The enthalpy change required for converting 1.00 mol of ice at -25.0 °c to water at 50.0 °c is 10.71 kJ.
This process is step by step step change hence all we got to do is to calculate the amount of heat evolved by each step the steps being ice at -25 to 0 C
next being melting of ice at 0C
and last being heated by 50 from 0 to 50 C
so q (heat )= m C delta T
so q1 = (18.0 ) (25 ) (2.09 ) = 0.9405 kJ
now fusion of ice or melting of ice evolves a heat of
q2 = m l (l is latent heat of fusion)
we have 1 x 6.01 = 6.01 kJ
and finally heat evolved in changing tempature from 0 ti 50 C
q3 = m C deta T
= 18 X 50 X 4.184 = 3.765 kJ
hence adding all three
q1 + q2 + q3 = 0.9405 + 6.01 + 3.765
= 10.71 kJ
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How many atoms are in 0.540 moles of sodium?
Answer:
3.24108 Raised to 23 I'm pretty sure
The pressure inside a sealed container is 97.9 kPa when the temperature is 298 K.
What will the pressure be if the temperature is 376 K?
Answer:
123.5 kPa
Explanation:
P2=P1T2/T1
You can check this by knowing that P and T at constant V have a proportional relationship. Hence, this is correct.
The photograph shows a mixture of nuts and bolts that are made of either steel or aluminum. Which physical property is best used to separate the two types of substances in the mixture? A. boiling point B. particle density C. magnetic attraction D. particle size
Answer:magnetic attraction
Explanation:
It's C I just took the quiz mark me beainliest
A physical property of a substance
Answer:
Hi, There!
Mass. Density. Volume. Boiling point. Melting point. Conductivity. Heat capacity.
These Are All examples Of A physical property of a substance!
xXxAnimexXx
Have a great day!
What is the proper attitude with which you should approach a laboratory experience
the awnser is : b serious
which transition in the hydrogen atom produces emitted light with the longest wavelength? which transition in the hydrogen atom produces emitted light with the longest wavelength? n
The transition 4-->3 has the longest wavelength.
What is wavelength?One of a group of six named series that describe the spectral line emissions of the hydrogen atom is the Balmer series, often known as the Balmer lines in atomic physics. The Balmer formula, an empirical equation discovered by Johann Balmer in 1885, is used to calculate the Balmer series.Four wavelengths in the visible spectrum of hydrogen light—410 nm, 434 nm, 486 nm, and 656 nm—are associated with photon emissions by excited electrons transitioning to the quantum level denoted by the primary quantum number n = 2. With wavelengths less than 400 nm, a number of conspicuous ultraviolet Balmer lines can be observed. As they get closer to the UV limit of 364.5 nm, the number of these lines becomes an infinite continuum.Longest wavelength means that lowest energy.
The transition energy of the H atoms is given by the following expression-
\(1/l = R_{H}{ (1/n^{2} _{1} ) - (1/n^{2} _{2} )}\)
l is the wavelength, RH is tge Rydberg constant, n1 and n2 are the energy levels (n₁ < n₂)
So, the wavelength will be the the longest when the term in parentheses is the smallest.
So for the transition 4-->3,
The term in parentheses = (1/9) - (1/16) = 0.05
For 2-->1 = 1 - (1/4) = 0.75
For 3-->2 = (1/4) - (1/9) = 0.14
So, the transition 4-->3 has the longest wavelength
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What make up molecules
Answer:
atom
Explanation:
because the definition of molecule is the group of an atom is called molecule
Answer:
Molecules are made up of One Or More atoms.If they contain More than One atom,the atom can be the Same Or different.
What is the mass in grams of 2.3 moles of barium sulfate?
Answer:
536.79608
Explanation:
PLEASE HELP 45 POINTS + BRAINLIEST
please help, this is for chemistry and i've been absent a lot. this is due tomorrow
begging for help.
please show work for all questions
1.) How many moles of neon are in 7.53 x 10^23 atoms of neon?
