Answer:
= 4 * 10-8 = 400 Angstrom
Explanation:
EF = 5 eV, K = 4.29 x 102 J/(s m K), and Cvel = 1% of the lattice heat capacity
K= 1/3 (Cv)*v*l
v is fermi velocity which is equal to [tex]v = (2E_f/m)^{0.5}[/tex]
after putting mass of electron as [tex]9.1 * 10^{-31}kg[/tex] and [tex]E_f = 5 eV[/tex] we get [tex]v= 1.33 * 10^6 m/s[/tex]
[tex]C_v[/tex] is 1% of lattice heat capacity
Heat Capacity of Aluminium is [tex]0.897 J g^{-1}K^-1[/tex]
Density = [tex]2.6989 g \ cm^{-3}[/tex]
For lattice heat capacity you need to use the heat capacity for alimunium given and then multiply with density to get per unit volume term
Heat Capacity per unit volume = [tex]0.897 J g^{-1}K^-1[/tex] * [tex]2.6989 g \ cm^{-3}[/tex]
[tex]= 2.42 J K^{-1} cm^{-3} \\\\= 2.42* 10^6 J K^{-1} m^{-3}[/tex]
Cv = 1% of heat capacity per unit volume
[tex]=0.01 * 2.42* 10^8 J K^{-1} m^{-3} \\\\= 2.42* 10^4 J K^{-1} m^{-3}[/tex]
Putting values in this equation K= 1/3 (Cv)*v*l
[tex]l = 3K/(C_v * v )\\\\ = 3 * 4.29 * 10^2 / (2.42* 10^4 * 1.33 * 10^6 )[/tex]
[tex]= 4 * 10^{-8 }[/tex]
= 400 Angstrom
If an experiment produces 5 g but should have made 500 g, what is the percent
yield?
Answer:
Percentage of yield = 1%
Explanation:
Given:
Amount of yield = 5g
Total amount of product = 500 gram
Find:
Percentage of yield = ?
Computation:
⇒ Percentage of yield = [Amount of yield / Total amount of product]100
⇒ Percentage of yield = [5g / 500g]100
⇒ Percentage of yield = [0.01]100
⇒ Percentage of yield = 1%
How many grams of lead (ll) sulfate would be produced from the complete reaction of 23.6 g lead (iV) oxide ?
Answer:
59.8287
Explanation:
I put that answer in and it is correct.
Since density depends on the mass and volume of an object, we need both of these values combined in the correct way to solve for density. Keep in mind that we may not be given the mass and volume directly, or the values may not be given in the units we want and we need to convert to the correct units before solving for density.When converting between metric units, use the prefixes to help you determine the magnitude of a value. The prefix k indicates kilo, 1000. Therefore 1000 g = 1 kg.A 11.0 kg iron weightlifting plate has a volume of 1400 cm3 . What is the density of the iron plate in g/cm3?Express your answer in grams per cubic centimeter to three significant figures.
Answer:
7.86 g/cm³
Explanation:
11.0 kg = 11,000 g
The density in g/cm³ is ...
(11,000 g)/(1,400 cm³) = 7.86 g/cm³
If you can help answer the question if you can't then don't
a candle burning can be considered both chemical and physical change explain how is that possible ????
Answer:
Yes its both a physical and chemical change heres why.
When heated , the wax melts to form a liquid wax . The liquid wax then becomes a solid wax upon cooling ( Physical change )
When the candle is lit, the wax near the tip of the candle will melt . The wick then absorbs the liquid wax . The liquid wax then vapourizes due to the heat emitting from the flame . The wax vapour then burns to give off a black substance ( what we will to as CO₂ , soot ) , heat and water vapour
(Chemical change )
Brainliest ? Hope I answered your question
Wich substances is most likely to form in a precipitation reaction?
Answer:
A precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined. The insoluble salt that falls out of solution is known as the precipitate, hence the reaction's name.
Explanation:
According to one acid base theory a base is an 1, h2 acceptor 2, h2 donor 3, h+ acceptor 4,h+ donor
Answer:
3, H⁺ acceptor
Explanation:
Let's consider Bronsted-Lowry acid-base theory.
