Answer:
i think its true
Explanation:
How many total atoms are in 4Al2O3?
Answer:20
Explanation:
The number of atoms that are present in 4Al₂O₃ is 24×10²³atoms.
What is Avogadro's number?Avogadro's number is the number of entities that are present in one mole of any substance, i.e.
1 mole = 6.022 × 10²³ atoms
Coefficient present in the given compounds gives idea about the moles of that substance. In 4Al₂O₃ number of moles of Al₂O₃ is 4.
Number of atoms of Al₂O₃ in 4 mole = 4mol × 6.022 × 10²³atoms/mol = 24×10²³atoms
Hence number of atoms of Al₂O₃ in 4 moles of 4Al₂O₃ is 24×10²³atoms.
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What is the average speed of the toy car during the two trials?
Answer:
2.3?
Explanation:
Fat and water in the sausage changed state
Answer:
Susie cooked sausages on a barbecue. (a) Fat and water in the sausages changed state. Draw one line from each statement to the correct change of state.
Explanation:
brailest/ crown please
The weight loss of an aluminum alloy corroding in a solution of hydrochloric acid was observed to be 0.250 g/cm2 after an 8 h immersion period [13]. What is the corresponding anodic current density in milliamperes per square centimeter, assuming that all the corrosion is due to the following anodic half-cell reaction:
This question is incomplete, the complete question is;
The weight loss of an aluminum alloy corroding in a solution of hydrochloric acid was observed to be 0.250 g/cm² after an 8 h immersion period [13]. What is the corresponding anodic current density in milliamperes per square centimeter, assuming that all the corrosion is due to the following anodic half-cell reaction:
Al → Al³⁺ + 3e⁻
The atomic weight is 58.7 g/mol
Answer:
Current density in milliamperes per square centimeter is 45.81 mA/cm²
Explanation:
Given the data in the question;
we know that Faradays law of electrolysis states that;
amount of substance produced at each electrode is directly proportional to the quantity of charge flowing through the cell.
so
m = ( Q/F) (M/z)
where m is the mass of substance liberated at an electrode( 0.250 g/cm²)
Q is the total electric charge passed through the substance
F is Faradays constant (96,500 C/mol)
M is the molar mass of the substance( 58.7 g/mol ) and Z is the number of electrons transferred(3)
Also
we know that; Q = It
where I is current and t is time( 8hrs × 60 × 60 = 28800 sec )
we substitute Q = It into our equation'
we have;
m = ( It/F) (M/z)
m = ItM / Fz
mFz = ItM
I = mFz / tM
so we substitute
I = [0.250 g/cm² × 96,500 C/mol × 3] / [ 28800 × 58.7 g/mol]
I = 72375 / 1690560
I = 0.04581 A/cm²
we know that; 1 ampere = 1000 milliampere
so
I = 0.04581 × 1000
I = 45.81 mA/cm²
Therefore, current density in milliamperes per square centimeter is 45.81 mA/cm²
The Sun is to a planet as...?
A. Earth is to the Moon
B. The tides are to the Sun
C. A moth is to a flame
D. The seasons are the Moon
Answer:
B the rides are to the sun
Answer:
The answer is b
Explanation:
which of the following best describes the definition of an ion?
A. An atom with a neutral charge
B. An element that has an unequal number of protons and neutrons
C. An element that has unequal number of protons and electrons
D. An element that has unequal number of electrons and neutrons
Answer:
A
Explanation:
An ion is a particle, atom or molecule with a net electrical charge.
Answer:
C. An element that has an unequal number of protons and electrons
Explanation:
An element has an equal number of protons and electrons, because the positive and negative energy has to cancel out so the atom is neutral. Ions are versions of atoms that lose electrons so they have a different energy than the initial atom, but they're still that atom because the number of protons determines the identity of the atom, and that number doesn't change.
