what is the sum of protons and neutrons in an atomic nucleus?
Which of the following reactions is not an example of an oxidation-reduction reaction? ( 2 points) Select one: a. H2 + F2yields 2HF b. Fe + CuSO4yields FeSO4 + Cu c. CuSO4 + 2NaOH yields Cu(OH)2 + Na2SO4 d. Cl2 + ZnI2yields ZnCl2 + I2
The chart seen here shows the decay of a sample of carbon-14 over a period of 33,000 years. What is the approximate half-life of carbon 14?
5,500 ears if u using usatestprep
How many valence electrons are in the trimethylammonium ion ch33nh+ ?
The trimethylammonium ion (CH3)3NH+ has a total of 25 valence electrons after accounting for its positive charge; 26 electrons from the combined valence electrons of nitrogen, carbon, and hydrogen atoms and subtracting one electron for the positive charge.
Explanation:To calculate the number of valence electrons in the trimethylammonium ion (CH3)3NH+, we first need to sum the valence electrons of all the atoms. Nitrogen (N) has 5 valence electrons, each hydrogen (H) atom has 1, and each carbon (C) atom has 4. Since there are three methyl groups (CH3), we have 3 carbons and 9 hydrogens:
Nitrogen: 5 valence electrons3 Carbons: 3 × 4 = 12 valence electrons9 Hydrogens: 9 × 1 = 9 valence electronsAdding these up gives 5 + 12 + 9 = 26 valence electrons. However, since we have a positively charged ion (NH+), we need to subtract one electron to account for the charge. This leaves us with a total of 25 valence electrons in the trimethylammonium ion. When drawing the Lewis structure of this polyatomic ion, it is also common practice to enclose the structure in brackets and denote the charge outside of it.
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The trimethylammonium ion, [tex](CH\(_3\))\(_3\)NH\(^+\)[/tex], has 0 valence electrons.
The trimethylammonium ion, [tex](CH\(_3\))\(_3\)NH\(^+\),[/tex]is composed of a nitrogen atom bonded to three methyl groups [tex](CH\(_3\))[/tex] and a hydrogen atom, with an additional positive charge indicating the loss of an electron compared to the neutral molecule.
First, let's consider the valence electrons in the neutral trimethylamine molecule, [tex](CH\(_3\))\(_3\)NH,[/tex] before it gains a positive charge:
Each hydrogen atom contributes 1 valence electron, and there are 12 hydrogen atoms in total (3 from each methyl group and 1 from the amine group), contributing 12 valence electrons.Each carbon atom contributes 4 valence electrons, and there are 3 carbon atoms in total (one in each methyl group), contributing 12 valence electrons.The nitrogen atom contributes 5 valence electrons. Adding these up gives us the total number of valence electrons in the neutral molecule: 12 (from hydrogen) + 12 (from carbon) + 5 (from nitrogen) = 29 valence electrons. Now, when the molecule gains a positive charge to become the trimethylammonium ion, it loses one electron. Therefore, the number of valence electrons in the ion is 29 - 1 = 28 valence electrons. However, the question asks for the number of valence electrons that are not involved in bonding, which is the definition of a lone pair. In the trimethylammonium ion, all of the valence electrons are involved in bonding: each hydrogen is bonded to a carbon or nitrogen, each carbon is bonded to three hydrogens and the nitrogen, and the nitrogen is bonded to three carbons and one hydrogen. There are no lone pairs of electrons on the nitrogen because it has formed four bonds, which means all eight of its valence electrons are involved in bonding.
Decide if the following statements regarding Intermolecular forces are True or False.
Cl2 will have a higher boiling point than Ar.
NH3 will have a lower vapor pressure at -50oC than NO.
LiF will have a higher vapor pressure at 25oC than H2S.
As the polarity of a covalent compound increases, the solubility of the compound in CCl4 decreases.
Cl2 will have a higher melting point than HBr.,
The correct options are the following:
False -Cl2 will have a higher boiling point than Ar.
True -NH3 will have a lower vapor pressure at -50oC than NO.
