Electrons in the Bohr model follow the number of elements in the rows of the periodic table.
2 in the first orbit
8 in the second and third ring
18 in the fourth etc...
The Bohr model is a simplistic means of explaining the placement of the subatomic particles of the elements of the periodic table.
The Bohr model arrangement of electrons follows the same pattern as the periodic table.
2 elements in the first row, and 2 electrons in the first orbit.
8 elements in the second row, and 8 electrons in the second orbit.
8 elements in the third row, and 8 electrons in the third orbit.
The fourth and fifth orbits would therefore hold 18 electrons.
For most chemists, the Bohr model does not work well beyond the third row of the periodic table because the model becomes quite oversized and bulky.
explain hyaluronic acid
Answer:
Explanation:Hyaluronic acid is a natural substance found in the fluids in the eyes and joints. It acts as a cushion and lubricant in the joints and other tissues.
Different forms of hyaluronic acid are used for cosmetic purposes. Hyaluronic acid might also affect the way the body responds to injury and help to decrease swelling.
Hyaluronic acid injections are US FDA-approved for several conditions, including cataracts, osteoarthritis, and as an injectable gel filler (Juvedérm) for facial wrinkles. People also commonly take hyaluronic acid by mouth and apply it to the skin for UTIs, acid reflux, dry eyes, wound healing, aging skin, and many other conditions, but there is no good scientific evidence to support most of these other uses.
How does it work ?
Uses & Effectiveness ?
Likely Effective for
Cataracts. Injecting hyaluronic acid into the eye is effective when used during cataract surgery by an eye surgeon.
Swelling (inflammation) and sores inside the mouth (oral mucositis). Applying an FDA-approved hyaluronic acid gel is effective for treating mouth sores. It's not clear if other products help.
Answer:
Explanation:
Hyaluronic acid is a natural substance found in the fluids in the eyes and joints. It acts as a cushion and lubricant in the joints and other tissues. Different forms of hyaluronic acid are used for cosmetic purposes. Hyaluronic acid might also affect the way the body responds to injury and help to decrease swelling.
(❛◡❛✿)!
Chemistry: Please make sure to answer each question. Thank you in advance.
Create a diagram of your electroplating apparatus (an electrolytic cell). Then submit your drawing with the following terms labeled correctly. Or, beginning with the positive terminal of the battery and ending with the negative terminal of the battery, describe the path that the electricity takes and where each of the following occurs:
anode
cathode
copper strip
battery
positive terminal
negative terminal
place where oxidation occurs
place where reduction occurs
electrolyte solution
coin (or nail)
direction of electron flow
Answer:
(Score for Question 2: ___ of 7 points)
Describe the results of your procedure with the coin.
Answer:
(Score for Question 1: ___ of 6 points)
Write the two half-reactions that occur in this electroplating process. Be sure to include the states of the elements or ions.
Answer:
The electroplating process of the coin results in the coating of the coin with copper metal.
What is electroplating?Electroplating is the process of using coating the surface of a metal with another one electrolytic cell.
The electroplating of the coin is done using copper as the anode and the coin as the cathode. The electrolyte is copper sulfate solution.
Oxidation occurs at the anode with the copper metal being converted to copper (ii) ions.
Reduction occurred at the cathode as the copper (ii) ions in the solution accept electrons to become copper metal and the coin being coated with copper.
The half-reactions are shown below:
At the anode:
[tex]Cu(s) \rightarrow Cu^{2+}(aq) + 2e^{-}[/tex]
At the cathode:
[tex]Cu^{2+}(aq) + 2e{-} \rightarrow Cu(s)[/tex]
Therefore, the electroplating process of the coin results in the coating of the coin with copper metal.
Learn more about electroplating at: https://brainly.com/question/3913850
#SPJ1
Question 3:
The force of gravity between a planet and its moon is 371 N. If the planet has a mass of 4 x 1022 kg and the moon has a mass of 5 x 105 kg, what is the distance between their centers?
