Answer:
Explanation:
To find the concentration; let's first compute the average density and the average atomic weight.
For the average density [tex]\rho_{avg}[/tex]; we have:
[tex]\rho_{avg} = \dfrac{100}{ \dfrac{C_{Fe} }{\rho_{Fe}} + \dfrac{C_v}{\rho_v} }[/tex]
The average atomic weight is:
[tex]A_{avg} = \dfrac{100}{ \dfrac{C_{Fe} }{A_{Fe}} + \dfrac{C_v}{A_v} }[/tex]
So; in terms of vanadium, the Concentration of iron is:
[tex]C_{Fe} = 100 - C_v[/tex]
From a unit cell volume [tex]V_c[/tex]
[tex]V_c = \dfrac{n A_{avc}}{\rho_{avc} N_A}[/tex]
where;
[tex]N_A[/tex] = number of Avogadro constant.
SO; replacing [tex]V_c[/tex] with [tex]a^3[/tex] ; [tex]\rho_{avg}[/tex] with [tex]\dfrac{100}{ \dfrac{C_{Fe} }{\rho_{Fe}} + \dfrac{C_v}{\rho_v} }[/tex] ; [tex]A_{avg}[/tex] with [tex]\dfrac{100}{ \dfrac{C_{Fe} }{A_{Fe}} + \dfrac{C_v}{A_v} }[/tex] and
[tex]C_{Fe}[/tex] with [tex]100-C_v[/tex]
Then:
[tex]a^3 = \dfrac { n \Big (\dfrac{100}{[(100-C_v)/A_{Fe} ] + [C_v/A_v]} \Big) } {N_A\Big (\dfrac{100}{[(100-C_v)/\rho_{Fe} ] + [C_v/\rho_v]} \Big) }[/tex]
[tex]a^3 = \dfrac { n \Big (\dfrac{100 \times A_{Fe} \times A_v}{[(100-C_v)A_{v} ] + [C_v/A_Fe]} \Big) } {N_A \Big (\dfrac{100 \times \rho_{Fe} \times \rho_v }{[(100-C_v)/\rho_{v} ] + [C_v \rho_{Fe}]} \Big) }[/tex]
[tex]a^3 = \dfrac { n \Big (\dfrac{100 \times A_{Fe} \times A_v}{[(100A_{v}-C_vA_{v}) ] + [C_vA_Fe]} \Big) } {N_A \Big (\dfrac{100 \times \rho_{Fe} \times \rho_v }{[(100\rho_{v} - C_v \rho_{v}) ] + [C_v \rho_{Fe}]} \Big) }[/tex]
Replacing the values; we have:
[tex](0.289 \times 10^{-7} \ cm)^3 = \dfrac{2 \ atoms/unit \ cell}{6.023 \times 10^{23}} \dfrac{ \dfrac{100 (50.94 \g/mol) (55.84(g/mol)} { 100(50.94 \ g/mol) - C_v(50.94 \ g/mol) + C_v (55.84 \ g/mol) } }{ \dfrac{100 (7.84 \ g/cm^3) (6.0 \ g/cm^3 } { 100(6.0 \ g/cm^3) - C_v(6.0 \ g/cm^3) + C_v (7.84 \ g/cm^3) } }[/tex]
[tex]2.41 \times 10^{-23} = \dfrac{2}{6.023 \times 10^{23} } \dfrac{ \dfrac{100 *50*55.84}{100*50.94 -50.94 C_v +55.84 C_v} }{\dfrac{100 * 7.84 *6}{600-6C_v +7.84 C_v} }[/tex]
[tex]2.41 \times 10^{-23} (\dfrac{4704}{600+1.84 C_v})=3.2 \times 10^{-24} ( \dfrac{284448.96}{5094 +4.9 C_v})[/tex]
[tex]\mathbf{C_v = 9.1 \ wt\%}[/tex]
The octet rule states that atoms in molecules share electrons in such a way that each atom has a full valence shell. Determine whether each structure has the correct number of electrons and obeys the octet rule. Classify structures that have the correct number of electrons and obey the octet rule as valid, and those that do not as invalid. valid structure invalid structure
Answer:
Their must be a picture with this question so we can answer it
Explanation:
According to octet rule the bonded valence shells are completely filled. All the compounds except the first one, CH₃CH₃O is invalid since H does not obey the rule and invalid.
