Answer:
In atomic physics, the Bohr model or Rutherford–Bohr model, presented by Niels Bohr and Ernest Rutherford in 1913, is a system consisting of a small, dense nucleus surrounded by orbiting electrons—similar to the structure of the Solar System, but with attraction provided by electrostatic forces in place of gravity.
Answer:
BOHR'S MODEL OF ATOM :
In order to overcome the objections raised against Rutherford's model of the atom, Neils Bohr put forward the following postulates about the model of an atom:
(i) Only certain special orbits known as discrete orbits of electrons, are allowed inside the atom.(ii) While revolving in discrete orbits the electrons do not radiate energy.These orbits or shells are called energy levels. Energy levels in an atom are shown in Fig.
There orbis for shells are represented by the letters K,L,M,N... or the number n = 1,2,3,4...
ABOUT BOHR :
Neils Bohr (1885-1962) was born in Copenhagen on 7 October 1885. He was appointed professor of physics at Copenhagen University in 1916. He got the Nobel prize for his work on the structure of atom in 1922. Among Professor Bohr's numerous writings. three appearing
s books are:
(i) The Theory of Spectra and AtomicConstitution. (ii) Atomic Theory and.(iii) The Description of Nature————————————————GIVING OUT BRAINLIEST!!!!!!!!!
Which substance has the lowest specific heat?
O Beach sand
O
Beach water
O Ice
Pool water
___C3H8 + ___O2 --> ___H2O + ___CO2
Answer:
C3H8 + 5O2 ‐‐‐‐‐‐‐‐> 4H2O + 3CO2
QUESTION 4
How many significant figures are in the number 0.000020?
O A. 1
OB.2
O C.3
OD.4
Answer:
B) 2
Explanation:
There are two significant figures in given measurement,
2, 0
Significant figures:
1= The given measurement have four significant figures 1534.
2= All non-zero digits are consider significant figures like 1, 2, 3, 4, 5, 6, 7, 8, 9.
3= Leading zeros are not consider as a significant figures. e.g. 0.03 in this number only one significant figure present which is 3.
4= Zero between the non zero digits are consider significant like 107 consist of three significant figures.
5= The zeros at the right side e.g 2400 are also significant. There are four significant figures are present.
What is one reason a fuse may blow out? NEED HELP NOW
Answer:
Too high voltage which can't be held by the fuse
A solution with a pH value between 1 and 6
Answer:
One possible answer could be lemon juice
Explanation:
We had to do a water test, and I was looking up what pH levels were. Then I learned about it in school, so I know a thing or two about it :)
Possible other answers include stomach acid and cola.
Hope this helps!!
A 15 L tank is filled with oxygen gas for use in a hospital. How many grams of O2, is inside the tank if the pressure is 75 psi at 28°C?
Answer:
Mass = 99.2 g
Explanation:
Given data:
Volume of oxygen = 15 L
Mass of oxygen = ?
Pressure of oxygen = 75 psi ( 75/14.696 = 5.10 atm)
Temperature of oxygen = 28°C (28+273 = 301 K)
Solution:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
Now we will convert the temperature.
n = PV/RT
n = 5.10 atm× 15 L / 0.0821 atm.L/ mol.K × 301 K
n = 76.5 atm.L/24.71 atm.L/ mol
n = 3.1 mol
mass of oxygen:
Mass = number of moles × molar mass
Mass = 3.1 mol × 32 g/mol
Mass = 99.2 g
water vapour is the solid form of water.
True
False
Answer and I will give you brainiliest
Answer:
False
Explanation:
Water vapour exists in gas phase!
If a gas effuses 2.17 times faster than Xe, what is its molar mass?
