Answer:
2
Explanation:
because first shell ( k shell ) needs only 2 electron to complete its octet .
hope it helps
Which of the following is NOT a heterogenous mixture:
Salad
Beef Stew
Cereal in milk
Vinegar
Answer:Vinegar
Explanation:
Which equation could be used to solve for the average speed of a car that travels 90m in 20 seconds?
Answer:
Vav=d/t
Explanation:
Because the question already gave d=90m and t=20s. Because the car is the thing that can not travel the same distances at the same times.So the equation is V[tex]\\_{av}[/tex]=[tex]\frac{d}{t} \\[/tex]
How do we use positive and negative signs to communicate the direction of a vector
Answer:
Two vectors are equal if they have the same magnitude and the same direction. Just like scalars which can have positive or negative values, vectors can also be positive or negative. A negative vector is a vector which points in the direction opposite to the reference positive direction.
flourine is more reactive than chlorine . why ? with short reason.
Answer:
Electronegativity is probably the biggest thing that plays into reactivity. Therefore, since fluorine has a higher electronegativity than chlorine, fluorine is more reactive.
Explanation:
I got it right
Which organisms are producers? (SELECT ALL THAT APPLY.)
grass
bear
human
oak tree
fungus
Answer:
Grass
Oak tree
Explanation:
Bear and human are definitely not and fungus are decomposers.
Which of the following is a radioactive element?Sodium, Fluorine,Oxygen
francium
Answer:
Fluorine
Explanation:
These particles stick in the atoms and make them radioactive.
The modern form of the periodic table results in the _____ ,which states that when elements are
arranged according to increasing atomic number
Answer:
The periodic law states “When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties
calculate the molar mass of iron oxide
Explanation:
The molar mass of iron oxide is 159.7 ghope it helps you
Number of atoms in 4.5 moles of Au?
Atoms are stationary and don't move when in solid form.
False
True
Answer:
True? The don't stay exactly still i dont think, but i'd say true.
Explanation:
Answer:
TRUE
Explanation:
In a solid, atoms are packed tightly together and move very slowly. In fact, they do not flow at all: they simply vibrate back and forth.
Key words vibrate, not movement.
Correct me if I'm wrong of course
(5) Use scientific notation, make the following conversions:
6.20 km to m
Answer:
6200 meters
Explanation:
To convert from km to m you have to multiply the number by a thousand
Answer:
6.2×10^3 m
Explanation:
6.20×1000=6200m
In scientific notation 6200 = 6.2×10^3
What is the value of 4a? when a= 3?
Answer:
12
Explanation:
4x3 is 12
Answer:
To solve this simple expression you must substitute [tex]a[/tex] for the number you are given, so, 3.
4[tex]a[/tex] -> 4 3
Now, when numbers are next to each other like this, they are always multiplied. So, the find the answer you would multiply 4 times 3...
4 x 3 = 12
So, you answer will be 12!
What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an energy level with n = 4 to an energy level with n = 2?
Answer:
[tex]4.86\times10^{-7}\ \text{m}[/tex]
Explanation:
R = Rydberg constant = [tex]1.09677583\times 10^7\ \text{m}^{-1}[/tex]
[tex]n_1[/tex] = Principal quantum number of an energy level = 2
[tex]n_2[/tex] = Principal quantum number of an energy level for the atomic electron transition = 4
Wavelength is given by the Rydberg formula
[tex]\lambda^{-1}=R\left(\dfrac{1}{n_1^2}-\dfrac{1}{n_2^2}\right)\\\Rightarrow \lambda^{-1}=1.09677583\times 10^7\left(\dfrac{1}{2^2}-\dfrac{1}{4^2}\right)\\\Rightarrow \lambda=\left(1.09677583\times 10^7\left(\dfrac{1}{2^2}-\dfrac{1}{4^2}\right)\right)^{-1}\\\Rightarrow \lambda=4.86\times10^{-7}\ \text{m}[/tex]
The wavelength of the light emitted is [tex]4.86\times10^{-7}\ \text{m}[/tex].
