Answer:
5.1044844 x 10^7/cm^3 = 5E7
Explanation:
The atomic weight and density (at 25 ° C) for copper are 63.5 g/mol or 0.0635 kg/mol and 8,960 kg/m^3
First lets find the value of N, number of atomic sites per cubic meter for copper, from its atomic weight Acu, its density, and Avogadro’s number NA
N = NA x ρ / Acu = 6.023 x 10^23 x 8,960 kg/m^3 / 0.0635 kg/mol = 8.4985953 x 10^28 atoms / m3
Temperature dependency can be given as :
Arrhenius equation
Nv = N e^(-EA/KT)
N = no. of atoms initially
Ev = activation energy
Nv = 8.4985953 x 10^28 atoms / m^3 exp^-(0.9ev/atom /8.617x10-5 eV/(atom-K) x 298 K
Nv = 5.1044844 x 10^13 /m3
vacancies per cm^3 = 5.1044844 x 10^7/cm^3 = 5E7
An object has a mass of 0.0124 kg and a volume of 1893 mm^3. What is its density in grams per cubic centimeter?
Answer:
[tex]d=6.34g/cm^3[/tex]
Explanation:
Hello there!
In this case, since the calculation of density is performed by dividing the mass over volume:
[tex]d=\frac{m}{V}[/tex]
Which gives us a better understanding of the degree of compactness of the object; we can find the required density in grams per cubic centimeter by applying the following dimensional analysis in the aforementioned equation:
[tex]d=\frac{0.0124kg}{1893mm^3} *(\frac{10mm}{1cm} )^3*\frac{1000g}{1kg}\\\\d=6.34g/cm^3[/tex]
Regards!
CHEMISTRY FORM THREE Exercise 2.1 1) Not all metals share the typical metal properties.name a metal that is: a. hard and strong b. malleable at room temperature
a) The strongest metal on the planet is tungsten.
When it comes to tensile strength, tungsten tops all other metals. One of the strongest metals known to man, tungsten has an ultimate strength of 1510 Megapascals.
In addition to having the greatest melting point of any unalloyed metal, tungsten boasts greater strength. Tungsten is frequently employed in electrical and military applications due to its strength.
Tin is a malleable, silvery-white metal that is highly flammable at ambient temperature.
Metal malleability is a complex subject. There is no objective test available to measure this feature, as we previously stated. We most frequently test it for hardness.
The most malleable and ductile metals are gold and silver. Pure gold and silver are too soft to be used to create items that will keep their shape.
Metals may be molded into different shapes, such as thin sheets or foils, without breaking or shattering because they are malleable. They are also ductile, making it simple to draw them into wires.
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List all the metals in the alkaline earth metals group
Answer:
beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
Alkaline earth metals are those that have two valence electrons in their outermost shell.
Barium (Ba), Radium (Ra), Strontium (Sr), Magnesium (Mg), Calcium (Ca), and Beryllium (Be) are the six alkaline earth metals.
By donating their outermost electrons, they take on the noble gas electron configuration, which increases their stability. When electrons are transferred to an atom with an electronegative charge, the alkaline earth metals get a positive charge.
The second column of the periodic table contains alkaline earth metals, which are very reactive metals. These metals are the building blocks of the entire world. These metals are typically found as sulfates in nature.
A few examples of minerals are gypsum, calcium sulfate, epsomite, magnesium sulfate, barite, and barium sulfate.
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What is the name of the charge that orbits the nucleus called?
Answer:
Electrons
Explanation:
"An electron is a negatively charged particle that orbits the nucleus of an atom."
"Electrons are negatively charged particles arranged in orbits around the nucleus of an atom"
Nitrogen monoxide and oxygen can be formed from the thermal decomposition of nitrogen dioxide.
2NO2 (g) = 2NO (g) + O₂(g)
In an experiment, 4 moles of nitrogen dioxide were put into a 1.0 dm³ container and heated
to a constant temperature. The equilibrium mixture contains 0.8 moles of oxygen.
What is the value of the equilibrium constant, Kc?
1.5 POINTS
A
C
E
LU
0.032
0.853
0.426
B
D
0.222
0.356
FINISH QUIZ
Answer:
0.355 moldm^-3
Explanation:
How many grams are in 3.4 moles of Sulfur
Answer:
109.02 grams
Explanation:
Multiply the molar mass of sulfur by the moles: 3.4 * 32.065 = 109.02 grams
sap can be turned into syrup by
Answer: by boiling it
Explanation:
By boiling the sap to remove water, also to concentrate the sugar that makes maple syrup.
Compound composed of sulfur and fluorine is found to contain 45.77% by mass of sulfur is the molar mass of the compound is 140.12 g per mole what is its molecular formula
Answer: Molecular formula is S2F4
Explanation: Assume mass of sample is 100 g.
