Answer:
1.99 grams of methane
Explanation:
A combustion reaction always produces the product carbon dioxide and water. So the chemical equation for this reaction would be:
CH₄ + O₂ → CO₂ + H₂O
To answer this question, you need to first determine which is the excess reactant. First step is to balance the equation:
CH₄ + 2O₂ → CO₂ + 2H₂O
Next we get the number of moles of each reactant we actually have:
8.00 g of O₂ = ? moles of O₂
You can get the number of moles, by first computing how many grams of the molecule is present in 1 mole.
O = 15.999g/mole. Since there are 2 oxygens in one mole of O₂, all you need to do is add up the atomic mass of 2 oxygens. You will get:
O₂= 31.998 g/mole
You can use this then to determine how many moles of O₂ there are in 8.00g.
[tex]8.00g\times\dfrac{1mole}{31.998g}=0.250moles[/tex]
So there are 0.250 moles of O₂ in 8.00 g of O₂.
We do the same for CH₄
4.00g of CH₄=? moles of CH₄
C H₄
CH₄= 12.011 + 1.008(4) = 16.043 g/mole
[tex]4.00g\times\dfrac{1mole}{16.043g}=0.249moles[/tex]
So let's sum up our new given. We now have:
0.250 moles of O₂
0.249 moles of CH₄
Next we look at the molar ratio of reactants to produce products:
CH₄ + 2O₂ → CO₂ + 2H₂O
According to this equation we can assume the following:
We need 1 mole of CH₄ for every 2 moles of O₂ in this reaction. Using what we have, we will see how much of reactant of the other reactant we need to use up the other.
[tex]0.25molesofO_{2}\times\dfrac{1moleofCH_{4}}{2molesofO_{2}}=0.125molesofCH_{4}\\\\0.249molesofCH_{4}\times\dfrac{2molesofO_{2}}{1moleofCH_{4}}=0.498molesofO_{2}[/tex]
Compare the results with what we have:
What we have What we need
0.250 moles of O₂ < 0.498 moles of O₂
0.249 moles of CH₄ > 0.125 moles of CH₄
This means that since we have less O₂ that what we need to use up CH₄, then O₂ is the limiting reactant and CH₄ is the excess.
To compute how much we have in excess, we use the number of moles produced when we use up limiting reactant which we did earlier and convert it into grams to determine how much in grams we used up.
Earlier we solved that we need 0.125 moles of CH₄ to use up all the O₂. Now convert that value into grams:
[tex]0.125molesofCH_{4}\times\dfrac{16.043gofCH_{4}}{1moleofCH_{4}}=2.005g of CH_{4}[/tex]
This means that 2.005g of CH₄ will be used up.
Subtract that from the CH₄ we already have:
4.00 g - 2.005 g =1.99 g of CH₄
What is the equilibrium constant expression for the following reaction?
COCl2(g) = CO(g) + Cl2(g)
Keq=(COCl2)/(CO)+(Cl2)
Keq= (CO)(Cl2)/(COCl2)
Keq=(COCl2)/(CO)(Cl2)
Keq=(CO)+(Cl2)/(COCl2)
Answer:
Keq = [CO][Cl₂]/[COCl₂].
Explanation:
For the balanced reaction:
COCl₂(g) ⇄ CO(g) + Cl₂(g).
The equilibrium constant can be expressed as concentration equilibrium constant (Kc) or pressure equilibrium constant (Kp).
The equilibrium constant is the ratio of the product of products concentrations to the product of the reactants concentrations.
Keq = [CO][Cl₂]/[COCl].
The atomic mass of carbon is 12.01, sodium is 22.99, and oxygen is 16.00. What is the molar mass of sodium oxalate (Na2C2O4)?
Answer:
134g/mol
Explanation:
Do valence electrons show a repeating or periodic pattern? Explain.
Answer:
Yes, valence electrons show a repeating or periodic pattern.Explanation:
It is precisely the repeating pattern of the valence electrons which is the responsible for the repeating pattern of the chemical properties: elements on a same group (column) of the periodic table have similar chemical properties because they have the same number of valence electrons.
