give some example of scientific method with sample of experiments
The Scientific Method is a method of research in which a problem is identified, relevant data are gathered, a hypothesis is formulated from these date, and the hypothesis is empirically rested.
The Scientific Method was used even in ancient times, but it was first documented by England's Sir Francis Bacon (15-61-1626) who set up inductive methods for scientific inquiry.
Scientific method is often spelled out in a simplistic stepwise fashion in textbooks as if it were some sort of recipe or set of instructions that scientists follow. It’s somewhat mythical, not something a working scientist necessarily thinks of and consciously follows step by step. But textbook authors have very limited space and must simplify.
Briefly, scientific method is not a set of instructions for research, but a habit of thought and investigation by which we gain the most reliable and objective information on how the world works—from the world of subatomic particles to the world of galaxies and beyond.
A scientist is, above all, an endlessly curious and highly disciplined person. A scientist has a question about nature. He or she conceives of a possible answer to it framed in the context of what we already know about the subject. That possible answer is called a hypothesis.
A hypothesis is useless and not really scientific at all unless there’s some conceivable way of empirically testing it—i.e., by direct observation. (Stephen Hawking even went so far as to say the string theory of particle physics isn’t really science at all, because there’s no conceivable way of putting it to an empirical test.) So a scientist’s next step is to formulate a way of observationally testing his or her hypothesis.
The test might be simple qualitative observation (not manipulating nature but just observing it with a trained and careful eye—as in much field research in animal behavior and paleontology), or it might be by experimentation (manipulating some variables to see what effect that produces on a system, as medical research, most laboratory science, and some field science).
The test should generate information—data, usually in numerical form. Next, one must ask whether those data really mean anything. Do they truly show an effect of your manipulated (independent) variables on the behavior of a system (dependent variables). This calls for tests of statistical significance—mathematical procedures of great variety, depending on the kind of data one is testing (Student’ t-test, analysis of variance, Person’s product-moment correlation coefficient, Tukey’s range test, and many others). These tests are meant to minimize subjective bias in the interpretation of data. The product of such tests is probability statements. Experimental scientists speak in probabilities, not certainties. Scientists will not say, for example, This proves that disease X is caused by virus Y, or that this new drug controls hypertension or produces leukemia remission better than the old one. Rather, they will make such statements as, There’s at least a 99.5% chance that variable X caused the observed change in variable Y. A careful scientist doesn’t assert “My findings prove ___,” but “My findings are consistent with the hypothesis that ___.”
Then, to have truly “done science,” one must make one’s findings available to the scientific community and the public—that is, publish them. Some say, if you don’t publish it, it’s not science. You’ve contributed nothing to the world’s understanding if you don’t publish. Public knowledge is the ultimate goal of science, not just the satisfaction of personal curiosity.
To publish one’s findings, one must first demonstrate that the work was important enough to warrant a share of the limited and expensive space in a recognized scientific journal; then show that one’s hypothesis and methods were sound; then show that the results were meaningful—often, but not always, by demonstration of statistical tests of confidence.
All of this entails surviving a process of peer review, in which an editor or grant agency sends your draft publication out to other experts in your field, whose job is basically to find fault (if there is any) with what you’ve done: to closely scrutinize your logic, assumptions, methods, findings, and tests of significant to see if they can find anything wrong with it, serious enough that you need to revise your paper or the journal editor should outright reject it for publication. The prestigious journals Cell, Science, and Nature reject 97% of all papers that scientists submit for publication, for various reasons including insufficient importance to warrant publication, inappropriateness of subject matter to those journals, unclear hypotheses, fallacious methods, poor analysis of the results, violation of research ethics, or poor writing.
Reaction A: consider a solution of acetophenone (AKA methyl phenyl ketone) and sodium trifluoroperacetate (deprotonated trifluoroperacetic acid). Draw these two reactants and then show a full arrow-pushing mechanism providing the flow of electrons, showing how the two react with one another and the resulting product
The reaction between acetophenone and sodium trifluoroperacetate results in the formation of α-trifluoromethylphenylacetic acid.
