Answer: Option (b) is the correct answer.
Explanation:
According to Afbau's principle, an electron enters the orbital with lowest energy first and subsequent electrons are fed in the order of increasing energies.
Copper is the element which has atomic number 29. It is a transition metal and atomic number of an atom determines the number of electrons present in an atom.
So, the stable electronic configuration of copper is as follows.
[tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^{10}[/tex].
The electron configuration of an atom with an atomic number of 29 matches option C): 1s2, 2s2, 2p6, 3s2, 3p6, 4s1, 3d10. This configuration follows the Aufbau principle, showing how electrons fill up the lowest energy levels first.
Explanation:The atomic number of an element defines the number of protons, and in a neutral atom, the number of electrons. For an atom with the atomic number 29, the number of electrons will also be 29. The electron configuration describes the distribution of these electrons among the energy levels and orbitals of the atom. For an atom with an atomic number of 29, this arrangement correlates to the option C): 1s2, 2s2, 2p6, 3s2, 3p6, 4s1, 3d10. This pattern follows the principles of the Aufbau principle, which prescribes that electrons will fill the lowest available energy levels before moving up to higher energy levels.
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The condensation of water has a negative δh and a negative δs. what can you conclude about the spontaneity of the process? view available hint(s) the condensation of water has a negative and a negative . what can you conclude about the spontaneity of the process? spontaneous at low temperatures. spontaneous at all temperatures. spontaneous at high temperatures. nonspontaneous at all temperatures
Answer:
H S G spon/ non spont
- + - spont at all Temperature
+ - + non spont at all Temperature
- - - at low tenmperature spont
+ + - at high Temperature spont
For condensation to take place there should be noticeable difference between the temperature of the system and the atmosphere. The correct option is option A.
What is condensation?Condensation is a process in which the vapor state converts to liquid state. Condensation is the reverse process of evaporation. Condensation occur at dew point. Dew point is the temperature at which condensation starts.
To see the spontaneity of a reaction following reaction should be taken into consideration
ΔG=ΔH-TΔS
the value of ΔH and ΔS are given in negative. So for condensation to be spontaneous, ΔG should be negative and for this the value of ΔH must be more negative than the value of ΔS and this happens at low temperature.
ΔH ΔS ΔG spontaneous/ non spontaneous
- + - spontaneous at all Temperature
+ - + non spontaneous at all Temperature
- - - at low temperature spontaneous
+ + - at high Temperature spontaneous
Therefore, the correct option is option A.
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Polonium (Po) decays by alpha emission. What will be the mass number of the new atom produced by the alpha decay of Po?
The mass number of the new atom produced by the alpha decay of Polonium (Po) will decrease by 4, as an alpha particle (consisting of 2 protons and 2 neutrons) is emitted.
Explanation:The mass number of a new atom produced by the alpha decay of Polonium (Po) will be reduced by 4. This is because during alpha decay, an atom emits an alpha particle, which consists of 2 protons and 2 neutrons, equivalent to a helium-4 nucleus. Therefore, the subtraction of these particles from the parent atom result in a decrease in the mass number by 4.
For example, if we consider Polonium-209 undergoing alpha decay, we use the subtraction method (209 - 4 = 205) to determine the mass number of the resulting atom, which in this case would be Lead-205 (Pb-205). This is consistent with the general pattern observed in radioactive decay of heavy nuclei.
What is the molar mass of MgCl2? Report your answer to the nearest 0.1 g/mol.
Answer:
95.2 g/mol
Explanation:
To calculate the molar mass of MgCl2
We have to separately see the molar masses of Magnesium and Chlorine
Molar mass of Magnesium: 24.305 g/mol
Molar mass of Chlorine: 35.453 g/mol
As there are two atoms of chlorine in the said molecule so the molar mass of chlorine will be multiplied by 2.
35.453*2 = 70.906 g/mol
So the total molar mass of the said molecule = Molar mass of Mg + Molar mass of two atoms of chlorine
= 24.305 + 70.906
=95.211 g/mol
Rounding off to .1
95.2 g/mol
The molar mass of magnesium chloride (MgCl₂) is calculated by summing the molar mass of magnesium (24.31 g/mol) with twice the molar mass of chlorine (35.45 g/mol for each Cl), resulting in 95.21 g/mol.