The chemical changes (reactions) are the result of the interaction of the electrons of the elements, and, since the valence electrons are the outer most electrons, you can expect that it is the valence electrons which most influence the occurrence of the chemical reactions, which is what defines the chemical properties.
Here you have the pattern of the valence electrons shown by the representative elements on the periodic table:
Group number number of valence electrons
(column number)
1 1
2 2
13 3 (the ones digit of the column number)
14 4 (the ones digit of the column number)
15 5 (the ones digit of the column number)
16 6 (the ones digit of the column number)
17 7 (the ones digit of the column number)
18 8 (the ones digit of the column number)
The ph of a solution prepared by mixing 45.0 ml of 0.183 m koh and 35.0 ml of 0.145 m hcl is ________.
Answer:
12.6.
Explanation:
We should calculate the no. of millimoles of KOH and HCl:no. of millimoles of KOH = (MV)KOH = (0.183 M)(45.0 mL) = 8.235 mmol.
no. of millimoles of HCl = (MV)HCl = (0.145 M)(35.0 mL) = 5.075 mmol.
It is clear that the no. of millimoles of KOH is higher than that of HCl:So,
[OH⁻] = [(no. of millimoles of KOH) - (no. of millimoles of HCl)] / (V total) = (8.235 mmol - 5.075 mmol) / (80.0 mL) = 0.395 M.
∵ pOH = -log[OH⁻]
∴ pOH = -log(0.395 M) = 1.4.
∵ pH + pOH = 14.
∴ pH = 14 - pOH = 14 - 1.4 = 12.6.
12.6 is the pH of a solution prepared by mixing 45.0 ml of 0.183 m KOH and 35.0 ml of 0.145 m HCl.
How we calculate pH?
pH of the solution can be calculated as pH = 14 - pOH.
First of all we have to calculate the concentration of OH⁻ ions as follow:
Total volume of the solution = 45ml + 35ml = 80ml
Concentration of OH⁻ in terms of mole is calculated as:
[OH⁻]=(no. of millimoles of KOH - no. of millimoles of HCl)/Total volume
Given that, concentration of KOH = 0.183m
Volume of KOH = 45ml
Concentration of HCl = 0.145m
Volume of HCl = 35ml
Millimoles can be calculated as:
millimoles = concentration × volume
No. of millimoles of KOH = 0.183 M × 45.0 mL = 8.235 mmol
No. of millimoles of HCl = 0.145 M ×35.0 mL = 5.075 mmol
Now, [OH⁻] = 8.235 mmol - 5.075 mmol / 80.0 mL = 0.395 M
pOH = -log[OH⁻]
pOH = -log(0.395)
pOH = 1.4
Therefore, pH = 14 - 1.4 = 12.6
Hence, 12.6 is the pH of the solution.
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The tendency of an element to react with other elements to produce compounds is called
Answer:
Organic compound is the correct answer
Explanation:
How is radiation absorbed?
a. by increasing the molecular vibrations of molecules
b. by converting atoms to ions
c. by breaking chemical bonds
d. all of the above
By increasing the molecular vibrations
R-12 should be recycled instead of vented to the atmosphere because
A. recycling companies offer large financial incentives.
B. it has been proven to deplete the Earth's ozone layer.
C. R-12 is expensive.
D. R-12 is unstable.
I believe is B if not then it's A
Answer:
Option (B)
Explanation:
R-12 is known as the Dichloro-difluoro-methane and it is a colorless gas. It is was earlier used in the refrigerators, vehicles air conditioning, and aerosol spray. The use of this R-12 was found to be depleting the ozone layer which was not a positive effect on the earth. Due to this, the use of this gas was banned and alternative energy resources were used. Its products containing this R-12 gas were not expensive and they were stable enough.
Hence, the correct answer is option (B).
a beaker contains 500ml of 12m potassium nitrate .what is the molarity of the new solution if 250 ml more water is added
Answer:
8.0 M.
Explanation:
It is known that the no. of millimoles after dilution is equal to the no. of millimoles before dilution.∴ (MV) of KNO₃ before dilution = (MV) of KNO₃ before dilution.
Before dilution:
M = 12.0 M, V = 500.0 mL.
