Answer:
Quantum Mechanical
Explanation:
This current atomic model evolved from the earlier Rutherford-Bohr model, which compared electrons orbiting an atomic nucleus to planets orbiting the sun. The newest understanding of atomic makeup in the Electron Cloud Model better represents observed atomic phoneme since the Bohr model rose to prominence.
Answer:
Electron cloud model
Explanation:
Which of these is the smallest?
cells
atoms
molecules
cell membranes
Science 7th grade
Answer: atoms
Explanation: cell membrane is in a cell
Imagine you are a lab technician, and a colleague informs you there have been problems with the 25.0-mL samples you have been providing. You know you have been measuring the volume carefully and reading the meniscus correctly, so you decide to check the calibration of the graduated cylinder you have been using. You fill the graduated cylinder with water at 25 °C up to the 25.0 mL mark, and then measure the mass of this volume of water. You find that the mass is 22.4 g. The density of water at 25 °C is 0.99704 g/mL. What is the actual volume of the water?
Answer:
22.5mL is the volume of the water
Explanation:
When the graduated cylinder is in the 25.0mL mark, the mass of this volume is 22.4g. To convert this mass to volume we need to use density, as follows:
22.4g × (1mL / 0.99704g) = 22.5mL is the volume of the water.
That means the cylinder is uncalibrated in 2.5mL when the cylinder is in the 25.0mL mark
The closeness of particles of gas and their low speeds allow intermolecular forces to become important at certain
pressures and temperatures. Which best describes this statement?
Answer:
This is a limitation of the kinetic-molecular theory.
Explanation:
Which of these would MOST LIKELY cause an increase in the price of an item?
A)
declining popularity of the item
Eliminate
B)
a decrease in the price of a substitute product
improved technology in the production of that item
D)
an increase in the cost of raw materials for that item
Answer: D
Explanation:
It is the most likely one
Explanation:
sorry if you get it wrong but I think its b
Which of the following is least like the others on the list?
a. Estrogen
b. Cholesterol
c. Glycogen
d. Triglyceride
Answer:
Glycogen
Explanation:
a,b,d are lipidic and glycogen is glucide
The density of aluminum is 2.7 g/cm3. A metal sample has a mass of 52.0 grams and a volume of 17.1 cubic centimeters. Could the sample be aluminum? EXPLAIN your answer.
Answer:
The given metal sample is not aluminum because its density is 3.0 g/cm³ while density of aluminum is 2.7 g/cm³.
Explanation:
Given data:
Density of aluminum = 2.7 g/cm³
Mass of metal sample = 52.0 g
Volume of metal sample = 17.1 cm³
which sample is that = ?
Solution:
The given problem will be solve through density formula.
d = m/v
d = density
m = mass
v= volume
Now we will put the values in formula.
d = 52.0 g/ 17.1 cm³
d = 3.0 g/cm³
It is given in question the density of aluminum is 2.7 g/cm³. The given metal sample is not aluminum because its density is 3.0 g/cm³.
which surface events are examples of weathering
Answer:Weathering Erosion & Deposition
Changes in shape, size, and texture of land-forms (i.e. mountains, riverbeds, and beaches)
Landslides.
Buildings, statues, and roads wearing away.
Soil formation.
Washes soil, pollutants, harmful sediments into waterways.
Causes metals to rust.
Reduces beaches, shorelines.
Delta formation.
Explanation:
How many oxygen atoms are in 8.20 g Na 2SO 4?
Answer:
No. of atom =
no.of moles x avagardro's number xatomicity
= weight /molar mass x No x atomicity
=8.2/142 x6.02x10^23 x 4
=0.346 x 10^23(approximately)
. What is the density of a block of plastic if the volume of the block is 5 cm and the mass is 17.2 g?
Answer:
The answer is 3.44 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 17.2 g
volume = 5 cm³
We have
[tex]density = \frac{17.2}{5} \\ [/tex]
We have the final answer as
3.44 g/cm³Hope this helps you
Which statement best describes how an ionic bond forms?
The oxidation number that the Alkaline Earth Metals normally have when forming compounds is
Answer:
+2
Explanation:
All the alkaline earth metals have 2 valence electrons in their valence shell. Therefore, they lose 2 electrons to form cations with a +2 charge. For example, Mg²⁺.