How many moles are present in 2.95 x1024 molecules of water (H20)
ANSWER: 3020.8 moleclues of water (h20) Explanation I did the math and the quiz
What is a concussion, and how is it related to force?
Answer:
A head injury expert says that most concussions deliver 95 g's to the human body upon impact. G-force is a unit of force equal to the force exerted by gravity. In addition, the average football player receives 103 g's when hit during a game.
Explanation:
What volume of the 5.00% (w/v) citrie acid solution described above would be needed to provide 738 mg citric acid for a reaction?
738 mg of eitrie acid for a reaction Show your work using dimensional analysis and report yo
answer with the correct number of significant figures, (You should know the relationship betw
grams and milligrams.)
Answer:
[tex]V=14.76mL[/tex]
Explanation:
Hello!
In this case, since the given 5.00 % (w/v) can also be represented in terms of mass of solute over volume of solution, we need to make sure that the same system of units is used, in this case, the appropriate units for that unit of concentration should be g/mL, and therefore, we first need the mass of citric acid in grams:
[tex]m=738mg*\frac{1g}{1000mg} =0.738 g[/tex]
Thus, by using the w/v percent, we obtain the following volume of solution:
[tex]V=\frac{m}{m/w}*100\%[/tex]
So we plug in to obtain:
[tex]V = \frac{0.738g}{5.00\%}*100\% \\\\V=14.76mL[/tex]
Best regards!
An oxygen molecule is adsorbed onto a small patch of the surface of a catalyst. It's known that the molecule is adsorbed on 1 of 36 possible sites for adsorption. Calculate the entropy of this system.
Answer:
the entropy of this system is 4.9452 × 10⁻²³ J/K
Explanation:
Given the data in the question;
we take a look at the Boltzmann formula for entropy;
s = k × In( W )
k is the Boltzmann's constant ( 1.38 × 10⁻²³ m² kg s⁻² K⁻¹ )
W is the number of energetically equivalent possible microstates or system configurations ( 36 )
so we substitute
s = 1.38 × 10⁻²³ × In( 36 )
s = 1.38 × 10⁻²³ × 3.5835
s = 4.9452 × 10⁻²³ J/K
Therefore, the entropy of this system is 4.9452 × 10⁻²³ J/K
1. Compound description ionic or molecular? 1 Compound 1 is a hard white smooth odorless solid, which is insoluble in water. If the flame from an ordinary laboratory burner is held on the solid for 10 minutes, the solid grows hot to the touch but does not soften. ionic molecular (can't decide)
2 Compound 2 is a hard light gray solid made up of clusters of cube-shaped crystals. It can easily be ground into a fine powder. If that powder is compressed to form a block, the block is an insulator. However, if the block is moistened slightly, it starts to conduct electricity much better. ionic molecular (can't decide)
3 Compound 3 is a clear liquid with a strong pleasantly fruity smell. If cooled it freezes at about −10°C. In the solid state it does not conduct electricity. ionic molecular (can't decide)
Answer:
Compound 1 - Can't decide
Compound 2 - Can't decide
Compound 3 - molecular
Explanation:
The solid that has been designated as compound 1 is difficult to really classify because, we can see that the solid only became hot when heated but does not soften. This can be an attribute of an ionic solid. However, the same solid is not soluble in water. This insolubility in water is a property of molecular solids. As a result of these, we will find it difficult to classify the solid.
Compound 2 is also difficult to decide upon because ionic solids are crystalline and can not be ground into powder. Amorphous substances can be ground into powder easily. Then, we can see that the substance does not conduct electricity in block form but does so when moistened. This means that we can not conveniently classify it as a molecular solid since molecular substances do not conduct electricity.
A molecular substance usually has a low melting and freezing point and also does not conduct electricity hence compound 3 is molecular solid.
Please help me understand how to...
Calculate the mass of Cr2O3 that can be produced if the reaction of 56.2 g of chromium and sufficient oxygen has a 76.0 % yield.