The molar mass of magnesium chloride (MgCl₂) can be calculated by adding the molar masses of magnesium (Mg) and chlorine (Cl) in the compound. Magnesium has a molar mass of 24.31 g/mol, and since there are two chlorine atoms in MgCl₂, we must consider the molar mass of Cl (approximately 35.45 g/mol) twice.
Thus, the molar mass of MgCl₂ is calculated as:
24.31 g/mol (for Mg) + 2 * 35.45 g/mol (for Cl) = 95.21 g/mol.
Therefore, the molar mass of MgCl₂ is 95.21 g/mol, which we would report to the nearest 0.1 g/mol as required.
The viscosity of polymers __________ as the cross-linking increases within the polymer.
A)
increases
B)
decreases
C)
multiples
D)
stays the same
The viscosity of polymers A) increases as the cross-linking increases within the polymer.
Explanation:A cross-linking increases the viscosity of the polymer. Cross-link is the bond that links properly, one polymer to other. The viscosity is highly increased because it connects the separate gel polymers together and tightly.
As cross-linker links the polymer together so the actual molecular weight of the polymer is increased, which significantly increases the viscous property of the element. Not only viscosity, the cross linking also increases the strength of the compound.
Final answer:
The viscosity of water decreases as temperature increases due to molecular interactions. Chain entanglement affects polymer viscosity, and increased cross-linking in polymers results in increased viscosity.
Explanation:
B. As temperature increases, the viscosity of water decreases due to changes in molecular interactions. When temperature rises, the kinetic energy of the water molecules increases, causing them to move faster and disrupt the intermolecular forces, leading to decreased viscosity.
Chain entanglement is another factor affecting viscosity in polymers. When polymer chains are entangled, the viscosity of the solution increases due to the resistance encountered as the chains move. However, at very high rates of shear strain, where entanglements aren't formed, viscosity doesn't increase as expected.
In the case of polymers with increased cross-linking, the viscosity will increase as the rotational motion within the polymer decreases, requiring more energy to overcome the restrictions, ultimately leading to higher transitional temperatures.
#15 fill in the following table regarding ions
Answer:
[tex]P^{3-}[/tex] Anion Gained 3 18
[tex]Sr^{2+}[/tex] Cation Lost 2 36
[tex]Fe^{3+}[/tex] Cation Lost 3 23
Explanation:
Looking at the ionic notation, the negative symbol (-) indicates that there are more electrons than protons and the positive symbol (+) indicates that there are more protons than electrons.
The number tells you how many was gained or lost.
To determine how many electrons are left, you base this off how many protons there are. The number of protons in an atom is expressed by the atomic number. In a stable atom, you have an equal number of protons and electrons.
Ions occur when electrons are gained or lost.
A cation is positively charged because it LOST an electron. Since there are more protons than electrons, the charge would be positive.
An anion is negatively charged because it gained an electron. Since there are more electrons than protons, the charge would be negative.
Using the explanation above, you can see how the answers were obtained. As for the last column, just use basic math to do this.
The atomic number of Phosphorus (P) is 15, so this means that there are 15 protons. Since it gained 3 electrons, just add 3 to 15:
15 + 3 = 18
Sr has an atomic number 38. Since it lost 2 electrons, just subtract 2 from the atomic number.
38-2 = 36
Fe has an atomic number 26. It lost 3 electrons, so we subtract again.
26-3 = 23
What should one avoid if they are suffering from acid reflux (too much acid in the body)? (Choose all that apply)
Tomato juice
Black coffee
Lemon juice
Orange juice
Answer:
- Tomato juice
- Lemon juice
- Orange juice
Explanation:
If someone is suffering from acidic reflux then it would be for the best if that person avoids food and drinks that can contribute to even higher acidic content in that person's organism. The easiest way to know what should be avoided is to get informed about the Vitamin C content of the foods and drinks. The fruits in general are something that should be avoided in this kind of circumstances, especially the tomatoes, lemons, and oranges, as they are highly acidic, so any products from them, especially in the form of juice, should be avoided.
Hydrocarbons that have one or more double or triple bonds are _____.