Hope that helps.
6.An acid-base indicator is usually a weak acid with a characteristic color in the protonated and deprotonated forms. Because bromocresol green is an acid, it is convenient to represent its rather complex formula as HBCG. HBCG ionizes in water according to the following equation:HBCG + H2O = BCG- + H3O+ (yellow)(blue)The Ka (the equilibrium constant for the acid) expression is: Ka=[BCG−][H3O+][HBCG]When [BCG-] = [HBCG], then Ka = [H3O+]. If you know the pH of the solution, then the [H3O+] and Ka can be determined. What would be the color of the solution if there were equal concentrations of HBCG and BCG-?Solution Color: _______________What is the pH at the first appearance of this color?Solution pH: __________What is an estimate for the Ka for bromocresol green? Show your work to get full credit
Answer:
At equal concentration of HBCG and BCG^-, the colour is green. This colour first appears at pH = 3.8
Explanation:
HBCG is an indicator that is prepared by dissolving the solid in ethanol.
Since
Ka=[BCG−][H3O+][HBCG]When [BCG-] = [HBCG], then Ka = [H3O+].
If pH = 3.8
Ka= [H3O+] = -antilog pH = -antilog (3.8)
Ka= 1.58 ×10^-4
what is displacement give two examples
Explanation:
nothing it is just a question. you should know the answer . example:you,
Insoluble molecular compounds break apart into atoms when added to water.
True
O False
Answer:
False.
This is false because, no chemical reaction could possibly happen.
But in case of sodium it is highly reactive with water.......... so there will be a chemical reaction.
but as sodium is not a insoluble molecular compound this is not applicable to the situation.
What is a faze of matter
Answer:
solider liquid and gas plasma
Explanation:
in physical a state of matter is one of the distant form in which matter can exist four states of matter are observable in everyday life solid liquid and gas and plasma. hope it helps
In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma.
a jaguar can run up to 50 miles per hour, how many feet can he run per second? give your answer in scientific notation to one and three significant figures.
Answer:
50x10^0
Explanation:
1) Consider the dissolution of CaCO3 compound in aqueous medium.
a) Write down the equation of the chemical reaction that represents this dissolution.
b) Write the expression of the equilibrium constant for this reaction.
c) Explain how the addition of a certain amount of sodium carbonate to
water would affect this balance
2) The equilibrium constant for the reaction 2 SO2(g) + O2(g) 2 SO3(g) has a Kc value = 2.5x10^10 to 500 K. Find the kc value for each of the following reactions at the same temperature
(a) SO2(g) +1/2 O2 SO3(g).
(b) SO3(g) SO2(g)+1/2 O2(g)
(c) 3SO3(g)+ 3/2 O2(g) 3SO3(g)
3) A reaction mixture consisting of 0.400 mol H 2 and 1.60 mol I 2 was prepared in a 3.00 L flask and heated. In balance, 60.0% of the hydrogen gas reacted. What is the equilibrium constant for the reaction H 2(g) + I 2(g) 2 HI(g) at this temperature?
Explanation:
1a) CaCO₃(s) → Ca²⁺(aq) + CO₃²⁻(aq)
1b) Remember, solids are not included in the equilibrium equation.
K = [Ca²⁺] [CO₃²⁻]
1c) Adding CO₃²⁻ ions will shift the reaction to the left, producing CaCO₃(s) until equilibrium is restored.
2) 2 SO₂(g) + O₂(g) → 2 SO₃(g)
Kc = 2.5×10¹⁰ = [SO₃]² / ([SO₂]² [O₂])
2a) SO₂(g) + ½ O₂(g) → SO₃(g)
Kc = [SO₃] / ([SO₂] [O₂]^½)
Kc² = [SO₃]² / ([SO₂]² [O₂])
Kc² = 2.5×10¹⁰
Kc ≈ 1.58×10⁵
2b) SO₃(g) → SO₂(g) + ½ O₂(g)
Kc = [SO₂] [O₂]^½ / [SO₃]
Kc = 1 / (1.58×10⁵)
Kc ≈ 6.33×10⁻⁶
2c) 3 SO₂(g) + ³/₂ O₂(g) → 3 SO₃(g)
Kc = [SO₃]³ / ([SO₂]³ [O₂]^³/₂)
Kc = ([SO₃] / ([SO₂] [O₂]^½))³
Kc = (1.58×10⁵)³
Kc ≈ 3.95×10¹⁵
3) H₂(g) + I₂(g) → 2 HI(g)
K = [HI]² / ([H₂] [I₂])
Make an ICE table.