Answer:
Molar mass = 27.88 g/mol
Explanation:
The relationship between how gases effuses is given by Graham's law of effusion. This law is given as;
Rg / Rxe = [tex]\sqrt{}[/tex](Mxe / Mg)
Where;
Rg = Rate of effusion of gas g
RXe = Rate of effusion of Xe
Mxe = Molar mass of Xe = 131.29 g/mol
Mg = Molar mass of gas g
From the question;
Rg : Rxe = 2.17 : 1
Rg / Rxe = 2.17 / 1 = 2.17
2.17 = [tex]\sqrt{}[/tex]131.29 / Mg
Squaring both sides
4.7089 = 131.29 / Mg
Mg = 131.29 / 4.7089
Mg = 27.88 g/mol
Identify the products in the following chemical reaction: Multiply chose
2NaHCO3 + CaCl2 → CaCO3 + CO2 + 2NaCl + H2O
A. NaHCO3
B. CaCl2
C. CaCO3
D. CO2
E. NaCl
H2O
Answer:
C. CaCO3
D. CO2
E. NaCl
. H2O
List all possible oxidation numbers for the elements. 21. Al
22. Bi
23. Ni
24. Xe
25. Pb
Answer:
21. Al (Aluminium)
+3 (most common), -1, -2, +1, +2
22. Bi (Bismuth)
+3 (most common), -3, -2, -1, +1, +2, +4, +5
23. Ni (Nickel)
+2 (most common), -2, -1, 0,+1, +3, +4
24. Xe (Xenon)
0 (most common), +1, +2, +4, +6, +8
25. Pb (Lead)
+2 (most common), +4 (most common), -4, -2, -1, +1, +3
Explanation:
Now we proceed to present the answers for each element:
21. Al (Aluminium)
+3 (most common), -1, -2, +1, +2
22. Bi (Bismuth)
+3 (most common), -3, -2, -1, +1, +2, +4, +5
23. Ni (Nickel)
+2 (most common), -2, -1, 0,+1, +3, +4
24. Xe (Xenon)
0 (most common), +1, +2, +4, +6, +8
25. Pb (Lead)
+2 (most common), +4 (most common), -4, -2, -1, +1, +3
As ice cream freezes do the chemical properties of the substance change? Explain why or why not?
A certain chemical reaction releases of heat for each gram of reactant consumed. How can you calculate what mass of reactant will produce of heat
Answer:
Specific heat capacity formula
Explanation:
The heat capacity gives the exact heat energy at which a given mass of a substance is heated from one temperature to another.
This formula can help determine how much heat is gained or lost during the reaction and is given by:
Q = mcΔT
where:
Q = heat energy in Joules or Calories
m - mass of the substance (g)
c = Specific heat capacity (J/kg°C)
ΔT = change in temperature = (final temp - initial temp) (°C)
I hope this was helpful.
How many electrons will the lithium atom give up to become stable?
a. 1
b. 2
c. 3
d. 4
Answer: 2
Explanation: that’s the answer for the quiz
pleaseee help thank youu
Answer:
i just took it the answers is C
Explanation:
V2S3 chemical compounds?
Answer:
Hence the name of the compound is vanadium (III) sulfide
The chemical symbol for the vanadium(III) sulfide compound is [tex]V_2S_3[/tex]. In this chemical, vanadium (V) is found in +3 oxidation state and sulfur (S) is found in the form of sulphide ions.
The compound contains two vanadium ions, as indicated by the numerical prefix "di-" before the element symbol V. An inorganic compound having a crystal structure that produces a solid is called vanadium(III) sulfide.
It is composed of sulfide anions and vanadium cations arranged in a certain way. Vanadium(III) sulfide has many uses in various industries. It can be used as a catalyst in chemical reactions, as part of some types of batteries, and as a raw material for batteries to produce ceramics and materials with specific electrical and magnetic properties.
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The temperature of a sample of Rn is changed without changing its volume, causing a change in pressure from 8.6731 atm to 0.5761 atm. If the starting temperature was 187.8 K, what is the final temperature in kelvins?
Answer:
yeye
Explanation:
eq
What is the molarity of a solution of 10% by mass cadmium sulfate, CdSO4 (molar mass = 208.46 g/mol) by mass? The density of the solution is 1.10 g/mL.
a. 0.528 M
b. 0.436 M
c. 0.479 M
d. 0.048 M
e. 22.9 M
Answer:
a. 0.528 M .
Explanation:
Hello!