Then mass of S is 45.77 g and amount of substance is
n = m/M = 45.77 g / 32.07 g/mol = 1.427 mol
MAss of F is 54.23 g and n = 54.23 g / 19 g/mol = 2.854
n(S( : n(F) = 1.427 : 2.854 | : 1.427 gives proportion
n(S) : n(F) = 1:2 , empirical formula is also (SF2)x
Now M(SF2) = 32.07 + 2·19 = 70.07 g/mol
x = 140.12 / 70.07 = 2
Use the data in the table below to calculate the heat of vaporization (AHvap) in kJ/mol of pinene.
Vapor Pressure
(torr)
760
515
340
218
135
Temperature
(K)
429
415
401
387
373
kJ/mol
Use the value of AHyap determined in Part 1 to calculate the vapor pressure of pinene (in torr) at room temperature (23°C)
760
torr
Answer:
41 kJ/mol4 torrExplanation:
Given pinene has a (temperature, vapor pressure) relation (K, torr) = {(373, 135), (429, 760)}, you want the heat of vaporization in kJ/mol and the vapor pressure at room temperature (23 °C).
Clausius–Clapeyron EquationThe Clausius–Clapeyron equation can be used to find the heat of vaporization:
[tex]\ln{P}=-\dfrac{\Delta H_{\text{vap}}}{R}\left(\dfrac{1}{T}\right)+C[/tex]
Solving for ∆H, we find ...
[tex]\Delta H_{\text{vap}}=-\dfrac{R\cdot\ln{\dfrac{P_1}{P_2}}}{\dfrac{1}{T_1}-\dfrac{1}{T_2}}\\\\\\\Delta H_{\text{vap}}=-\dfrac{8.314\cdot\ln{\dfrac{760}{135}}}{\dfrac{1}{429}-\dfrac{1}{373}}\approx 41052.8[/tex]
The heat of vaporization of pinene is about 41 kJ/mol.
Vapor pressureRearranging the above equation to give P1, we have ...
[tex]\ln{\dfrac{P_1}{P_2}}=-\dfrac{\Delta H_\text{vap}}{R}\left(\dfrac{1}{T_1}-\dfrac{1}{T_2}\right) \\\\\\P_1=P_2\cdot e^{-\frac{\Delta H_\text{vap}}{R}\left(T_1^{-1}-T_2^{-1})}[/tex]
Using the same P2 and T2 as above, we find the vapor pressure at room temperature (296.15 K) to be ...
P1 ≈ 4.349 . . . . . torr
The vapor pressure of pinene at room temperature is about 4 torr.
What is the volume of 3.00 M sulfuric aid that contain 9.809 g of H2SO4 (98.09g/mol)
Given :
Molarity of sulfuric acid solution is 3.0 M.
Amount of sulfuric acid present in solution is 9.809 g.
To Find :
The volume of solution.
Solution :
We know, molarity is given by :
[tex]Molarity = \dfrac{number \ of \ moles \times 1000}{Volume\ ( ml )}\\\\M = \dfrac{w \times 1000}{M.M \times V}\\\\3 = \dfrac{9.809\times 1000}{98.09 \times V}\\\\V = \dfrac{1000}{10\times 3}\ ml\\\\V = 33.33 \ ml[/tex]
Therefore, volume required is 33.33 ml .
What can be added to a solution to control the pH?
a base
a liquid
a buffer
an acid
Answer:
liquid
Explanation:
Adjusting pH in Water
Pure or distilled water has a pH level of 7, which means it is neutral. If you want to increase the pH of water, you must add an alkaline substance, such as baking powder, to it. If you want to decrease the pH of water, you add an acidic substance, such as lemon juice, to it
A buffer can be added to a solution to control the pH. The correct option is c.
What is pH?PH is potential hydrogen. It is the value of how acidic or alkaline, the solution is.
The pH scale is consisting of 1 to 14 measure numbers, a pH less than 7 is acidic and a pH more than 7 is basic.
A buffer is a solution that maintains the pH of any solution.
Thus, the correct option is C, a buffer.
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Form a group and discuss the possible reasons why EA, is a positive quantity for oxygen atom.
Answer:
Possible reasons why EA, or electronegativity, is a positive quantity for oxygen atom include:
Explanation:
Which substance reacts with an acid or a base to control pH?
buffer
salt
titration
sodium ion
Answer:
Your answer would be a buffer, they control pH levels.
Explanation:
Buffer is a substance that reacts with an acid or a base to control pH. Hence, option A is correct.
What is pH?pH is a measure of how acidic/basic water is.
Buffers are solutions that resist a change in pH after adding an acid or a base. Buffers contain a weak acid (HA) and its conjugate weak base (A−).
Hence, option A is correct.
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How are fossils useful to scientists?
