Answer:
2
Explanation:
4s2 has 2 valence electrons
Valence shell is the shell which is the outermost shell, that is filled in the last, before valence shell is penultimate shell. Therefore 2 valence electron are there in the valence shell.
What is element?Element generally consist of atoms or we can say atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
From our question the electronic configuration of element is given as
1s²2s²2p⁶3s²3p⁶4s²
Valence electron is the one which is present in the outermost shell or orbit. So, form above electronic configuration we can say that 4 is the outermost shell and in this shell 2 electron is present. Therefore 2 electron are there in the valence shell as valence electron.
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name 2 elements that are liquid at room temperature and describe their colour
Answer:
Bromine
Mercury
Bromine (symbol Br and atomic number 35) is a reddish-brown liquid, with a melting point of 265.9 K. Mercury (symbol Hg and atomic number 80) is a toxic shiny silvery metal, with a melting point of 234.32 K.
How many total bonds (Total shared pairs) are in the lewis structure for HSiN and CO2?
Answer:
2
Explanation:
Hope it can help you lovelots
#LEARN WITH BRAINLY
Wyndirbu lie the following best describes the role played by
hydraulic fluid a hydraulic machine?
А
A source of fuel
B
A medium for the transfer of force
С
A coolant
D
A cleaning agent
Help pls
The role played by hydraulic fluid in a hydraulic machine is as a medium for
the transfer of force.
Hydraulic fluid is used primarily in a hydraulic machine for the transfer of
force from one point to another. This makes the system able to perform the
required functions.
Hydraulic fluid also has other functions such as being a coolant and as a
cleaning agent(removal of contaminants) which aren't its major function.
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what is chemical reaction ?
1) When a beam of white rays is dispersed by a prism which colour will be refracted to a larger extent?
Explanation:
since diferentes colours of light través at diferentes speeds, the refractiva index is diferentes for each color. The result? that whenthe White light países thought the prism it cover into a red light
How large
would be needed to hold
a Container
of water
Answer:
Since water has a density of 1 gram per cubic centimeter, then the container would need to be 800 cubic centimeters. if this container were a perfect cube, then the length of the side of the container would be equal to the cube-root of 800, which is approximately 9.28 cm to a side, or 3.65 inches to aside.
The
is the wind system responsible for the movement of weather from west to east across most of the continental United States
A
polar easterlies
B
prevailing westerlies
C
trade winds
Answer:
Westerlies are prevailing winds that blow from the west at midlatitudes. They are fed by polar easterlies and winds from the high-pressure horse latitudes, which sandwich them on either side.Nov 15, C answer
How many photons are produced in a laser pulse of 0.593 J at 671 nm?
Explanation:
May kwento po ba yan o yan na talaga
Fusion is a type of _____.
chemical reaction
nuclear reaction
physical reaction
Answer:nuclear reaction
Explanation: Nuclear fusion is a type of nuclear reaction where two light nuclei collide together to form a single, heavier nucleus. Fusion results in a release of energy because the mass of the new nucleus is less than the sum of the original masses.
Fusion is the process that powers the sun and the stars. It is the reaction in which two atoms of hydrogen combine together, or fuse, to form an atom of helium. In the process some of the mass of the hydrogen is converted into energy.
How many molecules are present in 4.61x10-2 mol of O2
Answer:
6.02 × 1023
The molar mass from the periodic table is 32.00 g O2 = 1 mol O2, and by definition, 1 mol O2 = 6.02 × 1023 molecules O2.
a guy walks into a bar and sees a non-linear person. he says hey wt y=mx+b is this? he threw a sploddy gun grenade in the place. how many non-linear people did he hurt?
1. Write a balanced chemical equation, including physical state symbols, for the combustion of methane in gaseous gaseous carbon dioxide.
Answer:
CH4(g)+2O2(g)→CO2(g)+2H2O(g)
Explanation:
For a complete combustion reaction of a hydrocarbon, oxygen is always one of the reactants, and the products are always carbon dioxide and water.
