Answer: A typical hydrogen fuel cell produces 0.5 V to 0.8 V per cell. To increase the voltage individual cells can be connected in series.
The covalent compounds are soluble in:
a) All acids
b) All bases
c) all solvents
d) nonpolar solvents
Answer:
d) Non-polar solvents
The stage in which the hair begins to destroy itself as it disconnects from the
papilla is called?
A 33.4−L volume of methane gas is heated from 22°C to 66°C at constant pressure. What is the final volume of the gas?
Answer:
38.38 L (3 d.p.)
Explanation:
In response to questions addressing the expansion of gas via heating, Charles's Law should be considered. Charles's Law is an experimental gas law explaining the tendency of gases to expand when heated.
The law states that the volume ([tex]V[/tex]) of a gas is directly proportional to its temperature ([tex]T[/tex]) given that the pressure ([tex]P[/tex]) and the amount of gas ([tex]N_{A}[/tex]) are constant.
[tex]\displaystyle\frac{V}{T} \ = \ k \ \ \ \ \ \ \ or \ \ \ \ \ \ \ V \ = \ kT[/tex], where k is a proportionality constant.
*Note that when substituting temperature into the equation, the temperature must be in terms of the Kelvin scale and not in degrees Celsius. The relation between the Kelvin scale and the Celsius scale is [tex]\mathrm{K} \ = \ ^{\circ}\mathrm{C} \ + \ 273[/tex].
Charles's law can be used to compare changing conditions of a particular gas. Let [tex]V_{1}[/tex] and [tex]T_{1}[/tex] be the initial volume and temperature for the gas, while [tex]V_{2}[/tex] and [tex]T_{2}[/tex] be the final volume and temperature. The mathematical relationship of Charles's law becomes:
[tex]\displaystyle\frac{V_{1}}{T_{1}} \ = \ \displaystyle\frac{V_{2}}{T_{2}}[/tex].
In accordance with the question,
[tex]V_{1} \ = \ 33.4 \ \mathrm{L}, \ T_{1} \ = \ (22 \ + \ 273) \ \mathrm{K} \ = \ 295 \mathrm{K}, \ T_{2} \ = \ (66 \ + \ 273) \ \mathrm{K} \ = \ 339 \ \mathrm{K}[/tex]
while [tex]V_{2}[/tex] is the final volume of the gas that we would like to find. Therefore,
[tex]V_{2} \ = \ \displaystyle\frac{V_{1} \ \times \ T_{2}}{T_{1}} \\ \\ V_{2} \ = \ \displaystyle\frac{33.4 \ \mathrm{L} \ \times \ 339 \ \mathrm{K}}{295 \ \mathrm{K}} \\ \\ V_{2} \ = \ 38.38 \ \mathrm{L}[/tex].
PLZ HELP ASAP! I need this done tonight please
The importance of wearing a seatbelt while riding in the car can best be explained using:
A) Newton's First Law (Law of Inertia)
B) Newton's Second Law (F=ma)
C) Newton's Third Law (Action-Reaction)
D none of the above
Explanation:
this is a chemistry question ???
anyway, it is clearly A, as seatbelts try to counteract the inertia a moving body (our bodies riding in a car) has, when the environment (the car) of this body is suddenly coming to a stop.
this inertia would otherwise try to move the body still forward resulting in a headfirst crash into and often through the windshield. which causes much more damage to the body than the bruises caused by the pressure of the seatbelts against the body counteracting the body's inertia.
but also clearly, all 3 laws play a role.
the force with which the moving body has to deal when smashing into the windshield and potentially then other objects outside the car is described by the second law.
and for any action (crash) there are corresponding reactions (like the conversion of the crash energy into some absorbing reaction : damaged soft and hard tissue in the human body, crumbled car bodies,...).
Michelle is trying to find the average atomic mass of a sample of an unknown
element. She finds that her sample contains 59.34% of an isotope with a mass of
113.6459, while the rest of the sample is an isotope with a mass of 115.8488. What
is the average atomic mass of her sample? Please round your answer to 0.01 amu.