Answer:
Yes they are
Explanation:
Answer:
Fossils are traces of ancient life. Scientists use fossils to gather information about the lives and evolutionary relationships of organisms, for understanding geological change.
How many Liters of a 4.5 M HCL solution can be prepared by using 250.0 mL of a 12.0 M HCl solution?
Answer:
0.667 L
Explanation:
From the question given above, the following data were obtained:
Initial volume (V₁) = 250 mL
Initial concentration (C₁) = 12 M
Final concentration (C₂) = 4.5 M
Final volume (V₂) =?
The final volume of the solution can be obtained by using the dilution formula as illustrated below:
C₁V₁ = C₂V₂
12 × 250 = 4.5 × V₂
3000 = 4.5 × V₂
Divide both side by 4.5
V₂ = 3000 / 4.5
V₂ = 667 mL
Finally, we shall convert 667 mL to L. This can be obtained as follow:
1000 mL = 1 L
Therefore,
667 mL = 667 mL × 1 L / 1000 mL
667 mL = 0.667 L
Thus, the volume of the solution prepared is 0.667 L
word equation for k2co3->k2o+co2
Answer:
potassium carbonate -> potassium oxide + carbon dioxide
Explanation:
remember to look at your periodic table, located each element so in this case you would locate k,c and o which are potassium, carbon and oxygen. From there you use nomenclature rules to get your answer.
Which of the following statements describes all
exothermic reactions?
A. Exothermic reactions form gases.
B. Exothermic reactions require a catalyst.
C. The energy of the reactants is lower than the
energy of the products,
D. The energy of the reactants is higher than the
energy of the products.
Answer:
D
Explanation:
The energy of the reactants is higher than the energy of the products.
PLS HELP DUE NOW
What is the pH of each solution?
[H3O+] = 4.78 x 10-2 M
and
pOH = 4.56
Answer:
First solution pH = 1.32
Second solution pH = 9.44
Explanation:
For the first solution:
[H₃O⁺] = 4.78 x 10⁻² MWhich is the same as saying 4.78 x 10⁻² M is [H⁺].
Knowing [H⁺], we can now calculate the pH:
pH = -log[H⁺]pH = 1.32As for the second solution, we can calculate the pH by keeping in mind the relationship between pOH and pH:
pOH + pH = 144.56 + pH = 14pH = 9.44When a person weighs himself in pounds, which system of measurement is he using?
Answers: customary or metric
Answer:
it is the British imperial and united states customary systems
Calculate the pH if the [OH-] concentration is 5.9x10-1 M.
How many moles of C6H12O6 are needed to produce 38.44 grams of CO2? Round your answer to three digits after the decimal point.
C6H12O6 + 6 O2 à 6 CO2 + 6 H2O
Explanation:
38.44 g CO2 = 0.873 mol CO2
0.873 mol CO2 × (1 mol C6H12O6 / 6 mol CO2)
= 0.146 mol C6H12O6 x (180.56 g C6H12O6/ 1 mol C6H12O6)
= 26.303 gm
What volume of solution must be added to 4.0 mol of NaCl to make a 1.2 M solution?
Answer:
[tex]\boxed {\boxed {\sf 3.3 \ liters}}}[/tex]
Explanation:
Molarity is a measure of concentration in moles per liter.
[tex]molarity=\frac{moles \ of \ solute}{liters \ of \ solution}}[/tex]
The solution has a molarity of 1.2 M or 1.2 moles per liter. There are 4.0 moles of NaCl, the solute. We don't know the liters of solution, so we can use x.
molarity= 1.2 mol/L moles of solute= 4.0 mol liters of solution =xSubstitute the values into the formula.
[tex]1.2 \ mol/L = \frac{4.0 \ mol}{x}[/tex]
Since we are solving for x, we must isolate the variable. Begin by cross multiply (multiply the 1st numerator and 2nd denominator, then the 1st denominator and 2nd numerator.
[tex]\frac {1.2 \ mol/L}{1}=\frac{ 4.0 \ mol}{x}[/tex]
[tex]4.0 \ mol *1=1.2 \ mol/L *x[/tex]
[tex]4.0 \ mol = 1.2 \ mol/L *x[/tex]
x is being multiplied by 1.2 moles per liter. The inverse of multiplication is division, so divide both sides by 1.2 mol/L
[tex]\frac{4.0 \ mol}{1.2 \ mol/L} = \frac{1.2 \ mol/L *x}{1.2 \ mol/L}[/tex]
[tex]\frac{4.0 \ mol}{1.2 \ mol/L}=x[/tex]
The units of moles (mol) will cancel.
[tex]\frac{4.0 }{1.2 } \ L =x[/tex]
[tex]3.33333333 \ L=x[/tex]
The original measurements both have 2 significant figures, so our answer must have the same. For the number we found, this is the tenths place.
The 3 in the hundredth place tells us to leave the 3 in the tenths place.