Hitting a ball with a baseball bat is an example of a force
True or False
What is the molarity of Ca(NO3)2 in a solution resulting from mixing 150.0 mL of 0.200 M HNO3 with 150.0 mL of 0.0100 M Ca(OH)2
The molarity of the Ca(NO3)2 solution would be 0.005 M
First, let us look at the balanced equation of the reaction:
[tex]2HNO_3+Ca(OH)_2 ---> Ca(NO_3)_2+2H_2O[/tex]
The mole ratio of HNO3 to Ca(OH)2 is 2:1.
Mole of HNO3 = molarity x volume
= 0.2 x 150/1000
= 0.03 mole
Mole of Ca(OH)2 = 0.01 x 150/1000
= 0.0015
Thus, there is no limiting or excess reactant.
Also from the equation, mole ratio of Ca(OH)2 to Ca(NO3)2 is 1:1. Hence, the mole of Ca(NO3)2 would also be 0.0015 mole.
The total volume of the resulting solution would be: 150 +150 = 300 mL
Thus, the molarity of the resulting Ca(NO3)2 would be:
Molarity = mole/volume
= 0.0015/0.3
= 0.005 M
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How does the structure of compounds determines the properties of the compounds?
All of these properties are due to the chemical structure of the compound. The chemical structure includes the bonding angle, the type of bonds, the size of the molecule, and the interactions between molecules. Slight changes in the chemical structure can drastically affect the properties of the compound.
How many aluminum ions are present in 65.5 mL of 0.210 M All3solution?
Answer:
Aluminium ions present's in 65.5mL of 0.210
M All 3solution is Given below-:
Answer and Explanation: 1
The first step is to determine the moles of aluminum ions. This utilizes the volume, molar concentration, and subscripts from the chemical formula of aluminum (III) fluoride as shown.
65.5 mL×1 L1000 mL×0.210 mol AlF31 L×1 mol Al3+1 mol AlF3=0.013755 mol Al3+65.5 mL×1 L1000 mL×0.210 mol AlF31 L×1 mol Al3+1 mol AlF3=0.013755 mol Al3+
To calculate for the number of aluminum ions, we use Avogadro's number as shown.
0.013755 mol Al3+×6.022×1023 ions1 mol Al3+=8.28×1021 ions Al3+.
Itz the ans. of collage ok man.
Answer:
m0.013755
m
o
l
A
l
3
+
×
6.022
×
10
23
i
o
n
s
1
m
o
l
A
l
3
+
=
8.28
×
10
21
i
o
n
s
A
l
3
+
L
×
1
L
1000
m
L
×
0.210
m
o
l
A
l
F
3
1
L
×
1
m
o
l
A
l
3
+
1
Explanation:
The first step is to determine the moles of aluminum ions. This utilizes the volume, molar concentration, and subscripts from the chemical formula of aluminum (III) fluoride as shown.
65.5. To calculate for the number of aluminum ions, we use Avogadro's number as shown.
Describe two or three ways in which the measurements you made could lead to errors in the results. Explain how each error would affect the answer of molar mass. In other words, would the molar mass go up or down and why
Answer:Physical and chemical laboratory experiments include three primary sources of error: systematic error, random error and human error
Explanation:
When examining the root mean square speed equation, we can see that the changes in temperature (T) and molar mass (M) affect the speed of the gas molecules. The speed of the molecules in a gas is proportional to the temperature and is inversely proportional to molar mass of the gas.
A sample of carbon dioxide gas has a pressure of 8.33 bar and a volume of 10.3 mL at a temperature of 29.1 °C. How many
molecules of carbon dioxide gas are in the sample?
molecules:
A carrot originally has a mass of 0.39g and after being left in a salt solution overnight it gained 0.3g. Calculate the percentage mass increase of the carrot.
Answer:
77%
Explanation:
The formula for finding percent change is change/original.
