A 0.425g sample of propane was mixed with excess oxygen in a calorimeter containing 98.72 g of water. The system was ignited and the temperature rose from 18.29ºC to 26.85ºC. the molar enthalpy of propane is 393851.1 J/mol
The mass of propane = 0.425 g
molar mass of propane = 44 g/mol
moles = mass / molar mass
= 0.425 / 44
= 0.009 mol
ΔH = mc ΔT
ΔH = n ΔHsol
ΔHsol = mc ΔT / n
= 98.72 × 4.18 ( 26.85 - 18.29 ) / 0.009
molar enthalpy of solution = 393851.1 J/mol
Thus, A 0.425g sample of propane was mixed with excess oxygen in a calorimeter containing 98.72 g of water. The system was ignited and the temperature rose from 18.29ºC to 26.85ºC. the molar enthalpy of propane is 393851.1 J/mol
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fourier transform techniques using an interferometer have not been used in uv-vis spectroscopy because
Fourier Transform techniques using an interferometer not used in UV-Vis spectroscopy because UV-Vis spectral regions require high level of stability.
The purpose of interferometer is to divide a single light beam into two separate ones so that the two beams follow different directions. But the atmosphere can cause vibrations in FT spectrometers, which can be bulky. These drawbacks prevent them from being effectively used in the UV-VIS spectral regions, which demand a high level of stability. While a broadband infrared source's wavelength is modulated by the FTIR spectrometer using an interferometer. Hence a detector determines how much light is transmitted or reflected in relation to its wavelength.
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If a hydrate of the formula mcly⋅xh2o decomposes when heated to produce hcl, what change would you expect to occur when a piece of blue litmus paper is held in the path of the vapor released?.
Blue litmus paper will turn red in an acidic solution.
Litmus paperLitmus paper is an indicator that can detect whether a solution is acidic or alkaline. Litmus paper is divided into red and blue litmus paper.
The addition of sulfuric acid or hydrochloric acid causes the litmus paper to turn red. Red litmus paper will turn blue when dipped in an alkaline solution.
Blue litmus is litmus paper which has a blue color. If it is dropped or dipped in an alkaline solution, then the color will not change (it remains blue). If it is dropped or dipped in an acid solution, the blue litmus paper will turn red.
Red litmus paper turns blue when immersed in an alkaline solution, while blue litmus paper turns red when immersed in an acidic solution.
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Convection ovens are ovens that are advertised to cook food more evenly than a standard thermal oven. Which statement best explains how a convection oven works?
a. Hot air is transferred through molecule to molecule contact.
b. Hot air is transferred through density differences with hot air rising and cool air sinking.
c. Hot air is transferred through heat being radiated from a thermal burner.
d. Hot air is transferred through density differences with cool air rising and hot air sinking.
A colorimeter is an instrument used to measure the amount of _________ absorbed by a solution. This absorbance is proportional to the __________of the solute in solution.
A colorimeter is an instrument used to measure the amount of light absorbed by a solution. This absorbance is proportional to the concentration of the solute in solution.
A colorimeter is a photosensitive device used to measure the transmission and absorption of light through liquid samples. Colorimetric devices also measure the intensity or concentration of color produced when a particular reagent is introduced into a solution. The
colorimeter is based on his two basic laws of photometry.
Beer's Law: This law states that the amount of light absorbed is always proportional to the concentration of dissolved substances in solution.
Log10 Io/It = asC
where 'C' is the concentration of the solution and 'as' is the absorption index.
Lambert's law: A = log10 Io/It = asb ,
"as" is standard absorbance, "A" is test absorbance, "b" is solution thickness/length. The disappearance of transitions depends on two extrinsic assumptions. The absorbance is directly proportional to the concentration (c) of the sample solution used in the experiment. Absorbance is directly proportional to the optical path length (l).
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How much heat is needed to raise 35 grams of gold from 25.0°C to 35.0°C? (The specific heat of gold is 0.13 J/g°C.)
45.2 J
-55.2 J
54.2 J
25.2 J
Answer:
45.5J
Explanation:
ΔT=10°C
specific heat=0.13J/g°C
mass Au=35g
heat=35g•0.13J/g°C•10°C
heat=45.5J=46J
NOTE:I apply significant figures here for the accuracy of the solution.
please rate it,Thanks.
a student is studying barium, a highly reactive element that is used in some paints. which characteristic of barium is most closely related to its chemical reactivity?
