Answer:
28.1 moles (three sig digits)
Explanation:
Using Ideal Gas Law
PV = n RT looking for 'n' R = .082057366 L-atm/K-mole
15.0 * 45.0 = n * .082057366 * 293
n = 28.1 Moles
The number of moles of helium that are in a 45.0-liter tank at 293 K and 15.0 atm is 28.1 Moles.
What are moles?Moles is the measuring unit that measures the quantity of a substance. Moles is a SI unit.
Helium is the lightest gas, which is used in the tires of an airplane if it is filled in the balloons, the balloon flies in the sky.
Given the volume is 45.0 liter
The pressure is 15.0 atm.
The temperature is 293 K
To calculate the moles, we will use the formula of an ideal gas:
PV = n RT
R = .082057366 is the gas constant.
We have to calculate the n
Putting the values in the equation
15.0 x 45.0 = n x .082057366 x 293
n = 28.1 Moles.
Thus, the moles of helium is n = 28.1 Moles.
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Which energy profile best shows that the formation of NO2 requires 33.1
kJ/mol?
The energy profile representing the reaction of the formation of NO2 is energy profile B; option D.
What is an energy profile diagram?An energy profile diagram is a diagram which illustrates in the form of a graph the energy changes that occur as reactant molecules react to form products.
An energy profile has energy of the molecules plotted on the y-axis and the reaction pathway or the reaction progress on the x-axis.
The shape of an energy profile depends on whether the reaction is an endothermic or exothermic reaction.
An exothermic reaction will have the energy of reactants higher than that of products, whereas an endothermic reaction will have the energy of products higher than the reactants.
The formation of NO2 is an endothermic reaction which requires 33.1kJ/mol of energy to complete.
Therefore, the energy profile representing the reaction is energy profile B.
In conclusion, an energy profile diagram shows energy changes that occur in a reaction graphically.
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Write a balanced chemical equation for the reaction of solid vanadium(V) oxide with hydrogen gas to form solid vanadium(III) oxide and liquid water.
V₂O₅ (s) + 2H₂ (g) → V₂O₃ (s) + 2H₂O(l) is the balanced chemical equation for the reaction of solid vanadium(V) oxide with hydrogen gas to form solid vanadium(III) oxide and liquid water.
What is Balanced Chemical Equation ?The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.
The word based equation is
Vanadium(V) oxide + Hydrogen gas → Vanadium (III) oxide + Water
Now write the chemical equation
V₂O₅ (s) + 2H₂ (g) → V₂O₃ (s) + 2H₂O(l)
Reactant side Product side
V = 2 V = 2
O = 5 O = 5
H = 4 H = 4
We can see that the number of atoms on reactant side is equal to the number of atoms on product side. So the given equation is balanced.
Thus from the above conclusion we can say that V₂O₅ (s) + 2H₂ (g) → V₂O₃ (s) + 2H₂O(l) is the balanced chemical equation for the reaction of solid vanadium(V) oxide with hydrogen gas to form solid vanadium(III) oxide and liquid water.
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below shows the dimensions of two colored cubes.
Dimensions of Cubes
Cube Side (cm) Mass (g)
Red: 4 12
Green: 3 10
Which cube is denser?
Red, because it has more volume and more amount of matter
Green, because it has less volume and less amount of matter.
Red, because it has less volume and more amount of matter
Green, because it has less volume and more amount of matter.
Green, because it has less volume and less amount of matter.
What is density?Density is the mass of a material substance per unit volume. d = M/V, where d is density, M is mass, and V is volume, is the formula for density. Grams per cubic centimeter are a typical unit of measurement for density.
Because it enables us to predict which compounds will float and which will sink in a liquid, density is a crucial notion. If an object's density is lower than the liquid's, it will often float.
The dimensions of two colored cubes.
Red: 4 12
Green: 3 10
density = mass/volume
so compare
[tex]12/4^{3}[/tex] and [tex]10/3^{3}[/tex]
None of the choices is the real reason. But is the closest. It is green because 10/27 > 12/64
But red would have been denser for a side of 3.9, and green would still have had less volume and less matter.