What is octet rule?Octet rule says that an atoms become stable when it completes its valence shell to 8 electrons or 2 electrons for K-shell. Thus bonded shells have to completely filled to be stable.
Each atom shares its electrons based on its valency. For example carbon have a valency of 4 and it forms for bonds and oxygen and sulfur have two and hydrogen forms only one bonds.
In the first compounds CH₃CH₃O, where one H forms two bonds which is not possible and invalid.
In the second compound CONH, all the atoms satisfies its valency including nitrogen having a valency of three forms three bonds. Similarly in CH₂F₂, one fluorine forms one bond and the structure is valid.
In the case of Br₂ , each bromine shares one electron with the other and complete their octet to eight electrons. In NH₃, SCO and COCl₂ all the atoms satisfies their valency and the structures are valid.
Therefore the only invalid structure is first compound, remaining all are valid.
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Your question is incomplete. But most probably your complete question was as in the uploaded image.
When preparing for work in the fume hood, be sure to gather all necessary tools, glassware, and chemicals _________ to minimize the number of times the hood sash is raised and lowered. Work as much as possible in the _________ of the work surface to keep the area tidy and promote air flow. If you need to step away from the experiment to obtain another item, _________ the sash during this time.
Answer:
In advance
middle
lower
Explanation:
These are the safety precautions needed when carrying out duties in the fume hood.
When planning and preparing to work in a fume hood (a locally designed area to reduce exposure to hazardous fumes). It is advisable to make all equipment readily available at your disposal in advance to reduce and minimize the raising and lowering of the hood sash at intervals.
It is also pertinent to understand that working in the middle of the work surface helps to promote the movement of air and keeps the area neat and tidy.
However, if any case where there is a need to get a new tool or equipment during the process of working in a fume hood, it is advisable to lower the sash at that point in time.
Riboflavin is one of the B vitamins It is also known as B6 and is made up of carbon, hydrogen, nitrogen and oxygen atoms. When 10.0 g of vitamin B6 is burned in oxygen, 19.88 g of CO2 and 4.79 g of H2O are obtained. Another experiment shows that vitamin B6 is made up of 14.89% of N. What is the simplest formula for vitamin B6
Answer:
C₁₇H₂₀N₄O₆
Explanation:
First, we need to determine the percentage of the atoms in the molecule. Then, assuming a basis of 100 we must convert the mass of each atom to moles. Simplest formula is the simplest ratio of atoms presents in the molecule:
%C:
19.88g CO2 * (12.01g/mol C / 44.01g/mol CO2) = 5.425g C
5.425g C / 10.0g * 100 = 54.25% C
%H:
4.79g H2O * (2*1.01g/mol / 18.015g/mol) = 0.537g H
0.537g H / 10.0g * 100 = 5.37%
%N:
14.89%
%O:
100 - 14.89% - 54.25% - 5.37% = 25.49%
Moles of each atom in a basis of 100g:
C: 54.25g * (1mol / 12.01g) = 4.517moles
H: 5.37g * (1mol / 1.01g) = 5.317 moles
N: 14.89g * (1mol / 14.01g) = 1.063 moles
O: 25.49g * (1mol / 16g) = 1.593 moles
Dividing each amount of moles in the lower number of moles (moles N):
C = 4.517mol / 1.063mol = 4.25
H = 5.317mol / 1.063mol = 5
N = 1.063mol / 1.063mol = 1
O = 1.593mol / 1.063mol = 1.5
This ratio multiplied 4 times to obtain whole-numbers:
C = 4.25*4 = 17
H = 5*4 = 20
N = 1*4 = 4
O = 1.5*4 = 6
The simplest formula for vitamin B6 is:
C₁₇H₂₀N₄O₆The number of atoms in 10. grams of calcium is equal to 6.0 x 1023 multiplied by which number?
Answer:
1.51×10²³ atoms.
Explanation:
From the question given above, the following data were obtained:
Mass of Calcium (Ca = 10 g
Number of atom of Calcium (Ca) =?