In this case, since the given by-mass percent can be written as:
[tex]\frac{10gCdSO_4}{100g\ sol}[/tex]
By using the density and molar mass of the solute, cadmium sulfate, we can compute the molarity, by also making sure we convert from mL to L of solution:
[tex]M=\frac{10gCdSO_4}{100g\ sol}*\frac{1molCdSO_4}{208.46gCdSO_4} *\frac{1.10g\ sol}{1mL\ sol}*\frac{1000mL}{1L} \\\\ M=0.528M[/tex]
Thereby, the answer is a. 0.528 M .
Best regards.
The molarity of the solution of 10% by mass cadmium sulfate [tex](CdSO_4)[/tex] is approximately 0.479 M. The correct option is C.
To calculate molarity we need to find out how many moles of CdSO4 are present in the solution.
Given:
Mass of [tex]CdSO_4[/tex]= 10% by mass of the solutionMolar mass of [tex]CdSO_4[/tex] = 208.46 g/molDensity of the solution = 1.10 g/mLWe need to calculate the mass of [tex]CdSO_4[/tex]:
Mass of [tex]CdSO_4[/tex] = (10% / 100%) * Total mass of the solution
Mass of [tex]CdSO_4[/tex] = (10 / 100) * 1000 g (since the volume is 1 L, and the density is 1.10 g/mL)
Mass of [tex]CdSO_4[/tex] = 100 g
So, the number of moles of CdSO4:
Number of moles of [tex]CdSO_4[/tex] = Mass of CdSO4 / Molar mass of CdSO4
Number of moles of [tex]CdSO_4[/tex] = 100 g / 208.46 g/mol
Number of moles of [tex]CdSO_4[/tex] ≈ 0.479 moles
Then, we calculate the molarity of the solution:
Molarity = Number of moles of CdSO4 / Volume of the solution (in liters)
Molarity = 0.479 moles / 1 L
Molarity ≈ 0.479 M
Hence, the molarity of the solution of 10% by mass cadmium sulfate [tex](CdSO_4)[/tex] is approximately 0.479 M. The correct option is C.
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Please help!!! The person who gets it right gets brainlist
Answer:B because all of the atoms exploded AND GRAVITY WAS CREATED AND forced molecules together (God caused it btw)
Explanation:The BIBLE
A 600. mL beaker has an inner diameter of 77.0 mm. What is the vertical distance between the 100. mL marks on the side of the beaker
Answer:
[tex]h=12.9cm[/tex]
Explanation:
Hello!
In this case, since we can consider the beaker until the 100-mL mark as a cylinder, we can use the following equation to relate its diameter, vertical distance or height and volume:
[tex]V=\pi h\frac{d^2}{4}[/tex]
Thus, since we know the diameter, volume (which is equivalent to 600 cm³) and π, we can plug in to obtain:
[tex]600cm^3=\pi *h*\frac{(77.0mm)^2}{4}[/tex]
It means it is necessary to take the mm to cm and solve for h:
[tex]h=\frac{600cm^3}{\pi*\frac{(7.70cm)^2}{4}} \\\\h=12.9cm[/tex]
Best regards!
The distance between each 100 mL mark is 2.15 cm.
The volume of a cylinder is obtained using the formula;
V = πr^2h
Now, we have the following information;
Volume of the cylinder = 600. mL or 600 cm^3
Diameter of the cylinder = 77 mm or 7.7 cm
Radius of the cylinder = 7.7/2 = 3.85 cm
Height of the cylinder = h
Hence;
600 = 3.142 × ( 3.85 )^2 × h
h = 600/3.142 × ( 3.85 )^2
h = 12.88 cm
There are six 100 mL marks on the beaker, the distance between each 100 mL mark = 12.88 cm/6 = 2.15 cm
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How many moles of each element are in one mole of Sr(HCO,),? (3 points)
O 1 mole of strontium, 1 mole of hydrogen, 1 mole of carbon, 5 moles of O
O1mole of strontium, 2 moles of hydrogen, 2 moles of carbon, 6 moles of O
O 2 moles of strontium, 2 moles of hydrogen, 2 moles of carbon, 5 moles of O
O2 moles of strontium, 2 moles of hydrogen, 2 moles of carbon, 6 moles of O
Answer: 1 mole of strontium, 2 moles of hydrogen, 2 moles of carbon, 6 moles of O
Explanation: i think i’m not sure
A mole corresponds to the mass of a substance that contains particles of the substance.