The most closely related characteristic of barium to its chemical reactivity is its high ionization energy.
Does barium have a high reactivity?
There are two valence (outermost) electrons in each of their atoms. Barium is in period 5, or row 5, therefore it keeps its valence electrons in its fifth shell but is very quickly oxidized or capable of losing the electrons. This explains why barium is so reactive, especially when it comes to electronegative components like oxygen. In a nutshell, the ionization energy decreases with increasing atom size. Barium has more energy levels and is larger than strontium because it is on the sixth period while strontium is on the fifth. Barium will therefore have a lower ionization energy.To learn more about barium, follow the link https://brainly.com/question/6034926
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Why was the metal sample heated in a dry test tube rather than in the boiling water.
The metal is heated in a dry test tube to measure the capacity of the metal.
Define metal.Metals are a class of materials characterized by high electrical and thermal conductivity, as well as malleability, ductility, and high light reflectance.
About three-quarters of known chemical elements are metals. The most common types found in the Earth's crust are aluminum, iron, calcium, sodium, potassium, and magnesium. The majority of metals are found in ores (substances containing minerals), but some, such as copper, gold, platinum, and silver, are commonly found in the free state because they do not react easily with other elements. .
When doing chemistry experiments it is important to have:
The materials readyMake sure the mixture and elements are in the right amount of water. It should be placed in a dry test tube first to measure the capacity by heating in test tubeWhen heated with boiling water, the metal cools and the water heats up over time. After all, the two objects have the same temperature. They are then in thermal equilibrium with each other. Hot metal, on the other hand, releases energy into the water.
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science subject.(please help me giving out points) A scientist wants to determine how a solvent’s properties affect its ability to dissolve a solute. The scientist decides to perform an experiment to see if the temperature of water impacts its ability to dissolve salt. The diagram below shows the experimental setup.
can someone help me find the independent, and dependent variable. I need a constant,a hypothesis,and an experimental question that was in the question and try and find a procedure for this.(giving max 100 points).
Based on the data provided:
Independent variable - temperatureDependent variable -solubility of a soluteConstant variable - solvent (water), water volume, etc.Hypothesis - the temperature of water affects the ability of salt to dissolve.Research question: Does the temperature of water affects the ability of salt to dissolve?Procedure - Dissolve the salt in water at various temperatures ad determine the maximum amount of salt that dissolves at each temperature.What are the variables in an experiment?The variables in an experiment are those factors or quantities that can be changed or controlled by the researcher while conducting the research.
There are three types of variables in an experiment:
Independent variable - this is the variable that does not depend on any other variable but which when changed by the researcher brings about changes in another variable known as the dependent variable.Dependent variable - this is the variable that changes when another variable known as the independent variable changes. The dependent variable is usually the variable that is being tested. Hence, it is also called the test variableConstant variable - this variable is kept constant and not altered.An experiment usually states a hypothesis that is tested.
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Identify the dominant intermolecular force in ammonia (nh3). Given that ammonia is a gas at room temperature, what can you infer about the relative strengths of the intermolecular forces between ammonia molecules and between water molecules?.
The intermolecular interactions between water molecules are greater than those between ammonia molecules.
What conclusions may be drawn regarding the relative potency of the intermolecular interactions between ammonia and water molecules?In a certain state of matter, substances are bound together by intermolecular forces. Three different states of matter exist;
Solid, sLiquid, sGas .
The level of intermolecular contact between molecules is greatest when matter is solid. Liquid states have weaker intermolecular interactions, while gaseous states have the weakest intermolecular contacts.
Since ammonia is a gas at room temperature, its molecules interact with one another less strongly than those of water at the same temperature.
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The main lipids found in cell membranes are called?
A. Waxes
B. Steroids
C. Phospholipids
The main lipids found in cell membranes are called Phospholipids.
Explanation:The most abundant membrane lipids are the phospholipids. These have a polar head group and two hydrophobic hydrocarbon tails. The tails are usually fatty acids, and they can differ in length (they normally contain between 14 and 24 carbon atoms).
write a 2-page plan on what would you do to secure your database project. be sure to consider the following: potential security risks recommended security protocols
Database security refers to all the precautions businesses take to guard against hacks into their database management system (DBMS) and every piece of associated software. This involves implementing policies, practices, and tools designed specifically to safeguard the stored sensitive data. Small businesses that manage and collect huge amounts of data should also have database security standards in place because this problem is not just a problem for big businesses.