According to this theory, an acid is a substance that donates H⁺ ions. For example, HCl is an acid.
HCl + H₂O = Cl⁻ + H₃O⁺
Cl⁻ is the conjugate base of HCl.
According to this theory, a base is a substance that accepts H⁺ ions. For example, NH₃ is a base.
NH₃ + H₂O = NH₄⁺ + OH⁻
NH₄⁺ is the conjugate acid of NH₃.
According to one acid-base theory, a base is an H+ acceptor.
What is the acid-base theory?The acid-base theory, also called the Brønsted-Lowry theory, is a theory developed by Johannes N. Brønsted and Thomas M. Lowry.
The acid-base theory states that an acid is a proton (H+) donor, whereas a base can be considered as an H+ acceptor.According to Brønsted-Lowry's theory, H2O may act as a base because this molecule acts as a proton (H+) acceptor.In conclusion, according to one acid-base theory, a base is an H+ acceptor.
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Write a chemical formula for each molecular model. (Blue ball represents nitrogen atom, red ball represents oxygen atom, white ball represents hydrogen atom, black ball represents carbon atom, yellow ball represents sulphur atom.)
Answer:
See answer below
Explanation:
In this case, you are missing the picture. Luckily I found one on another site, so I hope is the one you are asking for. If not, please post again with the picture.
According to the picture below, you need to write a chemical formula for each molecular model.
To do this, is just simple. Let's see each model per separate.
In the first model, we have a blue ball and three white balls. According to the nomenclature of the question a blue ball represents nitrogen atoms and white ball represents hydrogen, therefore, we have an atom of nitrogen bonded to three atoms of hydrogens, so, the chemical formula should be:
NH₃: This molecule corresponds to the Ammonia molecule.
The second picture, shows 4 black balls (representing an atom of carbon each) and each black ball holds a determinated number of white balls. The two of the middle have two white balls each, and the terminals have 3 white balls, therefore, the molecule should be the following:
CH₃ - CH₂ - CH₂ - CH₃: this corresponds to the butane
Finally, the last picture shows a yellow ball (which represents sulphur) and three red balls (representing oxygen each), so, the molecule that represents this would be:
SO₃: this is the sulfite ion.
Give 2 examples of a strong electrolyte
Answer:
Sodium Chloride, Potassium Chloride
Explanation:
Sodium Chloride, Potassium Chloride, are the most common example of a strong electrolyte. Most salts are strong electrolytes, such as hydrochloric acid, nitric acid, perchloric acid and sulphuric acid. Strong bases, such as sodium hydroxide and calcium hydroxide, are also potent electrolytes.
hope this helped!
How many grams of NO are required to produce 145 g of N2 in the following reaction?
4NH3(g) + 6NO(g) → 5N2(g) + 6H2O(l)
a. 155 g
b. 186 g
c. 125 g
d. 145 g
e. 129 g
Answer:
b. 186 g
Explanation:
Step 1: Write the balanced equation.
4 NH₃(g) + 6 NO(g) → 5 N₂(g) + 6 H₂O(l)
Step 2: Calculate the moles corresponding to 145 g of N₂
The molar mass of nitrogen is 28.01 g/mol.
[tex]145g \times \frac{1mol}{28.01 g} =5.18 mol[/tex]
Step 3: Calculate the moles of NO required to produce 5.18 moles of N₂
The molar ratio of NO to N₂ is 6:5.
[tex]5.18molN_2 \times \frac{6molNO}{5molN_2} = 6.22molNO[/tex]
Step 4: Calculate the mass corresponding to 6.22 moles of NO
The molar mass of NO is 30.01 g/mol.
[tex]6.22mol \times \frac{30.01g}{mol} =186 g[/tex]
The mass of NO required to produce 145 g of N₂ is 186 g.
The correct answer to the question is Option B. 186 g
We'll begin by calculating the mass of NO that reacted and the mass of N₂ produced from the balanced equation.
