Explanation:
a) Both A and R are true and R is the correct
explanation of A.
Answer:
[tex]\fbox {c) A is true but R is false.}[/tex]
Explanation:
Assertion (A):
⇒ Naphthalene balls disappear with time without leaving any solid.
⇒ True √
Reason (R):
⇒ Solid converted to liquid is called sublimation.
⇒ False ×
⇒ Solid converted to liquid is called melting
Calculate the mass of slver n grams depostedwhen 10.920 coulombs of electrcty s passed through a soluton of slver salt. (Ag= 180, 1 faraday-96500C)
In the nebular hypothesis, why did the nebula start to collapse?
Answer:
Because of gravity and as a result, created planets and stars.
(Likely by a nearby supernova shockwave also)
What is a step by step explanation of the nebular hypothesis?Although I'm not an expert, I seem to recall reading that solar systems often begin with clouds of unorganized matter measuring 20 parsecs (65 light years) across. Most of them are hydrogen molecules. The pressure required to hold the molecules together increases with temperature, but because the typical temperature is around 12 k, the pressure is negligible. It originates from the gravity of the cloud itself. Material from novas, colliding neutron stars, and high-speed material jets emerging from stars and black holes all contribute to the continuous enrichment of such clouds. That adds those heavy elements—like gold—that can only be produced by the rapid neutron capture (rNC) process as opposed to the simple nuclear fusion process (slow neutron capture). These clouds spontaneously emerge from floating pieces of material, hold together for millions of years, and eventually disperse. A component of the cloud condenses along the route for a variety of causes, including localized concentrations of greater density or shock waves from supernovae. Unbalances in the cloud lead it to split up when condensation takes place. Then those fragments shatter once again, leaving you with barely enough for a solar system. It would have been within 3.5 light years of the initial cloud for our galaxy. The contraction up to this point has been isothermal, which means that heat is being radiated so quickly that temperature stays mostly unchanged. The creation of a Bonnor-Ebert sphere comes next. Although such zones frequently appear in photographs in a faint manner, this is only a hypothetical area in which there is a certain amount of mass. The First Hydrostatic Core is located here (FHSC or First Core). The First Core can be imagined as a pre-proto Sun with an interior temperature of roughly 300 k and a radius of 1 AU (the same as the Earth's orbit) (26.85 C or 80.33 F). Although it first begins off chilly, it ultimately warms up to 300 k and then grows even hotter over the course of years. The friction of falling materials and adiabatic contraction provide the heat (the kind that makes things hotter). Hydrogen molecules start to break down into atomic hydrogen, which is more dense and falls to the center, at temperatures between 1500 k and 2000 k, on average. Eventually, the atomic hydrogen coalesces into a protostar-sized Second Core. Because the entire system is rotating swiftly and because momentum is being lost in some areas owing to gas shooting off, an accretion disk has already formed. Although in our instance it would have also been a protoplanetary disk, the disk is a protostellar disk. The protostar is regarded as a star until it becomes hot and brilliant enough to begin ejecting the gas and dust. (Prior to it, infalling gas and dust are still adding mass to the protostar.)
In the nebular hypothesis, the collapse of the nebula is believed to have been triggered by a disturbance or shock wave, such as a nearby supernova explosion or the gravitational influence of a passing star or gas cloud.
This disturbance caused the nebula, which was a large and diffuse cloud of gas and dust in space, to start collapsing under the force of its own gravity. As the nebula contracted, its particles came closer together, and the conservation of angular momentum caused it to spin faster.
The collapse and spin eventually led to the formation of a rotating protostellar disk at the center, which eventually evolved into a young star, while the surrounding material formed planets and other celestial bodies through accretion and gravitational attraction.
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3. Why did the solution change from blue to yellow (what chemical reaction happened)?
Answer:
it was more acidic
Explanation:
changing the pH of the solution and making it more acidic results in the color of the solution changing it from blue to yellow
solution is Bromothymol blue
in a ph below 6 it turns yellow because
a ph below 6 is acidic
a ph above 7.6 its blue because
a ph above 7.6 is basic
Bromothymol blue is made in a basic solution, so it starts out as blue, thus the name 'blue'. It changes to yellow in acidic conditions
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Ca is an atom. Why?
Help me asap pleased
Answer:
It has protons, neutrons and electrons
the electron configuration for sodium is 1s22s22p63s1. which subshell is said to contain the valence electron(s) for sodium?