The mechanism involves the nucleophilic attack of the enolate ion of acetophenone on the electrophilic carbon of the trifluoroperacetic acid, followed by the transfer of the trifluoromethyl group to the carbonyl carbon. The resulting intermediate then undergoes hydrolysis to form the final product.
The reaction is useful in organic synthesis as it provides a straightforward method for introducing a trifluoromethyl group onto an aromatic ring. This functional group is known to have unique properties that can enhance the biological activity of molecules, making it a valuable tool in drug discovery and development.
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Write a hypothesis for what you think will happen to the rate of the reaction as the concentration of the sodium thiosulfate is decreased. Write your hypothesis as an if/then statement.
If the concentration of sodium thiosulfate in the reaction mixture is decreased, then the rate of the reaction will also decrease.
How rate of a reaction depends upon the concentration of reactants?The rate of a chemical reaction is the speed at which reactants are consumed and products are formed in a chemical reaction. It is usually measured as the change in the concentration of reactants or products per unit time.
The concentration of reactants plays a crucial role in determining the rate of a chemical reaction. In general, the rate of a reaction increases with an increase in the concentration of reactants. This is because an increase in the concentration of reactants leads to a higher number of reactant molecules per unit volume, increasing the frequency of successful collisions between reactant molecules. The higher the frequency of collisions, the higher the probability of successful collisions resulting in the formation of products. Therefore, the rate of reaction is directly proportional to the concentration of reactants, according to the rate law of the reaction.
A decrease in the concentration of sodium thiosulfate would mean that fewer sodium thiosulfate molecules are available to react with the hydrochloric acid molecules. Thus, the frequency of successful collisions between reactant molecules will decrease, resulting in a slower rate of reaction.
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PLEASE HELP!!!! In a sporting event, the scoring area (shown here) consists of four concentric circles on the ice with radii of 4 inches, 4 feet, 6 feet, and 8 feet. If a team member lands a (43-pound) stone randomly within the scoring area, find the probability that it ends up centered on the given color (a) red (b) white (c) blue . (a) The probability that it ends up centered on red is ___.
The probability that the stone ends up centered on the red circle is 0.038.
To calculate the probability, we need to find the area of the red circle and divide it by the total area of the scoring area. The radius of the red circle is 4 feet (48 inches), so its area is π(48)² = 7,238.23 square inches. The total area of the scoring area is the sum of the areas of the four circles, which is π(4²) + π(4²) + π(6²) + π(8²) = 256π square inches. Therefore, the probability of the stone landing in the red circle is:
(7,238.23 square inches) / (256π square inches) = 0.038So the probability that the stone ends up centered on the red circle is 0.038 or approximately 3.8%.
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To calculate the Ksp value in the presence of ion activity, it is necessary to measure the ion product at the point of saturation for multiple
______. The ion product nears the Ksp value at (concentration, compounds, temperatures)
______due to lower ionic strength and (lower concentrations, lower temperatures, higher mass)
_____ is finally used to determine the Ksp value. ( a table, a plot, a spectrophometer)
Answer: compounds, lower, plot
A certain mass of nitrogen gas occupies a volume of 8.52 L at a pressure of 5.06 atm. At what pressure will the volume of this
sample be 10.90 L? Assume constant temperature and ideal behavior.
= P =
atm
At a volume of 10.90 L, the pressure of the nitrogen gas would be approximately 3.95 atm.
To solve this problem
Using the ideal gas law, we have:
PV = nRT
Where
P is pressureV is volume n is the number of moles of gas R is the universal gas constantT is the temperature in KelvinAssuming constant temperature and ideal behavior, we can set up a proportion:
(P1)(V1) = (P2)(V2)
Where
P1 is the initial pressureV1 is the initial volumeP2 is the final pressureV2 is the final volumeSubstituting the given values, we get:
(5.06 atm)(8.52 L) = (P2)(10.90 L)
Solving for P2, we get:
P2 = (5.06 atm)(8.52 L) / (10.90 L)
P2 = 3.95 atm
Therefore, at a volume of 10.90 L, the pressure of the nitrogen gas would be approximately 3.95 atm.
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What would be the percent yield if you actually reacted 316.0 g of aluminum
sulfide with 439.0 g of water to produce 125 g of aluminum hydroxide?