Answer:
=6×10^7metre
Explanation:
By using formula,
F=GMm/d^2
calculate the molecular weight of carbon dioxide
Answer:
44.01 g/mol
Explanation:
Carbon dioxide is produced when carbon and oxygen are burned.
To totally burn carbon into carbon dioxide, or CO2, we require one mole of oxygen for every gram of carbon by weight.
or alternatively:
You produce 12+216=44 g of carbon dioxide for every 12 g of carbon.
The weight of CO2 in kg may be calculated if the amount of CO2 in litres is known by converting it to moles and multiplying it by 44.
Three students are given a 200g object to weigh on a balance and record the following masses: 150g, 151g 150g. What can be said about the accuracy and precision of the balance?
A 2.49 g sample of aniline (C6H5NH2, molar mass = 93.13 g/mol) was combusted in a bomb calorimeter with a heat capacity of 4.25 kJ/°C. If the temperature rose from 29.5°C to 69.8°C, determine the value of ΔH°comb for aniline.
The value of delta H° for aniline = 6415 Kj/mol
calculation
Step 1: find heat
Q (heat) = C (specific heat capacity) x ΔT (change in temperature)
C= 4.25 kj/c°
ΔT = 69.8-29.5 = 40.3 c°
Q= 4.25 kj/c x 40.3 c = 171.28 kj
Step 2: find the moles of aniline
moles = mass/molar mass
= 2.49 g/ 93.13 g/mol =0.0267 moles
Step 3: find delta H
171.28 kj/0.0267 mol = 6415 kj/mol
since the reaction is exothermic delta H = 6415 Kj/mol
Answer:
-6.41x10^3
Explanation:
2.49 is 3 significant figures, so your answer should reflect that. Since heat is lost to the surroundings, the reaction is exothermic, and the answer should be negative.
pls tell this answers
Answer:
okay
Explanation:
9 . acidic
10. hydrogen
answer the following questions
11. Gold as a precious metal is used widely in making jewelry items. This metal is preferred over others for jewelry pieces for various reasons. One important reason for its popularity is that it does not react with atmospheric moisture and therefore, it does not rust.
12. corrosion is defined as rust it's due to humidity and moisture
13. Sulphur appears much below chlorine in the reactivity table and cannot displace chlorine from dilute HCl.
14. Highly conductive metal
Surpassed only by silver, copper is a highly conductive metal. This means electricity can pass through it with greater ease, making it ideal for use in electrical wires. Companies can use other conductive metals to create electrical wires.
15. Corrosion
Copper metal when exposed to air turns green in color due to corrosion. When the copper vessel is exposed to air in the rainy season, the metal reacts with gases, moisture, and atmospheric gases to form a mixture of copper carbonate and copper hydroxide. This gives a green color to the surface of the copper meta
16. Silicon
silicon is the backbone of the electronics industry. Because silicon is the reason for the fast development happened in the field of electronics. therefore, silicon is the backbone of electronics.
17. High chemical reactivity
Sodium is stored under kerosene because of its high chemical reactivity with almost all of the other elements (for example oxygen from the air which oxidizes it instantly). Kerosene and mineral oil are the only chemicals that make sodium inert. Usually, when Na reacts with a solvent it liberates hydrogen gas from its composition.
18. Metal oxides are oxides of metals. Nonmetal oxides are oxides of nonmetals. The main difference between metal oxides and nonmetal oxides is that metal oxides are basic compounds whereas nonmetal oxides are acidic compounds.
19. Silver is more likely to tarnish near a petroleum refinery than in a place far away from it because when silver reacts with petroleum or hydrogen sulfide present in it as a pollutant in the air, it starts forming a black coating of silver sulfide.
20. A noble metal is ordinarily regarded as a metallic chemical element that is generally resistant to corrosion and is usually found in nature in its raw form. Gold, platinum, and the other platinum group metals (ruthenium, rhodium, palladium, osmium, iridium) are most often so classified. Silver, copper, and mercury are less often to sometimes included as noble metals although each of these usually occurs in nature combined with sulfur.
What types of bonds and atoms are in the molecule shown below?