[tex]3.3 \ L\approx x[/tex]
Approximately 3.3 liters of solution are needed to make a 1.2 M solution with 4.0 moles of sodium chloride.
Today we are going to perform a titration. What is an acid-alkali titration?
a) A measurement apparatus
b) An analytic method
c) A chemical reaction
LABSTER
Answer:
A chemical reaction
Explanation:
You're doing acid-alkali. Acid is like a ph.
Titration is a method used to prepare salts if the reactants are soluble. Concentration and volumes of reactants can be calculated from titrations. The concentration of an acid or alkali can be calculated by carrying out an experiment called a titration.
We have that for the Question "Today we are going to perform a titration. What is an acid-alkali titration?" it can be said that
From the question we are told
Today we are going to perform a titration. What is an acid-alkali titration?
a) A measurement apparatus
b) An analytic method
c) A chemical reaction
Generally
acid-alkali titration is a popular chemical reaction that is used to obtain salts and this method is also used to determine many other variables of the reactants
Therefore
An acid-alkali titration is a
chemical reaction
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as a sample of water is heated, the kinetic energy of its molecules increases then, the energy is used to overcome the attractions between the molecules so that they are no longer help close together. Which sections of the heating curve illustrate this process
The sections of the heating curve illustrate this process Section A followed by B. Therefore, option D is correct.
What is the heating curve ?The term heating curve is defined as the graphical representation of the correlation between heat input and the temperature of a substance.
At section, A solid Ice at temperature 0°C can heat for about 10 mins and all the energy generated from heating up the ice is used to split the bonds which binds the ice together as a solid.
At Section, B the liquid water at 100°C covert to vapor because the heat energy required here split the bond between the water molecules then they are move in random directions as vapor.
Thus, option D is correct.
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Your question is incomplete, probably your question was
As a sample of water is heated, the energy is used to overcome the attractions between the molecules so that they are no longer held close together and can move in random directions. Then, the kinetic energy of its molecules increases. Which sections of the heating curve illustrate this process?
As a sample of water is heated, the energy is - 1
Image is attach below
When the conductivity is at a minimum, what must be true about the amount of Ba(OH)2?
When the conductivity is at a minimum, the true thing about the amount of Ba(OH)₂ is that the amount of the two reactants are the same when conductivity is low.
What is conductivity?The ability of an aqueous solution to carry an electric current is measured by its conductivity. Ionic strength is measured by conductivity monitors. In automated chromatography systems, conductivity is the main input control parameter used to enable the generation of salt gradients or to control buffer dilution or in-line buffer preparation.
Conductivity monitors can be used to automate and monitor cleaning and equilibration procedures. It's important to remember that temperature affects measurements of conductivity and pH.
When conductivity is low, the amounts of the two reactants are equal. Between the reactants, there are no excesses. The aqueous solution cannot dissolve the precipitate BaSO₄. Since there are no ions, the conductivity is at its lowest.
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Complete question
The Ba(OH)₂ dissociates as Ba+2 + 2 OH-. H₂SO₄ dissociates as 2 H+ + SO₄-2. When the conductivity is at a minimum, what must be true about the amount of Ba(OH)₂ compared to H₂SO₄
What is also known as neutralization? 1. Acid-base 2. Redox 3. Precipitation
Answer:
acid base
Explanation:
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What does the red line running through Earth represent?
Answer: The Equator because it divides the Earth into the Northern and Southern hemispheres.
Explanation:
Please i need help with this it is Which of the following is not a property of matter that you could use to distinguish one substance from another.
Answer:
I believe it's mass? I may be wrong though...
Carbon disulfide is a colorless, volatile, highly flammable liquid with a very unpleasant smell that is used as a solvent in some laboratory applications.
a. True
b. False
If 160 grams of a 200-gram sample of gold-198 decay in 6.25 days, what is the half-life of gold-198?
The half-life of gold-198 is 2.77 days
What is half-life of gold-198?Gold-198 decays with a half-life of 2.7 days to stable mercury-198 by emission of ß particles of maximum energy 0.960 Mev and Y -rays of energies 0.412, 0.68 and 1.09 Mev as shown schematically in In a gold grain, the thickness of the enveloping sheath of platinum is such that the ß particles: The amount of time it takes to disintegrate by half an initial amount. For a given reaction, a reactant's half-life t1/2 is the time it takes for its concentration to reach a value which is the arithmetic mean of its initial and final (equilibrium) value.Since Au-198 is 200 g originally and it decays to 160 g, so 40g leftthe fraction decay is 40/200 = 0.2the time base is 6.25 daysln0.2/6.25 = -0.25k=ln2/half life therefore half-life = ln2/k = ln2/0.25half life = 2.77 daysSo, half life of gold is 2.77 daysTo learn more about half-life of gold-198 refers to:
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