2.) How many moles on tungsten are in 6.31 x 10^24 atoms of tungsten?
3.) How many atoms of hydrogen are in 54 grams of water?
4.) How many grams are in 12.3 moles of dinitrogen pentoxide?
5.) What is the molar mass of carbon dioxide?
6.) How many grams are in 0.87 moles of aluminum oxide?
7.) How many moles are in 6 L of hydrogen gas at STP?
8.) How many liters are in 10.26 moles of neon at STP?
9.) When a wasp stings you, it releases into the wound histamine (C5H9N3) which causes an allergic reaction. Assuming a threshold of 3.4 x 1015 molecules of histamine are necessary to cause a reaction, is a human at risk of a reaction if they were stung with a 0.00056-gram amount of histamine?
10.) A compound is composed of 23.3% magnesium, 30.7% sulfur, and 46.0% oxygen. What is its empirical formula?
1. 7.53 x 10^23 moles of neon.
2. 6.31 x 10^24 atoms of tungsten is equal to 1 mole of tungsten.
3. In 54 grams of water, there are approximately 4.5 x 10^23 atoms of hydrogen.
4. How many grams are in 12.3 moles of dinitrogen pentoxide?
5. The molar mass of carbon dioxide is 44.01 g/mol.
6. Aluminum oxide has a molar mass of 101.96 g/mol. Therefore, 0.87 moles of aluminum oxide would be 87.17 g.
7. At STP (standard temperature and pressure), 6 L of hydrogen gas contains 0.024 moles of hydrogen.
8. At STP, 10.26 moles of neon will occupy a volume of 24.03 liters.
9.
No, a human is not at risk of a reaction if they were stung with a 0.00056-gram amount of histamine. 0.00056 grams of histamine is only 8.64 x 1010 molecules, which is far less than the threshold of 3.4 x 1015 molecules necessary to cause a reaction.
10. MgS2O6
i gotchu bro here you go
Which monatomic ions would you expect calcium (z = 20) and nitrogen (z = 7) to form?
Calcium is expected to form Ca2+ ions, while nitrogen is expected to form N3- ions.
Calcium (Ca) is a Group 2 element with an atomic number of 20. It has two valence electrons in its outermost energy level. In order to achieve a stable electron configuration similar to the nearest noble gas, which in this case is argon (Ar), calcium tends to lose its two valence electrons.
By losing these two electrons, calcium forms a 2+ cation, denoted as Ca2+. The loss of two electrons leaves calcium with a complete octet in its previous energy level, making it more stable.
On the other hand, nitrogen (N) is a Group 15 element with an atomic number of 7. It has five valence electrons in its outermost energy level. In order to achieve a stable electron configuration similar to the nearest noble gas, which in this case is helium (He), nitrogen tends to gain three electrons.
By gaining three electrons, nitrogen forms a 3- anion, denoted as N3-. The acquisition of three electrons allows nitrogen to complete its octet in the previous energy level, resulting in a more stable configuration.
In summary, calcium (z = 20) forms Ca2+ ions by losing two electrons, while nitrogen (z = 7) forms N3- ions by gaining three electrons.
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Pls, answer asap!
When two objects of different temperatures are placed in contact with one another, eventually: (choose one option from below)
a) both their average kinetic energy and temperature will be the same
b) their average kinetic energy will be the same
c) neither their average kinetic energy and temperature will be the same
d) their temperature will be the same
Answer:
a) both their average kinetic energy and temperature will be the same
Explanation:
Temperature is the measure of the average kinetic energy of a system. As temperature increases, so will kinetic energy. As kinetic energy increases, speed increases. As one decreases, so does the other. When two objects are in contact with each other, their molecules will exchange energy and cause an eventual equilibrium of temperature and kinetic energy.
