Explanation:
Atomic number of an atom means the sum of total number of protons present in an atom.
Mass number is the sum of total number of protons and neutrons present in an atom.
And, when we write the symbol of an atom then it is represented like this [tex]^{a}_{z}X[/tex], where "a" represents the mass number of the atom and "z" represents the number of protons.
Therefore, in plutonium-239 it is shown that mass number is 239 and atomic number of a plutonium atom is 94. Now, calculate its number of neutrons as follows.
Mass number = no. of protons + no. of neutrons
239 = 94 + no. of neutrons
no. of neutrons = 239 - 94
= 145
Thus, we can conclude that in plutonium-239 number of protons is 94, number of neutrons is 145 and its symbol is [tex]^{239}_{94}Pu[/tex].
A radioactive sample contains 1.55 g of an isotope with a halflife of 3.8 days. what mass of the isotope remains after 5.5 days?
Final answer:
To find the remaining mass of the isotope after 5.5 days, calculate the number of half-lives that have elapsed and then use the formula for radioactive decay. Approximately 0.445 grams of the isotope remain after the calculated time period.
Explanation:
To find out what mass of the radioactive isotope remains after 5.5 days given its half-life of 3.8 days, we use the concept of radioactive decay and half-life calculations. The number of half-lives that have passed can be calculated by dividing the elapsed time by the half-life time of the isotope.
Number of half-lives = Time elapsed / Half-life = 5.5 days / 3.8 days = 1.447
Next, we determine the fraction of the original sample that remains after 1.447 half-lives. The remaining fraction is given by (1/2) raised to the power of the number of half-lives. In this case:
Remaining fraction = (1/2)^1.447
Now, we can calculate the mass of the isotope that remains:
Remaining mass = Initial mass × Remaining fraction = 1.55 g × (1/2)^1.447
To find the exact value, we need a calculator to raise (1/2) to the power of 1.447. After calculating, if we assume that (1/2)^1.447 equals approximately 0.287, then the remaining mass is:
Remaining mass = 1.55 g × 0.287 ≈ 0.445 g
Therefore, approximately 0.445 grams of the isotope would remain after 5.5 days.
When a clean iron nail is placed in an aqueous solution of copper(ii) sulfate, the nail becomes coated with a brownish black material. (a) what is the name of the material coating the iron? (b) what are the oxidizing and reducing agents? (omit states-of-matter in your answer.) oxidizing agent: chempadhelp?
Why doesn\'t oil dissolve in water? g oil molecules covalently bond together, forming droplets that separate from water?
The_,or the number of protons an atom has determines what element it is.
Which is a spectator ion involved in the reaction of k2cro4(aq) and ba(no3)2(aq)?
Answer:
K⁺ and NO₃⁻ are the spectator ions.
Explanation:
First, we will consider the molecular equation because is the easiest to balance.
K₂CrO₄(aq) + Ba(NO₃)₂(aq) → BaCrO₄(s) + 2 KNO₃(aq)
Then, we will write the full ionic equation, which includes all the ions and the molecular species.
2 K⁺(aq) + CrO₄²⁻(aq) + Ba²⁺(aq) + 2 NO₃⁻(aq) → BaCrO₄(s) + 2 K⁺(aq) + 2 NO₃⁻(aq)
Finally, we will write the net ionic equation, which includes only the ions that participate in the reaction and the molecular species. The missing ions are the spectator ones.
CrO₄²⁻(aq) + Ba²⁺(aq) → BaCrO₄(s)
Final answer:
In the reaction between potassium chromate and barium nitrate, the spectator ions are NO3- and K+, as they appear unchanged on both sides of the chemical equation.
Explanation:
The question involves identifying the spectator ion(s) in the reaction between potassium chromate (K2CrO4) and barium nitrate (Ba(NO3)2). When these two aqueous solutions are mixed, a precipitation reaction occurs, forming barium chromate (BaCrO4) as the precipitate, and potassium nitrate (KNO3) remains in solution. Given that spectator ions are those ions that do not participate in the actual chemical reaction but are present in the same form on both sides of the equation, the NO3-(aq) and K+(aq) ions are the spectator ions in this reaction. They are present on both sides of the equation and remain unchanged.
When two electrons occupy the bonding molecular orbital above what type of bond results explain?
A covalent bond results when two electrons occupy a bonding molecular orbital, shared between two atoms due to the overlap of their atomic orbitals, creating a lower energy state.
Explanation:When two electrons occupy the bonding molecular orbital, a covalent bond results. This bond occurs when atomic orbitals from two atoms overlap in a way that their electron clouds are in phase, allowing the electrons to be shared between the atoms and creating a lower energy state than the original separate atomic orbitals. The type of covalent bond (single, double, triple) depends on the number of electron pairs shared and the orbitals involved, as described by the valence bond theory.