The subshell that contains the valence electron for sodium is the s subshell
Valence electronsValence electrons are the electrons located at the outermost shell of an atom
From the question, we are to determine the subshell that contains the valence electron(s) for sodium
The given electronic configuration for sodium is
1s²2s²2p⁶3s¹
The valence electron is the electron in the 3s orbital.
Hence, the subshell that contains the valence electron for sodium is s subshell
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What’s the name of this compound?
Answer:
decane
Explanation:
decane has 10 carbon and 22hydrogen
the hemiacetal below is treated with 18o-labeled methanol (ch3o*h) and acid. where will the label appear in the products?
The 18o-labeled methanol (CH3O*H) will appear in the products side at position b.
Position of 18o-labeled methanol in the products
The 18O label will appear at position b in the product as indicated in the image.
This methoxy group in the product formed in position b comes from the 18O-labeled methanol (CH3OH).
While the oxygens at positions a and c in the product come from the unlabeled hemiacetal.
Thus, the 18o-labeled methanol (CH3O*H) will appear in the products side at position b.
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Help!!! Will give brainliest to those who have the most accurate answer W/explanation!
Answer:
See below
Explanation:
Tap water, bottled water and lake water are all examples of FRESH WATER and likely have the same specific gravity ( or density) .
Ocean water is SALT WATER ....and depending on HOW MUCH salt is in the water, it can be quite a bit denser than fresh water ...which will allow the golf ball ( which is less dense) to float .
On a heating curve, in which section(s) would you use the equation, Q=mCΔT, to calculate the total heat required?
only on plateaus or flat parts of the curve
on a sloped part only if under 0oC
on a sloped part only if over 100oC
on all sloped parts of the curve
Answer:
all sloped parts
Explanation:
Sloped part of the curve - all as this would show a change in T ( or delta T)
the flat parts would involve no change in Temp
What is the simplest method of determining the composition of a compound?
Answer:
Chemical formulas tell you how many atoms of each element are in a compound, and empirical formulas tell you the simplest or most reduced ratio of elements in a compound. If a compound's chemical formula cannot be reduced anymore, then the empirical formula is the same as the chemical formula.
please give me brainliest
In a chemical reaction occurring in an open beaker, the reactants have a mass of 10.0 g and contain 1000 J of energy. The products in the beaker contain a mass of 5.0 g and 500 J of energy. Which best explains the difference in energy and mass as reactants are converted to products?
kinetic energy
closed systems
law of conservation of energy
electromagnetic energy
This happens because the beaker is open.
The Law of Mass Conservation says that in a close system all the mass and energy should be the same.
If the system is open, as in the case, we can have loss of mass, due to formation of gas, that will leave the beaker to the environment, and we can also have loss of energy, because the system will exchange the energy, as heat, with the environment, causing a loss on the total energy.
Answer:
Its C its C its C
Explanation:
i dislike expert verifeid beacause he wont say C
How many moles of propane
react when 294 g of CO2 form?
C3H8 +502 → 3CO₂ + 4H₂O
2.23 moles of propane react when 294 g of CO₂ is formed .
What is moles ?Moles is a unit which is equal to the molar mass of an element.
A reaction is given
C₃H₈ +50₂ → 3CO₂ + 4H₂O
Grams of CO₂ formed = 294 gm
In moles = 294 /44 = 6.68 moles.
Let x be the moles of C₃H₈ is x
Mole ratio of CO₂ to C₃H₈ = 3 : 1
so
6.68 /x = 3/1
x = 6.68 /3 = 2.23 moles
Therefore 2.23 moles of propane react when 294 g of CO₂ is formed .
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Help please help! Please help..
How many moles of hydrogen
gas will be produced at the same
time as 138 g NaOH?
2Na+ 2H₂O → 2NaOH + H₂
Answer:
1.72 moles of H₂
Explanation:
The balanced equation
2Na+ 2H₂O → 2NaOH + 1C
tells us we'll get 1 mole of H₂ for every 2 moles of NaOH. We can express this as a molar ratio: (1 mole H₂)/(2 moles NaOH).
The reaction produces 138 g of NaOH. Divide this mass by the molar mass of NaOH (39.99 g/mole)to obtain moles NaOH:
138g NaOH/(40 g/mole) = 3.45 moles of NaOH.
