Answer:
10.52g KOH
Explanation:
250.0 ml X 1L/1000ml X 0.75 mol KOH/1L X 56.105gKOH/1 mol KOH =10.52g KOH
Compute the concentration (count per volume) of vacancies in copper at room temperature if the lattice parameter of FCC copper is 0.3615 nm at room temperature (25oC, 298 K), and the activation energy to form a single vacancy is 0.9 eV. Use 8.617x10-5 eV/(atom-K), exactly, as Boltzmann's Constant.
Note: You could look up the density and atomic weight of copper to compute room temperature atom concentration you need for this problem.
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
12. What is the empirical formula for C10H30O5?
Answer:
Just use a text book.. So that you get the concept
The explosion of a bomb and the toxicity of a deadly poison are both chemical reactions.
•True
•False
Answer:
True
Explanation:
both are chemical, got it right on my test
(b) C.H.(g) + O2(g)
CO2(g) + H2O(g) balance ?
The complete question is: [tex]CH_{4}(g) + O_{2}(g) \rightarrow CO_{2}(g) + H_{2}O(g)[/tex] balance?
Answer: [tex]CH_{4}(g) + 2O_{2}(g) \rightarrow CO_{2}(g) + 2H_{2}O(g)[/tex] is a balanced equation.
Explanation:
A chemical equation which contains same number of atoms on both reactant and product side is called a balanced chemical equation.
For example, [tex]CH_{4}(g) + O_{2}(g) \rightarrow CO_{2}(g) + H_{2}O(g)[/tex]
Here, number of atoms on reactant side are as follows.
C = 1H = 4O = 4Number of atoms on product side are as follows.
C = 1H = 2O = 3To balance this equation multiply [tex]O_{2}[/tex] by 2 on reactant side and multiply [tex]H_{2}O[/tex] by 2 on product side. Hence, the equation can be re-written as follows.
[tex]CH_{4}(g) + 2O_{2} \rightleftharpoons CO_{2}(g) + 2H_{2}O(g)[/tex]
Here, number of atoms on reactant side are as follows.
C = 1H = 4O = 4Number of atoms on product side are as follows.
C = 1H = 4O = 4Since, there are same number of atoms on both reactant and product side. So, this equation is a balanced equation.
Thus, we can conclude that [tex]CH_{4}(g) + 2O_{2}(g) \rightarrow CO_{2}(g) + 2H_{2}O(g)[/tex] is a balanced equation.
_ S8 +_02 +_ SO3
How many grams of sulfur are needed to produce 167.82 grams of sulfur trioxide?
6.547 g sulfur
4302 g sulfur
67.22 g sulfur
537.7 g sulfur
URGENT PLEASE HELP
1) The following balanced chemical equations are for based on the combustions of various fuels. Calculate the heats of combustion for each reaction
a. C2H5OH(l) + 3O2(g) à 2CO2(g) + 3H2O(g)
b. 2C4H10(g) + 13O2(g) à 8CO2(g) + 10H2O(g)
c. C3H8(g) + 5O2(g) à 3CO2(g) + 4H2O(g)
2) Express the heats of combustion from the above reactions as energy changes per mole of fuel combusted. State the reason why energy changes are often expressed per mole of reactant.
3) An Electric Generator burns gasoline to produce electricity. The balanced equation is below:
2C8H18(l) + 25O2(g) à 16CO2(g) + 18H2O(g)
a. Calculate the energy change for the burning of gasoline.
b. If the generator produces 2000kJ of electrical energy for every mole of gasoline combusted calculate the efficiency of the generator.
Answer:
Explanation:
1) The following balanced chemical equations are for based on the combustions of various fuels. Calculate the heats of combustion for each reaction a. C₂H₂OH + ...
PLEASE HELP! 80 POINTS
Create a VESPR drawing for
NH3
CH20
N3
SO2CI2
BrF5
The VSEPR drawing for the compounds in the question are shown in the images attached.
What is the VSEPR theory?We have to know that according to the valence shell electron pair repulsion theory, the structure of the molecule can be found by looking at the number of electron pairs that surround the central atom in the molecule.
Now the structure of the compounds as we can see in the images that ahve been attached are based on the Vlence Shell electron pair repulsion drawing for each of the compounds that we have mentioned in the question.
We can see that the structure of the compound must have a central atom and then the other atoms in the molecule are arranged around the central atom of the molecule.
The molecule would have a definite shape that is based on the number of electron shells in the molecule.
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Which BEST represents a balanced equation?
