Answer:
true
Explanation:
22. In 4f12, the 12 stands for the
The 12 stands for the number of electrons that fill the f orbital
Further explanationIn an atom there are levels of energy in the shell and sub shell
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 sub shell is
• s: 2 electrons
• p: 6 electrons
• d: 10 electrons and
• f: 14 electrons
4f¹² :
4 : number of shell
12 : the number of electrons that fill the f orbital
Boron has two isotopes. Boron-10 which has a mass of 10.0129 and Boran-11 with a mass of 11.0093 occurs 52.69% of the time and B - 11 47.31% of the time. What is the average atomic mass of boron?
Help me
Answer:
Copper, a metal known since ancient times, is used in electrical cables and pennies, among other things. ... Calculate the average atomic mass of copper. ... The atomic masses of the two stable isotopes of boron 10B (19.78%) and 11B (80.22%) are 10.0129 amu ... (.1978)(10.0129 amu) + (.8022)(11.0093 amu) =10.81 amu.
Explanation:
I hope I help :)
Theodor Schwann was a German scientist who wanted to understand how different types of cells worked and performed functions in different tissues. He was one of the first to theorize that all living things are made up of cells.
Rudolf Virchow was a German doctor who wanted to discover the origin of diseases. He accepted the idea that all living things are made up of cells and extended the idea to theorize that many diseases are the result of bacterial cells infecting the body.
The example described above suggests that
A.
scientific discoveries are never made by doctors.
B.
scientists always have the same goals when making related discoveries.
C.
German scientists were the first to disprove cell theory.
D.
people with different goals can make contributions to scientific knowledge.
D. People with different goals can make contributions to scientific knowledge
Both Schwann and Virchow had different thoughts and ideas. Schwann wanted to understand how cells worked - Virchow wanted to know the origin of diseases. Different goals.
Answer:
D
Explanation:
I got it right on studyisland
How long will it take to do generate 70 watts of power if I do 4900 Jules of work? HELP ASAP WILL GOVE BRAINLIEST‼️‼️
Answer:
Is it multiple choice or what I need to know the details
Explanation:
which of the following is an example of
a physical property?
Answer:
physical property is property that you can touch, smell as it is bumpy it smells like eggs.
Explanation:
YW
Answer:
Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.
Explanation:
Which problem that the most scientists believe is partly caused by carbon dioxide?
Answer:
Climate change
Explanation:
Climate change is primarily a problem of too much carbon dioxide (CO2) in the atmosphere. This carbon overload is caused mainly when we burn fossil fuels like coal, oil and gas or cut down and burn forests
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NEED HELP ASAP!!!!!
Answer:
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Explanation:
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Answer:
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asap what is the meaning of it?
What masses of KCl and H2O are needed to make 250 g of 5.00 % solution?
____ g of KCl
____ g of H2O
Answer:
w/w means weight/weight
Therefore, in a 250 g of solution, 5% needs to be KCl,
i.e. 5% x 250 = 12.5 g of KCl is needed.
The masses of KCl and H2O are needed to make 250 g of 5.00 % solution is 12.5 g of KCl and 237.50 g of H2O.
Calculation of the masses:Since there is the solution of 250 g of 5.00 % solution
So, here
Mass of KCl is = 5% of 250 = 12.5 g
And, the mass of H2O is
= 250 - 12.5g
= 237.50 g
Hence, The masses of KCl and H2O are needed to make 250 g of 5.00 % solution is 12.5 g of KCl and 237.50 g of H2O.
Learn more about mass here: https://brainly.com/question/18470727.
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Answer:
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Explanation:
Chlorine (Cl) is 76% chlorine-35 and 24% chlorine-37. Determine the average atomic mass of chlorine. Show/Explain work.
Answer:
Average atomic mass of chlorine is 35.48 amu.
Explanation:
Given data:
Percent abundance of Cl-35 = 76%
Percent abundance of Cl-37 = 24%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (76×35)+(24×37) /100
Average atomic mass = 2660 + 888 / 100
Average atomic mass = 3548/ 100
Average atomic mass = 35.48 amu
Average atomic mass of chlorine is 35.48 amu.
Who was known as the ‘laughing philosopher’?
Answer:
Democritus
Explanation:
Answer:
Democritus
Explanation:
They called him that because of his cheerfulness and how he treated people .
Hoped I helped-
Sleepy-
How many molecules are in 650.0 g Mg(OH)₂ ?
Answer:
6.711 × 10²⁴ molecules Mg(OH)₂
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
650.0 g Mg(OH)₂
Step 2: Define conversions
Avogadro's Number
Molar Mass of Mg - 24.31 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of H - 1.01 g/mol
Molar Mass of Mg(OH)₂ - 24.31 + 2(16.00) + 2(1.01) = 58.33 g/mol
Step 3: Convert
[tex]650.0 \ g \ Mg(OH)_2(\frac{1 \ mol \ Mg(OH)_2}{58.33 \ g \ Mg(OH)_2} )(\frac{6.022 \cdot 10^{23} \ molecules \ Mg(OH)_2}{1 \ mol \ Mg(OH)_2} )[/tex]
= 6.71061 × 10²⁴ molecules Mg(OH)₂
Step 4: Check
We are given 4 sig figs. Follow sig fig rules.