So, you have to do 0.3/0.39
You have to divide this to get 0.769 which can be rounded 0.77
0.77 as a percentage is 77%
So, the percentage mass increase of the carrot is 77%
I am not feeling well
I hope you feel better soon! :)
Explain why Florida does not have long winters?
A city carrier resigns and trains as an office receptionist this is a person’s metabolism is likely to
A student experimentally determines the gas law constant, R, by reacting a small piece of magnesium with excess hydrochloric acid and then collecting the hydrogen gas over water in a eudiometer. Based on experimentally collected data, the student calculates R to equal 0.0832
Due to errors in volume and moles measurement by the student, the true value of the molar gas constant is less than the obtained value.
The Percent error is 1.39%
What is percent error?Percent error is defined as the ratio of error and true value of a measurement expressed as a percentage.
Percent error = (error/true value) × 100%Error = |true value - measured value|
The error in the students measurement = |0.08206 - 0.0832|
Error = 0.00114
Percent error = (0.00114/0.08206) × 100%
Percent error = 1.39%
The formula to determine the molar gas constant R is given below:
[tex]R = \frac{PV}{nT}[/tex]
Since the student value is higher than the true value, the possible sources of error include:
The student student does not equilibrate the water levels within the eudiometer and the beaker at the end of the reaction resulting in increased volumeThe student does not clean the zinc with sand paper, thus the number of moles of hydrogen gas produced is less than the actual value.Therefore, the true value of the molar gas constant is less than the obtained value.
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A piece of potato had an original mass of 3.2g and after being left in a sugar solution for 24 hours it then had a mass of 2.8g. Calculate the percentage mass decrease of the potato.
Answer: -13% to 3 sig figs
Explanation:
A piece of potato had an original mass of 3.2g and after being left in a sugar solution for 24 hours it then had a mass of 2.8g. Calculate the percentage mass decrease of the potato.
the change in mass is 2.8 -3.2 = -0.4 gm
the % change fro the origial piece is ( -0.4/3.2) X 100 = -12.5%
or -13% to 3 sig figs
What is the concentration of chloride ions in solution after the reaction of 5.8 mL 0.12 M ammonium chloride with 3.2 mL 0.21 M silver nitrate
Answer:
ok
Explanation:
What equipment is generally used to make lyophilized medications suitable for administering to the patient? a) Test tubes or sterile ampules b) Petri dishes and sterile droppers c) Sterile syringes or graduated cylinders d) Measuring cups and clean, warm water
Answer:
B) Sterile droppers and petri dishes
the role of haemoglobin in the transport of oxygen and carbon dioxide
Hemoglobin with bound carbon dioxide and hydrogen ions is carried in the blood back to the lungs, where it releases the hydrogen ions and carbon dioxide and rebinds oxygen. Thus, hemoglobin helps to transport hydrogen ions and carbon dioxide in addition to transporting oxygen.
Two students are identifying a sample of tap water.
Student A says that tap water is a mixture, while
Student B says that it is a compound. Which student
is correct? Justify your answer.
Tap water is a mixture not compound due to presence of many substance.
Tap water is an example of mixture not compound because in tap water, water is not available in pure form, it has many substances mix with water and those substances make no bond with water.
It has dissolved compounds like calcium carbonate, magnesium and fluoride. Different elements or compounds are physically combined rather than chemically linked together so we can conclude that student A is correct that tap water is a mixture.
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What is the percent composition of Be(OH)2?
Answer:
Ba 80.148%. H 1.77% O 18.657%
What is measurement??
0000000000
measurement is the process of finding the value of any Unknown physical quantities in standard value.
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Measurement has been defined as the concept widely used in math and science to quantify an object. It is used to denote the quantification of the event or the object with respect to other or individually.
Hence, the definition of measurement is the process of determining the size or smallness of a physical amount by comparing it to a reference quantity of the same kind as the object.
It has been used to determine the quantity to be small or large based on some predetermined standard or values. It compares the physical quantity like mass can be estimated using kilograms or grams.
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