6.58 grams of sulfur trioxide and 16.4 grams of water react to form H2SO4. identify the limiting reagent and the excess. how many grams of the excess is left over .
what mass of sulfuric acid is produced?
1. The limiting reagent is sulfur trioxide, SO₃ and the excess reagent is water, H₂O
2. The mass of the excess reagent leftover is 14.92 g
3. The mass of sulfuric acid, H₂SO₄ is produced is 8.06 g
1. How do i determine the limiting and the excess reagent?The limiting and excess reagent can be obtained as follow:
SO₃ + H₂O -> H₂SO₄
Molar mass of SO₃ = 80 g/molMass of SO₃ from the balanced equation = 1 × 80 = 80 g Molar mass of H₂O = 18 g/molMass of H₂O from the balanced equation = 1 × 18 = 18 gFrom the balanced equation above,
80 g of SO₃ reacted with 18 g of H₂O
Therefore,
6.58 g of SO₃ will react with = (6.58 × 18) / 80 = 1.48 g of H₂O
From the above calculation, we can see that only 1.48 g of H₂O out of 16.4 g is needed to react completely with 6.58 g SO₃.
Thus, the limiting reagent is SO₃ and the excess reagent is H₂O
2. How do i determine the mass of the excess reagent leftover?The mass of the excess reagent leftover can be obtained as follow:
Mass of excess reagent, H₂O given = 16.4 gMass of excess reagent, H₂O that reacted = 1.48 gMass of excess reagent, H₂O leftover =?Mass of excess reagent, H₂O leftover = Mass given - mass reacted
Mass of excess reagent, H₂O leftover = 16.4 - 1.48
Mass of excess reagent, H₂O leftover = 14.92 g
3. How do i determine the mass of H₂SO₄ produced?The mass of H₂SO₄ produced can be obtained as illustrated below:
SO₃ + H₂O -> H₂SO₄
Molar mass of SO₃ = 80 g/molMass of SO₃ from the balanced equation = 1 × 80 = 80 g Molar mass of H₂SO₄ = 98 g/molMass of H₂SO₄ from the balanced equation = 1 × 98 = 98 gFrom the balanced equation above,
80 g of SO₃ reacted to produce 98 g of H₂SO₄
Therefore,
6.58 g of SO₃ will react to produce = (6.58 × 98) / 80 = 8.06 g of H₂SO₄
Thus, the mass of H₂SO₄ produced is 8.06 g
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Which statement about the diagram, if electrons flow from
the right half-cell to the left one through the wire, is true?
The metal on the left oxidizes more easily than the
one on the right.
The metal on the right oxidizes more easily than the
one on the left.
You cannot tell from this system which metal is more
easily oxidized.
solid
Ag
AgNO
solution
Ag electrode
salt bridge
KNO, solution
light bulb
Cd(NO₂
solution
Cd electrode
solid
Cd
The true statement is that the metal on the right oxidizes more easily than the one on the left.
What is metal oxidization?Metal oxidation is known to often occur if an ionic chemical reaction is said to take place on a metal's surface at the presence of oxygen.
Note that Electrons often move from the metal to the oxygen molecules in course of this process and as such The true statement is that the metal on the right oxidizes more easily than the one on the left.
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Do particles vibrate more when they are hot or when they are cold?
Answer:
when they are cold
Explanation:
particles will only vibrate when they are hot due to heat transfer by conduction and temperature changes as well
MARK BRAINLIEST PLEASE....i will be glad ..thank you
Answer:
particles vibrate more when they are hot.
Explanation:
This is because the heat transfer from one particle to the other causes vibrations in particles of a substance..And if the substance is cold the particles will not move and will be held in a framework
i hope it will clear your concepts...