H₂C
C=C
H
CH₂-CH3
H
O A. Double bonds, triple bonds, carbon atoms, and hydrogen atoms
O B. Double bonds, triple bonds, carbon atoms, and helium atoms
OC. Single bonds, double bonds, carbon atoms, and hydrogen atoms
OD. Single bonds, double bonds, carbon atoms, and helium atoms
The types of bonds and atoms in the molecule shown below are C. Single bonds, double bonds, carbon atoms, and hydrogen atoms.
How many bonds can carbon form?Carbon can only form a bond with a maximum of 4 other molecules.
We have been given a molecule
H₂C CH₂-CH3
C=C
H H
In the given figure we can see that the molecule includes one double bond and other are single bonds.
Thus, The types of bonds and atoms in the molecule shown below are C. Single bonds, double bonds, carbon atoms, and hydrogen atoms.
Learn more about bonds;
https://brainly.com/question/17930825
#SPJ1
what is the new concentration of A if 7.7 ml of a .10 M solution of A is mixed with 18.3 mL of .20 M solution B and an additional 11.7 ml water?
Answer:
0.12 M
Explanation:
To find the new concentration, you need to (1) find the moles of Solution A (via the molarity equation), then (2) find the moles of Solution B, then (3) combine all of the moles and volumes, and then (4) calculate the new molarity. The final answer should have 2 sig figs to reflect the lowest amount of sig figs in the given values.
Solution A:
7.7 mL / 1,000 = 0.0077 L
Molarity = moles / volume
0.10 M = moles / 0.0077 L
0.00077 = moles
Solution B:
18.3 mL / 1,000 = 0.0183 L
Molarity = moles / volume
0.20 M = moles / 0.0183 L
0.00366 = moles
New Solution:
11.7 mL / 1,000 = 0.0117 L
New Volume = 0.0077 L + 0.0183 L + 0.0117 L
New Volume = 0.0377 L
New Moles = 0.00077 moles + 0.00366 moles
New Moles = 0.00443 moles
Molarity = moles / volume
Molarity = 0.0043 moles / 0.0377 L
Molarity = 0.1175 M = 0.12 M
If it requires 45.8 cal to melt 8.4 g of a substance, what is the heat of
fusion of the substance?
Answer:
5.452 cal/g
Explanation:
45.8 cal / 8.4 g = 5.4523 cal/g
384.72 J is the heat of fusion of the substance.
What is the heat of fusion?It is the change in the value of the enthalpy by providing energy i.e. heat, for a specific quantity of the substance.
Given data:
Heat of fusion =?
Mass of substance = 8.4 g
Unknown:
Amount of energy required to melt the given mass = 45.8 cal
Solution:
To solve this problem, the amount of energy required to melt the substance is given as;
H = m L
m is the mass
L is the heat of fusion
Insert the given parameters and solve;
H = 8.4 g x 45.8 cal = 384.72 J
Hence, 384.72 J is the heat of fusion of the substance.
Learn more about heat of fusion here:
https://brainly.com/question/19531870
#SPJ2
What type of reaction is represented by the following equation?
Mg(OH)2 (aq) + 2 HCl (aq) --> MgCl2 (aq) + 2 H2O (l)
Answer: Double replacement reaction
Explanation:
Identify the branch of chemistry being described.
a. _______________ study of the behavior and changes in matter including energy transfers, reaction mechanisms, and reaction rates.
b. _______________ study of compounds and chemicals containing carbon, which include pharmaceuticals, drugs, and plastics.
c. _______________ study of the components and composition of matter, including food nutrients, and quality control.
d. _______________ study of matter and processes that occur in biological organisms, including metabolism and fermentation.
Answer:
a. Physical Chemistry
b.Organic Chemistry
c.Food analysis, a very important branch of analytical chemistry
d. Biochemistry
Explanation:
Which buffer can be suitable to prepare a solution that needs to be buffered at pH 4? Explain your
choice.
A. Formic acid/Formiate buffer
B. Carbonic acid/Bicarbonate buffer
C. Ammonia/Ammonium buffer
D. Any buffer will work.
E. None of the buffers will be suitable.
34 Which of the following will form a buffer when mixed together? Explain
.