...Thank you!
Answer:
[tex]m_{Cr_2O_3}^{actual}=62.4gCr_2O_3[/tex]
Explanation:
Hello!
In this case, according to the reaction:
[tex]4Cr+3O_2\rightarrow 2Cr_2O_3[/tex]
We can see there is a 4:2 mole ratio between chromium and chromium (III) oxide, this, for the given 56.2 g of chromium, the theoretical yield of the oxide product is computed down below:
[tex]m_{Cr_2O_3}^{theoretical}=56.2gCr*\frac{1molCr}{52.0gCr}*\frac{2molCr_2O_3}{4molCr} *\frac{151.99gCr_2O_3}{1molCr_2O_3} =82.13gCr_2O_3[/tex]
Now, considering the 76.0-% yield for this reaction, the actual yield turns out:
[tex]m_{Cr_2O_3}^{actual}=82.13gCr_2O_3*\frac{76.0gCr_2O_3}{100gCr_2O_3} \\\\m_{Cr_2O_3}^{actual}=62.4gCr_2O_3[/tex]
Best regards!
The following do not represent valid ground-state electron configurations for an atom either because they violate the Pauli exclusion principle or because orbitals are not filled in order of increasing energy. Indicate which of these two principles is violated in each example or whether both or neither are violated.
Part 1
1s22s23s2
A) The orbitals are not filled in order of increasing energy.
B) The Pauli exclusion principle is violated.
C) Orbitals are not filled in order of increasing energy and the Pauli exclusion principle is violated.
D) The ground-state electron configuration is valid.
Part 2
[Rn]7s26d4
A) The orbitals are not filled in order of increasing energy.
B) The Pauli exclusion principle is violated.
C) Orbitals are not filled in order of increasing energy and the Pauli exclusion principle is violated.
D) The ground-state electron configuration is valid.
Part 3
[Ne]3s23d5
A) The orbitals are not filled in order of increasing energy.
B) The Pauli exclusion principle is violated.
C) Orbitals are not filled in order of increasing energy and the Pauli exclusion principle is violated.
D) The ground-state electron configuration is valid.
Answer:
For both cases the answer is C
Explanation:
We can see that the orbitals are not filled in the order of increasing energy and the Pauli exclusion principle is violated because it does not follow the correct order of the electron configuration; In the first exercise after the 2s2 orbital, the 2p2 orbital follows.
For the second exercise, you must start in order with level 1 and correctly filling each of the sublevels corresponding to each level until reaching level 7 and thus completing the desired number of electrons.
The Pauli exclusion principle shows the correct sequence of filling electrons into orbitals.
For the electron configuration; 1s22s23s2, we can see that the orbitals are not filled in order of increasing energy because the 3s orbital follows the 2p orbital which has been omitted.
For the configuration; Rn]7s26d4, the orbitals are not filled in order of increasing energy because the 6d orbital follows the 5f orbital and not the 7s orbital as written.
For the configuration; [Ne]3s23d5, orbitals are not filled in order of increasing energy and the Pauli exclusion principle is violated. one of the electrons in the 3s and 3d levels will have exactly the same value for all four quantum numbers.
The order of increasing energy of atomic orbitals is; 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p.
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Element X is more reactive than lithium and magnesium but less reactive than potassium. Which element is most likely to be X?
Na
Rb
Ca
BA
Answer:
It is Likely to Be Sodium (Na) coz as You Down The group the reactivity increase
A chemistry student is performing a lab exercise where they are reacting aqueous Lead (II) Nitrate with aqueous Potassium Iodide. The student begins the reaction with 10.0 g of Lead (II) Nitrate and 12.0 g of Potassium Iodide. At the end of the experiment the student has collected 11.4 grams of the bright yellow solid precipitate Lead (II) Iodide.
Write the full balanced equation. Include the appropriate states of matter.
How many atoms of Lead are found in the product collected by the student?