After dilution:M = ??? M, V = 500.0 mL + 250.0 mL = 750.0 mL.
∴ M after dilution = (MV) before dilution / (V) after dilution = (12.0 M)(500.0 mL)/(750.0 mL) = 8.0 M.
What is the best explanation for why electrolyte solutions conduct electricity?
The answer is: the presence of free-flowing ions. Explanation: ionic compounds dissociate in water forming a solution with free ions.
What is the concentration of hydrogen ions commonly expressed as
Answer: pH scale
Explanation:
A change in the amount of heat energy lost or gained by a system during a process is_________________________
Answer:
chemical change
Because the the individual components of any mixture are not _____ to each other, the composition of those components can vary. Also, some of the _____ properties of the individual components are still noticeable
Answer:
Because the individual components of any mixture are not bonded to each other, the composition of those components can vary. Also, some of the physical properties of the individual components are still noticeable.
Explanation:
A mixture is a combination of two or more pure substances that are present in any proportion and each pure substance keeps its own physical and chemical properties.
As oppossite to mixtures, the compounds are pure substances formed by two or more different elements which are chemically bonded to each other. So, while in the compounds the components (elements) are bonded in a fixed proportion, and their composition cannot vary, in the mixtures each component may be present in any proportion, which means that the composition can vary.
Take, for example, the simple case of talc and iron particles.This is a mixture. Talc is not bonded to the iron particles, and so their proportion, the compositoin, can vary in any form. Aslo, both talc and iron particles keep their own physical properties: you can perfectly separate the mixture by using a magnet to attract the iron particles, because they have not lost their magnetic property (a physical one).
Under which set of conditions is δgrxn for the reaction a(g) → b(g) most likely to be negative?
Answer:
delta G = -ve.. This means the rxn is spontaneous
Explanation:
For spontaneous rxn
Delta H = - ve
Delta S = +ve
And no. Of moles at product side should be less than tha reactant side.
I wrote all i know.. Hope this helps you
Answer:
This question is incomplete but the completed question is below
Under which set of conditions is ΔGrxn for the reaction A(g)→B(g) most likely to be negative?
Under which set of conditions is for the reaction most likely to be negative?
(a) PA=0.010 atm; PB=0.010 atm
(b) PA=0.010 atm; PB=10.0 atm
(c) PA=10.0 atm; PB =0.010 atm
(d) PA=10.0 atm; PB =10.0 atm
The correct option is (c)
Explanation:
The Gibb's free energy (ΔG) of the reaction will be negative when the reaction is spontaneous and a reaction is said to be spontaneous when more products are been formed.
When you consider the reaction provided in the question, the "g" in bracket means gas while A represent reactant(s) and B represents product(s)
When a reaction involves gases, an increase in pressure causes more products to be formed hence the pressure on the reactant side (PA) will most likely be more than the pressure on the product side (PB). The only option that has more pressure on the reactant side (PA = 10.0 atm) than on the product side (PB = 0.010 atm) is option c.
Cup A and cup B are identical. They contain equal volumes of soup at equal temperatures. Both cups are put in a refrigerator. Cup A has a lid, but cup B does not. Which statement best explains why cup A will cool more slowly than cup B?
A.
Water vapor won’t be able to escape from cup A.
B.
The most energetic water molecules from cup A will escape more rapidly.
C.
No molecules will be able to evaporate at the surface of cup B.
D.
No molecules will be able to evaporate at the surface of cup A.
Answer:
A
Explanation:
Answer: Option (D) is the correct answer.
Explanation:
It is known that in a closed system there will no exchange of heat or matter from the system to the surrounding. Whereas in an open system there will be exchange of both heat and energy from the system to the surrounding and vice versa.
Therefore, in the given situation cup A is a closed system and cup B is an open system. Hence, there will be no exchange of heat or matter from cup A to system and surrounding. So, it will cool slowly that cup B.
Thus, we can conclude that the statement no molecules will be able to evaporate at the surface of cup A, best explains why cup A will cool more slowly than cup B.
In what way does hemoglobin act as a buffer against changes in blood ph?
