rings you up
She know where you are
But I know differently
Now she sings along when you play guitar
Making brand new memories
Hope you treat her better than you treated me
Answer:
The answer is B.xd
Explanation:
Answer:
Ciao Adios by Anna-Marie
Explanation:
ooof I like that song
The empirically formula for a compound is CH3. If the multiplier is 2, what is the molecular formula?
Answer:
C₂H₆
Explanation:
Here,
The Empirical Formula is CH₃
Now, 2 × CH₃ = C₂H₆
Thus, The Molecular Formula of CH₃ is C₂H₆
-TheUnknownScientist
how many moles are in 100.0 g of gold?
Answer:
196.96655
Explanation:
The answer is 196.96655. I assume you are converting between grams Gold and mole. The molecular formula for Gold is Au. The SI base unit for the amount of substance is the mole.
The quantity present in an atom or molecules of a given substance is called moles it is written as mol and is calculated with the help of molar mass and mass of the given substance.
0.507699 mol is present in the 100 gm of gold.
Moles of gold can be calculated by:Given,
Mass (m) = 100 gmThe atomic weight of Au (M) = 196.967The formula for calculating moles is:
[tex]\rm Moles (n) = \dfrac{Mass}{Molar \;mass}[/tex]
Substituting values in the formula:
[tex]\begin{aligned}\rm n & = \dfrac{100}{196.967}\\\\ & = 0.507699 \;\rm mol\\\\& = 0.5077\;\rm mol\end{aligned}[/tex]
Therefore, 0.5077 mol is present in 100 gm of gold.
Learn more about moles here:
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what so ammonia and bleach make
blease help i know its something dangerous but I'm not sure and dont want to accidentally kill my family
Answer:
Mixing bleach and ammonia will create a toxic chloramine gas. Exposure to chloramine gas can cause irritation to your eyes, nose, throat, and lungs .
if you do accidentally mix bleach and ammonia, get out of the contaminated area and into fresh air immediately.
hope this help u ☆
Which of the following is an example of a physical change?
A) pouring hydrogen peroxide (H202) on a cut, causing oxygen (02) bubbles to form
B) mixing together flour, sugar, salt, eggs and butter to make cookies
c) baking a birthday for your best friend
D) enzymes within the digestive system breaking down the lunch you just ate
Answer:
B! i just learned this last week lol!
Explanation:
hope this helps♡♡
what is the charge of an anion
Answer:
negative charge
Explanation:
An anion has more electrons than protons, consequently giving it a net negative charge.
hope this helps, pls mark brainliest :D
Question 5
2 pts
Which regions did the Byzantine emperor Justinian conquer in an attempt to
revive the Roman Empire?
North Africa and Persia
North Africa and the Italian Peninsula
Persia and Egypt
Gaul and the British Isles
Answer:
I believe it's ... North Africa and the Italian Peninsula
Give an example of a diatomic molecule found in Earth's atmosphere.
Answer:
oxygen is an example of a diatomic molecule found in earth's atmosphere!
Explanation:
What is the ionic formula of the compound formed by Co3+ and the phosphorus ion? What is the name of the compound formed based on the ionic compound formula?
Answer: The ionic formula of compound is [tex]CoP[/tex] and the name is cobalt phosphide.
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here element Co is having an oxidation state of +3 called as [tex]Co^{3+}[/tex] cation and phosphprous forms [tex]P^{3-}[/tex] anion with oxidation state of -3. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral [tex]CoP[/tex]
The nomenclature of ionic compounds is given by:
1. Positive is written first followed by the oxidation state of metal in roman numerals in square brackets.
2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.
Thus the name of [tex]CoP[/tex] is cobalt phosphide.
Answer: A
Explanation: TOOK THE QUIZ !)) 200 YEARS AGOO
0.12g of rock salt was dissolved in water and titrated with 0.1moldm^-3 silver nitrate until the first permanent brown precipitate of silver chromate is seen. 19.70 cm^3 was required to titrate all the chloride ion. how many moles of chloride ion were titrated? what mass of sodium chloride was titrated? what was the % purity of the rock salt in terms of sodium chloride?
moles Cl⁻ : 0.00197
mass NaCl : 0.115
% purity : 95.83%
Further explanationMolarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution
[tex]\large \boxed {\bold {M ~ = ~ \dfrac {n} {V}}}[/tex]
Where
M = Molarity
n = Number of moles of solute
V = Volume of solution
So to find the number of moles can be expressed as
n = V x M
mol Cl⁻Reaction
AgNO₃ + NaCl ⇒ AgCl + NaNO₃
Molarity(concentration) of AgNO₃ = 0.1 mol/dm³(L) = 0.1 M
Volume=V of AgNO₃ = 19.7 ml(cm³)
so mol of AgNO₃ :
[tex]\tt mol=M\times V\\\\mol=0.1~mol/L\times 0.0197~L\\\\mol=0.00197[/tex].