6.71061 × 10²⁴ molecules Mg(OH)₂ ≈ 6.711 × 10²⁴ molecules Mg(OH)₂
find the volume of a gas at standard pressure if its volume at 1.9 atm is 80 ml?
given:
formula:
substitution:
answer:
Answer:
1.5 × 10² mL
Explanation:
Step 1: Given data
Initial pressure of the gas (P₁): 1.9 atmInitial volume of the gas (V₁): 80 mLFinal pressure of the gas (P₂): 1.0 atm (standard pressure)Final volume of the gas (V₂): ?Step 2: Calculate the final volume of the gas
For an ideal gas, we can calculate the final volume of the gas using Boyle's law.
P₁ × V₁ = P₂ × V₂
V₂ = P₁ × V₁/P₂
V₂ = 1.9 atm × 80 mL/1.0 atm
V₂ = 1.5 × 10² mL
Since the pressure decreased, the volume of the gas increased.
please help will give brainliest
Answer:
1st one is...
Explanation:
The 1st one is change in size or shape. 2nd one is formation of precipitate. 3rd one is physical change. 4th one is formation of gas.
which iconic compound is used as a building material?
Answer:
Magnesium oxide is an ionic compound that can be used as a building material. MO2 is actually a raw material that used in producing cement for building houses, buildings, and other constructions.
Explanation:
Classify which compounds will dissolve in water and which ones will not dissolve in water.
a. Accetone
b. I-propanol
c. Hexane
d. Methanol
e. Decane
Answer:
Dissolves in water: Acetone, 1-propanol, Methanol
Do not dissolve in water: Hexane, Decane
Explanation:
From the principle that like dissolves like,polar substances will dissolve in polar solutions, while non-polar substances will dissolve in non-polar substances.
Water is a polar solution, therefore, polar substances will dissolve in it.From the given options:
Acetone is a polar molecule, therefore, it will dissolve in water.
1-propanol is a polar molecule, therefore, it will dissolve in water.
Hexane is a non-polar molecule, therefore, it will not dissolve in water.
Methanol is a polar molecule, therefore, it will dissolve in water.
Decane is a non-polar molecule, therefore, it will not dissolve in water
___ The energy of moving particles.
a. Chemical Energy
b. Radiant Energy
c. Mechanical Energy
Is freeze-drying a physical change or chemical change?
Answer:
Physical change because it can go back to its original form.
Explanation:
as more discovers were made, whittaker proposed classifying orginsims into five _____
Answer:
As more discovers were made, Whittaker proposed classifying organisms into five Kingdoms
which two smaller groups is the animals kingdom is divided into
A. sponges and arthropods
B. vertebrates and invertebrates
C. ectotherms and endotherms
D. class and order
How long is a wave traveling at 120 m/s if it has a frequency of 30 Hz?
Answer:
4 m
Explanation:
HELP!!! 30 POINTS!!!
Explanation:
[tex]periodic \: law[/tex]
It's correctAnswer
you already got it
Explanation:
an objects kinetic energy increases as its velocity increases?
How many moles of H are present in 3 moles of carbon trihydride?
Answer:
4moles of carbon trihydride
is trying to plate gold onto his silver ring. He constructs an electrolytic cell using his ring as one of the electrodes. He runs this cell for 94.6 minutes at 224.8 mA. How many moles of electrons were transferred in this process
Answer:
0.013 mole.
Explanation:
From the question given above, the following data were obtained:
Time (t) = 94.6 mins
Current (I) = 224.8 mA.
Mole of electrons (e) =?
Next, we shall convert 94.6 mins to seconds. This is illustrated below:
1 min = 60 s
Therefore,
94.6 mins = 94.6 min × 60 s / 1 min
94.6 mins = 5676 s
Thus, 94.6 mins is equivalent to 5676 s.
Next, we shall convert 224.8 mA to ampere (A). This can be obtained as follow:
1 mA = 1×10¯³ A
Therefore,
224.8 mA = 224.8 mA × 1×10¯³ A / 1 mA
224.8 mA = 0.2248 A
Thus, 224.8 mA is equivalent to 0.2248 A.
Next, we shall determine the quantity of electricity flowing in circuit. This can be obtained as follow:
Time (t) = 5676 s
Current (I) = 0.2248 A
Quantity of electricity (Q) =?