The percent yield if you actually reacted 316.0 g of aluminum sulfide with 439.0 g of water to produce 125 g of aluminum hydroxide is 38.03%.
Percent yield refers to the percent ratio of actual yield to the theoretical yield. In chemistry, yield is a measure of the quantity of moles of a product formed in relation to the reactant consumed, obtained in a chemical reaction, usually expressed as a percentage. The amount of product actually made compared with the maximum calculated yield is called the percentage yield.
Given,
Mass of Aluminum sulfide = 316g
Mass of water = 439g
Moles of Aluminum sulfide = 316 / 150
= 2.107 moles
Al₂S₃ + 6H₂O = 2Al(OH)₃ + 3H₂S
From the reaction, 1 moles of aluminum sulfide gives 2 moles of aluminum hydroxide.
Thus, 2.107 moles will give 2.107 × 2 = 4.214 moles
mass of aluminum hydroxide = 4.214 × 78
= 328.7g
Actual yield = 125g
Percent yield = Actual yield × 100 ) ÷ Theoretical yield
= ( 125 × 100 ) ÷ 328.7
= 38.03%
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#1
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How much energy is required to warm 250.0 g of water from room temperature (23.00 °C) to 100.0 °C given that the
specific heat of water is 4.18 J/g °C?
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A 0.1946g piece of magnesium metal is burned in a constant-pressure calorimeter. The calorimeter contains 500.0g of water and the temperature rise for the water is 1.40°C. Calculate the heat of combustion of magnesium metal in kJ/mol, given that the specific heat of water= 4.184 J/g °C Question 13 options: -2929 kJ/mol -23kJ/mol 23 kJ/mol -366 kJ/mol 366 kJ/mol
A 0.1946g piece of magnesium metal is burned in a constant-pressure calorimeter. The calorimeter contains 500.0g of water and the temperature rise for the water is 1.40°C. 24.76 kJ/gram is heat of combustion of magnesium metal.
The quantity of heat of combustion created during the burning of a specific amount of a substance, typically a fuel and food (refer to food energy), is known as the thermal capacity (or energy value and calorific value) of that substance.
The total amount of energy that is released as heat whenever a substance completely burns with oxygen takes on a calorific value under normal circumstances.
Heat of combustion =24.76 kJ/gram
Mass of magnesium sample = 0.1946 grams
Molar mass of magnesium = 24.3 g/mol
Heat capacity = 1349 J/°C
Mass of water = 500 grams
Temperature change = 1.40 °C
Q = (1349 J/°C × 1.40 °C) + (500 grams × 4.184 J/g°C ×1.40 °C)
Q =4817.4 J = 4.82 kJ
4817.4 J / 0.1946 grams = 24755.4 J/ gram = 24.76 kJ/ gram
Heat of combustion of magnesium metal=24.76 kJ/gram
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PLS HELP!!!!!
Convert the following measurements. Show all work, including units that cancel.
82.6 L of neon at STP -> mol
Answer: To convert 82.6 L of neon at STP to moles, we need to use the ideal gas law equation:
PV = nRT
where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature.
At STP, the pressure is 1 atm and the temperature is 273 K. The gas constant, R, is 0.0821 L·atm/(mol·K).
Therefore, we can rearrange the equation as:
n = PV/RT
n = (1 atm)(82.6 L)/(0.0821 L·atm/(mol·K))(273 K)
n = 3.43 mol
So, 82.6 L of neon at STP is equivalent to 3.43 mol of neon.
Explanation:
To convert from liters of a gas at STP (standard temperature and pressure) to moles, we can use the conversion factor of 1 mole of a gas occupies a volume of 22.4 L at STP.
So, to convert 82.6 L of neon at STP to moles, we can use the following calculation:
82.6 L neon x (1 mol neon / 22.4 L neon) = 3.69 mol neon
Therefore, 82.6 L of neon at STP is equivalent to 3.69 mol of neon.
At 27 °C, 3 mole of Bromine gas was found to occupy a volume of 6 Lat a pressure of 380 kPa. What is the value of the gas constant in L.kPa/ mol.K?