A. Mg + 2O₂ --> 2MgO
B. Mg + O₂ --> 2MgO
C. 2Mg + O₂ --> 2MgO
D. 3Mg + 2O₂ --> 2Mg₃O₂
Answer:
b
Explanation:
because it is the balanced one
A container is filled with helium gas. It has a volume of 2.25 liters and contains 9.00 moles of helium. How many moles of helium could be held in a 1.85 liter container at the same temperature and pressure?
Answer: There are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.
Explanation:
Given: [tex]V_{1}[/tex] = 2.25 L, [tex]n_{1}[/tex] = 9.0 mol
[tex]V_{2}[/tex] = 1.85 L, [tex]n_{2}[/tex] = ?
Formula used to calculate the moles of helium are as follows.
[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\[/tex]
Substitute the values into above formula as follows.
[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\\frac{2.25 L}{9.0 mol} = \frac{1.85 L}{n_{2}}\\n_{2} = \frac{1.85 L \times 9.0 mol}{2.25 L}\\= 7.4 mol[/tex]
Thus, we can conclude that there are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.
Which of these outcomes is a positive effect of ecotourism on the
environment?
A. Ecotourism can harm delicate ecosystems.
O B. Ecotourism takes money away from conservation.
C. Ecotourism can exploit local peoples and increase crime.
D. Ecotourism helps pay for conservation efforts.
Answer: D- ecotourism helps pay for conservation efforts
Explanation:
says help and the others exploit and harm
Which of the following compounds undergoes
an addition reaction with chlorine?
A. C2H4
B. C2H6
C. C2H5OH
D. CH3COOH
Answer:
A. C2H4
Ethene
step by step explanation:
Drawings/ diagram of polyatomic ions (structural formula)
PLEASE HELP I NEED IT
GIVING 100 points
PLEASE IT MAKE FAIR I NEED IMAGES OF IT
Polyatomic ions are ions made up of more than one atom.
What are Atoms?
Atoms are the smallest particles of matter that make up all objects. They are composed of protons, neutrons, and electrons. Protons and neutrons make up the nucleus of the atom, while electrons orbit around the nucleus. Atoms are the basic units of matter and are the building blocks of all living and nonliving things.
Polyatomic ions are ions that consist of two or more atoms covalently bonded together and carrying a net electric charge. Examples of polyatomic ions include nitrate (NO3−), sulfate (SO42−), phosphate (PO43−), and carbonate (CO32−).
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What is the ratio between the numbers 30 and 90
Rank the following fibers on the degree to which a dye will bind to the fabric and resist fading.
rank the following fibers on the degree to which a dye will bind
Answer:
polymer mear least receptive to dye
,
Plants help prevent erosion by?
A.) plants to not help prevent erosion.
B.) plowing across the slope to create slopes.
C.) anchoring soil in place so is not blown or washed away.
D.) allowing soil to be blown or washed away.
What ions are formed with AgNO3 dissolves in water? How does water stabilize the ions?
Answer:
Explanation:
In water, silver nitrate (AgNO3) dissolves to generate the ions Ag+ (silver) and NO3- (nitrate). When the substance is dissolved in water, the ions are separated and become solvated, or surrounded by water molecules. Water molecules' oxygen atoms join the metal ion in a coordinate covalent bond that gives the metal ion a pair of electrons. By preventing it from interacting with other ions or molecules in the solution, this aids in stabilising the metal ion. As a result of their hydrogen bonds with the water molecules around them, the nitrate ions are likewise stabilised in solution.
Help I need to finish this in 10 minutes!
Answer:
this is a animal cell..I hope you received this on time
One of the many isotopes used in cancer treatment is , with a half-life of 2.70 d. Determine the mass of this isotope that is required to give an activity of 205 C
The mass of this isotope that is required to give an activity of 205 C is 1.187 mg.
What is isotope?Isotope is defined as two or more different types of atoms with the same atomic number, but different nucleon values at different positions on the periodic table. Isotopes are forms of an element that have the same number of protons and electrons but differing numbers of neutrons.
Let's first translate the 2.70 day half life into seconds to obtain the following half life:
T(1/2) = 233300 sec
By subtracting the half life from ln(2)? = 2.971x10⁻⁶, determine the decay constant.
Now that we have the decay constant, we can solve for the quantity of isotopes required to produce an activity of 290 Ci (which is equal to 1.073x10¹³ decays per second) using the rate of decay equation. Due to the fact that we are discussing the beginning action, t = 0 for this equation.
-1.073x10³ = -A?e^(-? x 0)
Since we are losing isotopes rather than acquiring them, the left side of the equation is negative.
Fill in the blanks: A = 3.611x10¹⁸ isotopes
Find out how much mass is contained in all of these isotopes now.
(3.611x10¹⁸) x(198u) = 7.150x10²⁰ u
To get the final result, convert to mg at this point:
1.187 mg
Thus, the mass of this isotope that is required to give an activity of 205 C is 1.187 mg.