Q = it
Q = 0.2248 × 5676
Q = 1275.96 C
Finally, we shall determine the mole of electron by converting the quantity of electricity (i.e 1275.96 C) to number of electrons. This can be obtained as follow:
96500 C = 1 e
Therefore,
1275.96 C = 1275.96 C × 1 e / 96500 C
96500 C = 0.013 e
Thus, the mole of electron trasfered in the process is 0.013 mole.
A student performed the experiment in this module but failed to follow the procedure exactly, keeping the crucible completely covered during the entire heating and cooling processes. Be specific.
1. Explain the probable effect of this procedural change on the experimental results.
2. Would the student's calculated percent water in the hydrate be high, low, or unaffected? Briefly explain
Answer:
This question is incomplete
Explanation:
This question is incomplete but the answer to the question can be correctly predicted from the available information from the question.
1. If a "container" (in this case a crucible) is closed throughout a heating experiment. Then it must be noted that water vapor will not be able to escape during the course of the experiment. The water vapor will form a "cloud" of water droplets under the cover of the crucible. And when this crucible is cooled, this water droplets return back to the content/substance inside the crucible.
2. When compared with the initial amount of water present in the substance in the crucible, the percentage of water "left" in the hydrate or substance in the crucible would be high. This is because the water vapor that was suppose to leave the crucible did not leave because the crucible was closed (thus causing very low amount of water vapour to leave).
Because of the student error, the percent water of crystallization value the hydrate will be lower than its actual value.
What is evaporation?Evaporation is the process by which a liquid changes spontaneously to vapor.
In the experiment to determine percentage water of crystallization, the crucible is left open to ensure all the water molecules are removed by evaporation.
However,, since the student did not remove the crucible cover during heating, some water molecules will not be able to escape completely, but will return back to the salt.
Hence, the percent water of crystallization value the hydrate will be lower because the of mass of the anhydrous salt will be higher than its actual value.
Learn more about percent water of crystallization at: https://brainly.com/question/7805021
An open flask sitting in a lab fridge looks empty, but it is filled with a mixture of gases called air. Calculate the number of molecules of gas the flask contains if the flask volume is 2.50 L , and the air is at standard temperature and pressure (STP).
Answer: The number of molecules of gas the flask contains is [tex]0.674\times 10^{23}[/tex]
Explanation:
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 1 atm (STP)
V = Volume of gas = 2.50 L
n = number of moles = ?
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature = 273K (STP)
[tex]n=\frac{PV}{RT}[/tex]
[tex]n=\frac{1atm\times 2.50L}{0.0821 L atm/K mol\times 273K}=0.112moles[/tex]
According to Avogadro's law:
1 mole of gas at STP contains =[tex]6.023\times 10^{23}[/tex] molecules
Thus 0.112moles of gas at STP contains = [tex]\frac{6.023\times 10^{23}}{1}\times 0.112=0.674\times 10^{23}[/tex] molecules
The number of molecules of gas the flask contains is [tex]0.674\times 10^{23}[/tex]
Omar heated a small piece of calcium carbonate. It gave off carbon dioxide gas, solid calcium oxide was left behind.write equation.
Answer:
CaCO[tex]_{3s}[/tex] → CO[tex]_{2g}[/tex] + CaO[tex]_{s}[/tex]
Explanation:
Given reactants:
Omar heated small piece of calcium carbonate
Product;
it gave off carbon dioxide gas and solid calcium oxide;
Problem,
Equation of the reaction;
Solution:
Calcium carbonate → Carbon dioxide + Calcium oxide
CaCO[tex]_{3s}[/tex] → CO[tex]_{2g}[/tex] + CaO[tex]_{s}[/tex]
A ballon that contains 0.75 l of gad at 25 c is cooled to - 100 c. Calculate the new volume of the baloon
Answer:
0.44L
Explanation:
Given parameters:
Initial volume = 0.75L
Initial temperature = 25°C = 273 + 25 = 298K
Final temperature = -100°C = 273 + (-100) = 173K
Unknown:
New volume of the balloon = ?
Solution:
According to Charles's law;
"the volume of a fixed mass of a gas varies directly as its absolute temperature if the pressure is constant".
Mathematically;
[tex]\frac{V_{1} }{T_{1} }[/tex] = [tex]\frac{V_{2} }{T_{2} }[/tex]
V and T are temperature values
1 and 2 are the initial and final states
Insert the parameters and solve;
[tex]\frac{0.75}{298}[/tex] = [tex]\frac{V_{2} }{173}[/tex]
298V₂ = 129.75
V₂ = 0.44L
28.The chemical formula of a compound indicates
the source of the elements in the compound.
b. how elements are joined in the compound.
the alchemy symbols for the elements in the compound.
d. the relative proportions of the elements in the compound.
Answer:
d. the relative proportions of the elements in the compound.
Explanation:
The chemical formula of a compound indicates the relative proportions of the element in the compound.
The chemical formula of a compound is a representation which shows all the elements therein and the mole relationship between them expressed as subscripts. For example HCl, contains one mole of hydrogen and 1 mole of Cl.