Answer: 2.53
Explanation: The ideal gas equation is formulated as:[tex]PV = nRT[/tex]P = Pressure of the ideal gas,
V = Volume of the ideal gas,
n = Total amount of ideal gas that is measured in terms of moles,
R = Gas constant, and
T = Temperature
By rearranging the ideal gas equation we get,
[tex]R = PV/nT[/tex]P = 380 kPa
V = 6 L
n = 3 moles
T = 27+273 = 300 K
Put the value given in this equation:
R = 380 kPa . 6L / 3 mol . 300 K
R = 2.53
Calculate the hydroxide ion concentration, [OH−]
, for a solution with a pH of 8.81
The hydroxide ion concentration of the given solution is 7.94 x 10⁻⁶ M.
The hydroxide ion concentration, [OH⁻], can be calculated from the pH of a solution using the equation:
pH + pOH = 14.
Since we have the pH of the solution as 8.81, we can first calculate the pOH as follows:
pOH = 14 - pH
pOH = 14 - 8.81
pOH = 5.19
Now, we can use the definition of pOH to calculate the hydroxide ion concentration:
pOH = -log[OH⁻]
5.19 = -log[OH⁻]
[OH⁻] = 7.94 x 10⁻⁶ M
The pH of a solution is a measure of its acidity or basicity, which is determined by the concentration of hydrogen ions, [H⁺], in the solution. A pH value of 8.81 indicates that the solution is slightly basic, meaning that it has a lower concentration of hydrogen ions and a higher concentration of hydroxide ions.
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We've figured out what part of the salt causes the flame to change color, so now let's measure the wavelengths created with four metals.
Use the ruler under the "tools" icon in the upper right of the video player to measure the wavelengths of light released by each compound.
The wavelength of one of the spectral lines for lithium chloride (LiCl) is 610.3 nanometers (nm).
In the case of lithium chloride (LiCl), the spectral lines are caused by the emission of light when the electrons in the lithium and chlorine atoms are excited to higher energy levels. One of the prominent spectral lines for LiCl is at a wavelength of 610.3 nm.
This corresponds to the transition of an electron in the lithium atom from the 2p to the 3s energy level. The spectral lines for LiCl have been extensively studied using techniques such as atomic absorption and emission spectroscopy, and they are important for a variety of applications in fields such as chemistry and physics.
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The complete question is:
What is the wavelength of one of the spectral lines for lithium chloride LiCl?
Based on the data in Figure 1 and Figure 2, annotate the diagrams for NH, NFs, and PH, in Figure 1. Include (a) the electronegativity values, (b) the partial charge symbol for each atom in a bond, (c) the dipole vector for each bond, (d) the electronegativity difference between each bonded pair of atoms, (e) the resulting overall dipole vector for each molecule.
The overall dipole moments of the compounds have been shown in the image attached to this answer
What is the dipole moment?The polarity of a chemical bond or molecule is determined by the dipole moment. It is a vector variable that denotes the division of a molecule's positive and negative charges along a specific axis.
The difference in electronegativity between the atoms in a bond is what causes the dipole moment to form. A measure of an atom's ability to draw electrons to itself is its electronegativity.
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Determine the pH of a 3.4 x 10^-6 M solution of HNO3
Considering the definition of pH, the pH of a 3.4×10⁻⁶ M solution of HNO₃ is 5.47.
Definition of pHpH is a measure of acidity or alkalinity and indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions:
pH= - log [H⁺]
pH in this caseStrong acids are those that are completely, or almost completely, dissociated in dilute solution (of concentration less than 0.1 M). So the concentration of protons is equal to the initial concentration of acid.
HNO₃ is a strong acid. So [H⁺]= [HNO₃]= 3.4×10⁻⁶ M
So, the pH can be calculated as:
pH= - log (3.4×10⁻⁶ M)
Solving:
pH= 5.47
Finally, the pH is 5.47.
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Please help! What is the shape of the right carbon?
The shape of the right carbon is tetrahedral (option C).
How does carbon shape in a compound?A carbon atom with four attachments, and bond angles of approximately 109.5° is called a tetrahedral carbon.
The overall shape is that of a tetrahedron (i.e., a pyramid with all faces being equilateral triangles, or nearly so). The carbon atoms uses sp³ orbitals to achieve this geometry.
