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]
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.
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
What is the total pressure in a 6.00-l flask which contains 0.127 mol of h2(g) and 0.288 mol of n2(g) at 20.0°c?
The total pressure in a 6.00-L flask with a mixture of 0.127 mol H₂ and 0.288 mol N₂ at 20.0°C is calculated using the ideal gas law PV = nRT. After converting the temperature to Kelvin and determining the total moles of gas, the pressure is found to be approximately 1.68 atm.
Explanation:To calculate the total pressure in a 6.00-L flask containing 0.127 mol of H₂(g) and 0.288 mol of N₂(g) at 20.0°C, we can use the ideal gas law, which is PV = nRT. Here, P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in Kelvin.
First, convert temperature from Celsius to Kelvin: T = 20.0 + 273.15 = 293.15 K.
Next, use R = 0.0821 L·atm/(K·mol), which is the ideal gas constant appropriate when pressure is in atmospheres and volume is in liters.
Combine the moles of gases: total moles (n₂₄₂al) = 0.127 mol H₂ + 0.288 mol N₂ = 0.415 mol.
Then calculated the pressure using the ideal gas law: P = (nRT)/V = (0.415 mol * 0.0821 L·atm/(K·mol) * 293.15 K) / 6.00 L = 1.68 atm (rounded to two decimal places).
The total pressure in the flask at 20.0°C is therefore approximately 1.68 atmospheres.
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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:
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 atoms exist as diatomic molecules?
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.
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,
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.
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.
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.
In the balanced reaction below, what is the mole ratio comparing iron (Fe) and oxygen gas (O2)?
4Fe + 3O2 --> 2Fe2O3
Question options:
4:2
1:3
2:3
4:3
The given balanced reaction is,
[tex] 4Fe(s) + 3O_{2}(g) --->2Fe_{2}O_{3} (s) [/tex]
The stoichiometric coefficients of each element or compound represents the number of moles of that element or compound required for the complete reaction to take place.
The mole ratios of different products and reactants will be:
[tex] \frac{Fe}{O_{2}} = \frac{4 mol Fe}{3 mol O_{2}} [/tex]
[tex] \frac{Fe}{Fe_{2}O_{3}} = \frac{4 mol Fe}{2 Fe_{2}O_{3}} [/tex]
[tex] \frac{O_{2}}{Fe_{2}O_{3}} =\frac{3 mol O_{2}}{2molFe_{2}O_{3}} [/tex]
So the mole ratio comparing iron (Fe) and oxygen gas ([tex] O_{2} [/tex]) is
4 : 3
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?
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:
Severe shock occurs when blood loss of
30,20,50,10,5%
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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if a solution has a hydronium ion concentration of 1x10^-9 m the solution is
a) acidic and has a pH of 5
b) basic and has a pH of 9
c) basic and has a pH of 5
d) acidic and has a pH of 9
The acidity or alkalinity of a solution depends upon the hydronium ion concentration and hydroxide ion concentration. If a solution has a hydronium ion concentration of 1x10⁻⁹ m the solution is basic. The correct option is B.
What is pH of a solution?The pH of a solution is defined as the negative logarithm to the base 10 of the value of the hydronium ion concentration in moles per litre. The pH scale introduced by Sorensen is more convenient in expressing the hydronium ion concentration of a solution.
The pH can be calculated as:
pH = -log [H₃O⁺]
If the concentration of [H₃O⁺] is less than 10⁻⁷ M, then the solution is found to be basic.
Here pH is:
pH = - log [1 x 10⁻⁹]
= 9
So the pH of the solution is 9.
Thus the correct option is B.
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How many moles of copper are needed to react with sulfur to produce 0.25 moles of copper (I) sulfide
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.
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:
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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Help please? Will give brainliest...!!!!!!!
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.
A sample of chlorine gas is confined in a 5.0 L container at 328 torr and 37 degrees C. How many moles of gas are in the sample?
PLEASE HELP!!! BIG TEST TMRRW!!!! WORK WOULD BE GREATLY APPRECIATED
Answer:
what he/she/they said
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.
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?
elements can be broken down through ______ processes.
Which one has more mass a bag of cotton balls or a bag of nails and explain