False -LiF will have a higher vapor pressure at 25oC than H2S.
True -As the polarity of a covalent compound increases, the solubility of the compound in CCl4 decreases.
True -Cl2 will have a higher melting point than HBr.
What are intermolecular forces?Intermolecular forces are those forces which intermediate the interaction between different molecules.
If the intermolecular force between molecules is lower, then the vapor pressure will be lowered and higher the boiling point will be.
Thus, the options are:A -false, B -True, C -False, D -True, E -True.
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Final answer:
The boiling point of a substance is determined by the strength of its intermolecular forces. Cl2 will have a higher boiling point than Ar due to stronger dispersion forces. NH3 will have lower vapor pressure than NO due to stronger hydrogen bonds. LiF will have higher vapor pressure than H2S due to stronger electrostatic interactions. As the polarity of a covalent compound increases, its solubility in CCl4 decreases. Cl2 will have a higher melting point than HBr due to stronger London dispersion forces.
Explanation:
The boiling point of a substance is determined by the strength of the intermolecular forces between its particles. In general, substances with stronger intermolecular forces have higher boiling points. Therefore, we can determine the relative boiling points of the given substances based on their intermolecular forces:
Cl2 will have a higher boiling point than Ar. Cl2 is a nonpolar molecule that exhibits London dispersion forces, while Ar is also a nonpolar molecule but with larger and heavier atoms, resulting in stronger dispersion forces.NH3 will have a lower vapor pressure at -50oC than NO. NH3 is a polar molecule that can form hydrogen bonds, which are stronger than the dipole-dipole interactions in NO.LiF will have a higher vapor pressure at 25oC than H2S. LiF is an ionic compound with strong electrostatic interactions, while H2S is a covalent compound with weaker London dispersion forces.As the polarity of a covalent compound increases, the solubility of the compound in CCl4 decreases. Polar covalent compounds tend to dissolve better in polar solvents like CCl4, while nonpolar covalent compounds are less soluble.Cl2 will have a higher melting point than HBr. Both Cl2 and HBr are nonpolar molecules, but Cl2 has a larger molar mass than HBr, resulting in stronger London dispersion forces and thus a higher melting point.The combustion of acetylene gas is represented by this equation: 2c2h2(g) + 5o2(g) → 4co2(g) + 2h2o(g) how many grams of co2 and grams of h2o are produced when 52.0 g c2h2 burn in oxygen?
A. The mass of CO₂ produced is 176 g.
B. The mass of H₂O produced is 36 g
We'll begin by calculating the mass of C₂H₂ that reacted and the masses of CO₂ and H₂O produced from the balanced equation.
2C₂H₂ + 5O₂ —> 4CO₂ + 2H₂O
Molar mass of C₂H₂ = (2×12) + (2×1) = 26 g/mol
Mass of C₂H₂ from the balanced equation = 2 × 26 = 52 g
Molar mass of CO₂ = 12 + (16×2) = 44 g/mol.
Mass of CO₂ from the balanced equation = 4 × 44 = 176 g
Molar mass of H₂O = (2×1) + 16 = 18 g/mol
Mass of H₂O from the balanced equation = 2 × 18 = 36 g
SUMMARY:
From the balanced equation above,
52 g of C₂H₂ reacted to produce 176 g of CO₂ and 36 g of H₂O.
From the above, we can see that 52 g of C₂H₂ produced:
176 g of CO₂36 g of H₂OLearn more about stoichiometry:
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What is the maximum amount of kcl that can dissolve in 200 g of water? (the solubility of kcl is 34 g/100 g h?
Which of these redox reactions is spontaneous as written?
A. Ni + Mg2+ → Ni2+ + Mg
B. Al + Fe3+ → Al3+ + Fe
C. Hg + Al3+ → Hg2+ + Al
D. Zn + K+ → Zn2+ + K,
Redox reactions is spontaneous as written- Zn + K+ → Zn2+ + K. Option D is correct.