According to this question, a chemical compound called acetate is given. It is made up of two carbon atoms. The second (right) carbon is surrounded by two oxygen atoms.
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A 5.00 mL aqueous sample containing hydrogen peroxide was diluted to 35.0 mL and analyzed by titration with perm nganate in acidic pH such that the following reaction took place: MnO4 + H2O2 → O2 + Mn2+ Knowing that the sample required 64.2 mL of 0.0125 M permanganate to reach the end point, what is the concentration of hydrogen peroxide in the original sample
The concentration of hydrogen peroxide in the original sample is 0.061 M.
What is hydrogen ?Hydrogen is the first element on the periodic table. It is the lightest and most abundant element in the universe. Hydrogen is an odorless, colorless gas that is highly flammable. It is a nonmetal and has the atomic number of one. Hydrogen has a valence of one, meaning it can form one bond with other elements. Hydrogen is found in most compounds, either as a single atom or as part of a molecule. It is the main component of water and is also found in many organic compounds, such as carbohydrates and proteins. Hydrogen is used in many industries, including the production of ammonia for fertilizer, the production of methane for fuel, and the production of methanol for fuel and other products.
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Choose the orbital diagram that represents the ground state of Be
Explanation:
The orbital diagram that represents the ground state of Be would have two electrons in the 1s orbital and two electrons in the 2s orbital, with the following configuration:
1s↑↓ 2s↑↓
The "1s" and "2s" notations refer to the energy levels of the orbitals, with "1s" being the lowest-energy level and "2s" being the next highest. The arrows indicate the spin of each electron; up arrows represent "spin up" electrons, while down arrows represent "spin down" electrons.
It's worth noting that the Aufbau principle (which states that electrons fill the lowest-energy orbitals first) and the Pauli exclusion principle (which states that no two electrons can have the same set of quantum numbers) are both reflected in this orbital diagram for the ground state of Be.
Calculate the potential of a zinc/silver cell. The zinc electrode is in 0.300 M zinc nitrate solution. The silver electrode is in a 0.600 M silver nitrate solution.
The zinc/silver cell has a potential of 1.23 V.
What is a few half cells' standard electrode potential?In order to obtain a half-unique cell's reduction potential, a standard electrode potential becomes necessary. It is measured with a reference electrode called the standard hydrogen electrode (abbreviated to SHE).
Zinc(s) → Zinc2+(aq) + 2e- E° = -0.76 V
Silver+(aq) + e- → Silver(s) E° = +0.80 V
We employ the following formula to get the cell potential:
Ecell = E°cell - (0.0592 V/n) log(Q)
where n is the number of electrons transported in the balanced equation, Q is the reaction quotient, and E°cell is the standard cell potential. For a concentration cell like this, n =
Q = [Zinc2+]/[Silver+]
Plugging in the values:
n = 2 (because 2 electrons are exchanged in each half-reaction) (since 2 electrons are transferred in each half-reaction)
E°cell = E°cathode - E°anode = +0.80 V - (-0.76 V) = +1.56 V
[Zinc2+] = 0.300 M
[Silver+] = 0.600 M
Q = [Zinc2+]/[Silver+] = (0.300 M)/(0.600 M) = 0.500
Substituting all the values into the formula:
Ecell = +1.56 V - (0.0592 V/2) log(0.500) = +1.23 V
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Calculate the number of repetitions of the β‑oxidation pathway required to fully convert a 18
-carbon activated fatty acid to acetyl‑SCoA molecules.
The β-oxidation pathway involves the breakdown of fatty acids into acetyl-CoA molecules. For an 18-carbon activated fatty acid, a total of nine repetitions of the β-oxidation pathway would be required to fully convert it to acetyl-CoA molecules.
The β-oxidation pathway occurs in the mitochondria and is a four-step process that involves the following reactions: (1) oxidation, (2) hydration, (3) oxidation, and (4) thiolysis.