The finest database security practices listed below can help keep your databases secure from intruders.
1. Separate Web and Database ServersIn the conventional sense, this entails securing, locking, and providing access controls for your database server to keep away unauthorized visitors. It also entails maintaining the database on a distinct physical system from those used to operate web servers or applications.
2. Use firewalls for web applications and databases.A firewall should be used to safeguard your database server against threats to database security because it by default blocks traffic. Only traffic from certain applications or web servers that require access to the data should be permitted. The firewall ought to prevent your database from opening outbound connections unless absolutely necessary.
3. User Access to a Secure DatabaseThe database should only be accessible by the fewest individuals feasible. Administrators should only be granted access when they need it and only for as long as they need it to do their duties. Although this may not be feasible for smaller businesses, at the very least permissions should be handled through the use of groups or roles rather than being directly granted.
4. Update Your Operating System And Patches FrequentlyTo safeguard against the most recent vulnerabilities, it's crucial to routinely upgrade your operating system and database software with all security patches installed. Unless there is a compelling reason for any to be disabled, you should also make sure that any database security controls offered by the database are enabled (most are by default).
5. Auditing and tracking database activityThis entails keeping an eye on logins (and login attempts) to the database and operating system as well as routinely checking logs to look for unusual activity. To inform the appropriate team members when potentially dangerous activity is found, you may also generate alerts.
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What are the 10 organisms?.
Producers, eaters, herbivore, carnivore, omnivores, scavengers, parasite, predators, and decomposers are only a few of the various sorts of creatures.
In biology, what is an organism?An organism is a collection of molecules working to together form a mostly stable whole that demonstrates the characteristics of life. With phrases like "any sense of life, such as with a plant, animal, fungus, or bacterial, capable of growth & reproduction," dictionary definitions are very general.
What types of organisms are examples?A living creature with a organized approach, is capable of responding to stimuli, can reproduce, develop, adapt, and preserve homeostasis is referred to as an organism. Therefore, every animal, plant, fungi, protist, microbe, or archaeon found on Earth would be considered a life.
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How many moles of Carbon are in 38 g of C
Answer:
It is exactly 0.67 moles of carbon.
Select the best answer for the question
6. The primary source of sound is vibration. This vibration has to travel through a medium, whether it's a gas, liquid, or solid. A sound wave with a higher energy will
have what kind of intensity in relation to a sound wave of a lower energy?
A.The sound wave with higher energy will have lower intensity
B.The sound wave with lower energy will have higher intensity
C. The intensity of a sound wave has nothing to do with the original energy
D. The sound wave with higher energy will have more intensity
Answer: the answer would be C
Explanation:
I took the test
There are __ ___________ that make up everything we know and love.
Answer:
There are 92 elements that make up everything we know and love.
Explanation:
Complete these sentences by selecting the correct answers from the drop-down menus. After one half-life, % of the atoms will change to a stable isotope and % will remain radioactive. After three half-lives, % of the atoms will change to a stable isotope and % will remain radioactive.
After one half life, 50% of the atoms will change to a stable isotope.
After one half life, 50% of the atoms will remain radioactive.
After three half lives, 87.5% of the atoms will change to stable isotope.
After three half lives, 12.5% of the atoms will remain radioactive.
When the initial value of any compound is 100%, after one - half it will reduce to 50%, after the second half -life, it will reduce to 25%, after third half it will reduce to 12.5%.
Half- life may be described as the time required for the radioactivity of a specified isotope to drop to half its initial value.
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Assuming the density of your initial acid solution is 1.0 g/ml, what is the concentration (in molarity) of the diluted acetic acid, [ch3cooh], solution? show your work and include units. hint: an initial 4.5% w/w solution (w/w means 4.5 g of acid per 100 g of solution) of ch3cooh (mw
the concentration (in molarity) of the diluted acetic acid, solution is 0.75 M
the molarity can be calculate as follows:
Generally, the equation for Molarity is mathematically given as
M = n X V
M = W X 1000
MW mL
where M represent molarity
W represent mass( weight)
MW represent molecular weight
MW CH3COOH = (2 x Ar C) + (4 x Ar H) + (2 x Ar O) = ((2 x 12.0107) + (4 x 1.00794) + (2 x 15.9994)) gram/mol = (24 + 4 + 32) gram/mol = 60.05 gram/mol
Therefore,
M = W X 1000
MW mL
M = 4.5 X 1000
60.05 100
M = 0.75 M
therefore, the concentration(in molarity) of diluted acetic acid, solution is 0.75 M
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what is the atomic radius in picometers of an argon atom if solid argon has a density of 1.623 g/cm3 and crystallizes at low temperature in face-centered cubic unit cell?