Dr. lee asked you to write a blog post that describes and explains the solution you read about in "climate change solutions." when you write your explanation, remember that the general public is your audience. try to be as convincing as possible. carefully explain the solution, how it would affect climate change, and why it is needed.
word bank: absorb, atmosphere, carbon dioxide, energy, enter, exit, methane, redirect, surface
Reduce the burning of fossil fuels by using electrical vehicles and instruments is the only solution to stop climate change.
How climate change can be stopped?
Climate change is a process which occurs due to the release of greenhouse gases such as methane and carbondioxide gases. When fossil fuel is burn, it releases energy along with carbondioxide gas which blocks the escape of solar radiation.
This blockage leads to the warming of surface temperature. So if we switched to electrical vehicles instead of conventional vehicles, this climate change can be stopped.
So we can conclude that reduce the burning of fossil fuels by using electrical vehicles and instruments is the only solution to stop climate change.
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We can reduce the effects of global warming by reducing the release of greenhouse gases such as CO2
What is climate change?The term climate change has to do with the gradual changes that occur in our atmosphere as a result of the emission of greenhouse gases into the atmosphere. These greenhouses gases include; methane, CO2, water vapor and N2O.
These gases are able to redirect the infrared rays that ought to escape the atmosphere back to the earth surface thereby leading to a gradual rise in the temperature of the earth called global warming.
Global warming leads to certain effects such as flooding and the melting of the polar ice caps.
We can reduce the effects of global warming by reducing the release of greenhouse gases such as CO2 by eliminating the use of fossil fuels and producing electric vehicles.
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Distillation is a _____________ separation technique.
chemical
physical
Answer:
Chemical
Explanation:
Because it's being done by chemical means
what are the properties of a match before it's light on fire
Answer:
The fire sucks the match
Explanation:
It is peedo
Can anyone help me with these I’m really co fused on what to do it’s for chemistry?
Answer:
It's just asking you to rearrange to equations to get what you want, so no numbers involved it's just teaching you the basics.
Explanation:
An isotope contains 25 protons, 30 neutrons, and 23
electrons. Construct the symbol for the isotope.
Answer:
The symbol is a triangle
Explanation:
cuz it is
How many hydrogen bonds exist between this DNA strand and its complementary strand?
5'-TCCGGAG-3'
Answer:
19 hydrogen bonds
Explanation:
Between every thymine and adenine, there are 2 hydrogen bonds.
Between every guanine and cytosine, there are 3 hydrogen bonds.
Since there are 2 total thymines and adenines, they contribute 4 hydrogen bonds overall.
-----> 2 H bonds x 2 nucleotides = 4 H bonds
Since there are 5 total cytosines and guanines, they contribute 15 hydrogen bonds overall.
-----> 3 H bonds x 5 nucleotides = 15 H bonds
Therefore, there are 19 hydrogen bonds between the complementary strands.
The boat only moves up and down. The
wave is moving left to right. This proves
waves carry energy NOT matter.
the boat goes with the wave.
This proves waves carry energy NOT matter. the boat goes with the wave. False/
A transverse wave is a wave in which particles of the medium vibrate at proper angles, or perpendicular, to the route that the wave travels. The wake of any ship or boat consists of the waves created by means of the hull of the vessel because it acts through the water.
Waves involve the shipping of power without the shipping of remember. In conclusion, a wave may be defined as a disturbance that travels via a medium, transporting electricity from one vicinity (it's supply) to some other area without transporting count.
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In this vLab you used a complex machine to launch a projectile with the ultimate goal of hitting a target. Assume you built a really big machine that could launch the projectile a “significant” distance; for instance, several hundred miles. Write a brief essay discussing the issues that would need to be accounted for with a projectile with that type of range. Be sure to include how those issues affect the range of the projectile.
Launching a projectile over a significant distance, such as several hundred miles, presents a range of complex challenges that must be carefully addressed. The success of achieving such a long range relies on accounting for various factors that influence the projectile's trajectory, including aerodynamics, atmospheric conditions, Earth's curvature, and external forces.