The number of atoms present in 10 g of Ca be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This implies that 1 mole Ca contains 6.02×10²³ atoms.
1 mole of Ca = 40 g.
Now, if 40 g of Ca contains 6.02×10²³ atoms.
Therefore, 10 g of Ca will contain = (10 × 6.02×10²³) / 40 = 1.51×10²³ atoms.
Thus, 10 g of calcium contains 1.51×10²³ atoms.
(will give brainliest!! please help me! thank you!)
a) The rows on the periodic table are called periods. How many energy levels are in the atoms of each element in period 2 (lithium-neon)
b) What is the group number of the halogens?
c) What do the elements in each group have in common?
please please help me, i will give brainliest
Answer:
A two energy levels K and L
B halogen are present in group 17
C in same group elements have same valence electrons
Explanation:
Which of the following choices is not evidence supporting the theory of plate tectonics?
Answer:
B
Explanation:
What is the charge is the ion when lithium reacts with chlorine
Plz help ASAP i will give brainlists
2AgNO3 + BaCl2 + 2AgCl + Ba(NO3)2
How many grams of silver chloride are produced from 15.0 g of silver nitrate reacting with an excess of barium chloride?
A)9.44 g Agci
B)16.4 g Agci
C)12.7 g Agci
D)0 20.1 g Agci
In the Energy and Specific Heat lab, what temperature should be recorded as the final temperature of the water when measuring the food sample?
A. The temperature of the water when the food sample is first lit
B. The temperature of the water when the food sample has finished burning completely.
C. The highest temperature the water reaches as the sample burns
D. The temperature of the water after the food sample ash has been removed
Answer:
B. The temperature of the water when the food sample has finished burning completely.
Explanation:
Heat or thermal energy is a form of energy that transfers from one object to another due to a temperature difference between the objects. The units for heat are joules or calories.
Calorimetry is the measurement of heat energy released or absorbed in a chemical reaction. A calorimeter is used in calorimetry. The calorimeter operates on the Law of Conservation of Energy which states that energy is never created or destroyed but is transformed from one form to another or between objects.
In food calorimetry, the energy released when food is burned is measured by recording the rise in temperature of water in a calorimeter when a given mass of a food sample is burned completely.
Energy can be calculated using the formula: Q = mc ∆T
where Q = the energy in joules or calories, m = the mass in grams, c = specific heat and ∆T = the change in temperature (final temperature - initial temperature).
The temperature of the water when the food sample has finished burning completely is taken as the final temperature of the water. The sample is allowed to smolder for sometime before recording the final water temperature. This is because the water temperature will continue to rise after the flame has gone out.
helppp nowwww plsssss!!
Answer:
The sun will appear to rise and set more slowly
have a nice day! (^o^)
As a part of a clinical study, a pharmacist is asked to prepare a modification of a standard 22g package of a 2% mupirocin ointment by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment. How many mg of mupirocin powder are required?
Answer:
226.8 mg of mupirocin powder are required
Explanation:
Given that;
weight of standard pack = 22 g
mupirocin by weight = 2%
so weight of mupirocin = 2% × 22 = 2/100 × 22 = 0.44 g
so by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment
mg of mupirocin powder are required = ?, lets rep this with x
Total weight of ointment = 22 + x g
Amount of mupirocin = 0.44 + x g
percentage of mupirocin in ointment is 3?
so
3/100 = 0.44 + x g / 22 + x g
3( 22 + x g ) = 100( 0.44 + x g )
66 + 3x g = 44 + 100x g
66 - 44 = 100x g - 3x g
97 x g = 22
x g = 22 / 97
x g = 0.2268 g
we know that; 1 gram = 1000 Milligram
so 0.2268 g = x mg
x mg = 0.2268 × 1000
x mg = 226.8 mg
Therefore, 226.8 mg of mupirocin powder are required
We have that for the Question "How many mg of mupirocin powder are required? "
It can be said that
[tex]0.2268g[/tex] of mupirocin powder is required
From the question we are told
a pharmacist is asked to prepare a modification of a standard 22g package of a 2% mupirocin ointment by adding the needed quantity of mupirocin powder to prepare a 3% w/w mupirocin ointment
Weight of standard package = 22g
mupirocin = 2%
Therefore,
Weight of mupirocin = [tex]\frac{2}{100}*22[/tex]
[tex]=0.44g[/tex]
Let amount of mupirocin to be added to prepare 3% w/w mupirocin ointment = X
Therefore,
Total weight of ointment = [tex](22 + X)g[/tex]
amount of mupirocin = [tex](0.44+X)g[/tex]
% of mupirocin in ointment = [tex]3\%[/tex]
therefore,
[tex]\frac{3}{100} = \frac{0.44+X}{22+X}\\\\66+3X = 44+100X\\\\X = 0.2268g[/tex]
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What role do wolves play in the tundra?