Which buffer can be suitable to prepare a solution that needs to be buffered at pH 4? Explain your
choice.
A. Formic acid/Formiate buffer
B. Carbonic acid/Bicarbonate buffer
C. Ammonia/Ammonium buffer
D. Any buffer will work.
E. None of the buffers will be suitable.
34 Which of the following will form a buffer when mixed together? Explain a weak acid/base and its conjugate base/acid in the form of salt
Which regulates the flow of electrical current to the filament of the x-ray tube? a. high-voltage circuit
b. low-voltage circuit
c. high-voltage transformer
d. low-voltage transformer
When 50.0 g iron(III) oxide reacts with carbon monoxide, 32.5 g iron is produced. What is the percent yield of the reaction?
Fe2O3(s)+3CO(g)→2Fe(s)+3CO2(g)
Answer:
92.9%
Explanation:
You have been given the actual yield of the reaction. First, you need to find the theoretical yield of the reaction. To do this, you need to (1) convert grams Fe₂O₃ to moles Fe₂O₃ (via molar mass from periodic table values), then (2) convert moles Fe₂O₃ to moles Fe (via mole-to-mole ratio from reaction coefficients), and then (3) convert moles Fe to grams Fe (via molar mass).
Once you have found the theoretical yield, you need to use the percent yield equation to calculate the final answer. This number should have 3 sig figs to match the given values.
(Step 1)
Molar Mass (Fe₂O₃): 2(55.845 g/mol) + 3(15.998 g/mol)
Molar Mass (Fe₂O₃): 159.684 g/mol
1 Fe₂O₃(s) + 3 CO(g) ---> 2 Fe(s) + 3 CO₂(g)
Molar Mass (Fe): 55.845 g/mol
50.0 g Fe₂O₃ 1 mole 2 moles Fe 55.845 g
-------------------- x ------------------ x --------------------- x ---------------- = 35.0 g Fe
159.684 g 1 mole Fe₂O₃ 1 mole
(Step 2)
Actual Yield
Percent Yield = --------------------------- x 100%
Theoretical Yield
32.5 g Fe
Percent Yield = ---------------------- x 100% = 92.9%
35.0 g Fe
Hey there.
Explain JJ Thomson's model.
Thomson discovered the electron, the first subatomic particle. In 1904, Thomson proposed atomic model where electrons are embedded within spherically distributed, positive charge (so-called "plum pudding" model).
J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup."
☆...hope this helps...☆
_♡_mashi_♡_
Which of the following methods correctly describes the preparation of 1.00 L of an aqueous solution of 0.500 M NaOH?
Answer:
Place 20.0 g NaOH(s) in a flask and dilute to 1.00 L with water.
Explanation:
What can help engineers develop ways to prevent rusting?
OA. Understanding the solubility of metal ions
B. Understanding double-displacement reactions
C. Understanding oxidation-reduction reactions
D. Understanding the phase changes of metals
Answer: Understanding oxidation-reduction reactions
Explanation:
Rusting occurs when electrons are exchanged between iron and oxygen.
NH3 is produced by the reaction of 0.450 moles of N2 and 0.600 moles of H2 according to the following equation: 2N2 + 3H2 ⟶ 2NH3. (a) How many moles of NH3 are produced? (b) What is the percent yield if 5.52g of NH3 is produced?
The moles of nitrogen produced is 0.40 moles of ammonia.
The Percent yield of ammonia is 81.2%
What moles of ammonia is produced?The moles of ammonia produced is obtained from the mole ratio of the reaction.
The mole ratio of hydrogen to nitrogen is 3 : 2
Based on the mole ratio, the limiting reactant is hydrogen.
Moles of nitrogen produced = 0.600 * 2/3 = 0.40 moles of ammonia.
mass of ammonia expected = 0.4 * 17 g = 6.8 g
Percent yield = 5.52/6.8 * 100% = 81.2%
Learn more about mole ratio at: https://brainly.com/question/19099163
#SPJ1
1. For CCl4, upload a photo including the following: (1) work arriving at total # valence electrons
(2) hand drawn Lewis structure (3) molecular model (4) signature(s) and (5) date.