To find the moles H₂ produced, we can multiply the moles NaOH by the molar ratio from above:
(3.45 moles NaOH)*((1 mole H₂)/(2 moles NaOH) = (3.45/2) moles H₂. [Note how the "moles NaOH" unit cancels, leaving just "moles H₂"]
We should produce 1.72 moles of H₂.
Which of the following is the correct balanced equation for the reaction in which methane (CH4) burns in atmospheric oxygen (0₂) to make carbon dioxide and water vapor?
Answer: [tex]\text{CH}_{4}+2\text{O}_{2} \longrightarrow \text{CO}_{2}+2\text{H}_{2}\text{O}[/tex]
Explanation:
The unbalanced equation is
[tex]\text{CH}_{4}+\text{O}_{2} \longrightarrow \text{CO}_{2}+\text{H}_{2}\text{O}[/tex]
Balancing this equation, we get:
[tex]\boxed{\text{CH}_{4}+2\text{O}_{2} \longrightarrow \text{CO}_{2}+2\text{H}_{2}\text{O}}[/tex]
The valence electrons found in metallic bonds are different from other bonds
because
A. their valance electrons are free-roaming
B.they allow conductivity of electricity
C.their valence electrons are immobile
D. They’re able to share electrons with other atoms
Answer:
their valence electrons are free roaming
A cup of hot water loses 265 cal
of energy to its surroundings.
How many joules of energy is
this?
[?] joules
Answer:
-1071 Joules
Explanation:
The Joule was introduced as the SI unit for energy in 1925. One calorie is equal to approximately 4.184 joules(J). This is a conversion factor that we can write two ways:
(1cal/4.184J) or (4.184J/1cal)
(265 cal)*(4.184J/1cal) = 1071 J
Since the energy is leaving the system, it should be written with a minus sign: -1071J
Answer:
1,108.76 joules
Explanation:
There are 4.184 joules per calorie
4.184 x 265 = 1,108.76
Please Answer!!!!
Which equation is balanced?
A) H₂+ O2 → H₂O + O2
B) 4H2₂+ O2 → H₂O + O
C) 2H₂ + O2 → 2H₂O
D) H₂ + O2 → H₂O
Option C is the correct answer
2H₂ + O2 → 2H₂OIn LHSNo. of hydrogen atoms is 4No. of oxygen atoms is 2In RHS No. of hydrogen atoms is 4No. of oxygen atoms is 2Hence , LHS = RHS
A balanced equation obey the law of conservation of mass. According to this law mass can neither be created nor be destroyed. Among the given options, the balanced equation is 2H₂ + O₂ → 2H₂O. The correct option is C.
What is a balanced equation?A chemical equation in which the number of atoms of reactants and products are equal on both sides of the equation is defined as the balanced chemical equation. The numbers which are used to balance the equation are called the coefficients.
The coefficients are generally placed in front of the formulas. The substances on the left hand side are called the reactants and the substances on the right hand side are called the products.
Here the balanced equation is:
2H₂ + O₂ → 2H₂O
The number of 'H' and 'O' atoms are equal on both sides.
Thus the correct option is C.
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Select the correct answer from each drop-down menu.
Scientific theories are always
testable
. A theory may be changed as a result of
.
Scientific theories are always testable. A theory may be changed as a result of new observations.
What are Scientific theories ?A scientific theory is a set of laws, facts and hypotheses that have a complete vision of an aspect of reality.
It is a proposed explanation for a set of observable phenomena.
It allows in this way to organize and understand the observations and to be able to predict or provoke other future observations.
Theories can be modified or improved as more information is collected.
That is, theories can continue to be tested indefinitely, and eventually rejected, if the tests lead to it.
Therefore, a scientific theory is testable by using a research method.
As mentioned, any theory can be tested or rejected as more information is collected.
This information to prove or reject theories are interpretations of observable facts, which generates new statements or allows to accept those already included in the theory.
Then, a theory may be changed as a result of new observations.
Finally, scientific theories are always testable. A theory may be changed as a result of new observations.
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Answer:
testable & new observations
Explanation:
If u can write like a sentence or two would be amazing:
Outline the differences between respiration and combustion.
Respiration is the process of oxidation of food materials like glucose, Amino acids, fatty acids to water and carbon dioxide. Respiration does not require any external heat to carry on the process. Combustion is only done by applying external heat to the sugar molecule to burn.
