Answer:
See explanation
Explanation:
The solar system consists of the sun at the core surrounded by all the planets in their proper order. Similarly, the Bohr model of the atom upholds Rutherford's planetary model in which the atom was said to have a positive core surrounded by electrons moving in orbits just as the planets orbit round the sun.
The difference between the two models is that electrons are able to move from one energy level to another. This assumption violates the principles of the solar system because the position of the planets are fixed in their orbits.
The theoretical basis behind this assumption is that each spectral line is produced by the transition of electrons from one energy level to another.
please help. im freaking out rn. i have like 40 missing assignments please
Answer:
I'm pretty sure its the one that says very little at the beginning but if I get it wrong I'm sorry
Write the equilibrium expression of each chemical equation.
2H2S(g) 2H2(g) + S2(g)
Answer:
[H2]2[S2][H2S]2Kc=[H2]2[S2][H2S]2
Explanation:
2H2S(g)⇋2H2(g)+S2(g)2H2S(g)⇋2H2(g)+S2(g)
The equilibrium constant expression in terms of concentrations is:
Kc=[H2]2[S2][H2S]2Kc=[H2]2[S2][H2S]2.
The equilibrium expression for the given reaction can be written in terms of equilibrium constant which is the ratio of power of molar concentration of the product to the product of power of molar concentration of the reactants.
What is equilibrium?Equilibrium is a state for a reversible reaction where, the rate of forward reaction is equal to the rate of backward reaction. The rate of a reaction is the rate of decrease in the concentration of reactants or the rate of increase in the concentration of the products.
The given reaction at equilibrium state is written as:
[tex]\rm 2H_{2}S (g)\leftrightharpoons 2H_{2} (g)+ S_{2}(g)[/tex]
The equilibrium constant Kb is ratio of power of molar concentration of the product to the product of power of molar concentration of the reactants.
[tex]Kb = \rm \frac{[H_{2}S]^{2}}{[H_{2}]^{2} [S_{2}]}[/tex]
The rate of the reaction will be r = Kb [H₂]² [S₂].
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which temperature do they need to perform the experiment for perovskite to conduct electric current?
A: T=1980°C
B: T>1980°
C: T>_ 1980°C
D:T< 1980°C
For C it's suppose to be an less than equal sign .
Answer:
Correct answer is D : T < 1980°C
Explanation:
Correct answer is D:T< 1980°C
Perovskite proton conductors belong to the class of high temperature proton conductors (HTPCs) , solid that conduct electricity by transporting H⁺ ions (protons ) at temperatures above ambient , typically 400 - 1000°C
So, we get T < 1980°C
How many atoms of Kr (Krypton) are in a balloon that contains 2.00 mol of Kr? (4)
Answer:
[tex]atoms= 1.204x10^{24}atoms[/tex]
Explanation:
Hello!
In this case, according to the Avogadro's number, it is possible to compute the atoms of Kr in 2.00 moles as shown below:
[tex]atoms=2.00mol*\frac{6.022x10^{23}atoms}{1mol} \\\\atoms= 1.204x10^{24}atoms[/tex]
Best regards!
Liquid octane CH3CH26CH3 will react with gaseous oxygen O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O. Suppose 2.3 g of octane is mixed with 12.4 g of oxygen. Calculate the minimum mass of octane that could be left over by the chemical reaction. Round your answer to 2 significant digits.
Answer: Octane will be used completely.
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of octane}=\frac{2.3g}{114g/mol}=0.0202moles[/tex]
[tex]\text{Moles of oxygen}=\frac{12.4g}{32g/mol}=0.388moles[/tex]
The balanced chemical reaction will be
[tex]2C_8H_{18}+25O_2(g)\rightarrow 16CO_2(g)+18H_2O(g)[/tex]
According to stoichiometry :
2 moles of octane require = 25 moles of [tex]O_2[/tex]
Thus 0.0202 moles of octane will require=[tex]\frac{25}{2}\times 0.0202=0.2525moles[/tex] of [tex]O_2[/tex]
Thus octane is the limiting reagent as it limits the formation of product and [tex]O_2[/tex] is the excess reagent.
Thus octane will be used completely.