The average atomic mass of her sample is 114.54 amu
Let the 1st isotope be A
Let the 2nd isotope be B
From the question given above, the following data were obtained:
Abundance of isotope A (A%) = 59.34% Mass of isotope A = 113.6459 amuMass of isotope B = 115.8488 amuAbundance of isotope B (B%) = 100 – 59.34 = 40.66%Average atomic mass =?The average atomic mass of the sample can be obtained as follow:
[tex]Average \: atomic \: mass \: = \frac{mass \: of \: A \times A\%}{100} + \frac{mass \: of \: B \times B\%}{100} \\ \\ Average \: atomic \: mass \: = \frac{113.6459\times 59.34}{100} + \frac{115.8488\times 40.66}{100} \\ \\ Average \: atomic \: mass \: = 114.54 \: amu \\ \\ [/tex]
Thus, the average atomic mass of the sample is 114.54 amu
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what layers of protection can be used tot detect and respond to abnormal reactions or process conditions
In the body, the main protective layer is known as the epithelium, this can be found in the skin as well as other organs such as the lungs.
The body is often exposed to external factors that can damage it; due to this, throughout evolution, most animals and multicellular organisms have developed protective mechanisms.
In the case of humans and other animals, the protective layer is known as the epithelium, which is composed of epithelial cells. This protective layer can be found internally and externally.
External layer: This is the first protective layer, commonly known as skin, this layer protects the inner organs from extreme temperatures, changes in pressure, etc.
Internal layer: Organs such as the lungs or the ones in the gastrointestinal system are all covered by a thin epithelial layer that helps each organ to be protected.
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soaps do not work well in hard waters. But they can still be effected it large quantities of soap are added to water. Explain why.
Answer to question in picture
Answer:
methyl 2-methyl-ethane
Explanation:
Which element gives up its valence electrons most readily?
Bi
Fr
Be
Ar
Answer:
Fr
Explanation:
I took the test
Look at the diagram of 2 basic cell types. Which of the following describes cell 2?
A) a plant cell
B) an animal cell
C) a eukaryote cell
D) a prokaryote cell
How many moles in 44.7 kg of carbon dioxide
Answer:
What is the number of moles of carbon present in 44 grams of carbon dioxide? One. 44 grams is a mole of carbon dioxide and there is one carbon atom in CO 2 so there is one mole of carbon. That’s how chemistry works.
Explanation:
What is the number of moles of carbon present in 44 grams of carbon dioxide? One. 44 grams is a mole of carbon dioxide and there is one carbon atom in CO 2 so there is one mole of carbon. That’s how chemistry works.
Draw the Lewis structures for
Calcium bromide, CaBr2
The Lewis structure is the way of expressing the covalent bonding in molecules. The covalent bond formation takes place by the sharing of electrons in a molecule.
What is Lewis structure?In Lewis dot structures or simply the Lewis structures, the dots are used to represent the electrons. They provide a picture of bonding in molecules in terms of the shared pair of electrons and the octet rule.
The concept of covalent bond is introduced by the scientist G.N Lewis. According to him, the atoms achieve stable octet when they are linked with each other by sharing of one more pairs of electrons. The covalent bonding occurs between the atoms which do not differ much in their electronegativity.
The Lewis structure of CaBr₂ is denoted below. Here two bromine atoms acquires a stable electronic configuration by sharing electrons. There are two single bonds between them.
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Pressure is exerted in all directions when an object is in fluid/water. *
A. True
B. False
Answer:
False
Explanation:
Fluid pressure has no direction, being a scalar quantity, whereas the forces due to pressure have well-defined directions: They are always exerted perpendicular to any surface. The reason is that fluids cannot withstand or exert shearing forces.
Lead has an atomic number of 82. Which statement describes all neutral atoms and ions of lead?
A) Neutral atoms of lead must have 82 electrons. Ions must have 82 electrons, as well.
B)Neutral atoms of lead must have 82 protons, but ions can have more or fewer.
c) Neutral atoms of lead must have 82 neutrons, but ions can have more or fewer.
D0 Neutral atoms of lead must have 82 protons. Ions must have 82 protons, as well.
1. The neutral atoms of lead has 82 protons.
2. The ions of lead also have 82 protons.
The correct answer to the question is Option D. Neutral atoms of lead must have 82 protons. Ions must have 82 protons, as well.
Lead, Pb is a metal with an atomic number (i.e proton number) of 82
Metals can only form ions by losing their valence electron(s)
NOTE: In the formation of ions, only the electrons are involved. The protons are not involved. Thus, the protons of the neutral atom and the ion remains the same.