A. unsaturated
B. saturated
C. aromatic
D. substituted
Answer:
A. Aromatic
Explanation:
Answer: A. unsaturated
Explanation:
Saturated hydrocarbons are defined as the hydrocarbons in which a single bond is present between carbon and carbon atoms. The general formula for these hydrocarbons is [tex]C_nH_{2n+2}[/tex]
Unsaturated hydrocarbons are defined as the hydrocarbons which have double or triple covalent C-C bonds. They are known as alkenes and alkynes respectively. The general formula for these hydrocarbons is [tex]C_nH_{2n}[/tex] and [tex]C_nH_{2n-2}[/tex]
Aromatic hydrocarbons are those hydrocarbons in which Huckel's rule [tex](2n+2)\pi[/tex] is obeyed. Example: Benzene
Substituted hydrocarbons are those hydrocarbons in which hydrogen is replaced by some other element. Example: [tex]CH_3Cl[/tex]
What is another name of a chain of amino acids
Answer:
Amino acids are the structural units (monomers) that make up proteins. They join together to form short polymer chains called peptides or longer chains called either polypeptides or proteins.
Explanation:
These polymers are linear and unbranched, with each amino acid within the chain attached to two neighboring amino acids.
A protein is made up of one or more polypeptide chains are chains of amino acids, whose sequence is encoded by a gene.
What is protein ?A structure composed of amino acids. The body need proteins to operate correctly. They serve as the building blocks for several bodily components, including the skin, hair, and enzymes, cytokines, and antibodies.
These amino acids are arranged in a long chain and joined to one another by covalent peptide bonds to form proteins. Consequently, polypeptides are another name for proteins.
The substances known as amino acids, or the "building blocks of proteins," serve a variety of vital functions in your body.
Thus, protein is made up of one or more polypeptide chains are chains of amino acids, whose sequence is encoded by a gene.
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Acetylene gas, c2h2 is used for welding. a 5 liter supply of acetylene being stored at -23 °c, exerts a pressure of 5 atm. at what temperature would the same number of moles of acetylene, moved to a 10 liter container, produce a pressure of 2 atm
Answer:
T₂(°C) = 200 K = - 73°C.
Explanation:
We can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
If n is constant, and have different values of P, V and T:(P₁V₁T₂) = (P₂V₂T₁)
Knowing that:
P₁ = 5.0 atm, V₁ = 5.0 L, T₁ = -23°C + 273 = 250 K,
P₂ = 2.0 atm, V₂ = 10.0 L, T₂ = ??? K,
Applying in the above equation(P₁V₁T₂) = (P₂V₂T₁)
∴ T₂ = (P₂V₂T₁)/(P₁V₁) = (2.0 atm)(10.0 L)(250 K)/(5.0 atm)(5.0 L) = 200 K.
∴ T₂(°C) = 200 K - 273 = - 73°C.
The temperature at which the same number of moles of acetylene gas will produce a pressure of 2 atm in a 10-liter container is approximately -73.15°C.
Based on the given data, initially, the acetylene gas is stored at -23°C (which is 250.15 K), in a 5-liter container, exerting a pressure of 5 atm.
Step-by-Step Solution:
1. Using the combined gas laws, the formula is:
(P₁ * V₁) / T₁ = (P₂ * V₂) / T₂2. Substitute the known values into the formula:
(5 atm * 5 L) / 250.15 K = (2 atm * 10 L) / T₂3. Simplify and solve for T₂:
T₂ = (2 atm * 10 L) * 250.15 K / (5 atm * 5 L)T₂ = 10000 / (25)T₂ = 200 K4. Convert the temperature back to Celsius:
T₂ = 200 K - 273.15T₂ ≈ -73.15°CHow would the measured ph of the diluted material compare to the ph of the original undiluted sample?
Answer:
It would become more neutral when diluted
Explanation:
Assuming you dilute it with water, the more diluted the substance, the more neutral (and closer to 7), it would be. Ie straight lemon juice is more acidic than lemonade, which is more acidic than water. I hope this helps :)
The pH of a diluted sample would usually be higher than that of the undiluted original, due to the lesser concentration of hydrogen ions in the diluted sample. During titration, there are three main states - initial, pre-equivalence and post-equivalence - and the pH behaves differently in each of these states.
Explanation:The measured pH of a diluted sample would be higher compared to the pH of the original undiluted sample. This is because when a solution is diluted, it has a lower concentration of hydrogen ions (H+), which means it is less acidic and in turn, has a higher pH.
In the initial state, the pH is determined by the acid being titrated. If you have two samples that are equally concentrated; a weaker acid will have a higher initial pH compared to a stronger one.