Answer:
predator
Explanation:
Wolves, arctic foxes, and snowy owls are predators in the tundra.
When a substance undergoes a chemical change, its identity does not change.
O True
O False
Answer:
False
Explanation:
Chemists make a distinction between two different types of changes that they study—physical changes and chemical changes. Physical changes are changes that do not alter the identity of a substance. Chemical changes are frequently harder to reverse than physical changes.
If 1.546 g of copper was used by a student at the start of the lab, and 0.732 g of copper were obtained at
the end of the series of reactions, what was the percent recovery? Briefly explain how you found your
answer.
Answer: Percent recovery is 47.34 %
Explanation:
Percent yield is defined as the ratio of experimental yiled to theoretical yield in terms of percentage.
[tex]{\text{ percent yield}}=\frac{\text{amount recovered}}{\text{total amount}}\times 100[/tex]
Putting in the values we get:
[tex]{\text{ percent yield}}=\frac{0.732}{1.546}\times 100=47.34\%[/tex]
Therefore, the percent recovery is 47.34 %
Today, ammonia is synthesized through a series of reactions (called the Haber-Bosch process) that take place between methane, air (which is four parts N2, one part O2), and potassium carbonate:
7 CH4(g) + 8 N2(g) +2 O2(g) + 17 H2O(g) + 7 K2CO3(s) ?? 16 NH3(g) + 14 KHCO3(s)
What is the equilibrium expression for the Harber-Bosch process?
Answer:
K = [NH₃]¹⁶ [KHCO₃]¹⁴ / [CH₄]⁷ [N₂]⁸ [O₂]² [H₂O]¹⁷ [K₂CO₃]⁷
Explanation:
The equation for the reaction is given below:
7CH₄(g) + 8N₂(g) +2O₂(g) + 17H₂O(g) + 7K₂CO₃(s) —> 16NH₃(g) + 14KHCO₃(s)
Equilibrium constant (K) =..?
Equilibrium constant, K for a reaction is simply defined as the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.
Thus, the equilibrium expression for the Harber-Bosch process for the synthesis of ammonia can be written as shown below:
K = [NH₃]¹⁶ [KHCO₃]¹⁴ / [CH₄]⁷ [N₂]⁸ [O₂]² [H₂O]¹⁷ [K₂CO₃]⁷
The reaction that occurs in a Breathalyzer, a device used to determine the alcohol level in a person's bloodstream, is given below. If the rate of appearance of Cr2(SO4)3 is 1.24 mol/min at a particular moment, what is the rate of disappearance of C2H6O at that moment
Answer:
The rate of disappearance of C₂H₆O = 2.46 mol/min
Explanation:
The equation of the reaction is given below:
2 K₂Cr₂O₇ + 8 H₂SO₄ + 3 C₂H₆O → 2 Cr₂(SO₄)₃ + 2 K₂SO₄ + 11 H₂O
From the equation of the reaction, 3 moles of C₂H₆O is used when 2 moles of Cr₂(SO₄)₃ are produced, therefore, the mole ratio of C₂H₆O to Cr₂(SO₄)₃ is 3:2.
The rate of appearance of Cr₂(SO₄)₃ in that particular moment is given 1.64 mol/min. This would than means that C₂H₆O must be used up at a rate which is approximately equal to their mole ratios. Thus, the rate of of the disappearance of C₂H₆O can be calculated from the mole ratio of Cr₂(SO₄)₃ and C₂H₆O.