Work arriving at total valence electrons are 24
The valence electron is an electron in the outer shell associated with an atom, and that can participate in the formation of a chemical bond
For a main-group element, a valence electron can exist only in the outermost electron shell; for a transition metal, a valence electron can also be in an inner shell.
Lewis structures, also known as Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures (LEDS), are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons that may exist in the molecule.
Calculating the work arrival at total valence electrons
We know 1 bond contains
2 valence electrons
Here CCl4 contains 4 bonds that is 8 valence electrons
Therefore ,
Total valence electrons are 32
Now valence electrons remain after bond formation =
32 - 8
=24 valence electrons
A molecular model is a physical model of an atomistic system that represents molecules and their processes
Molecular image and lewis hand drawn structure is as shown below
Learn more about lewis structure here
https://brainly.com/question/6224949
#SPJ10
How many valence electrons does Rb (rubidium) have?
Answer:
The total number of electrons in a valence shell is called valence electrons. The electron configuration of rubidium shows that the last shell of rubidium has an electron. Therefore, the valence electrons of rubidium(Rb) are one.
How many moles are in 24 g of carbon
Answer:
[tex]\fbox {2 moles}[/tex]
Explanation:
Relation between grams of Carbon and moles :
[tex]\fbox {12 g Carbon = 1 mole}[/tex]
Multiply both sides by 2 :
⇒ 1 x 2 moles = 12 x 2 g
⇒ 2 moles = 24 g
Compared to infrared radiation, an electromagnetic wave that has a lower frequency will also have a ________.
longer wavelength and lower speed
longer wavelength and equal speed
shorter wavelength and lower speed
shorter wavelength and equal speed
Compared to infrared radiation, an electromagnetic wave that has a lower frequency will also have a longer wavelength and equal speed
What is Electromagnetic wave ?Electromagnetic waves or EM waves are waves that are created as a result of vibrations between an electric field and a magnetic field.
It can be also defined as waves are composed of oscillating magnetic and electric fields.
One important feature fo electromagnetic radiation is that all have the same speed in vacuum, c, in vacuum, which is the speed of light.
Since, the speed, wavelength and frequency of the waves are related you can infere any of them when the other two are known.
The equation is:
speed = frequency × wavelength
s = ν × λ
c = ν × λ . . . for the specific case of electromagnetic radiation
That inverse relation between frequency and wavelength, where the speed is the constant, shows that the lower the frequency the longer the wavelength.
Therefore, the correct statment is that an an electromagnetic wave that has a lower frequency will also have a longer wavelength and equal speed (option B).
Learn more about Electromagnetic wave here ;
https://brainly.com/question/3101711
#SPJ1
7. Name the representative particle (atom, molecule, ion or formula unit) of Radon
Answer: A representative particle can be an atom, and an ion. a molecule, or a formula unit.
Explanation:
A representative particle is the smallest unit in which a substance naturally exists. For the majority of elements, the representative particle is the atom. Iron, carbon, and helium consist of iron atoms, carbon atoms, and helium atom, respectively.
Radon is a naturally occurring radioactive gas that is odorless and tasteless.
Atoms-the smallest particle of an element
Ions-atoms with positive or negative charges.
Molecules- two or more covalently bonded atoms.
Formula units- the simplest ratio of ions that make up an ionic compound.
why is it important to convert currency units from one type to another chemistry
easy to compare
easy in calculation
adjust to units commonly used in certain places
Identify if the following substances (a-h) are elements or compounds.
Answer:
Boron, Hydrogen, Helium, Lithium, Beryllium, Carbon, Nitrogen, Oxygen, etc.
Explanation:
These are all elements, not all of them.