With the above information in mind, we can conclude that neutral atoms of lead must have 82 protons. Ions must have 82 protons, as well.
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Answer:
C. Neutral atoms of lead must have 82 neutrons, but ions can have more or fewer
Explanation:
O Neutral atoms of lead must have 82 neutrons, but ions can have more or fewer. O Neutral atoms of lead must have 82 protons, but ions can have more or fewer.
What was the name of the original supercontinent that wegener proprosed in his theory
Answer:
pangea
Explanation:
. What is meant by periodic in Periodic Table?
a. the table has b. the elements
repeated cycles occur more than
once
c. the table is only d. the table can be
good for so long changed as
needed
Answer:
B
Explanation:
Periodic refers to properties that repeat at certain intervals. Click to see full answer. In respect to this, what does periodic mean in the term periodic table? In the context of chemistry and the periodic table, periodicity refers to trends or recurring variations in element properties with increasing atomic number.
Which bond is the most polar?
Answer:
A
Explanation:
reason:
H-F is most polar
because bond is polarized negative towards F which is the more electronegative atom.
Who did the ram caught in the thicket (Genesis 22:13) represent?
Answer:
“Rams Caught in a Thicket” as an allusion to the biblical story of Abraham. They more likely represent goats, which could often be seen standing on their hind legs, to reach leaves in the trees, as seen here.
does the following atomic model of a chemical reaction correctly demonstrate the law of conversation of matter why or why not
plzzz help
Answer:
Yes
Explanation:
You can tell because there are 2 moles of H2 on the reactants side and 1 mole of O2, and on the products side we see the same amount, meaning that no moles of H2 or O2 were added or destroyed, meaning that it follows the law of conservation of matter.
For a reversible reaction, what would a large equilibrium constant indicate? Question 9 options: A) At equilibrium, the concentration of the reactants will be much higher than the concentration of the products. B) At equilibrium, the concentration of the products will be about the same as the concentration of the reactants. C) At equilibrium, the concentration of the products will be much higher than the concentration of the reactants. D) At equilibrium, there will be no reactants left because they will all have been turned into products.
What is the pH of a solution with a 3.2 x 10−5 M hydronium ion concentration? (5 points)
Select one:
a.4.3
b.4.5
c.11
d.12
Answer:
b. 4.5
Explanation:
Since it is hydronium ion concentration, that means it is an acid.
pH formula = -log[H3O+]
-log(3.2 x 10^{-5} = 4.5
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In an experiment, equal amounts of water and sand were heated under a lamp. The initial and final temperatures of each were recorded. A partial record of the temperature is shown.
Experimental RecordSubstance Initial Temperature Final Temperature
Sand 20 °C 26 °C
Water 20 °C ?
Which statement about the final temperature of water is correct?
A. It will be less than 26 °C as sand has a relatively higher specific heat than water.
B. It will be less than 26 °C as water has a relatively higher specific heat than sand.
C. It will be more than 26 °C as sand needs relatively higher energy than water to raise its temperature.
D. It will be more than 26 °C as water needs relatively higher energy than sand to raise its temperature.
hi have a nice day
will be less than 26 °C as water has a relatively higher specific heat than sand.
Explanation:
The specific heat of a substance is the amount of heat energy absorbed by one unit of mass of the substance when its temperature increases one unit.
From that, you can derive the equation for the specific heat of a substance:
specific heat = heat / (mass × ΔT)
Thus, assuming that all the heat provided by the lamp to both samples is the same and, as given, the amount (mass) of both samples is also the same, you have that the specific heat of the samples will be:
specific heat = constant / ΔT
So, specific heat and ΔT are inversely related.
It is known that water has a higher specific heat than sand (that is why the sand on the shore of a beach is, during the day, hotter than the water and your feet get burned when you walk on a sandy beach on a sunny day
A) Oxygen
B) Sulfur
C) nitrogen
D) no elements have that mass
Answer:
The answer would be oxygen.
What is one advantage of asexual reproduction?
O A. It is advantageous in a changing environment.
B. It is the slowest way to reproduce.
O C. It results in genetically different offspring.
D. It requires only one parent.
Answer: D.
Explanation:
Asexual reproduction requires only one parent, making it more efficient and take a shorter amount of time than sexual reproduction.
how much sucrose can dissolve in 200g of water at 70 °C?