At the pre-equivalence point (where the volume of added titrant is between 0 and 25 mL), the solution’s pH increases gradually as the acid reacts with added titrant. The observed solution will include unreacted acid and its reaction product, its conjugate base. At the equivalence point one observes a drastic rise in pH as the transition happens from acidic to either neutral (for strong acid sample) or basic (for weak acid sample).
Post-equivalence, the pH is determined by the amount of excess strong base titrant added. Similarly with the increase in volume of the added titrant (> 25 mL), you would notice that the titration curves of the two samples will look quite similar.
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Give the number of covalent bonds that a carbon atom can form.
Answer:
four covalent bonds
Explanation:
A carbon atom would form 4 covalent bonds.
For a covalent bond to be formed, an atom would share its valence electrons with another. In this process, each atom would require unpaired electrons for this bond to be formed. The number of available unpaired electrons would represent the number of electrons needed to complete the outer energy level of the atom.
In a carbon atom, we have no lone pair of electrons and 4 unpaired electrons. When these 4 electrons are shared with those of other atoms, they produce a complete octet which perfectly mimics the noble gases.
1. Criminal profiling assigns crimes as one of two kinds. If a criminal profiler was looking at a case that involved a sophisticated crime ring that was responsible for a string of high-end robberies over the course of two decades, which type of crimes would these be classified as?
Forensic
Behavioral
Organized
Disorganized
2. Profilers are trained that certain psychological disorders tend to arise and peak during certain decades of life.
True
False
Answer:
So, for 1 I am most certain it has to be Organized so C. And for 2 that would be true if my brain isn't failing me- I hope this helps!
Explanation:
Answer: 1. Organized
2. True
Explanation:
1. An organized crime can be define as the crime which is committed by planning. In this crime generally the group of criminals or criminal uses same modus operandi (habit, planning, rule to commit crime).
The given example of crimes is the organized crime. This is because a sophisticated crime ring was found associated with many robberies. Hence, this can be said that similar modus-operandi is involved.
2. The profilers are those who are occupational criminals. They are trained with the fact that psychological disorders so as to defend themselves when they are caught red handed while committing crimes. They pose an evidence of their unstable or unsound mind.
A sample of nitrogen occupies 10.0 liters at 25°c and 98.7 kpa. What would be the volume at 20°c and 102.7 kpa?
Answer:
9.4 literExplanation:
1) Data:
V₁ = 10.0 L T₁ = 25°C = 25 + 273.15 K = 298.15 K P₁ = 98.7 Kpa T₂ = 20°C = 20 + 273.15 K = 293.15 K P₂ = 102.7 KPa V₂ = ?2) Formula:
Used combined law of gases:
PV / T = constant P₁V₁ / T₁ = P₂V₂ / T₂3) Solution:
Solve the equation for V₂:
V₂ = P₁V₁ T₂ / (P₂ T₁)Substitute and compuite:
V₂ = P₁V₁ T₂ / (P₂ T₁)V₂ = 98.7 KPa × 10.0 L × 293.15 K / (102.7 KPa × 298.15 K) V₂ = 9.4 liter ← answer
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The correct volume of the nitrogen sample at 20°C and 102.7 kPa is approximately 11.3 liters.
To solve this problem, we can use the combined gas law, which states that for a given amount of gas, the product of pressure and volume divided by the temperature is constant:
[tex]\[\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}\][/tex]
Given:
[tex]\(P_1 = 98.7\) kPa\\ \(V_1 = 10.0\) liters\\ \(T_1 = 25C + 273.15 = 298.15\) K (converted to Kelvin)\\ \(P_2 = 102.7\) kPa\\\(T_2 = 20C + 273.15 = 293.15\) K (converted to Kelvin)[/tex]
We want to find [tex]\(V_2\)[/tex], the final volume. Rearranging the combined gas law equation to solve for [tex]\(V_2\)[/tex], we get:
[tex]\[V_2 = \frac{P_1V_1T_2}{P_2T_1}\][/tex]
Substituting the given values:
[tex]\[V_2 = \frac{(98.7\text{ kPa})(10.0\text{ L})(293.15\text{ K})}{(102.7\text{ kPa})(298.15\text{ K})}\] \[V_2 = \frac{(98.7)(10.0)(293.15)}{(102.7)(298.15)}\] \[V_2 = \frac{289480.05}{306469.85}\] \[V_2 \approx 11.3\text{ L}\][/tex]
Therefore, the volume of the nitrogen sample at 20°C and 102.7 kPa is approximately 11.3 liters.