Air resistance can gradually decrease the projectile's speed, and the influence of wind could lead to the projectile drifting off the target. The size and shape of the projectile must be taken into consideration because these attributes can have a significant impact on the drag coefficient, which is a key factor in projectile performance. The larger the projectile's size, the more air resistance it will experience, lowering its range. The projectile's shape may cause the air to circulate over it, decreasing air resistance, which may result in a greater range. Finally, the materials used in the projectile's construction must be able to withstand the forces and heat generated when it is launched, particularly if it travels a long distance. The projectile must also be aerodynamic in order to be able to travel a long distance with ease.Thus, it can be concluded that the range of the projectile can be affected by factors such as air resistance, wind, size, shape, material, and aerodynamics.For such more questions on projectile
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Which of the following is a nonrenewable energy source? O A. Solar B. Hydroelectric C. Natural gas D. Biomass
Answer:
C. natural gas
Explanation:
Solar comes from the sun, which if it became nonrenewable, we would be dead. hydroelectric comes from water and Dams, which water is reproduced through rain. Biomass are things like leaves, which are seasonally reproduced.
Name the second element with 6 valence electrons
Answer:
Any element in group 18 has eight valence electrons (except for helium, which has a total of just two electrons). Examples include neon, argon (Ar), and krypton . Oxygen, like all the other elements in group 16, has six valence electrons.
use standard enthalpies of formation to calculate δh∘rxn for the following reaction: cao cao3
The value of ΔH°rxn for the given reaction CaO + CO2 → CaCO3 is -178.4 kJ/mol.
The standard enthalpy of formation (ΔH°f) is the heat energy evolved or absorbed when one mole of a compound is formed from its constituent elements in their standard states under standard conditions.
ΔH°rxn = ∑ΔH°f(products) - ∑ΔH°f(reactants)Given reaction:CaO(s) + CO2(g) → CaCO3(s)
The standard enthalpy of formation of CaO (s) is - 635.1 kJ/mol
The standard enthalpy of formation of CO2 (g) is - 393.5 kJ/mol
The standard enthalpy of formation of CaCO3 (s) is -1207.0 kJ/molNow,ΔH°rxn =
∑ΔH°f(products) - ∑ΔH°f(reactants)= ΔH°f (CaCO3) - [ΔH°f (CaO) + ΔH°f (CO2)]
= [-1207.0 kJ/mol] - [-635.1 kJ/mol - 393.5 kJ/mol]= -1207.0 kJ/mol + 1028.6 kJ/mol= -178.4 kJ/molMAIN ANSWER:ΔH°rxn = -178.4 kJ/mol
The standard enthalpy of formation is used to calculate the heat energy that is absorbed or evolved when one mole of a compound is formed from its elements in their standard states under standard conditions. We have been given a chemical reaction, and we are required to calculate the ΔH°rxn. The standard enthalpies of formation of CaO (s), CO2 (g), and CaCO3 (s) were given, and we have to substitute these values in the formula to get the final answer.
By adding the sum of the standard enthalpies of formation of the products to the sum of the standard enthalpies of formation of the reactants, we obtain the ΔH°rxn. In this reaction, the ΔH°rxn is -178.4 kJ/mol.
Therefore, the value of ΔH°rxn for the given reaction CaO + CO2 → CaCO3 is -178.4 kJ/mol.
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2NaBr + Cl2 → 2 ------ + ------- 2
Answer:
2NaCl2+Br......hope it helps u
Answer:
its 2nacl +br2.
hope it will help uh..
why is it better to use deionized water in chemistry experiments
Calculate degree of dissociation of 0010 m solutions of boric acid ( ka=3.8×10−10 k a = 3.8 × 10 − 10 ).
The degree of dissociation of a 0.010 M solution of boric acid is approximately 0.9996.