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What mass of 65% and 20% nitric acid must be mixed to produce 4.5 kg of 30% nitric acid?
The mass of 65% and 20% nitric acid that must be mixed to produce 4.5 kg of 30% nitric acid are 1.306 kg and 3.189 kg respectively.
What is the volume of 4.5 kg of 30% nitric acid?The volume of 4.5 kg of 30% nitric acid is determined using the formula below:
Volume = mass/densityThe density of 30% nitric acid is 1.18 g/mL
The mass of the 30% nitric acid is 4.5 kg or 4500 g
Hence, the volume will be:
The volume of 30% nitric acid = 4500 / 1.18
The volume of 30% nitric acid = 3813.56 mL
The volume of 65% and 20% nitric acid required is then determined.
Let the volume of the 65% and 20% nitric acid be x and y respectively;
x + y = 3813.56 ---(1)
amount of acid in 3813.56 ml solution = 30% * 3813.56
amount of acid in 3813.56 ml solution = 1144.07 mL
therefore;
60% * x + 20% * y = 1144.07 mL
0.6x + 0.2y = 1144.07 ----(2)
Solving for x and y in the two equations
From (1), x = 3813.56 - y
Substitute x = 3813.56 - y in (2)
0.6(3813.56 - y) + 0.2y = 1144.07
0.4y = 1144.07
y = 2860.18 mL
x = 3813.56 - 2860.18
x = 953.38 mL
The mass of the acids required is then determined as follows:
The density of 60% nitric acid is 1.37 g/mL
Mass of 60% nitric acid required = 953.38 mL * 1.37 g/mL
Mass of 60% nitric acid required = 1306 g or 1.306 kg
The density of 20% nitric acid is 1.115 g/mL
Mass of 20% nitric acid required = 2860.18 mL * 1.115 g/mL
Mass of 20% nitric acid required = 3189 g or 3.189 kg
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Four hundred and fifty two
bullfrogs live in a marsh that
is sixty eight square
kilometers. What is the
population density of the
bullfrogs per
square
kilometer?
WILL GIVE BRAINLIEST
Answer: 6.65bullfrogs/km²
Explanation:
The population density of the bullfrogs per square kilometer will be gotten by dividing the number of bullfrogs that live in the marsh by the land area. This will be:
= 452 bullfrogs/68km²
= 6.65bullfrogs/km²
The population density of the bullfrogs per square kilometer is 6.65.
Use the solubility generalizations on the information page to predict if one or more precipitates will form when aqueous solutions of ammonium sulfate ((NH4)2SO4) and aluminum nitrate (Al(NO3)3) are mixed. Write the formula of any precipitate that could form in one of the boxes. If a box is not needed, leave it blank. If no precipitate is predicted, leave both boxes blank.
Answer:
3 (NH4)2SO4(aq) + 2 Al(NO3)3(aq) → 6 NH4NO3(aq) + Al2(SO4)3(aq)
Explanation:
In solubility rules, all ammonium and nitrates ions are solubles and all sulfates are soluble except the sulfates that are produced with Ca²⁺, Sr²⁺, Ba²⁺, Ag⁺ and Pb²⁺. That means the NH4NO3 and the Al2(SO4)3 produced are both soluble and no precipitate is predicted.
The reaction is:
3 (NH4)2SO4(aq) + 2 Al(NO3)3(aq) → 6 NH4NO3(aq) + Al2(SO4)3(aq)For a solution with OH- concentration of 5.6 x 10-7 M, calculate the pH AND classify the solution of acidic, neutral, or basic.
a. 7.7 basic
b. -6025 acidic
c. 6.25 acidic
d. 0 basic
Answer:
la respuesta es la letra: a
The hydroxide of the solution can give the pOH of the solution used to determine the pH of the solution. The solution has a pH of 7.7 and is basic. Thus, option a is correct.
What is pH?The hydrogen potential of the solution is given by the concentration of the hydrogen or the hydroxide concentration dissolved in the solution.
The pH or the pOH of the solution can be used to determine the acidic and basic nature of the solution based on the range in which it lies.
If the pH of the solution lies below 7 then they are said to be acidic, whereas above 7 are alkaline in nature.
Given,
[OH⁻] =5.6 x 10⁻⁷ M
First, pOH is calculated as,
pOH = -log [OH⁻]
pOH = - log (5.6 x 10⁻⁷ M)
pOH = 6.252
Now, pH from pOH is calculated as:
pH = 14 - pOH
pH = 14 - 6.252
pH = 7.748
Therefore, option a. the pH of the solution is 7.7 and is basic.