The concept of moles are used in various ways:-
Chemical equation. Law of constant proportion.
According to the question, the formula required is:-
[tex]n=\frac{Number\ of\ molecules}{na}[/tex]
The Na is defined as the Avogadro constant is the proportionality factor that relates the number of constituent particles in a sample with the amount of substance in that sample.
According to the question, the compound is [tex]Sr(HCO_{3})_{2}[/tex].
Hence the correct option is 2, that is 1 mole of strontium, 2 moles of hydrogen, 2 moles of carbon, 6 moles of oxygen.
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A sample of limestone (calcium carbonate, CaCO3) is heated at 950 K until it is completely converted to calcium oxide (CaO) and CO2. The CaO is then all converted to calcium hydroxide by addition of water, yielding 8.47 kg of solid Ca(OH)2. Calculate the volume of CO2 produced in the first step, assuming it to be an ideal gas at 950 K and a pressure of 0.976 atm.
Answer:
Therefore, volume of CO₂ produced in the first step is 9141.404 L
Explanation:
Equations of reactions:
A: CaCO₃(s) ---> CaO(s) + CO₂(g)
B: CaO(l) + H₂O(l) ---> Ca(OH)₂(s)
Molar mass of CaCO₃ = 100 g; molar mass of CaO = 56 g; molar mass of CO₂ = 44 g molar mass of H₂P = 18 g; molar mass of Ca(OH)₂ = 74 g
From equation B, 1 mole of CaO produces 1 mole of Ca(OH)₂
This means that 56 g of CaO produces 74 g of Ca(OH)₂
mass of CaO that produces 8.47 kg or 8470 g of Ca(OH)₂ = 8470 g * 56/74 = 6409.73 g of CaO
Therefore, 6409.73 g of CaO were produced in reaction A
From reaction A, 1 mole of CaCO₃ produces 1 mole CaO and 1 mole of CO₂
Number of moles of CaO in 6409.73 g = 6409.73 g/56 g/mol = 114.46 moles
Therefore, 114.46 moles of CO₂ were produces as well.
Molar volume of gas at STP = 22.4 litres
Volume of CO₂ produced at STP = 114.46 * 22.4 L =2563.904 L
However, the above reaction took place at 950 K and 0.976 atm, therefore volume of CO₂ produced under these conditions are obtained using the general gas equation
Using P₁V₁/T₁ = P₂V₂/T₂
P₁ = 1.0 atm, V₁ = 2563.904 L, T₁ = 273 K, P₂ = 0.976 atm, T₂ = 950 K, V₂ = ?
V₂ = P₁V₁T₂/P₂T₁
V₂ = (1.0 * 2563.904 * 950)/(0.976 * 273)
V₂ = 9141.404 L
Therefore, volume of CO₂ produced in the first step is 9141.404 L
What are the rows of the periodic table called?
Answer:
"The elements are arranged in seven horizontal rows,called periods or series,and 18 vertical columns,called Groups."
Explanation:
Risk*
Why is your body going through physical and chemical changes?
Answer:
Physical and chemical changes can occur almost everywhere, even in our bodies! Food must be broken down into a form that our cells can use. When we eat, our bodies physically break down food into small pieces. Our bodies also chemically break down those small pieces of food into tiny organic molecules.
Explanation:
What kind of ions does metal form?
* ionic bond
* covalent bond
* anions
* cations
* melting point
* boiling point
conductivity
* Polyatomic Ions
* Valence electron
* Metal
* Nonmetal
* Metaloids
Answer:
Option D: Cations
Explanation:
Have a great day.
Do earthquakes occur at convergent plate boundaries?
Yes or no?