For instance, a single bond (σ bond) arises from end-to-end overlap and involves one electron pair, whereas double and triple bonds involve, respectively, one or more additional side-by-side π bonds created by the overlap of p orbitals. These concepts are also in line with the molecular orbital theory, where the filled bonding orbitals contribute to the bond strength of a molecule. The bond order, calculated from an energy level diagram showing the net number of bonding electrons, determines the strength and type of bond.
A student hypothesizes that since elements in the same row have the same number of energy levels they should behave the same in chemical reactions explain why you agree or disagree
write the symbolic notation of an isotope of an element having 8 protons 8 electrons and 11 neutrons click on the Templates button
The isotope with 8 protons (atomic number), 8 electrons, and 11 neutrons is Oxygen. The symbolic notation of this isotope would be represented as 19\8O, where 'O' is the symbol for Oxygen, '19' is the mass number (protons + neutrons), and '8' is the atomic number (protons).
Explanation:The element with 8 protons and 8 electrons is Oxygen. Therefore, the element you're asking about is an isotope of Oxygen. Isotopes are distinguished by the number of neutrons. In this specific case, we have 11 neutrons.
The symbolic notation of an isotope is represented as follows: The symbol for the isotope is the element's symbol (X), the mass number (A) is written as a superscript, and the atomic number (Z) is written as a subscript. In your case:
Z = 8 (number of protons)
X = O (symbol for Oxygen)
A = Z + N = 8 + 11 = 19 (Sum of protons plus neutrons)
Therefore, the symbolic notation of the isotope would be 19\8O.
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The density of silver is 10.5 g/cm3 . what is its density in ng/(mm)3
In the reaction HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (l), if 45.0 milliliters of a 2.0 M HCl react in an excess of NaOH, how many grams of H2O will be produced?
Answer:
0.045 L × 2.0 M = 0.09 mol
0.09 mol × 1 mol H2O/1 mol HCl = 0.09 mol H2O
0.09 mol H2O × 18 g/1 mol = 1.62 g
Solution: 1.62 grams of H2O
Explanation:
Answer from edmentum
Your license can be suspended for three months if you accumulate 18 points within a(n) ____________ period.
Answer:
18 months
Explanation:
The point system gives points for the traffic violations in which you might incur. If you accumulate a certain number of points in a period of time, your license can be suspended. As a consequence of this system, if you accumulate 18 points within an 18 months period, your license can be suspended for three months.
Can somebody please help me with this question, I'm very confused! I thought i did it right because i found Kb and the conc. of OH- ions and then used pOH to find pH but the answer i get is very wrong!!!
What is the pH of a 0.51 mol L-1 CH3NH3+Cl- aqueous solution? pKb(CH3NH2) = 3.44 Answer to 2 decimal places.
(answer = 5.43)
Thank you!!!!
The empirical formula of styrene is ch; its molar mass is 104.1 g/mol. what is the molecular formula of styrene? select one:
a. c2h4
b. c8h8
c. c10h12
d. c6h6
e. none of these
The molar mass of styrene is 104.1 g/mol and its molecular formula is C8H8. Therefore, option B is correct.
Given information,
Molar mass = 104.1 g/mol
The molar mass of styrene (104.1 g/mol) is significantly larger than the molar mass of the empirical formula (CH). This means that there must be multiple CH units in the molecular formula.
a. C₂H₄: (2 × 12.01 g/mol) + (4 × 1.01 g/mol) = 28.06 g/mol
b. C₈H₈: (8 × 12.01 g/mol) + (8 × 1.01 g/mol) = 104.16 g/mol
c. C₁₀H₁₂: (10 × 12.01 g/mol) + (12 × 1.01 g/mol) = 132.22 g/mol
d. C₆H₆: (6 × 12.01 g/mol) + (6 × 1.01 g/mol) = 78.11 g/mol
Therefore, option B is correct.
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You dissolve 4.5 mol of potassium hydroxide to make a 2 L solution. What is the molarity of the solution?
What is the oxidation state of cl in hclo4?
Final answer:
The oxidation state of chlorine in HClO4 is +7, determined by assigning known oxidation states to hydrogen and oxygen and using the rule that the sum of oxidation states in a molecule must equal its overall charge.
Explanation:
The student has asked to determine the oxidation state of chlorine in HClO4. To find this, we will use the available rules for assigning oxidation numbers.
The sum of the oxidation states in a molecule must equal the overall charge of the molecule. For HClO4, the molecule is neutral, so the sum must be zero.
Oxygen usually has an oxidation state of -2, so with four oxygen atoms, we have a total of -8.
Hydrogen generally has an oxidation state of +1.
With these values, we can set up the equation x + 1 + 4(-2) = 0, where x is the unknown oxidation state of chlorine. Solving for x gives us x = +7.