Based upon the information above, what is the percent yield of this student’s lab?
Answer: Pb(NO3)2(aq) + 2KI(aq) —> PbI2(s) + 2KNO3(aq)
1.57x10^22 atoms of Pb
87% yield
Explanation:
10.0 g Pb(II) nitrate = 10/333 moles = 0.03 moles
12.0 g KI = 12/166 moles = 0.072 moles (0.06 moles required)
11.4 g PbI2 = 11.4/421 moles = 0.026 moles
expected yield 0.03 moles, yield = 87%
atoms in 11.4 g = 0.026 moles = 0.026*6.02214076*10^23 atoms = 1.57*10^22
What is the vapor pressure of ethanoic acid at 105°C?
How much energy would it take to heat a section of the copper tubing that weighs about 535.0 g , from 15.29 ∘C to 21.30 ∘C ? Copper has a specific heat of 0.3850 (J/g)⋅∘C.
Answer:
1238 J
Explanation:
Step 1: Given data
Mass of copper (m): 535.0 gSpecific heat of copper (c): 0.3850 J/g.°CInitial temperature: 15.29°CFinal temperature: 21.30°CStep 2: Calculate the change in the temperature
We will use the following expression.
ΔT = 21.30°C - 15.29°C = 6.01°C
Step 3: Calculate the energy required to heat the temperature of the copper tubing (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 0.3850 J/g.°C × 535.0 g × 6.01°C
Q = 1238 J
Methane (CH4), ammonia (NH3), and oxygen (O2) can react to form hydrogen cyanide (HCN) and water according to this equation:
CH4+NH3+O2→HCN+H2O. A student has 8 g of methane and 10 g of ammonia in excess oxygen.
a. What is the balanced equation for this reaction?
b. Which reagent is limiting? Explain why.
c. How many grams of hydrogen cyanide will be formed?
Answer: a. [tex]2CH_4+2NH_3+3O_2\rightarrow 2HCN+6H_2O(g)[/tex]
b. [tex]CH_4[/tex] is the limiting.
c. 13.5 g of hydrogen cyanide will be formed
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of methane}=\frac{8g}{16g/mol}=0.50moles[/tex]
[tex]\text{Moles of ammonia}=\frac{10g}{17g/mol}=0.59moles[/tex]
The balanced reaction will be :
[tex]2CH_4+2NH_3+3O_2\rightarrow 2HCN+6H_2O(g)[/tex]
According to stoichiometry :
2 moles of [tex]CH_4[/tex] require = 2 moles of [tex]NH_3[/tex]
Thus 0.5 moles of [tex]CH_4[/tex] will require=[tex]\frac{2}{2}\times 0.5=0.5moles[/tex] of [tex]NH_3[/tex]
Thus [tex]CH_4[/tex] is the limiting reagent as it limits the formation of product and [tex]NH_3[/tex] is the excess reagent as it is present in more amount than required.
As 2 moles of [tex]CH_4[/tex] give = 2 moles of [tex]HCN[/tex]
Thus 0.5 moles of [tex]CH_4[/tex] give =[tex]\frac{2}{2}\times 0.5=0.5moles[/tex] of [tex]HCN[/tex]
Mass of [tex]HCN=moles\times {\text {Molar mass}}=0.5moles\times 27g/mol=13.5g[/tex]
Thus 13.5 g of [tex]HCN[/tex] will be produced from the given masses of both reactants.
Which conclusion was a direct result of the gold foil experiment?
To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. Therefore, each atom in the foil was composed mostly of empty space because most alpha particles directed at the foil.
What is atom?Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.
In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.
Each atom in the foil was composed mostly of empty space because most alpha particles directed at the foil. This conclusion was the direct result of the gold foil experiment.
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Drag the tiles to the correct boxes to complete the pairs.
Identify the type of chemical reaction involved in each action.
combustion reaction
photosynthesis
respiration
Michael uses a car that burns
fossil fuels.