A crane lifts a 5,800-N block from the ground to 20 m above the ground in 80 seconds. How much Power
did the crane use?
Answer:
1450 W
Explanation:
5800n x 20m =1450w
80s
What is the percent composition of Mg in the compound Mg3(PO4)2?
A 21.92%
B 23.57%
C 32.32%
D 27.74%
Answer:
D 27.74%
Explanation:
Percent composition of Magnesium (Mg) in Magnesium Phosphate compound ie Mg3(PO4)2 = 27.74%
Answer:
The answer is D
Explanation:
I took the test
What is the ratio
amount (mol) Fatoms
amount (mol) Xe atoms
Enter your answer as an integer.
Pls help
Answer:
Empirical formula
Explanation:
The empirical formula of a compound is the simplest whole number ratio of atoms of each element in the compound. It is determined using data from experiments and therefore empirical.
Vitamin C is a covalent compound with the molecular
formula C6H8O6. The recommended daily dietary
allowance of vitamin C for children aged 4-8 years is
0.000142mol. What is the mass of this allowance in grams?
The mass allowance of Vitamin C for children aged 4-8 years is equal to 0.025 grams.
What is a mole?A mole can be defined as a standard unit that can be utilized to evaluate the number of entities such as atoms, molecules, ions, or other particular particles in a particular amount of the substance.
The number of elementary entities present in one mole of any chemical substance was found to be equal to 6.023 × 10²³ which is also known as the Avogadro number.
Given, the number of moles of vitamin C = 0.000142 moles
Given, the molecular formula of Vitamin C is C₆H₈O₆.
The mass of one mole of C₆H₈O₆ = 176 g
One mole of Vitamin C has mass = 176 g
0.000142 mol of Vitamin C has mass = 0.000142×176 = 0.025 g
Therefore, the mass of 0.000142 mol of Vitamin C is 0.025 g.
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I need help with this!
Answer:
2.68 cm^3
Explanation:
Density= Mass/Volume
so...
8.96 g/cm^3 = 24.01 g/ V
and then u solve so it would be 2.68 cm ^3
((:
I need help with this!!!
Answer:
0.73g/cm^3
Explanation:
d=m/v
d=11/15
d=0.73
Glycerol (C3H8O3), also called glycerine, is widely used in the food and pharmaceutical industries. Glycerol is polar and dissolves readily in water and polar organic solvents like ethanol. Calculate the mole fraction of the solvent in a solution that contains 2.51 g glycerol dissolved in 21.10 mL ethanol (CH3CH2OH; density
Answer: The mole fraction of the solvent in a solution that contains 2.51 g glycerol dissolved in 21.10 mL ethanol is 0.93
Explanation:
Given : Volume of ethanol (solvent) = 21.10 ml
density of ethanol (solvent)= 0.789 g/ml
Mass of ethanol (solvent) = [tex]0.789g/ml\times 21.10ml=16.6g[/tex]
Mass of glycerol (solute) = 2.51 g
Mole fraction of a component is the ratio of moles of that component to the total moles present.
moles of ethanol =[tex]\frac{\text {given mass}}{\text {molar mass}}=\frac{16.6g}{46g/mol}=0.36mol[/tex]
moles of glycerol =[tex]\frac{\text {given mass}}{\text {molar mass}}=\frac{2.51g}{92g/mol}=0.027mol[/tex]
mole fraction of ethanol (solvent) = [tex]\frac{\text {moles of ethanol}}{\text {moles of ethanol + moles of glycerol}}=\frac{0.36}{0.36+0.027}=0.93[/tex]
The mole fraction of the solvent in a solution that contains 2.51 g glycerol dissolved in 21.10 mL ethanol is 0.93
Which of the following metals (M) will form an ionic compound with nitrogen with the general formula M3N2?
Answer:
There are no options provided dude,
But i guess the answer will be a metal with valency 2 for sure as the subscript given for N in 'M3N2' is 2 so the valency of the metal u need to select will be 2 for sure
It can be magnesium or some other if the provided options in real question has Mg then its the answer
Menthol is a crystalline substance with a peppermint taste and odor. When 0.533 g of menthol is dissolved in 25.0 g of cyclohexane, the freezing point of the solution is lowered by 2.84 ∘C. Look up the freezing point and f constant for cyclohexane in the Colligative Constants table. Calculate the molar mass of menthol.