An 18-carbon activated fatty acid will yield 9 acetyl-CoA molecules through β-oxidation. This is because each cycle of β-oxidation cleaves two carbon units, which are then converted to acetyl-CoA. Therefore, the number of repetitions required can be calculated as follows:
Number of repetitions = Number of carbons ÷ 2
Number of repetitions = 18 ÷ 2
Number of repetitions = 9
Therefore, 9 repetitions of the β-oxidation pathway are required to fully convert an 18-carbon activated fatty acid to acetyl-CoA molecules.
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The following diagrams represent reaction of A2 (shaded spheres) with B2 (unshaded spheres). How many moles of product can be made from 1.0 mol of A2 and 1.0 mol of B2
The number of moles of products based on the information given is 0.5 moles product.
How to explain the diagramIt is given that each unshaded sphere represents an atom A and shaded represents B. If we look at the diagram, we have 8 unshaded doubly attached units and 4 unshaded doubly attached units on the left side which means we have 8 A2 molecules that react with 4 B2 molecules.
Whereas in the right-side diagram(which are products), 4 molecules have 4 unshaded and one shaded sphere, which means it is BA4 and 2 moles have two shaded spheres which mean it is B2. Hence, the number of moles of products based on the information given is 0.5 moles product.
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which of the following would be the conjugate acid for the base HSO3-
1) Sulfurous acid
2) Sulfuric Acid
3) Sulfate
4) Sulfite
This acid is known as sulfurous acid, as it's the conjugate base for base HSO3.
Why is H2SO3 known as sulfurous acid?This compound is made up of three different elements: hydrogen, sulfur, & oxygen. According to the molecular formula, there are two hydrogen atoms, one sulfur atom, or three oxygen atoms. The sulfurous acid compound name is H2SO3 H 2 S O 3.
Why is sulphuric acid harmful?Sulfuric acid is a very corrosive chemical that, when concentrated, can be explosive. It can potentially cause skin burns, irritate the respiratory tract and make breathing difficult if inhaled, burn the eyes but instead possibly cause blindness if swallowed, and burn holes there in stomach if swallowed.
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who can help me? i need a grade or i’m going to summer school, please help me
The information for the equation of the circle is given as follows:
Coordinate F(7,0) - =8
Coordinate R(7,-4) = 8
Coordinate T(11,0) = 8
Where the following equation is given:
(x-9)² + (y+2)² = 8
If Coordinate F(7,0)
Substituting we have:
(7-9)² + (0+2)² = 8
(-2)²+ (2)² = 8
4 + 4 = 8
If Coordinate R(7,-4)
Substituting we have:
(7-9)² + (-4+2)² = 8
(-2)²+ (-2)² = 8
4 + 4 = 8
If Coordinate T(11,0)
Substituting we have:
(11-9)² + (0+2)² = 8
(2)²+ (2)² = 8
4 + 4 = 8
3) The length of the diameter of the circle is 8
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Question 14 of 25
For a certain chemical reaction, the reactants contain 52 kJ of potential
energy, and the products contain 32 kJ. How much energy is absorbed or
released by the reaction?
OA. 20 kJ is released.
о B. 84 kJ is relesed.
OC. 84 kJ is absorbed.
OD. 20 kJ is absorbed.
SUBMIT
Answer: The answer is (20 kj is released)
Explanation:
Have A Good Day :)
Why do sunspots look dark?
A. They are cooler than the surrounding area of the Sun.
B. The gas above it blocks the light making them hard to see.
C. Magnetic field absorb light making the sunspots dark in appearance.
D. They only emit light in gamma rays making them invisible to the unaided eye.
Answer:
A
Explanation:
A. They are cooler than the surrounding area of the Sun.
Sunspots are regions on the Sun's photosphere where the magnetic fields are extremely strong, inhibiting the convective flow of hot gas from the solar interior. These regions appear darker than the surrounding photosphere because they are cooler (around 3,500-4,500 K) than the surrounding areas (around 5,500 K), making them less luminous.
16. Why are some batteries considered non-rechargeable even
though they are based on the same reversible redox reac-
tions as those in rechargeable batteries?
Non-rechargeable batteries, also known as primary batteries, are designed with a limited amount of active materials in their electrodes. Once all the active materials are consumed, the battery cannot be recharged. This is because non-rechargeable batteries have significantly different chemistries than rechargeable batteries, despite both being based on reversible redox reactions.