Which statement best describes the electronegativity of an element?
A.
Electronegativity of an atom is its ability to lose electrons during cation formation.
B.
Electronegativity of an atom is its ability to share electrons during a covalent bond formation.
C.
Electronegativity of an atom is its ability to gain electrons during anion formation.
D.
Electronegativity of an atom is its ability to produce energy while losing an electron.
E.
Electronegativity of an atom is its ability to attract electrons during bond formation.
Answer: The correct answer is Option E.
Explanation:
Electronegativity is the chemical property of an element. This is defined as the tendency of an atom to attract the shared pair of electrons towards itself when a bond is formed.
This property of an atom increases as we move from left to right in a period because the number of charge on the nucleus increases.
But this property decreases as we move from top to bottom in a group because electrons get added up in the new shells which make it further far away from the nucleus.
Thus, the correct answer is Option E.
Urgent 25 points!!
Amanda was asked to make a solution of salt water using 32.0 grams of NaCl and 0.75 Liter of water. Amanda realized that first, she needed to find the number of moles there are in 32 grams of NaCl. She set up the following calculation to find the number of moles of NaCl.
32.0 g NaCl x 1 mole NaCl = 0.55 moles of NaCl
58.45 g NaCl
A. Did Amanda find the number of moles of NaCl correctly? If not, explain.
B. What does Amanda need to do next to calculate the molarity of the NaCl solution? Show your work for full credit.
Answer:
A. Yes, Amanda find the number of moles of NaCl correctly.
B. 0.73 M.
Explanation:
A. Did Amanda find the number of moles of NaCl correctly? If not, explain.
Yes, Amanda find the number of moles of NaCl correctly.The relation to find the no. of moles of NaCl is:No. of moles (n) of NaCl = mass/molar mass.
mass of NaCl = 32.0 g, molar mass of NaCl = 58.45 g/mol.
∴ No. of moles (n) of NaCl = mass/molar mass = (32.0 g)/(58.45 g/mol) = (32.0 g NaCl)*(1 mol of NaCl)/(58.45 g NaCl) = 0.547 mol ≅ 0.55 mol.
B. What does Amanda need to do next to calculate the molarity of the NaCl solution? Show your work for full credit.
Molarity is the no. of moles of solute dissolved in a 1.0 liter of a solution.
∴ M = (no. of moles of NaCl)/(volume of solution (L)) = (0.55 mol)/(0.75 L) = 0.73 M.
Can Sodium be used to distinguish between cyclobutanol and butanoic acid
Answer:
[tex]\boxed{\text{No}}[/tex]
Explanation:
Na reacts with all OH groups to produce hydrogen.
The reaction with cyclobutanol is shown below.
The reaction with butanoic acid is
[tex]\rm CH_{3}CH_{2}CH_{2}COOH\xrightarrow{\text{Na}} CH_{3}CH_{2}CH_{2}COO^{-} + H_{2}[/tex]
Both compounds release bubbles of hydrogen, so you can't use sodium to distinguish between them.
Can y’all help me solve these three questions on my review packet?
Answer:
12.
Infrared has the lower frequency while visible light has a higher frequency.
13.
As = 33
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p³
K = 19
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
Sr = 38
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s²
Kr = 36
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶
14. SEE ATTACHED PICTURE
Explanation:
12. The relationship between wavelength and frequency can be seen in the equations:
[tex]F=\dfrac{c}{\lambda}[/tex] and [tex]\lambda=\dfrac{c}{F}[/tex]
Where:
λ = wavelength
F = frequency
c = constant (speed of light)
As you can see that they are indirectly proportional. So as the frequency increases, the wavelength decreases and vis-a-vis.
13. Electronic configuration of an element can be determined using the pattern attached. It determines the electronic structure of an atom. Remember:
s subshell holds 2 electrons
p subshell holds 6 electrons
d subshell holds 10 electrons
f subshell holds 14 electrons
You know when to stop when the number of electrons sum up to the atomic number (which is the number of protons) in a stable atom.
As = 33
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p³ (Stop here because the electrons sum up to 33)
K = 19
1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
Sr = 38
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s²
Kr = 36
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶
14. Lewis Dot symbol represents how many valence electrons an atom has. You can determine the Lewis Dot Structure also based on the electronic configuration of the element by adding up the number of electrons there are in the highest energy level. The energy level is indicated by the numerical coefficient.