4NH₃ + 6NO —> 5N₂ + 6H₂O
Molar mass of NO = 14 + 16 = 30 g/mol
Mass of NO from the balanced equation = 6 × 30 = 180 g
Molar mass of N₂ = 14 × 2 = 28 g/mol
Mass of N₂ from the balanced equation = 5 × 28 = 140 g
From the balanced equation above,
140 g of N₂ were produce by 180 g of NO
Finally, we shall determine the mass of NO required to produce 145 g of N₂
From the balanced equation above,
140 g of N₂ were produce by 180 g of NO
Therefore,
145 g of N₂ will be produce by = (145 × 180) / 140 = 186 g of NO
Thus, 186 g of NO is required for the reaction.
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Give TWO reasons, in terms of shielding, why potassium is the
most reactive of the three elements.
Answer:
Hi..? All three elements are in group 1 thus they have 1 valence electron which is easy to lose due to shielding.As Pottasium is larger than the rest,Pottasium's valence electron is at a greater distance from the attractive nucleus and is so removed more easily than Sodium's and Lithium's valence electrons.As it is removed more easily it requires less energy and can be said to be more reactive
A technician prepared a solution by heating 100 milliliters of distilled water while adding KCl crystals until no more KCl would dissolve. She then capped the clear solution and set it aside on the lab bench. After several hours she noticed the solution had become cloudy and some solid had settled to the bottom of the flask. Which statement best describes what happened?
A. As the solution cooled, evaporation of water increased the KCl concentration beyond its solubility
B. Water molecules, trapped with the KCl crystals, were released after heating
C. At lower temperatures the solubility of the KCl decreased and recrystallization occurred
D. At increased temperatures the solubility of KCl increased and remained too high after cooling
Answer:
At lower temperatures the solubility of the KCl decreased and recrystallization occurred
Explanation:
Solubility refers to the amount of solute that dissolves in one litre of water at a particular temperature. Solubility is a property referring to the ability for a given substance, the solute, to dissolve in a solvent. It is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium. The resulting solution is called a saturated solution.
Solubility is dependent on temperature. This is the reason why we must state the particular temperature at which a given solubility data was collected. Above or below the quoted temperature, the solubility data may no longer be accurate.
Let's return to the question, at elevated temperatures, we can see that the KCl is very soluble in water as evidenced by the clear solution obtained at high temperature. However, as the temperature decreases, the solubility of KCl also decreases accordingly and recrystallization of the solute occurred hence the formation of a cloudy solution and the settling of some solid at the bottom of the flask.
Answer:
C. At lower temperatures the solubility of the KCl decreased and recrystallization occurred
Explanation:
Polymers are large molecules composed of simple units repeated many times. Thus, they often have relatively simple empirical formulas. Calculate the empirical formulas of the polyethylene: 86% C, 14% H. You must show all work for credit. Polymers are large molecules composed of simple units repeated many times. Thus, they often have relatively simple empirical formulas. Calculate the empirical formulas of the polystyrene: 92.3% C, 7.7% H. You must show all work for credit.
Answer:
A. CH2.
B. CH.
Explanation:
A. Determination of the empirical formula of polyethylene.
Data obtained from the question include:
Carbon (C) = 86%
Hydrogen (H) = 14%
The empirical formula of the polyethylene can be obtained as follow:
C = 86%
H = 14%
Divide by their molar mass
C = 86/12 = 7.17
H = 14/1 = 14
Divide by the smallest
C = 7.17/7.17 = 1
H = 14/7.17 = 2
Therefore, the empirical formula of the polyethylene is CH2.
B. Determination of the empirical formula of polystyrene
Data obtained from the question include:
Carbon (C) = 92.3%
Hydrogen (H) = 7.7%
The empirical formula of the polystyrene can be obtained as follow:
C = 92.3%
H = 7.7%
Divide by their molar mass
C = 92.3/12 = 7.69
H = 7.7/1 = 7.7
Divide by the smallest
C = 7.69/7.69 = 1
H = 7.7/7.69 =
Therefore, the empirical formula of the polystyrene is CH.
How many moles of water form when one mole of NH3 reacts according to this reaction 4 NH3+ 5 O2= 4NO+ 6 H20
moles ratio of NH3 to H2O is 4:6
if 4=6
1. ?