Answer:
Explanation:
Hemoglobin removes excess protons from the red blood cells so that they can be excreted through the kidneys.
Hemoglobin binds some of the excess protons released by carbonic acid.
Subsequent binding of oxygen is drastically reduced after the first one is bound.
Hemoglobin produces protons or hydroxide ions as needed to alter the blood pH.
Answer:
Excess acids in the red blood cells are removed by the hemoglobin
Explanation:
In what way does hemoglobin act as a buffer against changes in blood ph?
Excess acids in the red blood cells are removed by the hemoglobin . it is a good receptor of excess proton released by carbonic acid.
It helps to remove acids before it affects the PH of the blood. deoxygenated hemoglobin are better receptor of proton than the oxygenated one.
If hemoglobin does not act as a buffer, there will be changes in the blood's PH and can poison the blood.
Which of the following has the shortest wavelength?
Ultraviolet light
Visible violet light
Visible red light
Infrared light
Answer:
ultraviolet light is the shortest wavelength
Explanation:
Answer:
The correct answer is the first option: Ultraviolet light.
Explanation:
Hello!
Let's solve this!
The ultraviolet light is the one with the shortest wavelength. It is between visible light and x-rays. The place where this is seen is in the electromagnetic spectrum, which is the set of all electromagnetic waves.
Therefore, we conclude that the correct answer is the first option: Ultraviolet light.
According to the storage ladder protocol, raw meat should be stored on shelves based on its? A.Minimum internal cooking temperature. B.Expiration date C. Meat should never be stored on shelves D.Maximum internal cooking temperature
Answer:
D.Maximum internal cooking temperature
Explanation:
According to the Storage Ladder Protocol, food storage in refrigerator should have a proper rules to store them. On the top most shelf, Prepared foods should be kept. On the second shelf, Fruits and Vegetable are kept. Fish and Sea foods are kept on the third shelf. The fourth shelf is reserved for the Beef and Porks. The next shelf is for Ground Meat. The last shelf is for Poultry items. So, this proves that the Ground Beef should be stored above the Chicken. A diagram is attached below to explain the storage order in a more appropriate manner.
According to the Storage Ladder Protocol, raw meat should be stored on shelves based on its Minimum internal cooking temperature
The storage ladder protocol is a sets of rules created to make sure that varieties of unprepared and prepared food are properly stored in a refrigerator.
Further ExplanationThe storage ladder protocol is meant to determine which shelf each variety of food should be stored on and also provides a guide as to which food should be below or above.
For example, prepared food must be stored on the top shelf, Foods and vegetables are stored on the second shelf, fish and seafood should be stored on the third shelf, beef and pork should be kept on the fourth shelf, Ground meat should be stored on the fifth shelve while poultry items should be kept on the bottom shelf.
Also, to ensure proper food hygiene, make sure that the temperature of your fridge is set between 0 and 5 degrees Celsius. If the temperature is maintained within that range, it will slow down the rate at which the food gets to spoil and also prevent harmful bacteria from multiplying.
Also, do not consume any food that has passed its expiry date because it will be easy for bacteria to grow on such food.
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How should food be stored to avoid cross-contamination: https://brainly.com/question/4415007According to the storage ladder protocol, raw meat should be stored on shelves based on its? https://brainly.com/question/12570432KEYWORDS:
refrigeratorstorage ladder protocolraw meattemperaturerulesWhich grouping identifies chemical properties?A. Density, luster, boiling point B. Melting point, hardness, conductivity C. Malleability, ductility, texture D. Combustibility, flammability, reactivity
Answer:
option D. Combustibility, flammability, reactivity.Explanation:
Physical properties: characteristics of the matter that can be observed and measured by physical media, withoud changing the composition of the matter.
Typical examples of physical properties are: mass, volume, density, boiling point, melting point, hardness, specific heat.
Chemical properties: they are ability of the matter to change by decompositon or combination with other substances to produce one or more different substances. They cannot not be observed or measured without changing the composition of the orignal sample.Typical examples of chemical properties are reactivity with oxygen, reactivity with water, and any reactitivy in general.
Hence, applying those definitions to the set of choices you get:
A. Density, luster, boiling point (incorrect)
All of them are physical properties since they are observable and measurable without altering the composition of the sample.