Green, because it has less volume and less amount of matter.
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When a hydrogen atom is part of a molecular structure, it is always a ___________ atom.
Answer:
terminal
Explanation:
When a hydrogen atom is part of a molecular structure, it is always a terminal atom.
1. Explain why halogens are rarely found in native state?
Halogens are rarely found in native state because halogens are highly reactive.
What is Halogens ?The group 17 elements are known as Halogen group. These elements include Fluorine, Chlorine, Bromine, Iodine and Astatine. Halogens react with metals to form salts. Halogens are non metals. Halogens are highly reactive and halogens are never found in pure form. Halogens not occur in free state.
How many valence electron are present in Halogens ?Halogens have seven valence electrons in the outermost shell. The electronic configuration of Halogen is ns² np⁵.
Thus from the above conclusion we can say that Halogens are rarely found in native state because halogens are highly reactive.
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Hydrocarbons (typically petroleum products), which separate in water and have a Specific Gravity less than one, represents a significant hazard to firefighters. Why
Hydrocarbons (typically petroleum products), which separate in water and have a Specific Gravity of less than one, represent a significant hazard to firefighters. Why?
In water, hydrocarbons float to the surface. Water has limited impact on Class B Flammable Liquids and Gases fires, unless water is used to supply a Class B foam/water mixture that can slow the spread of flammable vapors and allow extinguishment by excluding oxygen. Hydrocarbons emit flammable vapors with a significant risk of fire.Describe hydrocarbons.Any member of the class of organic chemical compounds known as hydrocarbons only includes the atoms carbon (C) and hydrogen (H). The hydrogen atoms bond to the carbon atoms in a variety of ways to create the compound's structural framework.
What percentage of crude oil is made up of hydrocarbons?Although there could be thousands of different hydrocarbon molecules in a given crude oil, these descriptions only focus on the type of hydrocarbon that predominates in the combination. Typically, each sort of molecule can be found in all naturally occurring crude oils.
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6) What is the pH of a solution with [H3O+] = 1 × 10-9 M?
A) 1.0 × 10-5
B) -9.0
C) 5.0
D) -5.0
E) 9.0
Answer:
E) 9.0
Explanation:
pH = -log [1×10^-9] = 9
Draw an atomic structure of Sodium (Na). What are sub-atomic particles?
Sodium represents by the (Na).
A gas diffuses 1/8 times faster than hydrogen gas. what is the molar mass of the gas?
129.02 g/mol
136.44 g/mol
140.81 g/mol
145.45 g/mol
Answer:
129.02 g/mol.
Explanation:
We apply grahams law of diffusion:
1/8 = √2.016/√m where m = molar mass
√m = 8√2.016
m = (8√2.016) = 129.02 g/mol.
Which four items are changes in the hazard communication standard for chemical labels and sds?.
The four items that change in the hazard communication standard for chemical labels and SDS
Product identifier.Signal word.Hazard statement.Pictograms.Precautionary statement.This is further explained below.
What is the hazard communication standard?Generally, The Hazard Communication Standard (HCS) was developed to ensure that employees have the "right to know" about any possible dangers that may be related to the work that they do. The HCS is a preventative strategy that is meant to distribute information to employees and employers about the health dangers that are associated with the chemicals that they handle and the protection that is necessary.
In conclusion, Hazard communication labels and SDS product identifiers have undergone four changes as a result of the new standard. The term serves as a signal to the driver. There is a risk. Pictograms. Statement of caution.
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Chlorine gas is applied at a rate of 40 pounds per day to a well operating at 1250 gpm. What is the chlorine dosage for this well, expressed in parts per million
2.7 is the chlorine dosage for this well, expressed in parts per million.
Unlike municipal water, well water does not go through a water treatment facility. That implies that it could be contaminated with poisons like lead, coliform bacteria, volatile chemical compounds, and others. chlorination in well water is done to fulfill the role that chlorine plays in municipal sources' water disinfection processes.
It is advised to start with a chlorine concentration of 50 to 100 parts per million (ppm).
Bacterial pollutants are eliminated from well water, well casings, holding tanks, and the entire water delivery system via shock chlorination. To shock chlorinate, a well driller with a license is trained.
Algae have been linked to green water, and they may thrive in both surface water and groundwater wells even in the absence of sunshine. Algae can color the water in both the pre-and post-decomposition stages with a variety of hues, including green, brown, and reddish.
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Can someone fill this out pleaseee for me
Filling out the table below following the outlined order:
Calcium - symbol = Ca; Group =2; Period = 4; Ar = 134; Am =40.078u; Ph = solid; Density = 1.55; Bp = 1757K; Mp = 1115K.Vanadium - symbol = V; Group =5; Period = 4; Ar = 197; Am =50.9415u; Ph = solid; Density = 6.11; Bp = 3680K; Mp = 2183K.Manganese - symbol = Mn; Group =7; Period = 4; Ar = 127; Am = 54.938044u; Ph = solid; Density = 7.21; Bp = 2334K; Mp = 1519K.Cobalt: - symbol = Co; Group =9; Period = 4; Ar = 125; Am =58.933195 u; Ph = solid; Density = 8.90; Bp = 3200K; Mp = 1768K.Zinc: - symbol = Zn; Group = 12; Period = 4; Ar = 134; Am =65.38 u; Ph = solid; Density = 7.14; Bp = 1180K; Mp = 692.68K.Arsenic: - symbol = As; Group = 15; Period = 4; Ar = 197; Am = 74.9216 u; Ph = solid; Density = 5.75; Bp = 889K; Mp = 889K.Bromine: - symbol = Br; Group =17; Period = 4; Ar = 120; Am = 79.904 u; Ph = Liquid; Density = 3.1028; Bp = 332K; Mp = 265K.Meaning of ElementAn element can be defined as a substance that can not be broken down into simpler substances.
An element serves as a building blocks for compounds and mixtures.
In conclusion, each element and its property as requested in the table are given above.
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A liquid solvent is added to a flask containing an insoluble solid. the total volume of the solid and liquid together is 81.0 ml. the liquid solvent has a mass of 40.5 g and a density of 0.865 g/ml. determine the mass of the solid given its density is 2.25 g/ml.
The mass of solid is 76.905 g.
Given that,
Total volume of solid and liquid = 81.0 mL
Mass of liquid = 40.5 g
Density of liquid = 0.865 g/mL
Density of solid = 2..25 g/mL
We need to calculate the volume of liquid
Using formula of density
[tex]Density = Mass/volume(V_{l} } )\\\\volume(V_{l} )=Mass/Density[/tex]
Put the value into the formula
[tex]V_{l} = 40.5/0.865\\\\V_{l} = 46.82 mL[/tex]
We need to calculate the volume of solid
Volume of solid = Total volume of solid and liquid- volume of liquid
[tex]V_{s} =81.0-46.82\\\\V_{s} =34.18 mL[/tex]
We need to calculate the mass of solid
[tex]P_{s}=M_{s} /V_{s} \\\\M_{s} =P_{s}V_{s}[/tex]
Using formula of density
Put the value into the formula
[tex]M_{s}=2.25 X 34.18\\\\M_{s}=76.905 g[/tex]
Hence, The mass of solid is 76.905 g.
What is density?A substance's density (more accurately, its volumetric mass density; sometimes known as specific mass) is its mass per unit volume. The most common symbol for density is (the lower case Greek letter rho).
There are three types of Density:
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EXPERIMENT 1: How do you expect your coarse titration volume at the color change to compare to your fine titration volumes?
In the endpoint when the indicator changes color it gives the information that the acid is neutralized by the base.
What is Titration ?Titration is also known as titrimetry is a technique where a solution of known concentration is used to calculate the concentration of the unknown solution. Titration is a laboratory technique.
What is Endpoint ?The point at which the indicator changes the color is known as Endpoint.
Thus from the above conclusion we can say that In the endpoint when the indicator changes color it gives the information that the acid is neutralized by the base.
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It is always feasible that a substance will dissolve in water when:
A. Enthalpy is negative and entropy is positive.
B. Enthalpy is negative and entropy is negative.
C. Enthalpy is positive and entropy is positive.
HELP PLEASE 15 points
The free energy is always negative and the dissolution is feasible when enthalpy is negative and entropy is positive. Option A
What is dissolution of a substance in water?Water is known as the universal solvent. Water is a polar substance hence it is often used to dissolve polar substances. It has a dipole and being that there is a high degree of electronegativity difference between the oxygen and the hydrogen atoms in water, it is feasible that the degree of hydrogen bonding between the two is high.
We know that dissolution is favored when there will be an increase in entropy as a result of that, that is; if more particles will appear. Now we know that ΔG = ΔH - TΔS.
Given the equation above, it then follows that the free energy is always negative and the dissolution is feasible when enthalpy is negative and entropy is positive. Option A
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Calculate the Kc for the following reaction if an initial reaction mixture of 0.500 mole of CO and 1.500 mole of H2 in a 5.00 liter container forms an equilibrium mixture containing 0.198 mole of H2O and corresponding amounts of CO, H2, and CH4. CO (g) 3 H2 (g) rightwards harpoon over leftwards harpoon CH4 (g) H2O (g)
Answer:
can you be more clear with your question :
You can practice converting between the mass of a solution and mass of solute when the mass percent concentration of a solution is known. The concentration of the KCN solution given in Part A corresponds to a mass percent of 0.208 % . What mass of a 0.208 % KCN solution contains 914 mg of KCN ? Express the mass to three significant figures and include the appropriate units.
The mass of the solution will be 4,394 mg
Mass percentThe mass percent of a component in a solution can be derived as follows:
Mass percent = mass of component/total mass of solution x 100%
In this case, the mass percent of KCN in the solution is 0.208 and the mass of KCN is 914 mg.
The mass of the 0.208% KCN solution will be:
914/0.208 = 4,394 mg
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why is fruit cake a heterogeneous mixture ??
6. M = mol solute
L solution
Rewrite this expression for L solution.
Answer:
L = mol solute / M
Explanation:
To rewrite the equation for liters (L), you need to:
M = mol solute / L <----- Given equation
M x L = mol solute <----- Multiply both sides by L
L = mol solute / M <----- Divide both sides by M
Where is information found concerning acceptable species substitutions for wood materials used in aircraft repair
The list of acceptable species of wood materials used in aircraft structure is found in Table 1-1 on Page 1-2 of AC 43.13-1B.
Which types of wood are used in aircraft repair?Construction of Aircraft with Wood There are four types of wood that are frequently used in the manufacture of aircraft. These include Douglas fir, Sitka spruce, birch, and ash. Additionally, gabon, mahogany, balsa, and pine serve specific purposes. Softwood Sitka Spruce grows in both Canada and the United States of America.
What wood is used for aircraft?Contrary to popular opinion, Howard Hughes' Spruce Goose was made of birch, not spruce, despite the fact that Sitka spruce is the most often used wood in airplanes. Spruce is regarded as the best natural material for building aircraft because it has one of the highest strengths-to-weight ratios.
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__Pb(NO3)2 + __NaCI = __NaNO3 + __PbCI2
Answer:
Pb(NO3)2 + 2NaCl = 2NaNO3 + PbCl2
A student weighs out a 7.24 g sample of , transfers it to a 300. mL volumetric flask, adds enough water to dissolve it and then adds water to the 300. mL tick mark. What is the molarity of zinc chloride in the resulting solutio
The molarity of the zinc chloride solution will be 0.089 M
MolarityMole of 7.24 g ZnCl2 = 7.24/136.286 = 0.5312 mol
Total volume of water used in preparing the solution = 300 + 300 = 600 mL
Molarity of the solution = mole/volume = 0.5312/0.6 = 0.089 M
The molarity of the zinc chloride solution is, therefore, 0.089 M
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Which diagram is the correct electron dot diagram for magnesium?
A.
A symbol of magnesium M g has four dots representing four free electrons.
B.
A symbol of magnesium M g has three dots representing three free electrons.
C.
A symbol of magnesium M g has one dot representing one free electron.
D.
A symbol of magnesium M g has two dots representing two free electrons.
A symbol of magnesium, Mg, with two dots representing two free electrons. The correct option is D.
Electron dot diagramMagnesium is represented by Mg.
Magnesium has an atomic number of 12. Thus the electron configuration will be 2,8,2.
This means that there are two valence electrons in every Mg atom.
Therefore, the electron do diagram would be the symbol of the element with two dots representing the two valence electrons.
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Answer:
Two dotted M
Explanation:
You picked up a dirty test tube with a sticky substance on the outside. You get some of this substance on your hand. What is the first thing you should do
You picked up a dirty test tube with a sticky substance on the outside. You get some of this substance on your hand. The first thing that I should do is wash my hand and then tell the teacher.
Define the test tube.A test tube often referred to as a culture tube or sample tube, is a typical item of lab glassware that is made up of a finger-like length of clear plastic or glass tubing that is open at the top and closed at the bottom. Usually, test tubes are stored on dedicated racks.
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Place the following substances in order of increasing vapor pressure at a given temperature. SF6 SiH4 SF4
Substances in order of increasing vapor pressure at a given temperature is SF4 < SF6 < SiH4
The substance with the lowest vapor pressure will also have the greatest boiling point. A liquid attribute associated with evaporation is vapor pressure. The distribution of kinetic energy among the molecules in a liquid (or any substance) is influenced by the system's temperature.How do you determine vapor pressure?Vapor pressure in chemistry is the force that an evaporating substance exerts against the walls of a sealed container (converts to a gas). Use the Clausius-Clapeyron equation to determine the vapor pressure at a specific temperature: ln(P1/P2) = (Hvap/R)((1/T2) - (1/T1)Which has highest vapor pressure?
At the normal boiling point of a liquid, the vapor pressure is equal to the standard atmospheric pressure defined as 1 atmosphere, 760 Torr, 101.325 kPa, or 14.69595 psi. For example, at any given temperature, methyl chloride has the highest vapor pressure of any of the liquids in the chart.Learn more about vapor pressure
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Look at picture for the question
The amount, in grams, of carbon tetrachloride that would be present, will be 22.99 grams.
Finding the mass from the number of particlesFor every one mole of any substance, there are 6.022 x [tex]10^{23}[/tex] atoms of particles. This is according to Avogadro.
Now, there are 9 x [tex]10^{22[/tex] particles in this particular carbon tetrachloride.
If 1 mole = 6.022 x [tex]10^{23}[/tex] particles
Then,
9 x [tex]10^{22[/tex] particles = 9 x [tex]10^{22[/tex] x 1/6.022 x [tex]10^{23}[/tex] particles
= 0.1495 moles
Carbon tetrachloride has the chemical formula CCl4 and has a molar mass of 153.82 g/mol.
Recall that: mole = mass/molar mass
Hence, mass = mole x molar mass.
Mass of 0.1495 moles CCl4 = 0.1495 x 153.82 = 22.99 grams
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A certain reaction has an activation energy of 54.0 kJ/mol. As the temperature is increased from 22C to a higher temperature, the rate constant increases by a factor of 7.00. Calculate the higher temperature.
The higher temperature will be:
As the temperature is increased from 22°C to a higher temperature, the rate constant increases by a factor of 7.00. The final temperature will be 271.74K.
What is the activation energy?
Activation energy is defined as the extra energy provided required to activate the molecules to start reacting and forming intermediate and later product.
Arrhenius equations given the relation rate constant and activation energy.
[tex]LnK=Ae^{-\frac{E_a}{RT}\\\\[/tex]
Where,
K= Rate constant
A= Pre exponential factor
[tex]E_a=[/tex] Activation energy
When two rate constants are given [tex]K_1\,[/tex] and [tex]\,K_2[/tex]
[tex]ln\frac{K_2}{K_1}=\frac{E_a}{R}(\frac{1}{T_2}-\frac{1}{T_1})[/tex]
Given,
[tex]T_1[/tex] = 22°C = 295K
Rate constant[tex](K_1)[/tex] increases by a factor of 7,i.e, [tex]K_2=7K_1[/tex]
[tex]E_a[/tex]= 54 kJ/mole = 54000 J/mole
R= 8.314 [tex]J\,mol^{-1}K^{-1}[/tex]
Putting the values,
[tex]ln\frac{K_2}{K_1}=\frac{E_a}{R}(\frac{1}{T_2}-\frac{1}{T_1})[/tex]
ln 7 x 8.31454000 = (1/[tex]T_{2}\\[/tex] - 1/295)
0.299 x [tex]10^{-3}[/tex] + 1/295 = 1/[tex]T_{2}[/tex]
0.00368 = 1/[tex]T_{2}[/tex]
[tex]T_{2}[/tex] = 1/0.00368
[tex]T_{2}[/tex] = 271.74 K
Therefore,
The increase in temperature will change from 295K to 271.74K.
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10.0 g of nickel is cooled to 2.0 °C and
placed into a sample of warm water.
The final temperature of the water and
nickel was 63.4 °C. How much energy
is absorbed by the nickel?
J
CNi = 0.120 g. C
9Ni = [?] J
Answer:
73.68 J
Explanation:
To find the energy absorbed by nickel, you need to use the following equation:
Q = mcΔT
In this equation,
-----> Q = energy (J)
-----> m = mass (g)
-----> c = specific heat (J/g°C)
-----> ΔT = change in temperature
The change in temperature is found by subtracting the initial temperature from the final temperature. You can plug the given values into the equation and simplify to find the energy absorbed.
m = 10.0 g
c = 0.120 J/g°C
ΔT = 63.4 °C - 2.0 °C = 61.4 °C
Q = mcΔT
Q = (10.0 g)(0.120 J/g°C)(61.4 °C)
Q = 73.68 J
pls help!! I need the answer to this ASAP
Answer:
I think the element is carbon and the atomic mass is 12.011
Find the empirical formula for a compound consisting of 63% MN and 37% O.
Answer:
Mn₁O₂
Explanation:
To find the empirical formula, you need to (1) determine how many grams of each element are within the compound, then (2) convert grams to moles (via the atomic masses of each element), and then (3) determine the mole-to-mole ratio of each element.
(Step 1)
Because the percents add to equal 100%, we can say that each percent is the mass of each element.
63% Mn ----> 63 grams Mn
37% O ----> 37 grams O
(Step 2)
We need to convert each mass to moles using the atomic masses. The atomic masses are a ratio comparing the mass of each element per every 1 mole.
Atomic Mass (Mn): 54.983 g/mol
Atomic Mass (O): 15.998 g/mol
63 grams Mn 1 mole
---------------------- x ------------------------- = 1.15 moles Mn
54.983 grams
37 grams O 1 mole
-------------------- x ------------------------ = 2.31 moles O
15.998 grams
(Step 3)
You can find the mole-to-mole ratio of each element in the compound by dividing the calculated mole values by the smallest mole value. In this case, since 1.15 moles was the smallest value calculated, it should be the divisor. The resulting amounts are the subscripts within the empirical formula.
1.15 moles Mn / 1.15 moles = 1 moles Mn
2.31 moles O / 1.15 moles = 2 moles O
Ratio of MnO = 1:2
This make the empirical formula: Mn₁O₂