Atomic radius of an argon atom in FCC unit cell is 185 picometer.
Density of argon = 1.83 g/[tex]cm^{3}[/tex] and atomic mass of Argon = 40
density (d) = [tex]\frac{n . M}{a3 . Na}[/tex]
where d= density , n= no. of atoms present M = atomic mass , a3 = volume, Na = Avogadro's constant
a3 = [tex]\frac{n . M}{d . Na}[/tex]
a3 = 4 x 40 / 1.83 x 6.023 x [tex]10^{23}[/tex]
= 14.51 x [tex]10^{-23}[/tex]
=145.1 x [tex]10^{-24}[/tex] = a3
a = 5.25 x [tex]10^{-8}[/tex] cm
a= 0.525 x [tex]10^{-7}[/tex] nm
For FCC unit cell [tex]\sqrt{2a}[/tex] = 4r
r =[tex]\sqrt{2a}[/tex] / 4
= 1.41 x 0.525 / 4
= 0.185 nm
= 185 picometer
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What are the essential benefits of the Affordable Care Act?.
The essential health benefits of the Affordable Care Act include preventive care, emergency services, hospitalization, prescription drugs, mental health services, and pregnancy care.
The Affordable Care Act does what?For households earning below 100% - 400% of both the federal poverty threshold, the law offers customers subsidies (referred to as "premium tax credits") that reduce prices (FPL). Increase Medicaid coverage to include all adults with incomes below 138% of the federal poverty level.
The Affordable Healthcare Act covers who?Obamacare allows people to purchase health insurance regardless of their financial level. You may be eligible for a prescription tax credit or other special discounts that will lower the cost of your health insurance if your family income between 100% or 400percent of total of both the federal poverty threshold (FPL).
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hat is the temperature of the filament, in degrees celcius (degc), when the bulb is on? the filament is made of tungsten.
The temperature of the filament, in degrees Celsius when the bulb is on the filament is made of tungsten is 2500 °C - 3000 °C.
The material used as filament is tungsten . the limit of working temperature of tungsten is 2500 °C - 3000 °C. The tungsten used as a filament in blub because it is an alloy. tungsten have high melting point. tungsten does not burn at room temperature because of high resistivity , it glows the bulb at high temperature.
Thus, The temperature of the filament, in degrees Celsius when the bulb is on the filament is made of tungsten is 2500 °C - The3000 °C.
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A model for the campfire is Wood + Oxygen → Water + Carbon Dioxide + Ashes
Which reactant will run out? Which reactant will not run out? Justify your answer. (3 pts)
Answer:
wood run out and anothers don't runout ithink i am right
identify the kind of chemical catalysis and then identify which of the given amino acids can act as a catalyst for the reaction.
The kind of chemical catalysis is covalent catalysis and among the given amino acids lysine will act as a catalyst for the reaction.
The generation of iminium ions in the transition state of the reaction confirms that it is a covalent catalysis. lysine is the only amino acid that can catalyze the iminium ion generated in the transition state of the reaction.
So the answer for the type of catalysis is covalent catalysis, and the answer for the type of amino acid among the given amino acids that can catalyze the reaction is lysine.
Complete question: (Reaction is attached as a picture)
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review your observations of the reactions of the metals with ions in solution including the hydrogen ion. which ion was the most reactive?
Active series ions with the highest reactivity among metals.
What is an activity series?The simplicity of chemical reactions is the main difference between metals. The most active metals in terms of reactivity are those in the lower left corner of the periodic table. For example, water reacts with lithium, sodium and potassium. However, as you move down this pillar, the more metallic the elements become, the more reactive they become, thus accelerating the rate of this reaction.
The order in which metals are arranged in descending order of reactivity is called the reaction sequence or activity sequence of metals.
The list of active or electromotive series metals is arranged in order of increasing reactivity with hydrogen ion sources such as water and acids.
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What could happen if they are tumbled rapidly? What could happen if they are tumbled rapidly?
If they are tumbled quickly, they might stick together because the static charge produced is now strong enough to do so, but it might not be close enough.