On the other hand, rechargeable batteries, or secondary batteries, are designed to be recharged because they contain more active materials in their electrodes that can be replenished when the battery is charged. Rechargeable batteries also have additional layers to protect their active materials from degrading during the charge and discharge process.
Therefore, the fundamental difference between non-rechargeable and rechargeable batteries is the amount of active materials contained in the electrodes and their corresponding battery chemistries – which results in the limited use of non-rechargeable batteries.
1. Calculate the enthalpy of the following reaction:
2. Calculate tbe energy change when 25.0 g of magnesium changes from from 27°C to 45°C. The specific heat of magnesium is 1.05 J/g*°C.
Heat capacity of a substance or system is defined as the amount of heat required to raise its temperature through 1°C. It is denoted by C. Heat capacity is an extensive property.
The specific heat capacity of a substance is defined as the amount of heat required to raise the temperature of 1 gram of the substance through 1°C.
1. The enthalpy change = sum of enthalpies of products - sum of enthalpies of reactants
ΔH = (-411 - 286) - (-92.3 + -426.7) = -178 kJ
2. The heat required to raise the temperature of a sample is:
q = mc ΔT
25.0 × 1.05 (45 - 27) = 472.5 J
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Consider the combustion of carbon monoxide in oxygen gas 2CO2+O2=2CO2, in this reaction, 10.8 moles of carbon dioxide was produced. Calculate the number of corbonmonoxide used in this reaction to produce such number of carbon dioxide.
In this process, 10.8 moles of carbon monoxide were converted into 10.8 moles of carbon dioxide.
What is the carbon monoxide to carbon dioxide mole ratio?The carbon dioxide and carbon monoxide have a 2:2 mole ratio according to the balanced chemical equation. The mole ratio will make it easier for us to determine how many moles of carbon dioxide will be created from the specified amount of carbon monoxide. (oxygen gas is excess).
The balanced chemical formula for carbon monoxide combustion is:
2carbon monoxide + oxygen → 2carbon dioxide
2 moles of carbon monoxide react with 1 mole of oxygen gas in this reaction, according to the stoichiometry, to produce 2 moles of carbon dioxide.
So, in order to generate 10.8 moles of carbon dioxide, we must:
10.8 moles carbon dioxide x (2 moles carbon monoxide / 2 moles carbon dioxide) = 10.8 moles carbon monoxide
In this process, 10.8 moles of carbon monoxide were converted into 10.8 moles of carbon dioxide.
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Which of the following fields is(are) part of the environmental movement? a. scientific b. social c. political d. all of the above Please select the best answer from the choices provided A B C D
The correct answer is D: All of the above. The environmental movement encompasses all of these fields, including scientific, social, and political aspects.
What is movement?Movement is a physical activity that involves the change of position of a person or object over a particular area of space. It can include the displacement of the body, such as walking, running, and dancing, or the movement of objects, such as throwing a ball or lifting a weight. Movement can be voluntary or involuntary, as in reflexes or twitches, or it can involve the movement of non-living objects such as a car moving on a road. Movement can be used to express social and emotional states, such as joy or sadness, or to coordinate with others in a group. Movement can also help to explore and learn about the environment, to socialize with others, or to simply have fun.
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How much heat is produced when 30.4 g of NO2 react?
4NO2(g) + O2(g) → 2N2O5(g) heat of reaction = –110.2 kJ
Answer:
Explanation:
We can use the molar mass of NO2 to convert grams to moles:
30.4 g NO2 x (1 mol NO2 / 46.0055 g NO2) = 0.6618 mol NO2
From the balanced chemical equation, we see that 4 moles of NO2 react to produce 2 moles of N2O5, so:
0.6618 mol NO2 x (2 mol N2O5 / 4 mol NO2) = 0.3309 mol N2O5
Finally, we can use the molar enthalpy of reaction to calculate the heat produced:
0.3309 mol N2O5 x (-110.2 kJ / 2 mol N2O5) = -18.16 kJ
Therefore, 30.4 g of NO2 reacting produces -18.16 kJ of heat. Note that the negative sign indicates an exothermic reaction, meaning heat is released.