The maximum amount of a substance that can be dissolved in a solvent at a given temperature is referred to as its solubility.
Sucrose has a solubility of 320 g/100 g H2O at 70°C.
How is solubility usually measured?The equilibration of a suspension followed by an assessment of the solution composition, from which the solution concentration can be determined, is a widely accepted and accurate method for measuring solubility.The maximum amount of a substance that can be dissolved in a solvent at a given temperature is referred to as its solubility. This type of solution is known as saturated. To calculate the solubility in g/100g, divide the mass of the compound by the mass of the solvent and multiply by 100 g.The ability of a compound to dissolve in a liquid that functions as a solvent aids in the determination of the solubility test. The tests are critical because they determine the polarity of unknown compounds.Sucrose has a solubility of 320 g/100 g H2O at 70°C.
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3 moles of nitrogen and 5 moles of hydrogen react to form ammonia. Use the balanced equation below to determine which is the limiting reactant.
N2 + 3H2 --> 2NH3
Answer:
H₂ is the limiting reactant
Explanation:
Balanced equations demonstrate the ratios of all reactants and products in terms of the number of atoms/molecules or moles;
In the given reaction:
1 mol of N₂ reacts with 3 mol of H₂ to produce 2 mol of NH₃
So the ratio of N₂ to H₂ to NH₃ will be 1:3:2
If we have 3 moles of N₂, we can apply the ratio to find that it will react with 9 moles of H₂ (3× the moles of N₂) to produce 6 moles of NH₃ (2× the moles of N₂);
Similarly, if we have 5 moles of H₂, then applying the ratio, we find that ⁵/₃ or 1.66... moles of N₂ (¹/₃× the moles of H₂) react with 5 moles of H₂ to produce ¹⁰/₃ or 3.33... moles of NH₃ (²/₃× the moles of H₂);
In order for all of the 3 moles of N₂ to react, it would require 6 moles of H₂;
There is only 5 moles of H₂ available, meaning there will be an excess of N₂;
5 moles of H₂ will react with 1.66... moles of the N₂, leaving 1.33... or ⁴/₃ moles of N₂ unreacted;
If the N₂ is in excess, then the H₂ is limited (i.e. the limiting reactant)
What is the mass of a 2.5 mole sample of MgO2
Most rain falls _____________________.
on land
in freshwater lakes, rivers, and streams
on the oceans
on the polar ice caps
Answer:
I think it is a)in freshwater lakes,rivers,and stream
Answer:
a) in freshwater lakes, rivers, and streams
#keep learning :)Which of the following statements are true about energy and bonds?
Check all that apply.
A. The formation of bonds does not absorb or release energy.
B. When bonds are formed, energy is released.
C. Energy is absorbed to break bonds.
D. Breaking bonds does not absorb or release energy.
Answer:
A. Energy is necessary for bond formation.
C. Breaking bonds takes energy.
D. When bonds are formed, energy is released.
Energy is always required for bond formation because when a chemical reaction occurs, either molecular bonds are broken or other bonds are formed to make different molecules. Energy is released during bond formation and is an exothermic process because bond formation represents a stable configuration and the energy lost is released as heat energy that makes it more stable. Breaking bonds takes energy and is an endothermic reaction because energy is absorbed to break bonds.
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The discrepancy between results given by the van der Waals equation and the ideal gas law will increase as:
This question is recalling the behavior of real gases in contrast to ideal gases, defined by the van der Waals equation and the ideal gas law respectively, and a reason behind the increasing discrepancy is required.
In such a way, we can start by considering the attached picture in which the choices are shown and clearly, the answer is "as the polarity of the molecules increase".
The aforementioned can be explained with the concept of intermolecular forces, because ideal gas theory states that ideal gas molecules do not interact one to another, and, as the polarity of the molecules increase, these intermolecular forces increase their frequency and strength, and will lead to the formation of associations, which fail to be numerically modelled by simple equations of state such as van der Waals, Redlich-Kwong, Peng-Robinson, etc,.
These associations are, of course, thoroughly neglected by the ideal gas law whereas the ones included in the van der Waals equation, which are not the most reliable, merely attempt to approach this phenomenon, which cause the mentioned discrepancy. As an additional data, robust equations of state, such as CPA (cubic plus association) are able to provide reliable results when working with highly polar gases but turn out really tough to work with due to its mathematical complexity.
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