What creates static electricity?When dipoles are not in equilibrium, static electricity is produced. While electrons want to hop all over the place, the neutrons and protons don't move around too much. An item (or person) has a negative charge when it possesses excess electrons.
What is referred to as static electricity?Negative and positive charges inside an object must balance out for there to be no static electricity. Until they discover a method to be freed or discharged, these charges may accumulate on an object's surface. Through a circuit is one approach to discharge them.
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A measurement of the heat produced when a known amount of sugar burns in a constant volume calorimeter would enable us to first calculate the.
For the burning of sugar, there is a molar internal energy change. For a comb calorimeter, w=0 because Delta V=0 and Delta E=q+w. So Delta
E = q.
What about water makes it a suitable medium for heat transfer in calorimetry?Water may absorb a lot of heat energy because of its large specific heat capacity without boiling or even significantly changing its temperature. Water is a useful medium for heat exchange in calorimetry because of this.
Heat transfer rates to or from a substance are measured using calorimetry. Heat is transferred to do this using a calibrated item (calorimeter). Calculating the quantity of heat transmitted by the process under study requires using the temperature change recorded by the calorimeter.
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a 9.148 mol sample of nitrogen gas is maintained in a 0.8008 l container at 303.6 k. what is the pressure in atm calculated using the van der waals' equation for gas under these conditions?
9.148 mol sample of nitrogen gas is maintained in a 0.8008 l container at 303.6 k. the pressure in atm is 330 atm.
The van der waal's equation is given as :
( P + ( an² / V² )) ( V - nb ) = RT
P = ( nRT / (V - nb )) - ( an² / V² )
n = 9.418
V = 0.8008 L
T = 303.6 K
a = 1.39 L² mol⁻² atm
b = 3.91 × 10⁻² L mol⁻¹ atm⁻¹
R = 0.821 L atm K⁻¹ mol⁻¹
P = ( 9.418 ×0.821 × 303.6 / ( 0.8008 - 9.148 × 3.91 × 10⁻² ) - ( 1.39 ×
(9.148)²/(0.8008)²
P = 330 atm
Thus, 9.148 mol sample of nitrogen gas is maintained in a 0.8008 l container at 303.6 k. the pressure in atm is 330 atm.
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how does the vasomotor center control peripheral resistance?
Answer: This is simple. It continually sends sympathetic impulses to the smooth muscles in the arteriole walls.
To Explain: Keeping them in a state of tonic contraction, This will help maintain the peripheral resistance associated with normal blood pressure.
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An atom of a certain element has an atomic number of 28 and a mass number of 59. How many neutrons does this atom contain?.
Answer:
28+59=87
Explanation:
you will add protons and neutrons together to become a mass number
A certain compound containing only carbon and hydrogen was found to have a vapor density of 2. 550 g/l at 100°c and 760 mm hg. If the empirical formula of this compound is ch, what is the molecular formula of this compound?.
The molecular formula for this given hydrocarbon is C6H6. IUPAC:- (n-hexyne).
To find the molecular formula, we first need to figure out the molar mass of the compound. Moving ahead, we need to know the mass of the molecule which can be calculated using the ideal gas equation. Assuming we do have 1 liter and 2.550 grams and the pressure is 760mmhg which is equal to 1atm. Divide the pressure and the volume by the gas constant and the Temperature (in kelvin) which equals to the number of moles. Now you have the number of moles and the mass of the compound (2.550grms) through which you can find the molar mass of the compound which is 78g/mol. We know that molar mass of carbon is 12g/mol and 1g/mol for hydrogen by which we can assume the molecular formula will have 6 carbon and 6 hydrogen. So the molecular formula for this compound is C6H6.
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The solubility product constant of li3po4 is 3. 2 × 10-9. What is the molar solubility of li3po4 in water?.
The molecular solubility of li3po4 in water is 7.52*10^−3 M.
Here, we have been told that the solubility product constant of li3po4 is = 3.2*10^-9 (i)
We know that the molecular stability of an ionic compound is defined as the concentration of the compound dissolved in the solution. We can calculate the molecular stability of the given ionic compound li3po4 by using the solubility product given.
= {Li] = {PO} = S
= 3.2*10^-9 = S^3-S
= S^4= 3.2*10^9
= S = 7.52*10^−3 M.
Therefore, the molecular stability of the given ionic compound li3po4 is 7.52*10^−3 M.
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