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Phenylephrine is a nasal decongestant and is the active ingredient in Sudafed, which contains phenylephrine hydrochloride (PEHCl).
a. True
b. False
Answer:
True
Explanation:
It is TRUE that Phenylephrine is a nasal decongestant and is the active ingredient in Sudafed, which contains phenylephrine hydrochloride (PEHCl).
Phenylephrine is considered a prescription formula that is used in the production of Sudafed. Due to its direct-acting sympathomimetic amine property, it is used as a significant ingredient in the formation of Sudafed, a drug usually prescribed for nasal decongestion from regular cold, upper respiratory allergies, hay fever, etc.
Plz help ASAP it’s dude soon
Given the Kf for water is 1.86°C/m, a 2.2 molal solution of glucose, C6H12O6, will have a new freezing point of...
A)4.09 °C
B) -4.09 °C
C) 1.18 °C
Answer:
a
Explanation:
When a local house was on fire, the firefighters were able to save most of it by dousing the house with water. What will happen when forensic cientists Investigate this fire? A. The water will have destroyed most of the critical evidence. B. The water will not interfere with the testing of flammable liquids. C. The point of origin will be impossible to determine due to wet walls. D. Most flammable liquids will have been washed off of furniture and floors.
Answer:
The water will not interfere with the testing of flammable liquids.
When forensic scientists investigate this fire, the water will not interfere with the testing of flammable liquids. Therefore, option B is correct.
What is flammable liquid ?A flammable liquid is one with a flash point at or below the nominal threshold temperatures specified by a variety of national and worldwide standards organizations. This means that it can easily ignite in air at room temperature.
our home probably contains a sizable number of flammable liquids. Rubing alcohol, nail polish remover, hand sanitizer, and wart remover are some items that quickly catch fire in addition to gasoline and lighter fluid.
Gasoline is one of the most hazardous liquids in the home and causes over 8,000 home fires each year. One explanation is the frequent inappropriate storage of items in garages. Store it at room temperature, away from heat sources like your hot water heater or furnace, in a UL-approved container.
Thus, option B is correct.
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Which animal is a primary consumer?
brown lemming
short tailed weasel
snowy owl
lichen
Snowy Owl i Think or weasel
If 4.00 moles of gasoline are burned according to the chemical
reaction below, what volume of oxygen at STP is needed for complete
combustion?
2C2H18(1) + 2502(g) → 16CO2(g) + 18H2O(g)
Answer: The volume of oxygen at STP is needed for complete given combustion is 1121.28 L.
Explanation:
The given reaction equation is as follows.
[tex]2C_{2}H_{18}(l) + 25O_{2}(g) \rightarrow 16CO_{2}(g) + 18H_{2}O(g)[/tex]
This shows that 2 moles of gasoline requires 25 moles of . Hence, moles of oxygen required to react with 4 moles of gasoline are calculated as follows.
[tex]\frac{25 mol O_{2}}{2 mol C_{2}H_{18}} \times 4 mol C_{2}H_{18}\\= 50 mol O_{2}[/tex]
At STP, the pressure is 1 atm and temperature is 273.15 K. Therefore, using ideal gas equation the volume of oxygen is calculated.
PV = nRT
where,
P = pressure
V = volume
n = no. of moles
R = gas constant = 0.0821 L atm/mol K
T = temperature
Substitute the values into above formula as follows.
[tex]PV = nRT\\1 atm \times V = 50 mol \times 0.0821 L atm/mol K \times 273.15 K\\V = 1121.28 L[/tex]
Thus, we can conclude that volume of oxygen at STP is needed for complete given combustion is 1121.28 L.
What is the percent by mass of a solution in which 60, of are dissolved in sufficient water to make 100 g of solution?
Answer:
the answer is C
Explanation:
helppppp meeeeeeeeeeeeeeeeeeeeeeeeeeeee ill mark brainlist
1.Analyze the food web. If the frog population decreases, what impact will this likely have on the food web?
A.The food chain will remain unchanged.
b.The population of grasshoppers will decrease.
c.The population of grasshoppers will increase.
d.The population of snakes will increase.
Answer: C
Explanation:
I think the answers correct because, A says that the food chain will stay the same, but thats not true because, the frog ate most of the insects. And B says the population will decrease, but that doesn't make sense because a animal that eats grasshoppers would no longer be there. And C says that the population will increase and i think that correct because, one animal that does eat the grasshopper wouldn't be there so the grasshoppers will increase in population. And D says the population of snacks will increase but that was one of the foods the snacks ate so they would decrease because they lost one species to eat off of.
Hope This Helps!
9. Triacylglycerols are
A.soluble in water
B.insoluble in water
C.soluble in water at elevated temperature
D.partially soluble in water
Answer:
b. insoluble in water
Explanation:
triacylglycerols are insoluble in water