B. Melting point, hardness, conductivity (incorrect)
They all are also physical properties. For example, melting point can be measured with a thermometer during the phase change.
C. Malleability, ductility, texture (incorrect)
Again, all physical properties. Ducitlity, for example, is the ability of the metals to form this wires.
D. Combustibility, flammability, reactivity (correct answer)
Combustibility: is the reaction with oxigen to form CO₂ and H₂OFlammability: is the ability to burn in flames, which is a chemical change.Reactivity: Already discussed.All these properties can only be measured by producing the correspondant chemical reaction (change), so they are chemical properties.
Answer:
The correct option is D
Explanation:
Explain why the pbcl2 dissolved when water was added
PbCl2 would not dissolve because it is insoluble based on the solubility rules for substances that will dissolve in water. This compound would instead form a solid precipitate at the bottom of the container.
PbCl2 dissolves in water as it dissociates into Pb²+ and Cl¯ ions which attract polar water molecules. Just like potassium chloride, lead(II) chloride dissolves due to hydration of ions. Solubility of PbCl2 may increase with temperature.
Explanation:When PbCl2 is dissolved in water, it dissociates into ions Pb²+ and Cl¯. These ions interact with water molecules due to the presence of polar bonds in water. Just like potassium chloride (KCl) dissolves in water by getting hydrated, or attracting water molecules, lead(II) chloride (PbCl2) dissolves in a similar fashion. Water, being a polar molecule, is attracted by the charges on both lead(II) and chloride ions. This hydration of ions is an important factor in the dissolution of many solids into liquids.
Moreover, the solubility of various solids in water tends to increase with temperature. Hence, if the PbCl2 was added to warm water, it might have increased its solubility, enabling more of PbCl2 to dissolve.
However, it is important to note that certain compounds like PbCl2 have relatively low solubility in water, and may still leave some solid undissolved even after thoroughly mixing.
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The table shows the characteristics of four substances after they are placed in water.
Substance
Ion concentration
Electrical conductivity
W
Medium
Good
X
Low
Poor
Y
High
Excellent
Z
None
None
Which compound is most likely the strongest electrolyte?
W
X
Y
Z
Answer:
Electrolytes are chemicals that break into ions (ionize) when they are dissolved in water. The positively-charged ions are called cations, while the negatively charged ions are called anions.
Strong electrolytes completely ionize in water. This means 100% of the dissolved chemical breaks into cations and anions.
Weak electrolytes partially ionize in water. Pretty much any dissociation into ions between 0% and 100% makes a chemical a weak electrolyte, but in practice, around 1% to 10% of a weak electrolyte breaks into ions.
If a substance doesn’t ionize in water at all, it’s a nonelectrolyte.
Explanation:
The substance that serves as a good electrolyte in the list is the substance labelled Y.
What is an electrolyte?An electrolyte is a solution that conducts electricity by the movement of ions in the solution. The high concentration of ions in the electrolyte implies that it has a good conductivity
Hence, the substance that serves as a good electrolyte in the list is the substance labelled Y.
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How many moles of helium are 8.84×10^24 atoms of He?
Answer:
14.77 mol.
Explanation:
It is known that every 1.0 mole of compound or element contains Avogadro's number (6.022 x 10²³) of molecules or atoms.Using cross multiplication:
1.0 mole of He contains → 6.022 x 10²³ atoms.
??? mole of He contains → 8.84 x 10²⁴ atoms.
∴ The no. of moles of He contains (8.84 x 10²⁴ atoms) = (1.0 mol)(8.84 x 10²⁴ atoms)/(6.022 x 10²³ atoms) = 14.77 mol.
The radioactive element carbon-14 has a half-life of 5750 years. a scientist determined that the bones from a mastodon had lost 72.6% of their carbon-14. how old were the bones at the time they were discovered?
In an electrolytic cell, is it a oxidation-reduction reaction? True or False.
Answer:
\boxed{\text{True}}
Explanation:
Consider the electrolysis of molten MgCl₂.