To determine which of these redox reactions is spontaneous as written, we can look at the standard reduction potentials of the involved half-reactions. In electrochemistry, spontaneous redox reactions occur when the reduction potential of the oxidizing agent (left side) is more positive than that of the reducing agent (right side). In other words, the spontaneous reaction goes from a higher reduction potential to a lower one. Let's evaluate each reaction:
A. Ni + Mg^2+ → Ni^2+ + Mg
Reduction potential for Ni^2+ → Ni: -0.25 V
Reduction potential for Mg^2+ → Mg: -2.37 V
The reduction potential for the left side is more positive than that for the right side, so this reaction is spontaneous as written.
B. Al + Fe^3+ → Al^3+ + Fe
Reduction potential for Al^3+ → Al: -1.66 V
Reduction potential for Fe^3+ → Fe: -0.04 V
The reduction potential for the left side is more positive than that for the right side, so this reaction is also spontaneous as written.
C. Hg + Al^3+ → Hg^2+ + Al
Reduction potential for Al^3+ → Al: -1.66 V
Reduction potential for Hg^2+ → Hg: -0.85 V
The reduction potential for the left side is more positive than that for the right side, so this reaction is spontaneous as well.
D. Zn + K^+ → Zn^2+ + K
Reduction potential for K^+ → K: -2.92 V
Reduction potential for Zn^2+ → Zn: -0.76 V
In this case, the reduction potential for the left side is less positive than that for the right side, so this reaction is not spontaneous as written.
Option D
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A chemist requires 0.446 mol na2co3 for a reaction. how many grams does this correspond to?
Final answer:
To calculate the mass of 0.446 mol Na₂CO₃, multiply the number of moles by its molar mass of 105.98 g/mol, resulting in 47.27 grams of Na₂CO₃.
Explanation:
To find out how many grams 0.446 mol of Na₂CO₃ corresponds to, we can use the molar mass of Na₂CO₃.
First, we should recall the molar mass of Na₂CO₃. Using the atomic masses Na (22.99), C (12.00), and O (16.00), the molar mass would be:
(2 × 22.99) + 12.00 + (3 × 16.00) = 105.98 g/mol
Now, we can calculate the mass of 0.446 mol of Na₂CO₃:
0.446 mol Na₂CO₃ × 105.98 g/mol = 47.27 grams
When protons and neutrons join together to make a nucleus, energy is?
When two substances that cannot dissolve each other are mixed, a mixture is formed. a heterogeneous mixture that has very small dispersed particles and stays mixed for a long time is
a. a heterogeneous mixture that has larger dispersed particles that settle over time is
a?
When two substances that cannot dissolve each other are mixed, a mixture is formed. a heterogeneous mixture that has very small dispersed particles and stays mixed for a long time is a "Colloid"
An example of colloid can be gels, sols, or emulsions; where solids or liquids are dispersed in the mixture. It usually takes very long time to settle down.
Answer 2) SuspensionExplanation :A heterogeneous mixture that has larger dispersed particles that settle over time is a "Suspension"
Suspensions are those mixtures which usually has large particles and which takes comparatively less time than colloids to get settled. Like salt water, muddy water, fine sand in water, etc.
Answer:
First one is: heterogeneous
Second one is: colloid
Third one is: suspension
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Explanation:
Upon combustion, a 0.8376 g sample of a compound containing only carbon, hydrogen, and oxygen produces 1.6003 gco2 and 0.9827 gh2o. find the empirical formula of the compound.
I really need some help and explaining with the Heat of Combustion Lab.
1. You may recall that the products of the complete combustion of a hydrocarbon are water vapor and carbon dioxide gas. Write the balanced equation showing the combustion of methane. Do not forget to include the states of matter of the reactants and the products. Hint: Methane is a gas at standard temperature and pressure.
______ tend to lose electrons in chemical reactions, forming positive ions. nonmetals tend to _____ electrons in chemical reactions, forming negative ¬¬¬¬¬¬¬ions. gaining or losing electrons makes an atom an ____. gaining or losing ______ makes an atom an isotope. however, gaining or losing a ______ makes an atom into a completely different _________.
Which of the following statements is true?
-Neon is inert because its outermost shell is complete.