A 25.0 g sample of metal is
warmed by 6.1 °C using 1259 ] of
energy.
What is the specific heat of the
metal?
Answer:
Below
Explanation:
Units of specific heat are J / (g- °C)
so to get these units :
1259 J / (25 g *6.1 °C) = 8.26 J / (g °C)
calculate mole fraction of benzene (70 g) having 30 gram of mass of carbon tetrahedral
Moles of benzene
70/90=7/9=0.8molmoles of CCl_4
30/1540.2molNow
[tex]\\ \rm\Rrightarrow \chi_{C_6H_6}[/tex]
[tex]\\ \rm\Rrightarrow \dfrac{\chi_{C_6H_6}}{\chi_{sol^n}}[/tex]
[tex]\\ \rm\Rrightarrow \dfrac{0.8}{0.8+0.2}[/tex]
[tex]\\ \rm\Rrightarrow \dfrac{0.8}{1}[/tex]
[tex]\\ \rm\Rrightarrow 0.8[/tex]
The difference in an area with high concentration and an area with low concentration is called.
The difference in an area with high concentration and an area with low concentration is called the concentration gradient.
What is Concentration Gradient ?
A concentration gradient occurs when the concentration of particles is higher in one area than another.
In passive transport, particles will diffuse down a concentration gradient, from areas of higher concentration to areas of lower concentration, until they are evenly spaced.
This difference in an area with high concentration and an area with low concentration is called the concentration gradient.
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N₂(g) + 3H₂(g) → 2NH3(g)
224 L of nitrogen reacts with
excess hydrogen at 2773 K and
95.0 atm. How many moles of
nitrogen react?
Answer:
93.5 moles N₂
Explanation:
To find the moles, you need to use the Ideal Gas Law. The equation looks like this:
PV = nRT
In this equation,
-----> P = pressure (atm)
-----> V = volume (L)
-----> n = number of moles
-----> R = constant (0.0821 atm*L/mol*K)
-----> T = temperature (K)
You can plug the given values into the equation and simplify to find moles. The final answer should have 3 sig figs to match the lowest number of sig figs among the given values.
P = 95.0 atm R = 0.0821 atm*L/mol*K
V = 224 L T = 2773 K
n = ?
PV = nRT
(95.0 atm)(224 L) = n(0.0821 atm*L/mol*K)(2773 K)
21280 = n(227.6633)
93.5 = n
Answer:
93.5 moles N₂
Explanation:
You can plug the given values into the equation and simplify to find moles. The final answer should have 3 sig figs to match the lowest number of sig figs among the given values.
P = 95.0 atm R = 0.0821 atm*L/mol*K
V = 224 L T = 2773 K
n = ?
PV = nRT
(95.0 atm)(224 L) = n(0.0821 atm*L/mol*K)(2773 K)
21280 = n(227.6633)
93.5 = n
Explanation:
Hello can someone help me please and thanksss
the equation of the parabola is given as [tex]y = 1/4 (x-6)^2 +1[/tex]. D
How to find the parabolaGiven the focus(6,2) and the directrix, y = 0
Use the formula
[tex]\sqrt{(x-6)^{2} + (y-2)^{2} } }[/tex] = (y - 0)
Find the square of both sides, square root is removed from the side with it and square added on the other side
[tex](x-6)^2 + (y-2)^2 = (y- 0)^{2}[/tex]
Expand the expression and bring all terms to one side
[tex]x^{2} - 6x - 6x + 36 +y^{2} -2y- 2y +4[/tex] = [tex]y^{2} - 0[/tex]
Collect like terms
[tex]x^{2} - 12x -4y + 40 = 0[/tex]
Make 'y' the subject of the formula
[tex]4y = x^{2} - 12x + 40[/tex]
Divide through by 4 and substrate 4 from 40 to give a perfect quadratic equation
[tex]y = 1/4( x^{2} - 12x + 36) + 4[/tex]
1/4 is dividing the quadratic equation [tex]x^2 - 12x +36[/tex]
Then divide factor by 4 to give 1, this is so because of the nature of the options given
[tex]y = 1/4( x^{2} -6x -6x +36) + 1[/tex]
Simplify the expanded quadratic equation
[tex]y = x (x -6) - 6 (x- 6)[/tex], we have [tex](x - 6) ^2[/tex]
Then insert in place into previous equation
[tex]y = 1/4 (x-6)^2 + 1[/tex]
Thus, the equation of the parabola is given as [tex]y = 1/4 (x-6)^2 +1[/tex]
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a burning candle wax reacts with oxygen. after a glass jar is placed over it, the candle goes out. what is the limiting reactant?