During electrolysis
Mg²⁺ gains electrons, so it is reduced. Cl⁻ loses electrons, so it is oxidized[tex]\rm Reduction: Mg^{2+} + 2e^{-} \longrightarrow Mg\\Oxidation: 2Cl^{-} \longrightarrow Cl_{2} + 2e^{-}\\Overall: MgCl_{2} \longrightarrow Mg + Cl_{2}\\\\\text{Electrolysis is a }\boxed{\textbf{redox reaction}}[/tex]
The specific heat for liquid argon and gaseous argon is 25.0 J/mol·°C and 20.8 J/mol·°C, respectively. The enthalpy of vaporization of argon is 6506 J/mol. How much energy is required to convert 1 mole of liquid Ar from 5°C below its boiling point to 1 mole of gaseous Ar at 5°C above its boiling point?6631 J229 J6735 J125 J6610 J
Answer:
6,735 JExplanation:
The total energy required to convert 1 mole of liquid from 5°C below its boiling point to 1 mole of gaseous Ar at 5° above its boiling point may be calcualted in three stages:
Heating the liquid Ar from 5°C below its boling point to the boiling pointVaporizing the liquid Ar at its boiling temperatureHeating the gaseous Ar from its boiling point to 5°C above it.1) Energy to heat the liquid Ar from 5°C below its boling point to the boiling point:
Q₁ = m × C × ΔT = 1 mol × 25.0 J/mol°C × 5°C = 125 J2) Energy to vaporize the liquid Ar:
Q₂ = m × Latent heat of vaporization = 1 mol × 6506 J/mol = 6506 J3) Energy to heat the gaseous Ar 5°C above its boiling point:
Q₃ = m × C × ΔT = 1 mol × 20.8 J/mol°C × 5°C = 104 J4) Total energy (E)
E = Q₁ + Q₂ + Q₃ = 125 J + 6506 J + 104 J = 6735 J ← answerThe total energy required to convert 1 mole of liquid Argon from 5°C below its boiling point to 1 mole of gaseous Ar at 5°C above its boiling point is calculated through a multi-step process. The steps involve increasing the temperature of the liquid to its boiling point, vaporizing at the boiling point, and further heating the gas above the boiling point. The sum of these three steps yields a total required energy of 6735 J.
Explanation:This is a multi-step thermodynamics problem in chemistry that requires the use of specific heat, change in temperature, and enthalpy of vaporization. The energy required to convert 1 mole of liquid Argon from 5°C below its boiling point to 1 mole of gaseous Ar at 5°C above its boiling point can be found through the equation: q = m*c*ΔT, where q is the heat energy, m is the amount of Argon in moles, c is the specific heat, and ΔT is the change in temperature.
First, we need to raise the temperature of the liquid argon from 5°C below the boiling point to the boiling point. Using the specific heat for liquid argon, this gives us q1 = (1 mol)(25.0 J/mol·°C)(5°C) = 125 J.
Next, we have to provide the heat of vaporization to convert the liquid to gas at the boiling point, which gives us q2 = 6506 J/mol. Then we have to further heat the gas from the boiling point to 5°C above it. Using the specific heat for gaseous argon, this gives us q3 = (1 mol)(20.8 J/mol·°C)(5°C) = 104 J.
Adding these three energy amounts together, we find that total energy required is q_tot = q1 + q2 + q3 = 125 J + 6506 J + 104 J = 6735 J.
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A stable atom that has a large nucleus most likely contains....?
A.) more neutrons than protons
B.) more protons than neutrons.
C.) equal numbers of protons and neutrons.
D.) changing numbers of protons and neutrons.
A. More neutrons than protons
it would likely include more neutrons than protons.
For compounds, the basic structural unit representing the compound is the atom.
a. true
b. false
The statement provided is false; the basic structural unit of a compound is the molecule, not the atom. Molecules consist of atoms from different elements bonded in fixed ratios, forming the substance known as a compound.
Explanation:The statement 'For compounds, the basic structural unit representing the compound is the atom.' is false. The smallest particle of most compounds is called a molecule. For instance, a water molecule (H₂O) is always made up of one atom of oxygen and two atoms of hydrogen. This molecule is the basic unit that represents the compound water, not a single atom. Compounds are characterized by atoms of different elements bonded together, and these atoms are in fixed, whole-number ratios.