Therefore, the oxidation state of chlorine in HClO4 is +7.
Which statement explains why the bonds between non metals tend to be covalent
Answer: C. They have small difference in electronegativity.
Explanation:
got it correct on text !
Nother metal phosphate is iron phosphate. it will behave similar to calcium phosphate in an acid solution. what is the net ionic equation including phases for fepo4(s) dissolving in h3o+(aq)? express your answer as a net ionic equation.
Calculate the vapor pressure (in torr) at 298 k in a solution prepared by dissolving 15.3 g of the non-volatile non-electrolye urea {co(nh2)2} in 107 g of water. the vapor pressure of water at 298 k is 23.76 torr. enter your answer to 2 decimal places
The vapor pressure of the solution at 298 K is 22.80 torr. This is calculated by determining the mole fraction of water in the solution using the given masses of urea and water, and applying Raoult's law with the vapor pressure of pure water.
Explanation:To calculate the vapor pressure of the solution at 298 K, we must apply Raoult's law, which states that the vapor pressure of a solution is directly proportional to the mole fraction of the solvent. In this case, we are given the mass of urea (15.3 g) and the mass of water (107 g), along with the vapor pressure of pure water at 298 K, which is 23.76 torr.
First, we need to convert the masses to moles. The molar mass of water (H2O) is about 18.015 g/mol, and the molar mass of urea (CO(NH2)2) is approximately 60.06 g/mol. Therefore:
Number of moles of water: 107 g / 18.015 g/mol = 5.942 molesNumber of moles of urea: 15.3 g / 60.06 g/mol = 0.255 molesThe total number of moles in the solution is the sum of moles of water and urea, which is 5.942 + 0.255 = 6.197 moles. Now we determine the mole fraction of water:
Mole fraction of water (XH2O) = Moles of water / Total moles = 5.942 / 6.197 ≈ 0.959
Using Raoult's law, the vapor pressure of the solution (Psolution) is the product of the mole fraction of water and the vapor pressure of pure water:
Psolution = XH2O * Vapor pressure of pure water = 0.959 * 23.76 torr ≈ 22.80 torr
Therefore, the vapor pressure of the solution at 298 K is 22.80 torr.
When a neutrally charged atom loses an electron to another atom, the result is the creation of
Final answer:
When a neutrally charged atom loses an electron to another atom, the result is the creation of an ion.
Explanation:
When a neutrally charged atom loses an electron to another atom, the result is the creation of an ion. An ion is a charged atom that has gained or lost electrons, so it has more or fewer electrons than protons and a negative or positive charge. For example, a neutral sodium atom can lose one electron to become a positively charged sodium atom (Na+), while a neutral chlorine atom can gain one electron to become a negatively charged chlorine ion (Cl-).
why is it appropriate to say the constitution is designed to "bend like a willow?
Identify the hybridization of the n atom in nf3.
Answer:
sp3 hybridization
Explanation:
Hello,
Based on the Lewis structure Nitrogen has 3 valence electrons with a lone pair of non-bonded electrons, thus, the hybridization calculation rule,
[tex]Hybridization=\#Attached.Atoms+\# lone.pairs\\[/tex]
Allows us to identify that the [tex]NF_3[/tex] has three attached atoms and one lone pair. Now, by considering the convention: sp3=4, sp2=3 and sp=2 , one finds that:
[tex]Hybridization=3+1=4[/tex]
Therefore, [tex]NF_3[/tex] has sp3 hybridization.
Best regards.
In NF3 (nitrogen trifluoride), the nitrogen (N) atom undergoes hybridization to form its bonding orbitals. So, the hybridization of the nitrogen atom in NF3 is sp3.
What is hybridizationThe nitrogen atom in NF3 has five valence electrons, with one being paired and three unpaired. To form four bonding orbitals and accommodate the three fluorine (F) atoms, the nitrogen atom undergoes sp3 hybridization.
In sp3 hybridization, one 2s orbital and three 2p orbitals of the nitrogen atom combine to form four new hybrid orbitals called sp3 orbitals. These sp3 orbitals are arranged in a tetrahedral geometry around the nitrogen atom, with the three fluorine atoms occupying three of the sp3 orbitals, and the remaining sp3 orbital containing a lone pair of electrons.
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Constants for water
Hvap 40.65 kJ/mol
Hf -285.83 kJ/mol
Hfusion 6.03 kJ/mol
specific heat 4.186 J/gC
molar mass 18.02 g
How much energy is generated from freezing 2.5 g water?
A. 2.5 g 1 mol/18.02 g (285.83) kJ/mol
B. 2.5 g 1 mol/18.02 g 4.186 kJ/mol
C. 2.5 g 1 mol/18.02 g 40.65 kJ/mol
D. 2.5 g 1 mol/18.02 g (-285.83) kJ/mol
The energy released from freezing 2.5 g of water can be calculated by converting the grams to moles and then multiplying by the negative enthalpy of fusion, which is -6.01 kJ/mol, indicating an exothermic process.