A solution is made by mixing 49.g of chloroform CHCl3 and 73.g of acetyl bromide CH3COBr. Calculate the mole fraction of chloroform in this solution. Round your answer to 2 significant digits.
Answer: The mole fraction of chloroform in this solution is 0.41
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]CHCl_3[/tex]
[tex]\text{Number of moles}=\frac{49g}{119g/mol}=0.41moles[/tex]
b) moles of [tex]CH_3COBr[/tex]
[tex]\text{Number of moles}=\frac{73g}{123g/mol}=0.59moles[/tex]
To calculate the mole fraction, we use the formula:
[tex]\text{Mole fraction of a component}=\frac{\text{Moles of the component}}{\text{total moles}}[/tex]
[tex]\text{Mole fraction of chloroform}=\frac{\text{Moles of chloroform}}{\text{total moles}}=\frac{0.41}{0.41+0.59}=0.41[/tex]
The mole fraction of chloroform in this solution is 0.41
11. Everybody loves Mr Brown
Answer:
NO I DON'T ✌✌✌✌✌✌✌✌✌
A mixture of ethyne gas (C2H2) and methane gas (CH4) occupied a certain volume at a total pressure of 16.8 kPa. When the sample burned, the products were CO2 gas and H2O vapor. The CO2 was collected and its pressure found to be 25.2 kPa in the same volume and at the same temperature as the original mixture. What percentage of the original mixture was methane
Answer:
50%
Explanation:
Let assume that there are:
"a" moles of CH4 & "b" moles of C2H2
Then by applying the ideal gas equation:
PV = nRT
[tex]16.8 \times 10^3 \times V = (a+b)RT[/tex]
Make (a+b) the subject of the formula:
[tex](a+b) = \dfrac{16800 \ V }{RT} mol[/tex] --- (1)
Since 1 mole of CH₄ yields 1 mol of CO₂ & 1 mol of C₂H₂ yields 2 moles of CO₂
Then;
the total moles of CO₂ = (a +2b)
Now:
[tex]25.3 \times 10^3 \times V = (a+ 2b)RT[/tex]
[tex](a + 2b) = \dfrac{25200 \ V}{RT \ mol}[/tex] ---- (2)
∴
By solving the above equations
[tex]a = \dfrac{8400 \ V}{RT} \\ \\ b = \dfrac{8400 \ V}{RT}[/tex]
Hence, the estimate of the percentage of methane in the original mixture is:
[tex]= 100 \times \dfrac{a}{(a+b)}[/tex]
[tex]= 100 \times \dfrac{8400\dfrac{ \ V}{RT} }{8400\dfrac{ \ V}{RT} + 8400\dfrac{ \ V}{RT}}[/tex]
= 50%
A 2.26 M solution of KOH is prepared. Calculate the moles and mass of solute present in a 15.2-mL sample of this solution. The molar mass of KOH is 56.11 g/mol.
Answer:
0.0344 moles and 1.93g.
Explanation:
Molarity is defined as the ratio between moles of a solute (In this case, KOH), and the volume. With molarity and volume we can solve the moles of solute. With moles of solute we can find mass of the solute as follows:
Moles KOH:
15.2mL = 0.0152L * (2.26mol / L) = 0.0344moles
Mass KOH:
0.0344 moles * (56.11g/mol) = 1.93g of KOH
Given the conditional statement ~p → q, which statement is logically equivalent?
A. p → ~q
B. ~p → ~q
C. ~q → ~p
D. ~q → p
Answer:
A. p → ~q
Explanation:
I am double checking.
The weight of an object is different on each planet because
O mass changes with location
O each planet has a different force of gravity
O each planet is a different distance from the sun
Omass of the object changes on each planet
Answer:
each planet has a different force of gravity
Explanation:
Weight = mass× gravity
As gravity changes from place to place and also from planet to planet so weight changes.
How are molecules built?
Bonding
Atomic Rays
Phase Changes
All of these
HC2H3O2 chemical compound?
Answer:
Ethanoic or acetic acid.
Explanation:
Hello!