Answer:yes
Explanation:
QUESTION 3 What mass (in g) of glucose, C6H1206, must be added to 300.7 g of water to prepare a 0.322 molal solution? Enter your answer with 3 significant figures and no units.
Answer:
17.42 g of glucose, C₆H₁₂O₆
Explanation:
From the question given above, the following data were obtained:
Mass of water = 300.7 g
Molar solution = 0.322 M
Mass of glucose =.?
Next, we shall convert 300.7 g to L. This can be obtained as follow:
1000 g = 1 L
Therefore,
300.7 g = 300.7 g × 1 L / 1000 g
300.7 g = 0.3007 L
Next, we shall determine the number of mole of glucose in the molar solution. This can be obtained as follow:
Volume of solution = 0.3007 L
Molar solution = 0.322 M
Mole of glucose =?
Molar solution = mole / Volume
0.322 = mole of glucose / 0.3007
Cross multiply
Mole of glucose = 0.322 × 0.3007
Mole of glucose = 0.0968 mole
Finally, we shall determine the mass of glucose, C₆H₁₂O₆, needed to produce prepare the solution. This can be obtained as follow:
Mole of C₆H₁₂O₆ = 0.0968 mole
Molar mass of C₆H₁₂O₆ = (12×6) + (1×12) + (16×6)
= 72 + 12 + 96
= 180 g/mol
Mass of C₆H₁₂O₆ =?
Mole = mass /Molar mass
0.0968 = Mass of C₆H₁₂O₆ / 180
Cross multiply
Mass of C₆H₁₂O₆ = 0.0968 × 180
Mass of C₆H₁₂O₆ = 17.42 g
Thus, 17.42 g of glucose, C₆H₁₂O₆ is needed to prepare the molar solution.
please explain energy flow from producer to consumer.
and please explain energy flow from consumer to consumer.
Answer:
1-Ecologists call this one-way flow of matter and energy from a producer to a primary, then to secondary, and perhaps to a tertiary consumer, a food chain. The food web shows all the organisms at each feeding level or trophic level.
2-Energy flows through an ecosystem in one direction: from producer to primary consumer to secondary consumer to higher consumers. A biomass pyramid provides a picture of the feeding and energy relationships within a food web and the direction of the flow of energy.
Answer:
food
Explanation:
Use the following reaction:
CuCl2 + 2 NaNO3 → Cu(NO3)2 + 2 NaCl
If 90.0 grams of copper (II) chloride react with 120.0 grams of sodium nitrate, how much sodium chloride can be formed (in grams)?
Answer:
78.4g
Explanation:
Given parameters:
Mass of copper (II) chloride = 90g
Mass of sodium nitrate = 120g
Unknown:
Mass of sodium chloride that can be formed = ?
Solution:
The balanced chemical reaction is:
CuCl₂ + 2NaNO₃ → Cu(NO₃)₂ + 2NaCl
Let us find the limiting reactant. This reactant will determine the extent of the reaction of the amount of product that will be formed.
First, convert the masses to number of moles;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of CuCl₂ = 63.5 + 2(35.5) = 134.5g/mol
Molar mass of NaNO₃ = 23 + 14 + 3(16) = 85g/mol
Number of moles of CuCl₂ = [tex]\frac{90}{134.5}[/tex] = 0.67mole
Number of moles of NaNO₃ = [tex]\frac{120}{85}[/tex] = 1.41mole
From the balanced reaction equation:
1 mole of CuCl₂ would react with 2 moles of NaNO₃
0.67mole of CuCl₂ would require 0.67 x 2 = 1.34mole of NaNO₃
So, CuCl₂ is the limiting reactant
1 mole of CuCl₂ will produce 2 mole of NaCl
0.67mole of CuCl₂ will therefore yield 0.67 x 2 = 1.34mole of NaCl
Mass of NaCl = number of moles x molar mass
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Mass of NaCl = 58.5 x 1.34 = 78.4g
Which of these factors are biotic? (SELECT ALL THAT APPLY.)
animals
light
minerals
water
plants
Answer:
plants
Explanation:
because it produces ( i am a third grade student and don't know if it is right or not)
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%