Explanation:Calculating Energy Released During Freezing of Water
To determine the energy generated from freezing 2.5 g of water, we need to use the enthalpy of fusion, which is the energy change when 1 mole of water freezes. Since the process of water freezing is exothermic, the enthalpy of fusion will be negative, reflecting the release of energy.
Step-by-step calculation:
Convert grams of water to moles: (2.5 g)2.5 g
1 mol/18.02 g
(-6.01 kJ/mol)
The correct answer is influenced by the fact that the energy change is negative in an exothermic process, which in this case is the freezing of water.
Therefore, the correct answer to the question is:
D. 2.5 g
1 mol/18.02 g
(-6.01 kJ/mol)
Explain why the column of a fractional distillation apparatus should be aligned as near to the vertical as possible
The column of a fractional distillation apparatus should be aligned as near to the vertical as possible for better separation, increased efficiency, and prevention of blockages.
Explanation:The column of a fractional distillation apparatus should be aligned as near to the vertical as possible for several reasons:
Aligning the column vertically allows for better separation of the different fractions. As the vapors rise through the column, the fractions with higher boiling points condense and collect at lower levels, while the fractions with lower boiling points remain in the vapor phase and rise towards the top.Alignment also ensures that the distillation process is more efficient. A vertical alignment allows for a greater surface area of contact between the vapor and the liquid fractions, facilitating the transfer of heat and increasing the rate of condensation.Lastly, a vertical alignment prevents any blockage or obstruction in the column. When the column is vertical, any liquid fractions that may condense and form droplets can easily fall back down towards the base of the column, avoiding any potential clogs or disturbances in the separation process.Which best describes the structure of 2-butene
The ΔHvap of a certain compound is 49.09 kJ·mol–1 and its ΔSvap is 53.69 J·mol–1·K–1. What is the boiling point of this compound?
The boiling point of the compound is 914.32°C.
What is compound?Compound is defined as a chemical substance made up of identical molecules containing atoms from more than one type of chemical element.
Molecule consisting atoms of only one element is not called compound.It is transformed into new substances during chemical reactions. There are four major types of compounds depending on chemical bonding present in them.They are:
1)Molecular compounds where in atoms are joined by covalent bonds.
2) ionic compounds where atoms are joined by ionic bond.
3)Inter-metallic compounds where atoms are held by metallic bonds
4) co-ordination complexes where atoms are held by co-ordinate bonds.
1 j - 0.001 kj
53.69 j -Kj
Kj = 53.69 ×0.001
=> 0.05369 Kj
T = ΔH / ΔS
T = 49.09 / 0.05369
T = 914.32 º C
Hence, the boiling point of the compound is 914.32°C.
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What is the volume of a sample of liquid mercury that has a mass of 76.2g, given that the density of mercury is 13.6g/mL?
Aluminum chlorohydrate, al2(oh)5cl, is an active ingredient in some antiperspirants. what is the mass percent of aluminum in this compound?
The mass percent of aluminum in aluminum chlorohydrate, Al2(OH)5Cl, is calculated by dividing the mass of aluminum in the compound by the compound's total molar mass and then multiplying by 100, which results in approximately 30.94%.
Explanation:To calculate the mass percent of aluminum in aluminum chlorohydrate, Al2(OH)5Cl, we first need to find the molar mass of aluminum and the molar mass of the entire compound. The molar mass of aluminum is approximately 26.98 g/mol and there are two aluminum atoms in the compound. Next, calculate the total molar mass of Al2(OH)5Cl using the molar masses of all the atoms involved.
For Al2(OH)5Cl:
Molar mass of Al: 26.98 g/mol × 2 = 53.96 g/molMolar mass of O: 16.00 g/mol × 5 = 80.00 g/molMolar mass of H: 1.01 g/mol × 5 = 5.05 g/molMolar mass of Cl: 35.45 g/molTotal molar mass of Al2(OH)5Cl = 53.96 + 80.00 + 5.05 + 35.45 = 174.46 g/mol
Mass percent of Aluminium in the compound = (Mass of Al in the formula / Molar mass of the compound) × 100 = (53.96 / 174.46) × 100 = 30.94%
At 25 °C, what is the hydroxide ion concentration, [OH–], in an aqueous solution with a hydrogen ion concentration of [H ] = 4.2 × 10–9 M?
[OH-] = ____ M
The decay curve shown below approximates the decay of phosphorus-32. what is the approximate half-life of phosphorus-32?
a mixture of two gases has a total pressure of 5.7 atm. it one gas has a partial pressure of 4.1 atm, what is the partial pressure of the other gas
Answer:
1.6 atm
Explanation:
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