1 * 6 /4 = 1.5
1.5 moles of water
Compound A (C9H12) shows prominent peaks in its mass spectrum at m/z 120 and 91. Compound B (also C9H12) shows prominent peaks at m/z 120 and 105. On vigorous oxidation with chromic acid, both compounds give benzoic acid. From this information, deduce the structures of both compounds.
Answer:
Compound A: Propylbenzene
Compound B: Cumene
Explanation:
On this case, we have two clues:
1) The mass spectrometry info
2) The formation of benzoic acid
If we have the formation of benzoic acid with a strong oxidant ([tex]H_2CrO_4[/tex]). It means that we have an alky group bonded to benzene. Therefore we have to add three carbons to a benzene ring in order to obtain the mass of the compound (120).
The next question is how these three additional carbons are bonded to the benzene. For this, we have to check the mass info. For compound A we have a fragmentation moeity on 91 therefore we have a loss of an ethyl group. Therefore compound A have a linear structure for the aditional three carbons.
For compound B we have a fragmentation moeity on 105 this means a loss of 15 units of mass therefore we loss a methyl group. This indicates that we have a non linear structure fo the three additional carbons.
See figures 1 and 2.
I hope it helps!
In an ionic compound, the size of the ions affects the internuclear distance (the distance between the centers of adjacent ions), which affects lattice energy (a measure of the attractive force holding those ions together). Based on ion sizes, arrange these compounds by their expected lattice energy. Note that many sources define lattice energies as negative values. Please arrange by magnitude and ignore the sign.
Compunds: RbCl ,RbBr ,Rbl ,RbF
Answer:
The correct answer will be " RbF > RbCl > RbBr > Rbl".
Explanation:
The size of the given ions will be:
RbCl:
⇒ 689kJ/mol
RbBr:
⇒ 660kJ/mol
Rbl:
⇒ 630kJ/mol
RbF:
⇒ 785kJ/mol
Now according to the size, the arrangement will be:
⇒ (785kJ/mol) > (689kJ/mol) > (660kJ/mol) >(630kJ/mol)
⇒ RbF > RbCl > RbBr > Rbl
The bond among all opposite charging ions seems to be strongest whenever the ions were indeed small.
over
In order for an object to be buoyant, there must be a difference in
the area of the object.
A. force of gravity
B. density
C. fluid pressure
D. mass
Answer:
fluid pressure
Explanation:
a p e x
An equilibrium mixture of the three gases in a 7.40 L container at 535 K contains 0.313 M PCl5, 0.119 M PCl3 and 0.119 M Cl2. What will be the concentrations of the three gases once equilibrium has been reestablished, if the volume of the container is increased to 16.6 L?
Answer:
PCl₅: 0.1192M
PCl₃: 0.0734M
Cl₂: 0.0734M
Explanation:
Based on the reaction:
PCl₅ ⇄ PCl₃ + Cl₂
K of reaction is defined as:
K = [PCl₃] [Cl₂] / [PCl₅]
Replacing with concentrations of gases in equilibrium:
K = [0.119] [0.119] / [0.313]
K = 0.0452
Moles of each gas is:
PCl₅: 7.40L × (0.313mol / L) = 2.3162 moles
PCl₃: 7.40L × (0.119mol / L) = 0.8806 moles
Cl₂: 7.40L × (0.119mol / L) = 0.8806 moles
When the volume of the container is increased the system will produce more moles, (That is, produce more products) in order to keep constant the pressure of the container -Le Chatelier's principle-. In equilibrium, molarity of each gas is:
PCl₅: 2.3162 moles - x / 16.6L
PCl₃: 0.8806 moles + x / 16.6L
Cl₂: 0.8806 moles + x / 16.6L
Where X is reaction coordinate.