[tex]\left[\begin{array}{cccc}&Initial&Change&Equilibrium\\H_{2}&0.400&-0.240&0.160\\I_{2}&1.60&-0.240&1.360\\HI&0&+0.480&0.480\end{array}\right][/tex]
K = (0.480)² / (0.160 × 1.360)
K = 1.06
The reaction between ethylene and hydrogen bromide to form ethyl bromide is carried out in a continuous reactor. The product stream is analyzed and found to contain 56.7 mol% C2H5Br and 10.3 mol% HBr. The feed to the reactor conains only ethylene and hydrogen bromide. Calculate the fractional conversion of the limiting reactant and the percentage by which the other reactant is in excess. If the molar flow rate of the feed stream is 265 mol/s, what is the extent of reaction
Answer:
Extent of reaction = 95.9 mol.
Fractional conversion of the limiting reactant = 0.846.
Percentage by which the other reactant is in excess = 25.2 %.
Explanation:
Hello.
In this case, for the undergoing chemical reaction:
[tex]CH_2=CH_2+HBr\rightarrow CH_3-CH_2Br[/tex]
We can write the mole balance per species also including the extent of the reaction:
[tex]CH_2=CH_2:A\\\\HBr: B\\\\CH_3-CH_2-Br:C[/tex]
[tex]x_AP=z_AF-\epsilon \\\\x_BP=z_BF-\epsilon \\\\x_CP=\epsilon[/tex]
Considering that P is the flow of the outlet product. In such a way, writing the data we know, we can write:
[tex]0.33P=z_A*265-\epsilon \\\\0.103P=z_B*265-\epsilon \\\\0.567P=\epsilon[/tex]
Whereas we can replace the C2H5Br mole balance in the others mole balances:
[tex]0.33P=z_A*265-0.567P \\\\0.103P=z_B*265-0.567P\\\\\\z_A*265-0.897P=0\\\\z_B*265-0.67P=0[/tex]
By knowing that [tex]z_B=1-z_A[/tex], we can write:
[tex]z_A*265-0.897P=0\\\\(1-z_A)*265-0.67P=0\\\\\\z_A*265-0.897P=0\\\\-z_A*265-0.67P=-265[/tex]
Thus, solving for P and [tex]z_A[/tex], we obtain:
[tex]z_A=0.572\\\\P=169.11mol[/tex]
It means that the extent of the reaction is:
[tex]\epsilon=0.567P=0.567*169.11mol\\\\\epsilon=95.9mol[/tex]
For the limiting reactant, due to the 1:1 mole ratio between the reactants, it is the one having the smallest flow rate:
[tex]F_A=0.572*265mol=151.58mol\\\\F_B=265mol-151.58mol=113.42mol[/tex]
It means that the limiting reactant is B which is HBr, whose fractional conversion is:
[tex]X_B=1-\frac{0.103*169.11}{113.42mol}\\ \\X_B=0.846[/tex]
Finally, the percentage by which the other reactant is in excess, corresponds to:
[tex]\% excess =(1-\frac{113.42mol}{151.58mol})*100\%\\ \\\%excess=25.2\%[/tex]
Regards.
Which of the following is a type of chemical reaction that releases energy from the bonds of a substance to form one or more new substances
Answer: any options like a or b
Explanation:
Which property is not a physical property?
A. Color
B. Ability to Burn
C. Density
D. Melting Point
Answer: Ability to Burn
Explanation: I TOOK THE TEST
Which graph shows acceleration?
Graph A and B both show acceleration.
Graph B shows acceleration, but Graph A does not.
Neither graph shows acceleration. They both show velocity.
Graph A shows acceleration, but Graph B does not.