Answer: The molar mass of menthol is 156.15 g/mol
Explanation:
Depression in freezing point is given by:
[tex]\Delta T_f=K_f\times m[/tex]
[tex]\Delta T_f=T_f^0-T_f=2.84^0C[/tex] = Depression in freezing point
[tex]K_f[/tex] = freezing point constant = [tex]20.8^0C/m[/tex]
m= molality
[tex]\Delta T_f=K_f\times \frac{\text{mass of solute}}{\text{molar mass of solute}\times \text{weight of solvent in kg}}[/tex]
Weight of solvent (cyclohexane)= 25.0 g = 0.025 kg
Molar mass of solute (menthol) = ?
Mass of solute (menthol) = 0.533 g
[tex]2.84^0C=20.8\times \frac{0.533}{xg/mol\times 0.025}[/tex]
[tex]x=156.15g/mol[/tex]
The molar mass of menthol is 156.15 g/mol
Two colorless chemicals combine inside a glow
stick. When the chemicals combine, they produce
brightly colored light. The glow stick's temperature
does not change.
emission of heat
emission of light
color change
formation of gas
Answer:
Option B & Option C
Explanation:
correct on edge! :D
When chemicals combine chemical change takes place which is accompanied by emission of heat and light.
What is a chemical change?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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18. What is one of the three things that cause the surface currents of the oceans?
A.differences in salinity
B.temperature differences
C. density differences
D. Coriolis effect
Answer:
b. temperature difference
Determine the chemical equation for the reaction between Fe3+ and Cu2+ with NH3
Answer:
Cu2 + 4 NH3 = Cu (NH3) 42+
so - - >
[Cu (NH3) 6] ^ 2+
Explanation:
Rank the effective nuclear charge Z* experienced by a valence electron in each of these atoms:
atom Z* experienced by a valence electron.
An atom of carbon.
An atom of fluorine.
An atom of beryllium.
An atom of boron.
Answer:
The atoms are ranked in decreasing order as follows:
Fluorine ---4
Carbon ----3
Boron ------2
Beryllium --1
Explanation:
Effective nuclear charge (Zeff) is defined as the difference between the actual nuclear charge (the atomic number, Z) and the shielding constant (S).
It is calculated by finding the atomic number and electronic configuration, attributing a shielding value to each electron, adding all the shielding values and using the formula:
Z eff = Z - S
Effective nuclear charges:
An atom of carbon: 3.25
An atom of fluorine: 5.20
An atom of beryllium: 1.95
An atom of boron: 2.60
The substance krypton has the following properties: normal melting point:
normal melting point: 115.9 K
normal boiling point: 119.8 K
triple point; 0.72 atm, 115.8 K
critical point: 54.3 atm, 209.4 K
A sample of krypton is initially at a pressure of 59.8 atm and a temperature of 107.7 K. The pressure on the sample is reduced to 0.720 atm at a constant temperature of 107.7 K. Which of the following are true?
a. The final state of the substance is a solid.
b. One or more phase changes will occur.
c. The final state of the substance is a liquid.
d. The sample is initially a gas.
e. The solid initially present will vaporize.
Answer:
Part 1
triple point; 0.72 atm, 115.8 K
Part 2
Option D, The sample is initially a gas.
Explanation:
Part 1
The triple point of krypton is 0.72 atm
and the melting point of Krypton is -157.4 °C or 115.8 K
Hence, option C is correct
Part 2
Option D
At 59.8 atm, Krypton is a gas. It changes its state from gas to liquid and solid when the temperature is extremely low. Here the temperature is same , hence only option D is correct
If expending 3500 kcal is equal to a loss of 1.0 lb, how many days will it take Charles to lose 5.0 lb? Express your answer to two significant figures. Charles consumes 1800 kcal per day.
Answer:31 days
Explanation:
3500kcal/lb x 5lb =17500
1800-1230=570
17500/570=30.70
Round up =31
This question involves the concepts of energy, weight, and time.
It will take Charles "9.7 days" to lose 5.0 lb.