The expression for the ionization constant of boric acid can be written as;`H3BO3 + H2O <=> H3O^+ + H2BO3^-`Now, let us put the initial concentration of boric acid equal to `C` and the degree of dissociation of boric acid is `α`. Consequently, the equilibrium concentration of boric acid is `C(1-α)` and the equilibrium concentration of hydrogen ions is `αC`.The equilibrium concentration of hydrogen ions and hydrogen borate ion can be written as `αC` and `(C - αC)`, respectively.So, Ka can be defined as;`Ka = (H3O^+)(H2BO3^-) / (H3BO3)`On substituting the concentrations, we obtain;`3.8×10^-10 = (αC)(αC) / (C - αC)`Now, let us rearrange the equation, as given below;`α^2C^2 - (Ka)C + 0.0 = 0`By solving this quadratic equation, we obtain;`α = (√[(Ka)^2 + 4Ka] - Ka) / 2`On substituting the values, we get;`α = (√[(3.8×10^-10)^2 + 4(3.8×10^-10)] - 3.8×10^-10) / 2 = 0.9996`Therefore, the degree of dissociation of a 0.010 M solution of boric acid is approximately 0.9996.
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Given the standard enthalpy changes for the following two reactions
Given the standard enthalpy changes for the following two reactions:
(1) 2C(s) + 2H2(g)C2H4(g)...... ΔH° = 52.3 kJ
(2) 2C(s) + 3H2(g)C2H6(g)......ΔH° = -84.7 kJ
what is the standard enthalpy change for the reaction:
(3) C2H4(g) + H2(g)C2H6(g)......ΔH° = ?
The standard enthalpy change for reaction (3) is 117.1 kJ.
The standard enthalpy change for reaction (3) can be calculated by using the enthalpy changes of reactions (1) and (2) and applying Hess's Law.
To do this, we need to manipulate the given equations so that the desired reaction (3) can be obtained.
First, we reverse reaction (1) to get the formation of C2H4(g) from C2H6(g):
C2H4(g)C2H6(g) ΔH° = -52.3 kJ
Next, we multiply reaction (2) by 2 and reverse it to obtain 2 moles of C2H6(g) reacting to form 3 moles of H2(g):
2C2H6(g)2C(s) + 3H2(g) ΔH° = 169.4 kJ
Now, we add the two modified equations together:
C2H4(g)C2H6(g) ΔH° = -52.3 kJ
2C2H6(g)2C(s) + 3H2(g) ΔH° = 169.4 kJ
When adding these equations, the C2H6(g) on the left side cancels out with the C2H6(g) on the right side, leaving us with the desired reaction (3):
C2H4(g) + H2(g)C2H6(g) ΔH° = -52.3 kJ + 169.4 kJ = 117.1 kJ
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green plants absorb sunlight to power photosynthesis, the chemical synthesis of food from water and carbon dioxide. the compound responsible for light absorption and the color of plants, chlorophyll, strongly absorbs light with a wavelength of 642 . calculate the frequency of this light. round your answer to significant digits.
Green plants absorb sunlight with a frequency of approximately 4.67 x 10^14 Hz to power photosynthesis.
To calculate the frequency of sunlight with a wavelength of 642 nm that is strongly absorbed by chlorophyll for photosynthesis, we'll need to use the following formula:
Frequency (ν) = Speed of light (c) / Wavelength (λ)
First, we'll convert the given wavelength from nanometers to meters:
1 nm = 1 x 10^(-9) m
642 nm = 642 x 10^(-9) m = 6.42 x 10^(-7) m
Now, we'll plug the values into the formula:
Speed of light (c) = 3.00 x 10^8 m/s
Wavelength (λ) = 6.42 x 10^(-7) m
Frequency (ν) = (3.00 x 10^8 m/s) / (6.42 x 10^(-7) m)
Frequency (ν) ≈ 4.67 x 10^14 Hz
So, green plants absorb sunlight with a frequency of approximately 4.67 x 10^14 Hz to power photosynthesis.
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