Answer:
graph a shows acceleration and b does not
Explanation:
the velocity increases in graph a, but stays constant in graph b
Answer:
graph a shows acceleration and b does not
Explanation:
Which of the following mixture can be separated by sedimentation?
A water and kerosene B. water and sand
C. water and sugar
D water and alcohol
Calculate the number of total atoms in 195 grams of Ni(OH)2. Use 6.022x10^23mol-1 for Avogadro’a number
195 g×
1 mol
Ni(OH)
2
92.71
g Ni(OH)
2
×
6.022×
10
23
formula units
mol
=1.27×
10
24
formula units of Ni(OH)
2
Since there are
5
atoms—one
Ni
atom, two atoms of
O
and two atoms of
H
—in each formula unit of
Ni(OH)
2
,
we multiply the number of formula units calculated above by
5
:
1.27×
10
24
formula units of Ni(OH)
2
×
5 atoms
formula unit of Ni(OH)
2
=6.33× 10^ 24 total atoms
The number of total atoms in 195 grams of [tex]Ni(OH)_2[/tex] is[tex]6.30\times 10^{24}[/tex] atoms
Explanation:
Given:
The 195 grams of nickel(II) hydroxide,[tex]Ni(OH)_2[/tex] .
To find:
The total number of atoms in 105 grams of nickel(II) hydroxide.
Solution:
The mass of nickel(II) hydroxide = 195 g
The molar mass of nickel(II) hydroxide = 92.708 g/mol
The moles of nickel(II) hydroxide:
[tex]=\frac{195 g}{92.708 g/mol}=2.10 mol[/tex]
According to the mole concept:
1 mole =[tex]N_A=6.022\times 10^{23} mol^{-1}[/tex]
The number of molecules of nickel(II) hydroxide =
[tex]N=2.10 mol\times 6.022\times 10^{23} mol^{-1} =1.26\times 10^{24} molecules[/tex]
In 1 molecule of nickel(II) hydroxide there is 1 nickel atom, then in N molecules of nickel(II) hydroxide:
[tex]=1\times 1.26\times 10^{24} atom=1.26\times 10^{24} atoms[/tex]
In 1 molecule of nickel(II) hydroxide there are 2 oxygen atoms, then in N molecules of nickel(II) hydroxide:
[tex]=2\times 1.26\times 10^{24} atom=2.52\times 10^{24} atoms[/tex]
In 1 molecule of nickel(II) hydroxide there are 2 hydrogen atoms, then in N molecules of nickel(II) hydroxide:
[tex]=2\times 1.26\times 10^{24} atom=2.52\times 10^{24} atoms[/tex]
The total number of atoms:
[tex]=1.26\times 10^{24} atoms+2.52\times 10^{24} atoms+2.52\times 10^{24} atoms=6.30\times 10^{24} atoms[/tex]
The number of total atoms in 195 grams of [tex]Ni(OH)_2[/tex] is[tex]6.30\times 10^{24}[/tex] atoms.
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Convert 9.13 decigram into milligram
Answer:
(9.13)
multiply the mass value by 100
=913 milligrams
Answer:
913 mg
Explanation:
913
A student puts a piece of ice into a beaker of cold water. Which two Statements are true ?A. Thermal energy will move from air to the water. B. Thermal energy will move from the water to the ice. C.Thermal energy will move from the ice to the air . D. Thermal energy will move from the water to the air.
Answer:
C.Thermal energy will move from the ice to the air.
Explanation:
The energy that is associate with the random movement of particles is called thermal energy. The water has a specific heat that is the energy that is needed to raise one gram of a substance to one degree Celsius as water can absorb a large amount of energy and produce a small number of changes the option C.Methylene Chloride (MC) is a common ingredient of paint removers. Besides being an irritant, it also may be absorbed through skin. When using this paint remover chemical protective clothing should be worn. If thick butyl rubber gloves (0.1 cm thick) are used, D in butyl rubber is 110 x 10-8 cm2/s, and surface concentrations are 0.44, and 0.02 g/cm3. If the surface of a glove is 50 cm2, the amount of MC transported through the glove in 3 hours will be: Answer in grams (g).