Isomers are molecules that have the same number and type of atoms but arranged differently. For example, molecules with the formulas CH₃CH₂COOH and C₃H₆O₂ could indeed be structural isomers since they have the same molecular formula but could have a different arrangement of the atoms within the molecule.
Atomic Elements
Most elements exist as individual atoms as their basic unit. When combined in specific ways, these atoms form molecules, which are the basic units of compounds. A single atom by itself cannot represent a compound; it is the molecule, composed of two or more atoms, that does so.
How many significant figures are in 253.00 g?
There are five significant figures
Hope this helps and have a fabulous day :)
It’s five significant figures
NEED HELP!!!
Which of the following is true about the concept of half-life?
a. Half-life measures the rate of decay of a radioisotope.
b. The shorter the half-life, the more dangerous the radioisotope.
c. Half-life predicts which atoms in a radioactive sample will decay.
Answer:
b. The shorter the half-life, the more dangerous the radioisotope.
The shorter the half-life, the more dangerous the radioisotope. Therefore, the correct option is option B.
What is half-life?The half-life is the length of time required for a single quantity (of substance) to drop to half its initial value (symbol t12). The phrase is widely used in nuclear physics to describe how quickly unstable atoms dissolve radioactively or how long stable atoms endure.
The term is often used more generally to indicate any type involving exponentially decaying. In the medical sciences, for example, the biological ½ of drugs and other chemicals in the human body is a word. Half-opposite life's in exponential growth is time's doubling. The shorter the half-life, the more dangerous the radioisotope.
Therefore, the correct option is option B
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Methane reacts with oxygen to produce carbon dioxide water and heat.how many kcal are produced when 5.00 g of methane react
Answer:
= 66.33 kCal
Explanation:
The combustion of methane is given by the equation;
CH4(g) + 2O2(g) → CO2(g) + 2H2O(l); ΔH = -890.3 kJ/mol
The molar enthalpy of combustion of methane is -890.3 kJ/mol
This means 1 mole of CH4 yields 890.3 kJ/Mol
But, molar mass of methane is 16.04 g/mol
Therefore;
Heat produced by 5.0 g of methane will be;
= (5.0 g/ 16.04 g/mol)× 890.3 kJ/mol
= 277.525 kJ/mol
But; 1 kcal = 4.184 kJ
thus; = 277.525 /4.184
= 66.33 kCal
Final answer:
To determine the amount of heat produced when 5.00 g of methane reacts with oxygen, convert the given heat production for 2.50 g of methane to kcal, find the heat value per gram, and then multiply by the mass of methane used (5.00 g).
Explanation:
The question asks how many kilocalories are produced when 5.00g of methane (CH₄) is reacted with oxygen (O₂) to produce carbon dioxide (CO₂) and water (H₂O) and release heat. To find this, we can use the information provided: the combustion of 2.50 g of methane produces 125 kJ of heat. As 1 kcal is equivalent to 4.184 kJ, we can first convert 125 kJ of heat to kcal, which gives us 29.8 kcal (125 kJ / 4.184 kJ/kcal).
Since this amount of heat is produced by 2.50 g of methane, we can find the heat produced by 1 g by dividing 29.8 kcal by 2.5, which gives us 11.92 kcal/g. For 5.00g of methane, the heat produced would be 5 times 11.92 kcal/g, equating to 59.6 kcal.
An electrolytic cell is based upon a nonspontaneous reaction; the Eocell for the reaction is _____.
greater than one
less than zero
equal to one
equal to zero
In an electrochemical cell in which the oxidation reaction is nonspontaneous the oxidation will not occur spontaneously at the anode and the reduction will not be spontaneous at the cathode. And according to the law for the calculation of the voltage potential of the electrochemical cell (Ecell):
Ecell = Eox. - Ere. where (Eox. is the potential of the oxidation at the anode and Ere. is the potential of the reduction at the cathode). The standard potential for an electrolytic cell is negative, because of the Ere. which is greater than Eox.
The answer is : less than zero.