TIME TO LOSE WEIGHTSince the loss of 1.0 lb weight requires expending 3500 kcal energy. Therefore, by using the unitary method,
1.0 lb loss = 3500 kcal
(5)(1.0) lb loss = (5)(3500 kcal)
5.0 lb loss = 17500 kcal ----- eqn(1)
Now, the time required to consume 1800 kcal is 1 day. Hence, by the unitary method,
1800 kcal = 1 day
1 kcal = [tex]\frac{1}{1800}\ day[/tex]
17500 kcal = [tex]\frac{17500}{1800}[/tex] day
17500 kcal = 9.7 days ------ eqn(2)
Comparing eqn (1) and eqn (2)
5.0 lb loss = 9.7 days
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There are four conditions an atom needs to meet to participate in hydrogen bonding. It needs to be_______ enough not to bump into other atoms when approaching the 1s orbital of the hydrogen, it needs to carry at least one________ atom, it needs to be_________enough to create a delta on the connected hydrogen, and it needs to have at least one________.
Answer:
The conditions are
1) Small enough
2) Electronegative atom
3) highly electronegative
4) lone pair of electrons
The correct statement therefore is
It needs to be small enough not to bump into other atoms when approaching the 1s orbital of the hydrogen, it needs to carry at least one electronegative atom, it needs to be highly electronegative enough to create a delta on the connected hydrogen, and it needs to have at least one lone pair of electrons.
Explanation:
Hydrogen bonding is a type of intermolecular bond that occurs between the partial positive charge (delta) on a hydrogen atom bonded to a small highly electronegative element (like nitrogen, oxygen or fluorine) and the free electrons on another electronegative element of another molecule.
The hydrogen atom with the partial positive charge (delta) is known as the hydrogen bond donor, while the electronegative element, carrying lone electrons is called the hydrogen bond acceptor.
Let's take a deeper look at these terms:
1) Hydrogen bond donor
Using water (H₂O) as an example, the high electronegativity of the oxygen atom covalently bonded to the hydrogen atom draws the lone electron in the 1s orbital of the hydrogen atom, creating a partial positive charge (d⁺) on the hydrogen atom. This is what happens within one water molecule
2) Hydrogen bond acceptor
When two or more molecules of water interact, the partial positive charge (d⁺) on the hydrogen atom of one molecule, is attracted to the valence or free electrons on the oxygen atom of a nearby molecule of water thus creating a dipole-dipole intermolecular bond known as a hydrogen bond.
For the hydrogen bond to be effective, the electronegative atom bonded to the hydrogen acting as the hydrogen bond donor in the first water molecule needs to be small enough so as not to disrupt the 1s orbital of the hydrogen atom. The smaller the size of the electronegative atom, the stronger the partial negative charge created on the hydrogen atom.
The valence or free pair of electrons on the electronegative (oxygen) atom of the second molecule of water (hydrogen bond acceptor) is what attracts the partial positive charge on the hydrogen atom to create the hydrogen bond
Name each of the following organic molecules. 
Please answer, this is due in 30 minutes
Answer:
0.591 g of magnesium phosphate is the theoretical yield.
Magnesium nitrate is the limiting reactant.
Explanation:
Hello!
In this case, since the balanced reaction turns out:
[tex]3Mg(NO_3)_2+2Na_3PO_4\rightarrow Mg_3(PO_4)_2+6NaNO_3[/tex]
Next, we compute the grams of magnesium phosphate yielded by each reactant, considering the present mole ratios and molar masses:
[tex]m_{Mg_3(PO_4)_2}^{by\ Mg(NO_3)_2}=1.00gMg(NO_3)_2*\frac{1molMg(NO_3)_2}{148.31gMg(NO_3)_2}*\frac{1molMg_3(PO_4)_2}{3molMg(NO_3)_2} *\frac{262.86gMg_3(PO_4)_2}{1molMg_3(PO_4)_2} \\\\m_{Mg_3(PO_4)_2}^{by\ Mg(NO_3)_2}= 0.591gMg_3(PO_4)_2\\\\m_{Mg_3(PO_4)_2}^{by\ Na_3PO_4}=1.00gNa_3PO_4*\frac{1molNa_3PO_4}{163.94gNa_3PO_4}*\frac{1molMg_3(PO_4)_2}{2molNa_3PO_4} *\frac{262.86gMg_3(PO_4)_2}{1molMg_3(PO_4)_2} \\\\m_{Mg_3(PO_4)_2}^{by\ Na_3PO_4} = 0.802gMg_3(PO_4)_2[/tex]
Thus, we infer that the correct theoretical yielded mass is 0.591 g as magnesium nitrate is the limiting reactant for which it produces the fewest grams of product.