S = 16
1s² 2s² 2p⁶ 3s² 3p⁴
Notice that the highest energy level that appears here is 3, so add up the number of electrons.
2 + 4 = 6 (This is how many valence electrons Sulfur (S) has.)
So we draw the symbol of Sulfur and put three dots around it.
C = 6
1s² 2s² 2p²
2 + 2 = 4
Sr = 38
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s²
2 valence electrons (Because there are only 2 electrons in the 5th energy level)
*Fe = 26
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
2 valence electrons (Because there are only 2 electrons in the 4th energy level)
Al = 13 1s² 2s² 2p⁶ 3s² 3p¹
2 + 1 = 3
*Note: Fe or Iron is a transition metal. Technically, 3d in this case is a higher energy level. However, when it comes to Lewis dot structure, d and f shells that are not filled are usually omitted, so it will follow the 4s. Generally when putting dots around we follow the sequence of the X element shown in the attached file.
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When 0.5 g of powdered iron (III) oxide was added to 100 cm3 of hydrogen peroxide, water and oxygen were produced. Iron (III) oxide was not used up in the reaction. Based on the information, which of the following is likely to increase the rate formation of the products?
A. Replacing the powdered iron oxide with its cubical crystals
B. Using 150 cm3 of hydrogen peroxide
C. Removing iron oxide from the reaction mixture
D. Using 1.0 gram of iron oxide
Its B. Using 150 cm3 of hydrogen peroxide
The answer is B because when you calculate it you will get the same amount of hydrogen peroxide.
Good luck,!
Which compound is bonded covalently? A.KF B.MgS C.BeO D.SO2
Answer:
SO2 is bonded covalently
Explanation:
Atoms that share electrons in a chemical bond have covalent bonds.
Radioactive iodine-131 has a half-life of eight days. The amount of a 200.0 gram sample left after 32 days would be
Answer:
12.5 g
Explanation:
Nuclear half-life,
t
1/2
, is the amount of time required for a quantity of a radioactive material to fall to half its value as measured at the beginning of the time period.
Iodine-131 is a radioactive isotope with a half-life of 8 days. After 32 days, or four half-lives, the original 200 gram sample of iodine-131 would decay leaving only 12.5 grams of the radioactive isotope.
Explanation:The subject of your question falls under Physics, particularly in the area of nuclear chemistry, where we study radioactivity and nuclear decay. In your case, you're talking about Iodine-131, a radioactive isotope with a half-life of 8 days.
The half-life concept means that, in a given time period, half of the initial sample would have decayed. Here, you have an initial amount of 200 grams, and after four half-lives (since 32 days is 4 times the half-life of 8 days), only 1/16th of the original sample is undecayed because the material halves each time (1/2 after 1 half-life, 1/4 after 2 half-lives, 1/8 after 3 half-lives, and so forth).
Accordingly, after 32 days, or four half-lives, 200 grams of Iodine-131 would reduce to 200/16 = 12.5 grams.
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In an acid-base neutralization reaction 38.74 ml of 0.500 m potassium hydroxide reacts with 50.00 ml of sulfuric acid solution. What is the concentration of the h2so4 solution?
Answer:
0.2 M.
Explanation:
For the acid-base neutralization, we have the role:The no. of millimoles of acid is equal to that of the base at the neutralization.
∴ (XMV) KOH = (XMV) H₂SO₄.
X is the no. of reproducible H⁺ (for acid) or OH⁻ (for base),
M is the molarity.
V is the volume.
For KOH:X = 1, M = 0.5 M, V = 38.74 mL.
For H₂SO₄:X = 2, M = ??? M, V = 50.0 mL.
∴ M of H₂SO₄ = (XMV) KOH/(XV) H₂SO₄ = (1)(0.5 M)(38.74 mL)/(2)(50.0 mL) = 0.1937 M ≅ 0.2 M.
The concentration of the sulfuric acid (H2SO4) in the solution is 0.1937 M, as calculated by using the balanced chemical equation for the reaction, the stoichiometric ratio of the reactants, and the principle of molarity.
Explanation:The student is asking about an acid-base neutralization reaction involving a known volume and concentration of potassium hydroxide reacting with a known volume but an unknown concentration of sulfuric acid. The goal is to calculate the concentration of the sulfuric acid.