Rate of disappearance of C₂H₆O = 1.64 mol/min of Cr₂(SO₄)₃ * 3 moles of C₂H₆O / 2 moles of Cr₂(SO₄)₃
Rate of disappearance of C₂H₆O = 2.46 mol/min of C₂H₆O
Therefore, the rate of disappearance of C₂H₆O = 2.46 mol/min
6. 7. A hyperbaric chamber has a volume of 200. L. (a) How many moles of oxygen are needed to fill the chamber at room temperature (23°C) and 3.00 atm pressure? b) How many grams of oxygen are needed? (Hint: Since moles have been asked, which equation has the moles listed in the equation. Use that to solve this problem. Also don’t forget to use the equation 1 mole = Formula weight or Molecular weight to calculate the grams of O2).
Answer:
a) 24.7 mol
b) 790 g
Explanation:
Step 1: Given data
Volume of the chamber (V): 200. LRoom temperature (T): 23 °CPressure of the gas (P): 3.00 atmStep 2: Convert "T" to Kelvin
We will use the following expression.
K = °C + 273.15
K = 23°C + 273.15 = 296 K
Step 3: Calculate the moles (n) of oxygen
We will use the ideal gas equation.
P × V = n × R × T
n = P × V/R × T
n = 3.00 atm × 200. L/(0.0821 atm.L/mol.K) × 296 K = 24.7 mol
Step 4: Calculate the mass (m) corresponding to 24.7 moles of oxygen
The molar mass (M) of oxygen ga sis 32.00 g/mol. We will calculate the mass of oxygen using the following expression.
m = n × M
m = 24.7 mol × 32.00 g/mol = 790 g
Describe the relationship between kinetic energy and the states of matter?
PLS HELP I DONT SCIENCE HELP ASAP HELP
Answer:
The kinetic molecular theory of matter states that: Matter is made up of particles that are constantly moving. All particles have energy, but the energy varies depending on the temperature the sample of matter is in. This in turn determines whether the substance exists in the solid, liquid, or gaseous state.
Explanation:
identified the nucleus that is found in an item that has a stable valance electron configuration
Answer:
Nucleus 3 i believe
is C5H10 ionic or covalent?
4. Which employees should be aware of how to turn off power to a shop in an emergency?
Answer:
All employees should know how to work the system
Ivy has a mixture salt and sand . She wants to separate the two substances by pouring the mixture into a jar of water . How could ivy speed up the separation of the two substance? Shake the jar , put the jar into the freezer, add a third substance such as soil to the jar , remove some of the water from the jar before adding the mixture
Answer:
Remove some water from the jar before adding the mixture.
Explanation:
She will speed it up when removing some water it will stay dry and not be sticky to separate the two ingredients
Answer: Remove a bit of water from the jar
Explanation:
Which water usage uses the least amount of water in a year in the United States? a industry
b livestock c irrigation d public water supply
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According to bond energy tables, the triple bond of N2 is 946 kJ/mol while the bond of I2 is 151 kJ/mol. Based on simple chemical ideas about what molecular properties lead to activation energies, it is reasonable to expect that the reaction of H with N2 will have a higher activation energy than the reaction of H with I2.
1. Yes, I2 is heavier than N2.
2. No, bond energies do not matter much; lone pairs are crucial.
3. Yes, in both cases the reactant bond must be stretched by collisions and more energy is required for the stronger bond.
4. Yes, in both cases the reactant bond must be broken before the H can bond.
5. No, activation energies have nothing to do with bond energies.
Answer:
Yes, in both cases the reactant bond must be broken before the H can bond.
Explanation:
Let us remind ourselves of the basics of the collision theory. According to this theory, chemical reaction occurs because of the collision of particles of substances in a chemical reaction system.
This means that the bond between reactants must first be broken and new bonds formed in products. Activation energy is the minimum energy required for a reaction to occur. This energy goes into the rearrangement of reactant bonds to enable them to recombine and form products.
Since the N2 bond energy is far higher than the I2 bond energy, a greater degree of energy is needed overcome the energy barrier in the reaction of H2 with N2 compared to the reaction of H2 and I2 . Therefore, the activation energy for the reaction of H2 and N2 is much higher than the activation energy for the reaction of H2 with I2.
