Answer:
Percent recovery of A = 77.78%
Percent recovery of B = 88.8 %
Explanation:
Mass of impure compound A = 117 mg
Mass of impure compound B = 89 mg
Mass of A recovered = 91 mg
Mass of B recovered = 79 mg
Percent recovery of A = 91 mg/117 mg * 100
Percent recovery of A = 77.78%
Percent recovery of B = 79 mg/89 mg * 100
Percent recovery of B = 88.8 %
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! :)
Which is higher 117°F or 46°C
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
What kind of intermolecular forces have the weakest attraction?
Answer:
This kind of interaction can be expected between any polar molecule and non-polar/symmetrical molecule. The induction-interaction force is far weaker than dipole–dipole interaction, but stronger than the London dispersion force.
Hope this is fine for youWhat 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
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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Along the length of the DNA strand, information is stored in the sequence of __________.
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
What is the vapor pressure of ethanoic acid at 105°C?
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
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?
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.
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.
Given 2Na + 2H2O → 2NaOH + H2, how many grams of oxygen are produced if 300.00 grams of Na are reacted with water?
First you have to find the number of moles , then you have to apply stoichometry to find the number of moles of H2 gas , after that you can determine its mass.
Why do electrons repel each other?
Answer:
Electrons repel each other due to electrostatic force of attraction between both of them as a result prevent the electron from entering the nucleus preventing it from collapsing
Electrons repel each other because they have the same charge present in
them.
What is Law of Magnetism?Law of magnetism states that:
Like poles repelUnlike poles attract.Electrons are subatomic particles which are negatively charged which
depicts them possessing like poles.
This explains why electrons which are in contact with each other will repel as
a result of the repulsive force present in like poles.
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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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Plz help ASAP question is on picture
Answer:
The arrow going directly from the sun to the earth (middle one)!
Explanation:
HOPE THIS HELPS! :)
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
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
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:
Calculate the pH of a buffer solution containing 0.1 M of ethanoic acid (CH3COOH) and 0.02 M Magnesium ethanoate (NB make sure you have the correct formula for the salt and therefore CH3COO-ions ). The Ka for ethanoic acid is 1.74 x 10-5 mol dm-3.
Answer:
By the end of this module, you will be able to: ... (a) Calculate the pH of an acetate buffer that is a mixture with 0.10 M acetic acid and 0.10 M ...
What is the average speed of the toy car during the two trials?
Answer:
2.3?
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 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
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
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 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!
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
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].
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!