To answer this, we first need to know that the balanced chemical equation for this reaction is: H2SO4 + 2KOH -> K2SO4 + 2H2O. According to this stoichiometry, it takes one molecule of sulfuric acid to neutralize two molecules of potassium hydroxide. Therefore, the moles of potassium hydroxide is 0.01937 mol (calculated by volume (in liters) multiplied by molarity).
Based on the stoichiometric ratio, the required moles of sulfuric acid to the given moles of potassium hydroxide is 0.009685 mol. We can then calculate the concentration of H2SO4 by dividing this value by its volume (in liters): 0.009685 mol / 0.05 L = 0.1937 M.
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A sealed, insulated calorimeter contains water at 310 K. The surrounding air temperature is 298 K, and the water inside the calorimeter remains at 310 K two hours later. What type of system does the calorimeter attempt to model?
A closed system, because energy can enter or leave the system, but matter cannot.
A closed system, because neither heat nor matter is entering or leaving the container.
An isolated system, because energy can enter or leave the system, but matter cannot.
An isolated system, because neither heat nor matter is entering or leaving the container.
Answer:
An isolated system, because neither heat nor matter is entering or leaving the container.
Explanation:
In a closed system there is no exchange of heat but matter is exchanged. In an isolated system there is no exchange of heat or matter. Here the temperature of water remains constant at 310 K, which means that no heat is exchanged. Also there is no decreases in volume of water the calorimeter after 2 hours, which means that no matter was lost either. Therefore this is an isolated system.
1.) What coefficient values will balance the reaction shown? CH4 + O2 ?CO2 + H2O
A.1,1,1,1
B.1,2,1,2
C.2,1,2,1
D.1,1,2,1
2.) Which is a balanced equation for this reaction?
A.KOH + H3PO4?K3PO4 + H2O
B.3KOH + H3PO4 ?K3PO4 + 3H2O
C.KOH + 2H3PO4?K3PO4 + 3H2O
D.3KOH + 2H3PO4?K3PO4 + 3H2O
3.) Which is a balanced equation for this reaction?A.NH3 + O2?NO + H2O
B.4NH3 + O2?2NO + 3H2O
C.2NH3 + O2?2NO + 3H2O
D.4NH3 + 5O2?4NO + 6H2O
4.) Which is a balanced equation for this reaction?A.B2Br6 + 6HNO3?2B(NO3)3 + 6HBr
B.B2Br6 + 3HNO3?B(NO3)3 + 3HBr
C.B2Br6 + 2HNO3?2B(NO3)3 + 6HBr
D.B2Br6 + 2HNO3?2B(NO3)3 + 3HBr
5.) Balance the equation by calculating the coefficients. P4 + O2?P2O5
A.1,5,2
B.1,1,2
C.1,5,1
D.1,2,3
Answer:
It's simpler than most questions :)
Explanation:
1) B
2) B
3) D
4) A
5) A
Hope this will help :)
The molar mass of an element is the mass of one
Answer:
The molar mass of an element is the mass of one mole of atoms of the element.Explanation:
The molar mass of an element is its atomic mass, i.e. the mass in grams of one mole of atoms of the element.
Remember 1 mol is approximately 6.022 × 10²³.
So, 1 mol of atoms is 6.022 × 10²³ atoms.
The molar mass is an average: it is the weighted average mass of the natural isotopes of the element, taking into account their relative abundance.
For example, the molar mass or atomic mass of carbon is 12,0107 g/mol, instead of 12.0000, becasue carbon exists in several forms (isotopes), and so the weighted average is not a whole number.
How much heat is released when 105 g of steam at 100.0°C is cooled to ice at -15.0°C? The enthalpy of vaporization of water is 40.67 kJ/mol, the enthalpy of fusion for water is 6.01 kJ/mol, the molar heat capacity of liquid water is 75.4 J/(mol • °C), and the molar heat capacity of ice is 36.4 J/(mol • °C).
Final answer:
To determine the amount of heat released when cooling 105 g of steam at 100.0°C to ice at -15.0°C, we calculate the heat released during condensation, cooling of water, freezing, and further cooling of ice to the final temperature, totaling 319.4 kJ of heat released.