From the equation, mol ratio AgNO₃ : NaCl = 1 ; 1, so mol NaCl= mol AgNO₃= 0.00197
NaCl⇒Na⁺+Cl⁻
mol Cl⁻ : mol NaCl = 1 : 1, mol Cl⁻ = 0.00197
mass NaCl (MW=58.5 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass= 0.00197\times 58.5=0.115~g[/tex]
% purity :[tex]\tt \%purity=\dfrac{mass~NaCl}{mass~rock}\times 100\%\\\\\%purity=\dfrac{0.115}{0.12}\times 100\%=95.83\%[/tex]
Which of the following elements would be in the same group or family?
A. K, Ca, Sc
B. Se, Br, Kr
C. K, Na, Li
D. Al, Ge, Sb
Answer:
d
Explanation:
which is NOT represented in a chemical change demonstrated chemical reactions?
Answer:
Option C
Explanation:
A) A chemical equation is simply the symbolic representation of a chemical reaction using the form of symbols and formulae. Thus, option A is not the answer.
B) A product is the substance that shows at the end of a chemical reaction. Thus, option B is not the answer.
C) Law of conservation of mass in chemistry states that even in chemical reactions or physical transformations, that mass cannot be created nor destroyed. Which means that mass is conserved. This has nothing to do with chemical change demonstrated chemical reactions. Thus, option C is correct.
D) reaction rate is the speed that a chemical reaction occurs. Thus, options D is not correct.
Your weight changes if you travel to the moon because _____.
Answer:
1/6 of your weight on Earth
Answer:
the amount of the force of gravity changes
how do people start alcohol consumption
Answer:
Explanation:Due to the mental pressure,
Due to peer pressure,
Lack of love and affection from the family members.
Influence from the T.V advertisement.
HELP! ASAP! WILL MARK BRAINLIEST!!
A metal atom that loses electrons is called a/an _______.
Answer:
It is called ions
Explanation:
Metal atoms lose some of their valence electrons through a process called oxidation, resulting in a large variety of ionic compounds including salts, sulfides, and oxides. The properties of metals, combined with the chemical action of other elements, results in the transfer of electrons from one atom to another.
Answer:
its called an ion
Explanation:
an ion is an electrically charged atom
PLEASE HELP ME DUDE MY CLASS ENDS IN LIKE HALF A DAY
Answer:
c.all atoms have the same arrangement for electrons
Answer:
C because the number of protons and neutrons add up to make the number of electrons.
Si dos elementos tienen igual valor del número cuántico n y diferente l, ml y ms entonces deben estar en : El mismo orbital, pero diferente nivel y sub nivel. Diferente nivel , subnivel y orbital El mismo nivel, sub nivel y orbital. El mismo nivel, pero diferente subnivel y orbital El mismo sub nivel y orbital pero diferente nivel.
Answer:
El mismo nivel, pero diferente subnivel y orbital
Explanation:
En un átomo, el número cuántico principal n muestra el nivel de energía del electrón.
Si dos electrones tienen el mismo valor del número cuántico principal n, simplemente significa que están en el mismo nivel de energía.
Sin embargo, cuando los números cuánticos l y ml difieren, los electrones deben estar en diferentes subniveles y orbitales.
10 points
3. Which of the following is the characteristic that all organisms have in
common?*
O A. All organisms are made up of cells.
O B. All organisms are multicellular.
C. All organisms can make their own food.
O D. All organisms have cells with a nucleus.
Answer:
A all organisms are made of 1 or more cells
URGENT !! PLEASE ANSWER !!
Is H-F a nonpolar or polar covalent bond? why?
Answer:
It's polar
Explanation:
Hydrogen has an EN of 2.1 and Fluorine an EN of 4.0 (highest EN of any element). So do: 4.0−2.1=1.9.
Why does oxygen bond with hydrogen to make water?
Group of answer choices
A) Because oxygen only has 6 electrons in its outer shell and it wants 8. It binds with 2 hydrogens because each hydrogen atom has 1 electron in its outer shell.
B) Because oxygen only has 8 electrons in its outer shell and it can take 4 more. It binds with 2 hydrogen atoms because each hydrogen atom can carry 2 electrons in its outer shell.
C) Because oxygen only has 2 electrons in its inner shell and it needs 6 more to make 8. It binds with 6 hydrogens to fill up its shell.
D) No answer text provided.
answer: c
because if you really picture it and look at each of them carefully it is c
The salt in ocean water comes from all of the following EXCEPT
A
eroding land.
В.
melting glacial ice.
C
volcanic emissions.
D
reactions on the sea floor.
Answer:B
Explanation:
Had the same test years ago
The salt in ocean water comes from various sources such as the volcanic emissions, land eruption, ionic reactions in sea floor etc. but not from the melting of glacial ice.
What is salt in ocean water?Salt in ocean water is the ionic compound NaCl that we are using as the table salt to add in foods. The Na+ and Cl- ions are reaching to the ocean through various geographical process.
One of them is volcanic eruptions by in the tectonic plate boundaries. Volcanoes containing sulfur and chlorine atoms which are falling to the ocean. Similarly land eruption also result in salt formation in oceans.
Land rocks contains minerals such as limestone, epsom salt, and table salt. Weathering process break down these minerals and dissolve in water. Melting of glacial ice increases the water level but does not make water salty.
To find more on weathering, refer here:
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