However, is not possible to compute the percent yield since no actual yield is given, and must be provided or indicated by the problem or an experiment and it not here, nevertheless, you may compute the percent yield by dividing the actual yield by the theoretical and then multiplying by 100:
[tex]Y=\frac{actual}{0.591g}*100\%[/tex]
Best regards!
Decide whether the element is a metal or nonmetal, if you can.
Element is a hard silvery-gray solid. Wires are fastened to each side of a 2 cm slab of it, and an ordinary household 9 V battery is hooked up so that it can feed electricity through the slab to an LED. But the LED stays dark
Answer:
The element is a nonmetal
Explanation:
Elements are broadly classified into metals and non metals. Metals conduct electricity while non metals do not conduct electricity.
If we look at this scenario described in the question, we can easily decipher that the element is a nonmetal because the LED stays dark. The LED should have been lit if electricity was passed through the element in question.
Hence, the element is a non metal.
Please explain to me!!!
Answer:
nice handwrtting
Explanation:
Why was d-day and the battle of France so important to American and the allies
Answer:
The Importance of D-Day
The D-Day invasion is significant in history for the role it played in World War II. It marked the turn of the tide for the control maintained by Nazi Germany; less than a year after the invasion, the Allies formally accepted Nazi Germany's surrender.
Can someone help me with this
Answer:
wow!
5. C
6. B
7. B
8. A
Explanation:
If 3.53 g of CuNO, is dissolved in water to make a 0.330 M solution, what is the volume of the solution in milliliters?
Answer:
84.8 mL
Explanation:
From the question given above, the following data were obtained:
Mass of CuNO₃ = 3.53 g
Molarity of CuNO₃ = 0.330 M
Volume of solution =?
Next, we shall determine the number of mole in 3.53 g of CuNO₃. This can be obtained as follow:
Mass of CuNO₃ = 3.53 g
Molar mass of CuNO₃ = 63.5 + 14 + (16×3)
= 63.5 + 14 + 48
= 125.5 g/mol
Mole of CuNO₃ =?
Mole = mass / Molar mass
Mole of CuNO₃ = 3.53 / 125.5
Mole of CuNO₃ = 0.028 moles
Next, we shall determine the volume of the solution. This can be obtained as follow:
Molarity of CuNO₃ = 0.330 M
Mole of CuNO₃ = 0.028 moles
Volume of solution =?
Molarity = mole /Volume
0.330 = 0.028 / Volume
Cross multiply
0.330 × Volume = 0.028
Divide both side by 0.330
Volume = 0.028 / 0.330
Volume = 0.0848 L
Finally, we shall convert 0.0848 L to millilitres (mL). This can be obtained as follow:
1 L = 1000 mL
Therefore,
0.0848 L = 0.0848 L × 1000 mL / 1 L
0.0848 L = 84.8 mL
Therefore, the volume of the solution is 84.8 mL.
Which of the following statements is false?
a. This class discussed four physical states of matter
b. An atom is the smallest particle of an element that still contains properties of the original element.
c. Gases can be colorless or colored
d. Mass is the measure of the earth’s gravitational attraction of a body
e. A pure substance has a fixed composition.
Answer:
d. Mass is the measure of the earth’s gravitational attraction of a body
This is FALSE. Mass is the measure of matter than an object contains.
Explanation:
b. An atom is the smallest particle of an element that still contains properties of the original element.
This is True
c. Gases can be colorless or colored
This is True
d. Mass is the measure of the earth’s gravitational attraction of a body
This is FALSE. Mass is the measure of matter than an object contains.
e. A pure substance has a fixed composition.
This is True.
the law of conservation of mass
Answer: The Law of Conservation of Mass dates from Antoine Lavoisier's 1789 discovery that mass is neither created nor destroyed in chemical reactions. In other words, the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction.
Explanation: