Final answer:
To find the average atomic mass of weapons-grade uranium, calculate the weighted average based on the percentages of each isotope: 80% of 235.044 amu (uranium-235) and 20% of 238.051 amu (uranium-238), yielding an average atomic mass of 235.6454 amu.
Explanation:
To calculate the average atomic mass of weapons-grade uranium, which consists of 80% uranium-235 and 20% uranium-238, you multiply the mass of each isotope by its relative percentage (expressed as a decimal) and then sum the results. The atomic mass unit (amu) for uranium-235 is 235.044 and for uranium-238 is 238.051.
The average atomic mass can be calculated as follows:
(80% of uranium-235) 80/100 × 235.044 amu = 188.0352 amu
(20% of uranium-238) 20/100 × 238.051 amu = 47.6102 amu
Add these values together: 188.0352 amu + 47.6102 amu = 235.6454 amu
Therefore, the average atomic mass of weapons-grade uranium is 235.6454 amu.
Help please? Will give brainliest...!!!!!!!
1. What mass of H2O will be produced if 9.5 g of H2 reacts with 1.2 g of O2?
__ H2 + __ O2 --> __ H2O
2. If 1.85 g of Mg(OH)2 reacts with 3.71 g of HCl, how much MgCl2 is produced? What is the limiting reactant?
__ Mg(OH)2 + __ HCl --> __ MgCl2 + __ H2O
3. What mass of potassium hydroxide is formed when 8.2 g of potassium oxide is added to 1.3 g of water?
__ K2O + __ H2O --> __ KOH
4. What mass of aluminum chloride could be made from 8.1 g of aluminum and 4.2 L of chlorine at STP?
__ Al + __ Cl2 --> __ AlCl3
I know this is a lot of questions but please help and show your work. Thank you.
1) The answer is: mass of water is 1.35 grams.
Balanced chemical reaction: 2H₂ + O₂ → 2H₂O.
m(O₂) = 1.2 g; mass of oxygen.
M(O₂) = 2 · 16 g/mol.
M = 32 g/mol, molar mass of oxygen.
n(O₂) = m(O₂) ÷ M(O₂).
n(O₂) = 1.2 g ÷ 32 g/mol.
n(O₂) = 0.0375 mol; amount of oxygen, limiting reactant.
m(H₂) = 9.5 g; mass of hydrogen.
M(H₂) = 2 g/mol, molar mass of hydrogen.
n(H₂) = m(H₂) ÷ M(H₂).
n(H₂) = 9.5 g ÷ 2 g/mol.
n(H₂) = 4.5 mol; amount of hydrogen.
From chemical reaction: n(O₂) : n(H₂O) = 1 : 2.
n(H₂O) = 0.0375 mol · 2.
n(H₂O) = 0.075 mol; amount of water.
m(H₂O) = n(H₂O) · M(H₂O).
m(H₂O) = 0.075 mol · 18 g/mol.
m(H₂O) = 1.35 g; mass of water.
2) The answer is: 3.05 grams of MgCl₂ is produced, the limiting reactant is Mg(OH)₂.
Balanced chemical reaction: 2HCl + Mg(OH)₂ → MgCl₂ + 2H₂O.
m(Mg(OH)₂) = 1.85 g; mass of magnesium hydroxide
n(Mg(OH)₂) = m(Mg(OH)₂) ÷ M(Mg(OH)₂).
n(Mg(OH)₂) = 1.85 g ÷ 58.32 g/mol.
n(Mg(OH)₂) = 0.032 mol; limiting reactant.
m(HCl) = 3.71 g; mass of hydrochloric acid.
n(HCl) = 3.71 g ÷ 36.46 g/mol.
n(HCl) = 0.102 mol; amount of hydrochloric acid.
From chemical reaction: n(Mg(OH)₂) : n(MgCl₂) = 1 : 1.
n(MgCl₂) =0.032 mol; amount of magnesium chloride.
m(MgCl₂) = n(MgCl₂) · M(MgCl₂).
m(MgCl₂) = 0.032 mol · 95.21 g/mol.
m(MgCl₂) = 3.05 g; mass of magnesium chloride.
3) The answer is: mass of potassium hydroxide is 8.1 grams.
Balanced chemical reaction: K₂O + H₂O → 2KOH.
m(K₂O) = 8.2 g; mass of potassium oxide.
n(K₂O) = m(K₂O) ÷ M(K₂O).
n(K₂O) = 8.2 g ÷ 94.2 g/mol.
n(K₂O) = 0.087 mol; amount of potassium oxide.
m(H₂O) = 1.3 g; mass of water.
n(H₂O) = 1.3 g ÷ 18 g/mol.
n(H₂O) = 0.072 mol; limiting reactant.
From chemical reaction: n(H₂O) : n(KOH) = 1 : 2.
n(KOH) = 2 · 0.072 mol.
n(KOH) = 0.144 mol.
m(KOH) = 0.144 mol · 56.1 g/mol.
m(KOH) = 8.1 g; mass of potassium hydroxide.
4) The answer is: mass of aluminum chloride is 16.66 grams.
Balanced chemical reaction: 2Al + 3Cl₂ → 2AlCl₃.
m(Al) = 8.1 g; mass of aluminium.
n(Al) = m(Al) ÷ M(Al).
n(Al) = 8.1 g ÷ 27 g/mol.
n(Al) = 0.3 mol.
V(Cl₂) = 4.2 L; volume of chlorine.
n(Cl₂) = 4.2 L ÷ 22.4 L/mol.
n(Cl₂) = 0.1875 mol; limiting reactant.
From chemical reaction: n(Cl₂) : n(AlCl₃) = 3 : 2.
n(AlCl₃) = 2 · 0.1875 mol ÷ 3.
n(AlCl₃) = 0.125 mol; amount of aluminium chloride.
m(AlCl₃) = 0.125 mol · 133.34 g/mol.
m(AlCl₃) = 16.66 g; mass of aluminium chloride.
Which defines reaction mechanism in chemistry? the mixing of two or more liquids to form a solution the steps in a chemical reaction in which products result from reactants a process in which a product is changed from one physical form to another intermolecular forces that cause attraction or repulsion between nearby particles?
Answer:
the answer is B : the steps in a chemical reaction in which products result from reactants
Explanation:
Is hot coffee an element a compound a heterogeneous mixture or a homogeneous mixture?
Hot coffee is a homogeneous mixture, consisting of substances that are uniformly distributed and cannot be easily separated.
Explanation:Hot coffee is neither an element nor a compound, but rather a type of mixture. Specifically, hot coffee is a homogeneous mixture. A mixture is a material composed of two or more substances that are combined without a chemical reaction occurring, and in a homogeneous mixture, these substances are uniformly distributed. Therefore, in the case of hot coffee, the coffee solids, water, and any added sugar or cream are thoroughly mixed and cannot be easily separated, which is typical of homogeneous mixtures.
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Hot coffee is a homogeneous mixture, characterized by a uniform composition throughout. It is not a heterogeneous mixture or a compound.
Explanation:Hot coffee is an example of a homogeneous mixture. This classification is due to the uniform composition throughout the coffee, which is a combination of several substances including water, coffee solids, and possibly sugar or milk. It remains homogeneous due to the heat which keeps the solids dissolved. It differs from a heterogeneous mixture, where the composition varies from point to point, and also from a compound, which is a substance formed by chemical union of two or more elements. In contrast, the constituents of a mixture like coffee can be separated by physical changes, such as evaporation.
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What is the balanced chemical equation for the reaction used to calculate ΔH∘f of SrCO3(s)?
If fractional coefficients are required, enter them as a fraction (i.e. 1/3). Indicate the physical states using the abbreviation (s), (l), or (g) for solid, liquid, or gas, respectively without indicating allotropes. Use (aq) for aqueous solution.
Answer:
[tex]Sr(s)+C(s)+ 3/2O_{2}(g)\rightarrow SrCO_{3}(s)[/tex]
Explanation:
The standard enthalpy of formation (ΔH°f) is defined as the enthalpy change which accompanies the formation of 1 mole of a compound from its constituent elements all of which are in their standard states i.e. either solid (s), liquid (l) , gas (g) or the aqueous phase (aq).
Strontium carbonate (SrCO3) contains 3 elements:
-Strontium (Sr) where the standard state is solid(s)
- Carbon (C) where the standard state is again a solid (s)
- oxygen (O) where the standard state is the gas phase (g)
The balanced chemical equation for the standard enthalpy of formation (ΔH°f) for SrCO3 would be:
[tex]Sr(s)+C(s)+ 3/2O_{2}(g)\rightarrow SrCO_{3}(s)[/tex]
The diagram shows Niels Bohr’s model of an atom.
What happens when the electron moves from the first energy level to the second energy level?
Energy is absorbed, and an emission line is produced.
Energy is released, and an emission line is produced.[wrong]
Energy is absorbed by the atom.
Energy is lost from the atom.
Answer: When the electron moves from the first energy level to the second energy level, energy is absorbed.
Explanation:
When an electron moves from first energy level to the second energy level,energy is being absorbed by the atom which means that the electron jumps from lower energy level to higher energy level.
Bohr's Equation
E=[tex]\frac{-E_0}{n^2}[/tex]
where,
E= energy of an electron in 'n' level (n=1,2,3...etc)
[tex]E_0[/tex]= energy of an electron in ground state.
as we can see from this equation energy is inversely proportional to the n principle quantum number which means that there will be decrease in energy. As the energy is decreasing in magnitude with the negative sign which actually means there is increase in energy.
How is most carbon dioxide transported from tissues to the lungs? view available hint(s) how is most carbon dioxide transported from tissues to the lungs? as carbonic acid. as carbon dioxide gas. as bicarbonate ions (hco3−). as protons (h+)?
what is a saturated solution in your own words, please!!!!
Answer:
A saturated solution is a solution that has the maximum amount of solute that is capable of being dissolved
Explanation:
Which are isotopes? an atom that has an atomic number of 20 and a mass number of 42 is an isotope of an atom that has which are isotopes? an atom that has an atomic number of 20 and a mass number of 42 is an isotope of an atom that has an atomic number of 20 and a mass number of 40. an atomic number of 21 and a mass number of 42. 22 protons and 20 neutrons. 22 neutrons and 20 protons?
Explanation:
Isotopes are defined as the species which contain same number of protons but different number of neutrons.
As the sum of all the protons present in an atom is known as atomic number. Whereas the sum of total number of protons and neutrons is known as atomic mass.
Hence, isotopes are also defined as atoms with same atomic number but different atomic mass.
For example, an atom that has an atomic number of 20 and a mass number of 42 will contain the following number of neutrons.
Mass number = no. of protons + no. of neutrons
42 = 20 + no. of neutrons
no. of neutrons = 42 - 20
= 22
So, isotope of this atom could be [tex]^{40}_{20}A[/tex]. This means that an element with atomic number of 20 and a mass number of 40.
Thus, we can conclude that an atom that has an atomic number of 20 and a mass number of 42 is an isotope of an atom that has an atomic number of 20 and a mass number of 40.
Since, both of them contains same number of protons but different number of neutrons.
What is the most important requirement for all living things? water carbon dioxide light vitamins
Water is the essential thing, since we are talking about ALL living organisms. The most basic and important necessity they all share is the need to hydrate.
How many protons, neutrons, and electrons are in a neutral atom with the symbol 41Ca
A) 20 protons, 21 neutrons, 21 electrons
B) 20 protons, 21 neutrons, 20 electrons
C) 21 protons, 21 neutrons, 20 electrons
D) 41 protons, 0 neutrons, 41 electrons
There are 20 protons, 21 neutrons,20 electrons are in a neutral atom with the symbol 41Ca.
Explanation:
Given:
The neutral atom with symbol 41Ca
To find:
The numbers of protons, neutrons, and electrons.
Solution:
The given symbol of an atom is Ca which means that the given atom is of calcium.
The atomic number of calcium = 20
The atomic number of atom = Number of protons in an atom
The number of proton in a given calcium atom = 20
The given atom is neutral which means that an equal number of protons and electrons will be present.
The number of electrons = Number of protons = 20
The number of electrons in a given calcium atom = 20
The mass number of an atom is a sum of the number of neutrons and the number of protons
The number of neutrons = n
In the given symbol of calcium atom, the mass number of calcium is also given which is 41.
The mass number of the calcium atom = 41
[tex]41=n+20\\n=41-20=21[/tex]
The number of neutrons = 21
The number of neutrons in a given calcium atom = 21
There are 20 protons, 21 neutrons,20 electrons are in a neutral atom with the symbol 41Ca.
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How many molecules (not moles) of nh3 are produced from 5.81×10−4 g of h2? express your answer numerically as the number of molecules?
At STP, two 5.0-gram solid samples of different ionic compounds have the same density. These solid samples could be dominated by their
The correct answer is option (b). At STP, two 5.0-gram solid samples of different ionic compounds have the same density. These solid samples could be dominated by their crystal structures.
A) Molar masses: The molar mass of a compound refers to the mass of one mole of that substance. While the molar mass affects the mass of the compound, it does not directly determine the density unless the volume occupied by the same mass of different compounds is considered.
B) Crystal structures: The crystal structure refers to the arrangement of ions in a solid. If two ionic compounds have the same density, it is likely that their ions are packed in a similar manner, resulting in the same volume for the same mass. The crystal structure determines how closely the ions are packed together, which directly influences the density.
C) Ionic charges: While ionic charges influence the electrostatic forces between ions, they do not directly determine the density of a solid. The arrangement of ions (crystal structure) has a more direct impact on density than the charges of the ions themselves.
D) **Solubilities**: The solubility of a compound refers to how well it dissolves in a solvent, such as water. This property does not affect the density of the solid form of the compound.
The complete question is:
At STP, two 5.0-gram solid samples of different ionic compounds have the same density. These solid samples could be dominated by their __________.
A) molar masses
B) crystal structures
C) ionic charges
D) solubilities
Which property could be a dominant factor for these solid samples to have the same density?
If exactly 50 ml of a 0.050m solution of hydrochloric acid is added to exactly 50 ml of 0.050m ammonia, what is the ph of the resulting solution?
elements can be broken down through ______ processes.
Sodium tends lose a single electron in natural settings. Based on what you know, what are two other elements that tend to do the same thing?
Question 4 options:
sodium and magnesium
hydrogen and helium
beryllium and boron
potassium and rubidium
**I said D**,
Answer:
D. potassium and rubdium
Severe shock occurs when blood loss of
30,20,50,10,5%
MEDAL, please help me understand.
Which best describes the oxidizing agent in this reaction?
Cl2(aq) + 2Brmc003-1.jpg(aq) mc003-2.jpg 2Clmc003-3.jpg(aq) + Br2(aq)
Bromine (Br) is the oxidizing agent because it gains an electron.
Bromine (Br) is the oxidizing agent because it loses an electron.
Chlorine (Cl) is the oxidizing agent because it gains an electron.
Chlorine (Cl) is the oxidizing agent because it loses an electron.,
Answer:
c
Explanation:
The solubility of a gas in a liquid is _____. proportional to the square root of the pressure of the gas above the liquid unrelated to the pressure of the gas above the liquid inversely proportional to the pressure of the gas above the liquid directly proportional to the pressure of the gas above the liquid
Answer:
directly proportional to the pressure of the gas above the liquid
Explanation:
Henry’s law,
Sg = k Pg
where Sg, k and Pg are solubility of the gas, Henry’s constant and partial pressure of the gas respectively.
According to Henry’s law the amount of gas that can dissolve in a liquid is directly proportional to the partial pressure of the gas above the liquid.
Which one has more mass a bag of cotton balls or a bag of nails and explain
Will medal!!!
The addition of hydrochloric acid to a silver nitrate solution precipitates silver chloride according to the reaction:
AgNO3(aq)+HCl(aq)→AgCl(s)+HNO3(aq)
When you combine 70.0mL of 0.185M AgNO3 with 70.0mL of 0.185M HCl in a coffee-cup calorimeter, the temperature changes from 23.16∘C to 24.25∘C.
Calculate ΔHrxn for the reaction as written. Use 1.00 g/mL as the density of the solution and C=4.18J/g⋅∘C as the specific heat capacity.,
A student is told that both energy and mass must be conserved in every chemical reaction. She measures the mass of Hydrochloric acid and a zinc strip separately. She then places the zinc strip into the acid and bubbles form as the zinc looks like it disappears. The combined mass afterward is less than the original. Which of these can explain this result? A) The student must have not measured the mass correctly. B) The zinc disappears and therefore the mass is less after the reaction. C) This is not a chemical reaction so the conservation laws do not apply. D) The bubbles indicate that a gas is created and mass is loss as it escapes from the container.
How can you determine the number of moles of a contained gas when the pressure, volume, and temperature are known values?
Under STP conditions (1 atm and 0°C), 1 mole of an ideal gas occupies 22.4 liters.
The Ideal Gas Law is a fundamental equation that relates the pressure (P), volume (V), and temperature (T) of an ideal gas to the number of moles (n) of the gas. The law is expressed by the equation:
[tex]\[ PV = nRT \][/tex]
where:
- [tex]P[/tex] is the pressure of the gas, typically measured in atmospheres (atm),
- [tex]V[/tex] is the volume of the gas, usually measured in liters (L),
- [tex]n[/tex] is the number of moles of the gas,
- [tex]\( R \)[/tex] is the ideal gas constant, which has a value of 0.0821 L·atm/(mol·K) when the pressure is in atm and the volume is in liters, and
- [tex]\( T \)[/tex] is the temperature of the gas in Kelvin (K).
To find the number of moles [tex]n[/tex], we can rearrange the Ideal Gas Law equation to solve for [tex]n:[/tex]
[tex]\[ n = \frac{PV}{RT} \][/tex]
For example, if we have a gas at a pressure of 1 atm, a volume of 22.4 L (which is the molar volume of an ideal gas at STP), and a temperature of 273 K (0°C), we can calculate the number of moles as follows:
[tex]\[ n = \frac{(1 \text{ atm})(22.4 \text{ L})}{(0.0821 \text{ L·atm/(mol·K)})(273 \text{ K})} \][/tex]
[tex]\[ n = \frac{22.4}{0.0821 \times 273} \][/tex]
[tex]\[ n \approx 1 \text{ mol} \][/tex]
This calculation confirms that under STP conditions (1 atm and 0°C), 1 mole of an ideal gas occupies 22.4 liters.
which atoms exist as diatomic molecules?
Sirius is a blue-white star with a surface temperature of about 9800 K. What is most likely the mass of Sirius? 1.0 solar mass 1.4 solar mass 2.0 solar mass 12 solar mass
The answer is actually 2.0 solar masses.
The equilibrium constant kc for the decomposition of phosgene, cocl2, is 4.63 10-3 at 527°c. cocl2(g) equilibrium reaction arrow co(g) + cl2(g) calculate the equilibrium partial pressure of all the components, starting with pure phosgene at 0.760 atm.
To determine the equilibrium partial pressures for the components of phosgene decomposition, we first establish the initial conditions and use the given equilibrium constant. We then set up an equation based on the changes at equilibrium and solve it to find the equilibrium partial pressures.
Explanation:Equilibrium Partial Pressure of Phosgene Decomposition ComponentsThe decomposition of phosgene (COCl2) into carbon monoxide (CO) and chlorine gas (Cl2) can be observed using the equation COCl2(g) ⇌ CO(g) + Cl2(g). From the problem, we can consider an initial pressure of 0.760 atm of COCl2 and a negligible amount of CO and Cl2. Given that the equilibrium constant (Kc) for this reaction is 4.63 x 10-3, we can set up an equation derived from the equilibrium expression: Kc = (PCO x PCl2)/PCOCl2.
As the reaction proceeds, the pressure of COCl2 decreases by an 'x' amount to establish equilibrium, and the pressure of CO and Cl2 increases by the same 'x' amount. Thus, at equilibrium: Kc = ((0.760-x)x)/x. Solving this equation for 'x', we can obtain the equilibrium partial pressure of all components in the system.
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can someone please help. A sucrose solution is prepared to a final concentration of 0.170M . Convert this value into terms of g/L, molality, and mass % (molecular weight, MWsucrose = 342.296g/mol ; density, ρsol′n = 1.02g/mL ; mass of water, mwat = 961.8g ). Note that the mass of solute is included in the density of the solution,
Which of the following radioisotopes is naturally occurring?
93^239Np
53^131I
102^254No
96^242Cm
Answer:
I - 131 is the correct answer.
I - 131 is the only naturally occuring radioactive isotope among these four options.
Explanation:
Np - 239 - Neptunium is also considered as an artificial element,as only trace amounts of it are found in nature.
And Np - 239 is not a naturally occuring radioactive isotope but it is synthesized artificially.
No - This is an artificial element.That means its not found in nature. Hence all its isotopes are also synthesized artificially.
Cm - This is also an artificial element and all its isotopes are also synthesized artificially.
Np - 239,No - 254,Cm - 242 are radioactive isotopes but they are not naturally occuring radioactive isotopes. But these three are artificially made radioactive isotopes.
And Iodine - 131 is the only naturally occuring radioisotope among these.
Determine the entropy change when 1.80 mol of HBr(g) condenses at atmospheric pressure?
Answer:
Entropy change = -168.3 J/mol-K
Explanation:
The entropy change is expressed as:
[tex]DeltaS = \frac{DeltaH}{T}[/tex]
For HBr, the enthalpy of condensation = -19.27 kJ/mol
Temperature T = -67 C = 273 - 67 = 206 K
Therefore, the entropy change when 1 mol of HBr condenses is:
= [tex]\frac{-19.27 kJ/mol}{206 K} =0.0935 kJ/mol-K = -93.5 J/mol-K[/tex]
Thus for the given 1.80 mol of HBr the entropy change would be:
[tex]= 1.80 mol * -93.5 J/mol- K = -168.3 J/mol-K[/tex]
The entropy change when 1.80 mol of HBr(g) condenses at atmospheric pressure can be determined using the equation ΔS = -ΔH/T, where ΔH is the enthalpy change and T is the temperature.
Explanation:The entropy change when a substance condenses can be calculated using the following equation:
∆S = -∆Hvap / T
where:
∆S is the entropy change (J/K·mol)
∆Hvap is the enthalpy of vaporization (kJ/mol)
T is the temperature of condensation (K)
The enthalpy of vaporization of HBr is -19.27 kJ/mol. The temperature at which HBr condenses at atmospheric pressure is its boiling point, which is -67°C. Converting this temperature to Kelvin, we get:
T = -67°C + 273.15 K = 206.15 K
Plugging in these values, we get:
∆S = -(-19.27 kJ/mol) / 206.15 K = 0.09348 kJ/K·mol
Converting kJ to J, we get:
∆S = 0.09348 kJ/K·mol * 1000 J/kJ = 93.48 J/K·mol
Therefore, the entropy change when 1.80 mol of HBr(g) condenses at atmospheric pressure is -168.3 J/K·mol.
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which of these stars is least likely to be categorized as a supergiant? A. Betelgeuse B. Pollux C. Sirius A D. Sun Reset Submit
Answer: The correct answer is option D.
Explanation: Super-giant stars are the stars which are greater than Sun. They have a mass hundred time greater than Sun and can be thousand times greater than Sun.
The masses of the stars are represented in Solar masses which is the mass of the Sun.
Mass of Betelgeuse = 20 Solar masses
Mass of Pollux = 1.7 Solar masses
Mass of Sirius = 2.02 Solar masses
Mass of Sun = 1 Solar mass.
As, the mass of Sun is the least from the given stars. Hence, it is least considered as a super-giant.
Final answer:
Pollux is the least likely to be categorized as a supergiant since it is an evolved giant star, while Betelgeuse is a known red supergiant, and both Sirius A and the Sun are main-sequence stars.
Explanation:
The star least likely to be categorized as a super giant among the options provided is Pollux. Betelgeuse is a well-known red super giant that is visible near Orion's belt as the bright red star marking the hunter's shoulder. Pollux, in contrast, is classified as an evolved giant star (a red giant), which is a less massive and less luminous stage compared to a super giant. Option B
Sirius A, known for being the brightest star in the sky after the Sun, is a main-sequence star, and also not a super giant. The Sun itself is a main-sequence star, not nearly massive enough to ever become a super giant. Therefore, while neither Pollux, Sirius A, nor the Sun are super giants, Pollux being an evolved giant is the furthest in its life cycle from the super giant category compared to the main-sequence state of Sirius A and the Sun.