In this case, since the chemical formula of the compound excludes the hydrogen from the CHO form, we can infer it is a leaving group, which is likely to be bonded with an oxygen due to the high polarity of the O-H bond. In such a way, the most feasible condensed structure is:
[tex]CH_3-COOH[/tex]
Whereas the COOH stands for the carboxyl group; therefore the compound is ethanoic acid or acetic acid.
Regards!
please help..............
rgrgtff
ghhbbbhhghghgghgggferer
30 POINTS HELP Which idea was supported by Aristarchus, Copernicus, and Galileo?
The planets have epicycles.
The planets revolve around the Sun.
The stars rotate around the Sun.
The center of the solar system is Earth.
Answer:
SO SORRY it took so long but the answer is B :)
Explanation:
Trust me and good luck :)
The theory that the planets move around the sun was endorsed by Aristarchus, Copernicus, as well as Galileo. The solar system revolves around the sun.
What is Aristarchus?Aristarchus of Samos was just a Greek astronomer that suggested the very first heliocentric model of the cosmos, wherein the sun, rather than the earth, was even at its center. Despite the fact that his hypothesis was acknowledged by other philosophers of the time, it was dismissed as unrealistic, and the geocentric model remained in use for the next 1,700 years.
What is Copernicus?Copernicus was also the first to assert that the Earth as well as the other planets orbit the sun. It was really a significant shift in thinking.
What is sun?Sun can be considered as a star in solar system.
The theory that the planets move around the sun was endorsed by Aristarchus, Copernicus, as well as Galileo. The solar system revolves around the sun.
Therefore, the correct answer will be option (b).
To know more about Aristarchus and Copernicus
https://brainly.com/question/12401405#SPJ2
What are 3 characteristics of all invertebrates
Answer:
None have backbones
No cell walls
Multicellular
Includes radial or bilateral body symmetry.
Explanation:
Predict the reactants of this chemical reaction. That is, fill in the left side of the chemical equation. Be sure the equation you submit is balanced. (You can edit both sides of the equation to balance it, if you need to.) Note: you are writing the molecular, and not the net ionic equation.
Answer:
Hydrogen chloride (HCl) and Calcium hydroxide (CaOH). (see balanced equation below)
Explanation:
In a neutralization reaction as is the case of the question (see attachment), an acid would be neutralized by a base to form salt and water.
The most plausible reactants for the reaction given the number of moles of the product, is therefore Hydrogen chloride (HCl) and Calcium hydroxide (Ca(OH)2).
[tex]HCl _{(aq)} + Ca(OH)_{2} _{(aq)}[/tex] →[tex]CaCl_{2}_{(s)} + H_{2} O_{(l)}[/tex]
Let me know if this was helpful.
Identify the ionic compound that can form between potassium as the metal and nitrogen as the nonmetal.
help!!
Answer:
[tex]6K _{(s)} + N _{2(g)} = = > \:2K _{3} N _{(s)} [/tex]
Potassium nitride
How many grams of H2O are in 34.53 moles of H2O??
Answer:
m=621.54g
Explanation:
number of moles= mass of H2O/molar mass of H2O
n=m/mm
make mass the subject of the formula
m=n*mm
find molar mass of water
H2O=1(16)+2(1)
mm= 18.0g/mol. n=34.53mol
hence, m=34.53mol*18.0g/mol
m=621.54g
8. As the temperature of a mixture increases, one part of the mixture may 2 points
melt while the other parts remain solid. *
True
Or
False
Answer:
It's false
Explanation:
Mixtures are always combinations of the same compounds that are at different states.
What do you notice about the movement of the molecules of the two samples?
Explanation:
For sample A, I put the temperature to 93.2 C and sample B to 6.8 C. Once I dragged them together, I noticed that the numbers were going down the second I put them together! Sample A was getting colder and Sample B was getting warmer. As I let both the samples do their thing, I realized they weren't changing temperatures anymore. Both samples stopped at 50.0 C and have never changed temperatures since then.
12. Which of these is a solution? *
Gold
Salt
Water
Carbonated Water
All of the above.
Answer:
carbonated water
remaining are single element