Alan grows tomatoes on
his farm.
Lisa eats eggs for breakfast.
Answer:
A - combustion
B - photosynthesis
C - respiration
The chemical change involved in each action is combustion, photosynthesis and respiration respectively.
What is 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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What do elements of the same period have in common?
number of valence electrons
O number of shells
O number of protons
O atomic mass
Answer:
no of valence electrons
Explanation:
because valence electrons are the electrons present in the outer orbital
Answer:
its actually the number of shells
Explanation:
valence electrons are the same down any group. atomic orbitals, or shells, are the same across periods
A sample of table sugar has a mass of 5.432g a) calculate the number of moles in the sample
B) calculate the number of moles carbon, moles hidrogen, moles oxygen
C)calculate the number of atoms of carbon, moles of hydrogen, moles of oxygen
The number of particles of atoms depends on the ratio of their composition in the compound
Further explanationGiven
5.432 g of table sugar
Required
moles of sample
moles of C, H and O
number of atoms
Solution
Table sugar : Sucrose : C₁₂H₂₂O₁₁
moles of sample := 5.432 : 342,3 g/mol
= 0.016
moles of C, H, and O :C = 12 x 0.016 = 0.192
H = 22 x 0.016 = 0.352
O = 11 x 0.016 = 0.176
number of atoms :C = 0.192 x 6.02 x 10²³ = 1.16 x 10²³
H = 0.352 x 6.02 x 10²³ = 2.12 x 10²³
O = 0.176 x 6.02 x 10²³ = 1.06 x 10²³
What do you think would happen to a rock after billion years?
Answer:
Explanation:
It probably would have been broken down to smaller pieces and spread out around the world. Hope this help! :)
What is a mole in chemistry terms?
a mammal found in Eurasia and North America
an IS unit for measuring the amount of a substance
a benign tumor sometimes found on human skin appearing as a small, sometimes raised area of skin, usually with darker pigment
a Mexican sauce made from chili peppers, other spices and chocolate
Answer:
the IS unit for measuring the amount of a substance
Explanation:
that's what it is
Methanol is stored at the temperature of 60degree, the vapor pressure of methanol is 13.2kPa at 20degree and 347kPa at 100degree.
Answer: im only in 6th grad sory
Explanation:
Plz help ASAP question is on picture
Answer:
The arrow going directly from the sun to the earth (middle one)!
Explanation:
HOPE THIS HELPS! :)
Which is higher 117°F or 46°C
What is the Wavelength of the frequency of 1.54 Hz
Answer:
[tex]\lambda=1.94\times 10^8\ m[/tex]
Explanation:
Given that,
The frequency of a wave, f = 1.54 Hz
We need to find the wavelength of the wave.
The relation between wavelength, frequency and speed is given by :
[tex]c=f\lambda\\\\\lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{3\times 10^8}{1.54}\\\\\lambda=1.94\times 10^8\ m[/tex]
So, the wavelength of the wave is [tex]1.94\times 10^8\ m[/tex].
4) Which of the following represent a valid hypothesis ?
A) Sodium metal reacts violently with water.
B) Oxygen is a gas at room temperature.
C) Lead is soft and malleable.
D) Neon does not react with oxygen.
E) Metals tend to lose electrons.
Answer:a
Explanation:
It can be tested and have a control, etc.
A hypothesis is a statement which can be confirmed experimentally. The correct answer is option A: Sodium metal reacts violently with water.
A hypothesis is a statement that can be confirmed by testing it. In other words, a hypothesis must be subjected to an experiment in order to ascertain whether it is true or false.
The only statement that can easily be confirmed experimentally in the laboratory is "Sodium metal reacts violently with water." Hence, this statement represents a valid hypothesis.
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You are visiting your Great Aunt Agnes. She is about 65 years
old...what are some changes that may be happening to Agnes,
compared to when she was in her 20s?