-Nitrogen is inert because its outermost shell has eight electrons.
-Oxygen is more reactive than fluorine because oxygen needs only one electron to fill its outermost shell.
-Fluorine is more reactive than neon because fluorine has to lose only one electron to fill its outermost shell.
The true statement is that neon is inert because its outermost shell is complete. Neon's full outer shell of eight electrons makes it unreactive, unlike fluorine which seeks an additional electron to become stable and is therefore highly reactive.
The correct statement among those provided is that neon is inert because its outermost shell is complete. According to the octet rule, atoms are more stable energetically when they have eight electrons in their valence shell, which is the outermost electron shell, with the exception of helium which has a full shell with two electrons. Neon, with its electron configuration of 1s² 2s²2p6, has a full outer shell and does not tend to gain or lose electrons, making it unreactive or inert.
Contrarily, fluorine, which has seven electrons in its outer shell, is more reactive than neon because it seeks one additional electron to complete its octet. The statement that fluorine is more reactive than neon because fluorine has to gain, not lose, one electron to fill its outermost shell is true. It's important to note that neither nitrogen nor oxygen are considered inert, as their outer shells do not have the complete octet, and moreover, oxygen is not more reactive than fluorine; fluorine is, in fact, the most reactive of the halogens because it needs only one more electron to achieve a full outer shell.
where is more than two thirds of earth's freshwater stored?
More than two-thirds of Earth's freshwater is stored in ice caps and glaciers, primarily in Antarctica and Greenland. These massive ice sheets contain an enormous amount of freshwater in the form of ice.
Ice Caps and Glaciers: These polar ice sheets hold the majority of the world's freshwater, accounting for roughly 68.7% of the total freshwater on the planet. Antarctica, the southernmost continent, has the largest ice sheet, followed by Greenland. These ice masses contain trillions of cubic meters of freshwater, which is locked up in the form of ice.
Groundwater: Approximately 30.1% of Earth's freshwater is stored underground in aquifers. These are layers of water-bearing rock and sediment beneath the Earth's surface. Groundwater is a vital source of freshwater for drinking, agriculture, and industry.
Surface Water: This includes all the freshwater on the Earth's surface, such as lakes, rivers, and reservoirs. Surface water accounts for about 0.3% of Earth's freshwater. While it represents a small percentage, it is crucial for various human activities and ecosystems.
Atmosphere: Water vapor in the atmosphere accounts for a tiny fraction of Earth's freshwater, approximately 0.001%. This water vapor plays a vital role in the Earth's climate and weather systems.
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An aqueous solution contains 0.100 m naoh at 25.0 °c. the ph of the solution is ________.
An aqueous solution contains 0.100 m NaOH at 25.0 °C. the pH of the solution is 13.00
To determine the pH of a 0.100 M NaOH solution, we need to understand that NaOH is a strong base and dissociates completely in water. The concentration of hydroxide ions (OH-) in the solution will be equal to the concentration of NaOH, which is 0.100 M.
The pOH of the solution can be calculated using the formula:
[tex]\[ \text{pOH} = -\log[OH^-] \][/tex]
where [tex]\([OH^-]\)[/tex] is the concentration of hydroxide ions.
Given that [tex]\([OH^-] = 0.100\)[/tex] M, we can calculate the pOH as follows:
[tex]\[ \text{pOH} = -\log[0.100] \][/tex]
[tex]\[ \text{pOH} = -(-1) = 1 \][/tex]
At 25.0 °C, the pH and pOH of a solution are related by the equation:
[tex]\[ \text{pH} + \text{pOH} = 14.00 \][/tex]
Using the calculated pOH, we can find the pH:
[tex]\[ \text{pH} = 14.00 - \text{pOH} \][/tex]
[tex]\[ \text{pH} = 14.00 - 1 \][/tex]
[tex]\[ \text{pH} = 13.00 \][/tex]
Which of the following atomic numbers represent an element that is radioactive on the periodic table.
The atomic number that represents a radioactive element is N = 100.
Therefore, the correct answer is option 4: N = 100.