Replacing in K formula:
0.0452 = [0.05305 + X/16.6] [0.05305 + X/16.6] / [0.13953 - X/16.6]
6.3068x10⁻³ - 2.723x10⁻³ X = 0.0028143 + 0.00639157 X + 0.00362897 X²
0 = -0.0034925 + 0.00911457X + 0.00362897 X²
Solving for X:
X = -2.8 → False answer. There is no negative concentrations
X = 0.3378 moles
Replacing:
PCl₅: 2.3162 moles - 0.3378 / 16.6L = 0.1192M
PCl₃: 0.8806 moles + 0.3378 / 16.6L = 0.0734M
Cl₂: 0.8806 moles + 0.3378 / 16.6L = 0.0734M
Beeing these concentrations the concentrations in equilibrium of the three gases
In a compound with molecular formula X2Y3, the valencies of Y and X are
Answer: In a compound with molecular formula [tex]X_2Y_3[/tex] ,the valency of Y and X are 2 and 3 respectively.
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
The given compound is [tex]X_2Y_3[/tex] where X and Y combine and their oxidation states or valencies are exchanged and written in simplest whole number ratios. Thus the oxidation state or valency of X is 3 and that of Y is 2.
The valency of X is 3 and the valency of Y is 2.
The valency is more simply defined as the combining power of an element. We can see the valency of an element from the subscript of the other atom in the compound. This will now serve as our guide in decoding the valencies of X and Y.
Valency of X - 3Valency of Y - 2Hence, the valency of X is 3 and the valency of Y is 2.
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Just need to know the one with the Hexagon
Answer:2,4-dichlorohexane
Explanation:
Hope it helps
When 161.0 mL of water at 26.0°C is mixed with 41.0 mL of water at 85.0°C, what is the final temperature
Answer: The final temperature is [tex]38.0^0C[/tex]
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
[tex]heat_{released}=heat_{absorbed}[/tex]
[tex]Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})[/tex]
[tex]-[m_1\times c_1\times (T_{final}-T_1)]=[m_2\times c_2\times (T_{final}-T_2)][/tex]
[tex]-[m_1\times (T_{final}-T_1)]=[m_2\times (T_{final}-T_2)][/tex] (as [tex]c_1=c_2[/tex])
Q = heat absorbed or released
[tex]m_1[/tex] = mass of water at [tex]85.0^0C[/tex] = [tex]volume\times density=41.0ml\times 1g/ml=41.0g[/tex]
[tex]m_2[/tex] = mass of water at [tex]26.0^0C[/tex] = [tex]volume\times density=161.0ml\times 1g/ml=161.0g[/tex]
[tex]T_{final}[/tex] = final temperature = ?
[tex]T_1[/tex] = temperature of 41.0 ml of water = [tex]85.0^0C[/tex]
[tex]T_2[/tex] = temperature of 161.0 ml of water = [tex]26.0^0C[/tex]
Now put all the given values, we get
[tex]-[41.0\times (T_f-85.0)^0C]=161.0\times (T_f-26.0)^0C[/tex]
[tex]T_f=38.0^0C[/tex]
Thus the final temperature is [tex]38.0^0C[/tex]
What are the differences between HDL and LDL?
Answer:
LDL is
low density lipid
HDL is
high density lipid
Explanation:
HDL helps rid your body is excess cholesterol so so it won't end up in your arteries
LDL is also called "bad cholesterol" because it takes cholesterol to your arteries
Write an equation that shows the formation of a magnesium ion from a neutral magnesium atom
Answer:
Mg ---> Mg^2+ + 2e^
Explanation:
hope it helps : )
Magnesium is a neutral atom that can lose two electrons two achieve stability and forms a cation. The magnesium ion is produced as, Mg ⇒ Mg²⁺ + 2e⁻.
What is a magnesium ion?Magnesium ion is a charged species that is produced as the result of the neutral magnesium donating its electron so as to achieve its stable and complete electronic configuration.
When an atom donates an electron to another atom then they themselves become positively charged whereas the other species that accepts the electron becomes negatively charged. The positive charge is called a cation.
The reaction of the neutral magnesium donating electrons to become ions is shown as,
Mg ⇒ Mg²⁺ + 2e⁻
Therefore, magnesium loses two electrons to become positively charged.