Answer:
The Oxygen
Explanation:
When fire is covered, it goes out due to the lack of oxygen to maintain itself.
The limiting reactant in the experiment of the burning candle is oxygen.
What is a limiting reactant?A limiting reactant is a reactant which determines the amount of product that ca be formed in a given reaction.
The limiting reactant is always used up in a reaction, after which the reaction stops.
In the experiment of the burning candle, covering the candle with the glass prevents more oxygen from taking part in the reaction.
Therefore, the limiting reactant is oxygen.
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How many moles of sulfur are in 80 grams of sulfur?
A. 1.5 moles
B. 2.5 moles
C. 1 mole
D. 2 moles
Answer:
2.5 moles
Explanation:
Number of moles = MassMolar mass
= 80⋅g32.06⋅g⋅mol−1 = ??mol
Note that sulfur likely exists in its elemental state as S8. I am perfectly justified in treating sulfur as S. The number of sulfur atoms is the same in each case.
1. What were the concentrations of samples A and B?
2. What are some possible sources of error in a titration experiment? Share some tips to minimize errors with your classmates.
3. What is an example of a problem that can be solved using titration in the real world?
4. Phenolphthalein was used as the indicator in the experiment. The universal indicator exhibits the rainbow of colors for the entire pH range. Do you think using the universal indicateor would also work for this lab? Justify your answer, and explain why you agree or disagree.
A food processing company might use titration to calculate the precise amount of salt in a particular food stuff.
What is Titration ?A process of determining the concentration of a dissolved substance in terms of the smallest amount of reagent of known concentration required to bring about a given effect in reaction with a known volume of the test solution
The general source of error in titration has been;
The measurement of volume in burette by at the lower meniscus. It has been corrected with the application of measurement at eye level.The air bubble in the burette results in the incorrect measurement of the volume of burette. It can be corrected by tapping the burette or by slowing adding the solution to remove the bubble.The absence of rinsing the burette before use has been resulted in the water droplets that has been results in the incorrect measurement and dilution of the solution. The correction has been made by the use of dried burette.A food processing company might use titration to calculate the precise amount of salt in a particular food stuff.
It can also be used to determine the concentration of vitamin C or vitamin E additives in foods.
Universal indicator can also work as the indicator in the lab.
When universal indicator is added to a solution, the color change can indicate the approximate pH of the solution.
Acids cause universal indicator solution to change from green toward red whereas, bases cause universal indicator to change from green toward purple.
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during chemical reactions do atoms get destroyed?
No. Atoms do not get destroyed during reactions.
Law of conservation of matterAccording to the law of conservation of matter, matters can not be created nor destroyed in any way. Be it during reactions or otherwise.
However, matters can be converted from one form to another during reactions.
Atoms are a form of matter, and thus, cannot be destroyed during reactions.
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A sample of gas collected at 685 mm Hg occupies 131 mL. At constant temperature, what pressure does the gas exert if the volume increases to 478 mL? a. 188 b. 1320 c. 128 d. -88.8
Answer:
a. P=188mmHg
Explanation:
A gas undergoing a change of volume and pressure at constant temperature (and not changing the number of molecules), follows Boyle's Law: [tex]P_1V_1=P_2V_2[/tex]
The units of these quantities can be any measure of pressure and volume, so long as long as the units are the same between beginning and ending conditions.
Substitute and solve:
[tex]P_1V_1=P_2V_2[/tex]
[tex](685[mmHg])(131[mL])=P_2(478[mL])[/tex]
[tex]\dfrac{(685[mmHg])(131[mL\!\!\!\!\!\!\!\!\!{--}])}{478[mL\!\!\!\!\!\!\!\!\!{--}]}=\dfrac{P_2(478[mL]\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{----})}{478[mL] \!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!{----}}[/tex]
[tex]187.730125523[mmHg]=P_2[/tex]
Accounting for significant figures, [tex]P_2=188[mmHg][/tex]