Answer:
2.5 g
Explanation:
First we have to calculate the diffusion flux (J). To calculate, we use the formula:
[tex]J=-D\frac{dC}{dx}=-D\frac{C_2-C_1}{x_2-x_1}\\ \\Given\ that:\\\\x_2-x_1=0.1\ cm,D=110*10^{-8}cm^2/s,C_2=0.02g/cm^3,C_1=0.44g/cm^3\\\\Substituting:\\\\J=-110*10^{-8}(\frac{0.02-0.44}{0.1} )=4.62*10^{-6}g/cm^2s\\\\But, J=\frac{M}{At}\\ \\t=3\ hours=10800\ s,A=50\ cm^2\\\\Substituting:\\\\4.62*10^{-6}=\frac{M}{50*10800}\\ \\M=4.62*10^{-6}*50*10800\\\\M=2.5\ g[/tex]
Give the net ionic equation for the reaction (if any) that occurs when aqueous solutions of lithium sulfide and copper (II) nitrate are mixed.
Answer:
S²⁻(aq) + Cu²⁺(aq) ⇒ CuS(s)
Explanation:
Let's consider the molecular equation that occurs when aqueous solutions of lithium sulfide and copper (II) nitrate are mixed.
Li₂S(aq) + Cu(NO₃)₂(aq) ⇒ 2 LiNO₃(aq) + CuS(s)
The complete ionic equation includes all the ions and the species that do not dissociate in water.
2 Li⁺(aq) + S²⁻(aq) + Cu²⁺(aq) + 2 NO₃⁻(aq) ⇒ 2 Li⁺(aq) + 2 NO₃⁻(aq) + CuS(s)
The net ionic equation includes only the ions that participate in the reaction and the species that do not dissociate in water.
S²⁻(aq) + Cu²⁺(aq) ⇒ CuS(s)
The net ionic equation includes only the ions that participate in the reaction and the species that do not dissociate in water.
S²⁻(aq) + Cu²⁺(aq) ⇒ CuS(s)
The molecular equation that occurs when aqueous solutions of lithium sulfide and copper (II) nitrate are mixed.
Li₂S(aq) + Cu(NO₃)₂(aq) ⇒ 2 LiNO₃(aq) + CuS(s)
The complete ionic equation includes all the ions and the species that do not dissociate in water.
2 Li⁺(aq) + S²⁻(aq) + Cu²⁺(aq) + 2 NO₃⁻(aq) ⇒ 2 Li⁺(aq) + 2 NO₃⁻(aq) + CuS(s)
The net ionic equation includes only the ions that participate in the reaction and the species that do not dissociate in water.
S²⁻(aq) + Cu²⁺(aq) ⇒ CuS(s)
Thus, net ionic equation is S²⁻(aq) + Cu²⁺(aq) ⇒ CuS(s).
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How many grams are 4.78x10*21 atoms of aluminum?
Chemistry
H
D
G
A
S
F
F
F
G
Vv
F
F
F
F
F
Answer:
i think its f because my teacher have been talking about this
Explanation:
Answer:
f
Explanation:
Many plants are poisonous because their stems and leaves contain oxalic acid, H2C2O4, or sodium oxalate, Na2C2O4. When ingested, these substances cause swelling of the respiratory tract and suffocation. A standard analysis for determining the amount of oxalate ion, C2O 2− 4 , in a sample is to precipitate this species as calcium oxalate, which is insoluble in water. Write the net ionic equation for the reaction between sodium oxalate and calcium chloride, CaCl2, in aqueous solution.
Answer:
Explanation:
Calcium chloride is a soluble salt which dissociates into calcium and chloride ions when dissolved in water.
CaCl₂(aq) ----> Ca²⁺(aq) + 2Cl⁻(aq)
Similarly, sodium oxalate when dissolved in water dissociates into sodium and oxalate ions.
Na₂CO₄(aq) ----> 2Na⁺(aq) + C₂O₄²⁻(aq)
However, in a double displacement reaction where the two solutions of the salts are mixed, the insoluble salt calcium oxalate is precipitated. The net ionic equation for the reaction is shown below:
Ca²⁺(aq) + C₂O₄²⁻(aq) ----> CaC₂O₄(s)