How many moles are in a gas with a temperature of 21°C, pressure of 1,351 mmHg and a volume of 2,000 mL
Answer:
.147 moles
Explanation:
PV = n RT choose the correct "R" to be 62.364 L torr /(K-mol)
T needs to be in K (so add 273.15)
1351 torr * 2 L = n * 62.364 * (21 + 273.15 )
solve for n = .147 moles
number 3 pls and thank u
The statement which is not true is as follows:
The repulsive force between electrons on different atoms does not matter at all.Thus, the correct option is C.
What is Equilibrium?An equilibrium may be defined as the condition in which both the reactants and products are present in concentrations that have no additional propensity to alter with time so that there is no noticeable transformation in the possessions of the system.
The causation of repulsive force was thought to be made by the overlap of atomic orbitals and in between the electrons of diverse atoms, it matters a lot.
The equilibrium distance between nuclei of two covalently bonded atoms is called the bond length of that atom. It is the atomic separation at equilibrium.
Equilibrium occurs when the attractive and repulsive forces neglected the effect of each other in a specific state.
Therefore, it is well described above.
To learn more about Covalent bonds, refer to the link:
https://brainly.com/question/11651796
#SPJ1
Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2 Mg(s) + O2(g) → 2 MgO(s) How many moles of O2 are consumed when 2.10 mol of magnesium burns?
Answer:
1.05 mols of O2 gas
Explanation:
For this type of problem, it's important to understand what the balanced Chemical equation tells us:
Balanced Chemical equationsLet's look at the balanced chemical equation:
[tex]2Mg(s)+O_2(g)-- > 2MgO(s)[/tex]
This equation two sides of the reaction arrow. On the left are the reactants (things you start with, and that react during the chemical reaction), and on the right side are products (things that are produced during the chemical reaction that you end with).
The numbers in front of each compound tell how many of molecules are involved for a full reaction without anything left over. A "mol" is a large quantity ([tex]6.022*10^{23}[/tex]), in this case, of molecules , since it's unlikely you're only taking a single molecule of each substance (it would be so tiny, you wouldn't even know you were doing the reaction).
So,for every 2 moles of Magnesium used, we'll also need 1 mole of Oxygen, and it will produce 2 moles of Magnesium Oxide.
In a way, during the reaction it's almost like 2 moles of Magnesium is equal to 1 mole of Oxygen and is equal to 2 moles of Magnesium Oxide:
[tex]2 mol Mg(s)=1mol O_2(g)=2molMgO(s)[/tex]
From here, we can build some unit ratios, to convert between the known quantity of moles we have, and find the unknown quantity of moles that are requested.
Finding the right unit ratioWe know that we are looking at 2.10 mol of Magnesium, so we want a unit ratio with moles of Mg on the bottom. We want to find moles of O2, so we want a unit ratio of moles of O2 on top.
The unit ratio we want is the middle part of the equation, divided by the left part of the equation.
[tex]2 mol Mg(s)=1mol O_2(g)\\\frac{2 mol Mg(s)}{2 mol Mg(s)}=\frac{1mol O_2(g)}{2 mol Mg(s)}\\1=\frac{1mol O_2(g)}{2 mol Mg(s)}[/tex]
Since this quantity is 1, it is a unit ratio and can be multiplied to other things to change their units (for this problem).
Finding the answerStarting with what we know, and multiplying by our unit ratio:
[tex]2.10 mol Mg(s)*\frac{1mol O_2(g)}{2 mol Mg(s)}=1.05mol O_2(g)[/tex]
Notice that the units from the first quantity cancel with the units on the bottom of the fraction, leaving only the unit on top of the fraction ... the exact units we wanted!
So, 1.05mols of O2 would be consumed during the reaction if exactly 2.10moles of Magnesium are burned.
Part E
From the observations of the simulation, which strategy was most effective for quickly and efficiently producing ammonia? Why do you think this strategy is most effective?
The production of ammonia will be favored at high pressure and low temperature.
What is an exothermic reaction?The term exothermic reaction has to do with a reaction in which the forward reaction is favored at lower temperatures.
Now looking at the reaction coordinate and the equation of the reaction, we know that the production of ammonia will be favored at high pressure and low temperature.
Learn more about ammonia:https://brainly.com/question/12276882
#SPJ1