To determine which of the given atomic numbers represent a radioactive element, we need to look at the periodic table and identify elements with atomic numbers corresponding to known radioactive elements.
1. N = 11 corresponds to sodium (Na), which is not radioactive.
2. N = 56 corresponds to barium (Ba), which is not radioactive.
3. N = 81 corresponds to thallium (Tl), which has two radioactive isotopes, but it also has stable isotopes.
4. N = 100 corresponds to fermium (Fm), which is a synthetic element and is highly radioactive.
So, the atomic number that represents a radioactive element is N = 100.
Therefore, the correct answer is option 4: N = 100.
The probable question may be:
Which of the following atomic numbers represent an element that is radioactive on the periodic table.
1. N=11
2.N=56
3.N=81
4.N=100
Mandy is testing an unknown solution to determine whether it is an acid or a base. she places a piece of red litmus paper into the solution and the paper turns blue. mandy's unknown solution
How many moles of sodium acetate (nach3coo) must be added to 1.000 liter of a 0.500 m solution of acetic acid (ch3cooh) to produce a ph of 5.061? the ionization constant of acetic acid is 1.8 Ã 10â5 . answer in units of mol?
To create a buffer with a pH of 5.061 in a 0.500 M acetic acid solution, 0.545 mol of sodium acetate must be added to 1.000 liter of the solution. This calculation uses the Henderson-Hasselbalch equation and takes into account the ionization constant of acetic acid.
To find out how many moles of sodium acetate ([tex]NaCH_3COO[/tex]) must be added to 1.000 liter of a 0.500 M solution of acetic acid ([tex]CH_3COOH[/tex]) to produce a pH of 5.061, we can use the Henderson-Hasselbalch equation:
pH = pKa + log([A-]/[HA])
where [A-] is the concentration of the acetate ion, [HA] is the concentration of acetic acid, and pKa is the negative logarithm of the ionization constant (Ka) of acetic acid.
First, we calculate pKa:
pKa = -log(Ka)
pKa = -log(1.8 * 10-5)
pKa = 4.74
Next, rearrange the Henderson-Hasselbalch equation to solve for [A-]:
[A-] = [HA] * 10(pH-pKa)
[A-] = 0.500 M * 10(5.061-4.74)
[A-] = 0.500 M * 100.321
[A-] = 0.500 M * 2.09
[A-] \\approx 1.045 mol/L
Since the initial concentration of acetic acid is 0.500 M, we need to add 1.045 mol - 0.500 mol = 0.545 mol of sodium acetate to the solution to achieve the desired pH.
A decrease in height of a column in a mercury barometer means that
Answer:
increase in the air pressure
Explanation:
The barometer is a device that is used for measuring the air pressure. It is a device that uses mercury in order to show the air pressure. The mercury reacts easily to the changes in the air pressure, so it is a nice indicator for it. The air pressure can simply be defined as the weight of the air masses, and the pressure they make it because of it on the objects. The lower the air pressure, the higher up the mercury will go, as it will experience less pressure from the air, and the higher the air pressure, the lower the mercury will drop, as it will experience more pressure from the air.
What is a saturated solution? a solution with as much dissolved solute as it can hold at a given temperature. a heated solution with more dissolved solute than it can hold at a lower temperature. a solution that holds less dissolved solute than is possible at a given temperature. a solution that holds as much solvent as possible at all temperatures?
Answer:
A
Explanation:
Edge
A saturated solution is a solution a solution with as much dissolved solute as it can hold at a given temperature. Thus option a is correct.
What is saturation point?Saturation is state of attaining maximum in any action. A solution is made of a solvent and solute. The solubility of the solute depends on its bond type, mass, temperature and pressure. The solute can be of non -soluble, partially soluble or completely soluble.
Solubility is the fraction of concentration of a solute that can be dissolved in a solvent. Some solutes can be dissolved easily by heating. However, the there is limit for the solvent to dissolve its maximum salt at a given temperature.
That limit is called its saturation point. Beyond that no more amount of solute can be dissolved even by heating. When the solvent reaches its saturation for a given temperature, diluting with more solvent can be results in better solubility.