In a laboratory setting, concentrations for solutions are measured in molarity, which is the number of moles per liter (mol/L). Concentrations are often converted to more common units on the labels of household products. For a particular brand of bleach, the concentration of sodium hypochlorite (NaClO) is reported on the bottle as 7.25% by mass. The following information can thus be used to calculate the molarity of NaClO in the bleach:
• 1L of bleach has a mass of 1,100 grams.
• 7.25% of the mass of bleach is NaClO.
• 1 mol of NaClO has a mass of 74.44 grams.
What is the molarity (mol/L) of NaClO in the bleach?
A.0.097
B.0.93
C.1.07
D.79.75
Answer:
its C
Explanation:
1/74.44 * 79.75 = 1.07
The molarity (mol/L) of NaClO in the bleach, given the data is 1.07 mol/L (Option C)
What is molarity?Molarity is defined as the mole of solute per unit litre of solution. Mathematically, it can be expressed as:
Molarity = mole / Volume
How to determine the mass of NaClO in the bleachMass of bleach = 1100 gPercentage of NaClO = 7.25%Mass of NaClO = ?Mass of solute = percent × mass of solution
Mass of NaClO = 7.25% × 1100
Mass of NaClO = 0.0725 × 1100
Mass of NaClO = 79.75 g
How to determine the mole of NaClO Mass of NaClO = 79.75 gMolar mass of NaClO = 74.44 g/moleMole of NaClO =?Mole = mass / molar mass
Mole of NaClO = 79.75 / 74.44
Mole of NaClO = 1.07 mole
How to determine the molarity Mole of NaClO = 1.07 moleVolume = 1 L Molarity of NaClO =?Molarity = mole / Volume
Molarity of NaClO = 1.07 / 1
Molarity of NaClO = 1.07 mol/L
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Find the mass in grams of 1.38 moles of Sr
Answer:
116.78 grams.
Explanation:
1 mol of Strontium (Sr) = 87.62 grams
1.38 mol of Strontium = x
Cross Multiply
1 * x = 1.38 * 87.62
x = 116.78 grams
An scientist located a nugget of an unknown substance. However, he determined that this nugget has a
mass of 63 g and a volume of 9 cm^3. What is the density of this nugget?
Answer: The density of this nugget is [tex]7\text{ g cm}^{-3}[/tex] .
Explanation:
We are given that,
Mass of nugget = 63 g
Volume = [tex]9\ cm^3[/tex]
The computation of density of a substance is given by :-
[tex]\text{Density}=\dfrac{\text{Mass}}{\text{Volume}}\\\\\Rightarrow\ \text{Density}=\dfrac{63}{9}\text{ g cm}^{-3}[/tex]
[tex]\Rightarrow\ \text{Density =}7\text{ g cm}^{-3}[/tex]
Therefore, the density of this nugget is [tex]7\text{ g cm}^{-3}[/tex] .
ASAP I WILL GIVE BRAINLIEST The diagram shows a lever. What is the mechanical advantage of the lever? O 2 03 3 m 6 m mi 0 9
Answer:
A) 2
Explanation:
Answer:
2, i got it right thanks to the other user :) <3
Explanation:
3.
What do we call materials
that let heat pass through
them easily?
Thermal conductors
Thermal insulators
Transparent
4.
Which of these is a good
thermal conductor?
Plastic
Wood
Steel
5.
Which of these is a good
thermal insulator?
Steel
Iron
Polystyrene
6.
To save on heating bills, do
you think the roof of a
building should be lined with...
a thermal conductor
a thermal insulator
nothing
7.
How does heat travel?
From cold things to hotter things
From hot things to colder things
Between things of the same temperature
Answer:
thermal conductors
steel
polystyrene
thermal insulator
between things of the same temp?
sorry to ask but if its ok with you, may i get brainly, i need to rank up all i need is two more, if not its fine. thank you and yours truly golden
Please help me thanks so much?!?!?
Answer:
color
Explanation:
Answer:
D
Explanation:
The five conditions of chemical change: color chage, formation of a precipitate, formation of a gas, odor change, temperature change and the others are just physical changes that would happen if you change containers, or let it evaporate.