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H3C-CH2-OH
What is the name of this
Answer:
H3C is the chemical name for the methyl group, and it can also be written as CH3
CH2 is a carbene
OH is hydroxide
What type of reaction would come from reactants Cu and O
Answer:
Synthesis
Explanation:
Because the reactants aren't compounds, it has to be a synthesis reaction, in which Cu and O combine to make copper oxide.
Answer:
Synthesis
Explanation:
d
What happens when a primary structure forms a secondary structure
Answer:
The oxygen atoms of the carbonyl groups and the hydrogen atoms attached to the nitrogen atoms form α-helices or β-pleated sheets. The order of the amino acids provides the R groups that interact to determine the tertiary structure
Explanation:
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What did Ernest Rutherford's work uncover?
Answer:
Ernest Rutherford is known in his work of pioneering studies of radioactivity and the specifics in the atom. He discovered that there are two types of radiation, which are alpha and beta particles, coming from uranium. He found that the atom consists mostly of empty space, with its mass concentrated in a central positively charged nucleus.
Explanation:
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Determine the value of the equilibrium constant, Kgoal, for the reaction N2(g)+H2O(g)⇌NO(g)+12N2H4(g), Kgoal=? by making use of the following information: 1. N2(g)+O2(g)⇌2NO(g), K1 = 4.10×10−31 2. N2(g)+2H2(g)⇌N2H4(g), K2 = 7.40×10−26 3. 2H2O(g)⇌2H2(g)+O2(g), K3 = 1.06×10−10 Express your answer numerically.
Answer:
K = 1.79x10⁻³³
Explanation:
Using Hess's law, it is possible to fin K of a reaction by the algebraic sum of another related reactions.
In the reactions:
1. N2(g)+O2(g) ⇌ 2NO(g), K1 = 4.10×10−31 2.
2. N2(g)+2H2(g) ⇌ N2H4(g), K2 = 7.40×10−26
3. 2H2O(g)⇌2H2(g)+O2(g), K3 = 1.06×10−10
The sum of 1/2 (1) + 1/2 (2) produce:
N2(g) + 1/2O2(g) + H2(g) ⇌ 1/2N2H4(g) + NO(g)
And K' = √4.1x10⁻³¹×√7.4x10⁻²⁶ = 1.74x10⁻²⁸
Now, this reaction + 1/2 (3):
N2(g) + H2O(g) ⇌ NO(g) + 1/2N2H4(g)
And K of reaction is:
1.74x10⁻²⁸×√1.06x10⁻¹⁰ = 1.79x10⁻³³
A sample of 0.3220 g of an ionic compound containing the iodide ion (I-) is dissolved in water and treated with an excess of AgHCO3. If the mass of the AgI precipitate that forms is 0.235 g, what is the percent by mass of I in the original compound? The molar mass of AgI is 234.8 g.
Answer:
39.44 %
Explanation:
Step 1: Write the balanced equation
I⁻(aq) + AgHCO₃(aq) = AgI(s) + HCO₃⁻(aq)
Step 2: Calculate the moles corresponding to 0.235 g of AgI
The molar mass of AgI is 234.8 g/mol.
[tex]0.235g \times \frac{1mol}{234.8g} = 1.001 \times 10^{-3} mol[/tex]
Step 3: Calculate the moles of I⁻ that form 1.001 × 10⁻³ mol of AgI
The molar ratio of I⁻ to AgI is 1:1. The reacting moles of I⁻ are 1/1 × 1.001 × 10⁻³ mol = 1.001 × 10⁻³ mol
Step 4: Calculate the mass corresponding to 1.001 × 10⁻³ mol of I⁻
The molar mass of I⁻ is 126.90 g/mol.
[tex]1.001 \times 10^{-3} mol \times \frac{126.90g}{mol} = 0.1270 g[/tex]
Step 5: Calculate the percent by mass of I⁻ in the original compound
[tex]\frac{0.1270g}{0.3220g} \times 100 \% = 39.44 \%[/tex]
molecules of glass are different from molecules of wood true or false
Which option correctly explains a metallic bond
Answer:
The chemical bond between atoms in metallic elements
Explanation:
Metallic bond is a bond that exist between metallic elements. It does not occur between metals and non metals.