Hence, the statement defining a saturated solution is option a.
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Does the biosphere have clear boundaries
No, the biosphere does not exhibit a clear boundary as life always comes to an end.
The biosphere comprises all the living things of the world, like all the plants and animals. It is considered as the global ecosystem, that is, the gathering of all the planet's ecosystems. It comprises the land and the atmosphere. It is usually considered as the zone of life, where all the species of the planet thrives.
What is the name for this molecule? 3-heptyne 3-heptene 3-hexyne 3-hexene
The iupac name of the compound will be hex-3-yne or 3-hexyne. By marking number of carbon in the given compound, it was found that triple bond comes at third position and there are total 6 carbon in the compound. So it will have Hex as a prefix and as it contains triple bond so it will have yne as a suffix and as the triple bond is at third position, so it will be hex-3-yne or 3-hexyne.
The correct name for the molecule is 3-hexyne.
To determine the name of the molecule, we need to follow the rules of IUPAC nomenclature for alkynes. The molecule has a total of 6 carbon atoms in its longest carbon chain, which makes the base of the name hexyne.
The triple bond, indicated by the yne suffix, is located at the third carbon atom from the end, hence the number 3 in the name. The other options provided contain either an incorrect number of carbon atoms or an incorrect type of bond (alkene instead of alkyne). Therefore, the correct IUPAC name for this molecule is 3-hexyne.
The complete question is- What is the name for this molecule?
a. 3-heptyne
b. 3-heptene
c. 3-hexyne
d. 3-hexene
Can someone eplain how to do this ? : identify the limiting reagent and the volume of CO2 formed when 11 L CS2 reacts with 18 L O2 to produce SO2 gas at STP. CS2(g)+3O2(g) → CO2(g)+2SO2(g),
What is missing from the temperature and volume graph shown at right?
Answer: The vertical axis should labelled as 'Volume (unit)' as it is missing from the given graph.
Explanation:
The labeling of vertical axis is missing from the given graph between the temperature and volume.
The vertical axis should labelled as 'Volume (unit)' because it is given that the graph is in between the temperature and the volume.And temperature is on the horizontal axis is already labeled in the graph.
On top of the graph name of the graph should also be written as Temperature vs Volume graph.
From the unit we mean that the unit in which is used in measuring the volume and in the graph like: L ,mL etc.
If the oxidation number of nitrogen in a certain molecule changes from +3 to -2 during a reaction, is the nitrogen oxidized or reduced? how many electrons are gained or lost by the nitrogen atom?
Since here we can see that there is a negative -2 charge on nitrogen so there is gain of electron and hence it is reduced.
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Which of these statements is not true?question 20 options:atoms of isotopes of an element have different numbers of protons.atoms of the same elements can have different masses.atoms are mostly empty space.the nucleus of an atom has a positive charge.save?
Explains why anyone in the classroom can hear that loud teacher across the hall even though the door is barley cracked open
A. Reflection
B. Refraction
C. Diffraction
1.) If a neutral atom of chlorine has 17 electrons and 18 neutrons, how many electrons are in the second energy shell of this atom?
2.) If a neutral atom of chlorine has 17 electrons and 18 neutrons, how many electrons are in the outermost, or valence, shell of this atom?
Answer: 1. 8 electrons
2. 7 electrons
Explanation: energy shell are orbits which Carry's electrons around an atom's nucleus.
To determine the number of electrons in an energy shell, use the formula
2(n^2)
n= number of energy shell
Therefore the second energy shell is n=2
Substituting n in the equation above,
2(2^2)=8
2. Valence electrons are the electrons on the outermost shell of an atomic nucleus.
The group number of an element is the same as the valence electrons of that element.
Therefore chlorine which belongs to group 7 elements has 7 valence electron.
We can also get the valence electrons using the K L M N shell.
The K shell which has maximum of 2 electrons, while other shells can contain maximum of 8 electron.
SEE PICTURE ATTACHED TO UNDERSTAND THE K L M N SHELL BETTER.