Explanation:
To calculate the total heat released when 105 g of steam at 100.0°C is cooled to ice at -15.0°C, we will break down the process into several steps and calculate the heat change for each step. The molecular weight of water (H2O) is approximately 18 g/mol, so the number of moles of water in 105 g is 105 g / 18 g/mol = 5.83 mol.
First, steam is condensed to liquid water at 100.0°C. The heat released is calculated using the enthalpy of vaporization: Heat = number of moles × enthalpy of vaporization = 5.83 mol × 40.67 kJ/mol = 237.3 kJ.Next, the liquid water is cooled from 100.0°C to 0°C. The heat released is: Heat = number of moles × heat capacity of liquid water × temperature change = 5.83 mol × 75.4 J/mol°C × 100°C = 43.9 kJ.Then, the liquid water is frozen at 0°C. The heat released during freezing is: Heat = number of moles × enthalpy of fusion = 5.83 mol × 6.01 kJ/mol = 35.0 kJ.Finally, the ice is cooled from 0°C to -15.0°C. The heat released is: Heat = number of moles × heat capacity of ice × temperature change = 5.83 mol × 36.4 J/mol°C × 15°C = 3.2 kJ.The total heat released during the whole process is the sum of heat released in each step: 237.3 kJ + 43.9 kJ + 35.0 kJ + 3.2 kJ = 319.4 kJ.
A bunch of amino acids attached together is called a
Answer:
They join together to form short polymer chains called peptides or longer chains called either polypeptides or proteins.
Explanation:
A bunch of amino acids attached together is called a protein.
Explanation:Proteins are complex macromolecules essential for various biological functions. They consist of amino acids linked together through peptide bonds. Amino acids, the building blocks of proteins, have distinct structures and properties. The specific sequence and arrangement of these amino acids in a protein dictate its unique function.
Proteins play crucial roles in the body, including enzymes that catalyze chemical reactions, structural components like collagen, and antibodies that defend against pathogens. They also serve as hormones, transport molecules, and provide mechanical support. The diversity of proteins and their functions underpins the complexity of life processes, making them fundamental to all living organisms.
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If you were given two transparent liquids how would you determine which is pure and which is salt water
Jeff used an equal arm balance to weigh a 4.312 g sample of sodium chloride. Which of these measurements made by Jeff is the most accurate? (5 points) 4.5 g 4.1 g 4.2 g 4.3 g
Answer:
4.3.
Explanation:
Measurements that are close to the known value are said to be accurate, whereas measurements that are close to each other are said to be precise.The most closest measurement to the known value is 4.3 g.So, the right choice is: 4.3 g.Answer: The most accurate measurement made by Jeff is 4.3 g
Explanation:
Accuracy is defined as the closeness of a measured value to a standard or known value.
For Example: If the mass of a substance is 58 kg and one person weighed 57 kg and another person weighed 60 kg. Then, the weight measured by first person is more accurate.
We are given:
Mass of the sample = 4.312 g
So, the measurement close to 4.312 grams will be the accurate value.
Hence, the most accurate measurement made by Jeff is 4.3 g
Which half-reaction correctly represents reduction?
A) Ag -> Ag+ + e–
B) F2 -> 2 F– + 2e–
C) Au3+ + 3e– -> Au
D) Fe2+ + e– -> Fe3+
The half-reaction that is correctly represents reduction is Au₃⁺ + 3e– -> Au. The correct option is C.
What is half-reactions?
The half-reaction is an oxidation and reduction reaction of a redox reaction. It can be either oxidation or reduction. The half-reaction occurs due to change in oxidation state of a reactant.
An example is Zn Cu galvanic cell.
Thus, the correct option is C) Au3+ + 3e– -> Au.
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What is the oxidation state of nitrogen in nano2
Answer:
Therefore, the oxidation state of N in NaNO₂ is +3
Explanation:
Problem: calculating the oxidation state of nitrogen N in NaNO₂
let us denote the oxidation number of Nitrogen as N:
We know from the periodic table that Na has an oxidation number of +1 i.e it will readily want to lose 1 electron so as to complete its octet.
Oxygen is known to have an oxidation number of -2
Summation of the oxidation number of each atoms is 0 for neutral compound.
Therefore to calculate the oxidation state of Nitrogen in NaNO₂, we express as:
+1 + N + (-2 x 2) = 0
1 + N = 4
N = 4-1 = +3
Therefore, the oxidation state of N in NaNO₂ is +3