A system performed 145 kJ of work on the surroundings and absorbed 105 kJ of heat from the surroundings. What is the change in energy of the system?

Answers

Answer 1

Answer:

250 kJ

Explanation:

Step 1: Given data

Work performed by the system (w): 145 kJ (By convention, when the system performs work on the surroundings, w > 0)Heat absorbed by the system (q): 105 kJ (By convention, when the system absorbs heat from the surroundings, q > 0)

Step 2: Calculate the change in the internal energy of the system

The internal energy of a thermodynamic system is the energy contained within it. We can calculate the change in the internal energy (ΔE°) using the following expression.

ΔE° = q + w

ΔE° = 105 kJ + 145 kJ = 250 kJ


Related Questions

Decide which element probably has a boiling point most and least similar to the boiling point of aluminum.
Comparing boiling point:
gallium rubidium magnesium oxygen
most similar to aluminum
least similar to aluminum

Answers

Answer:

The boiling point of gallium would be most similar to aluminum, and the boiling point of oxygen would be least similar to aluminum.

Explanation:

The atomic number of aluminum is 13, in the periodic table, magnesium lies in a similar period as Aluminum and Gallium is also present in a similar group. Thus, it can be expected that both magnesium and gallium exhibits similar boiling points with aluminum. However, gallium is a poor non-metal just like aluminum, while magnesium is a metal. Thus, it can be said that the boiling point of aluminum is more similar to gallium.

Now of the given elements, oxygen is a gas, thus, the boiling point of oxygen would be least similar to aluminum.

What is the molarity of a NaOH solution if 28.2 mL of a 0.355 M H2SO4 solution is required to neutralize a 25.0-mL sample of the NaOH solution?A) 0.801B) 0.315C) 0.629D) 125E) 0.400

Answers

Answer:

A) 0.801

Explanation:

The reaction that takes place is:

2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O

First we calculate the H₂SO₄ moles that reacted:

0.355 M * 28.2 mL = 10.011 mmol H₂SO₄

Now we convert H₂SO₄ moles to NaOH moles:

10.011 mmol H₂SO₄ * [tex]\frac{2mmolNaOH}{1mmolH_2SO_4}[/tex] = 20.022 mmol NaOH

Finally we calculate the molarity of the NaOH solution:

20.022 mmol NaOH / 25.0 mL = 0.801 M

So the answer is option A.

The molarity of the NaOH solution used in the neutralization reaction has been 0.801 [tex]\rm \times\;10^-^3[/tex] M. Thus, option A is correct.

The neutralization reaction has resulted in the formation of the salt and water on reacting an acid with a base. In the neutralization reaction, the strength of acid and base can be given as:

[tex]\rm 2\;NaOH\;+\;H_2SO_4\;\rightarrow\;Na_2SO_4\;+\;H_2O[/tex]

For the neutralization of 1 mole of sulfuric acid, 2 moles of NaOH has been required.

The moles of sulfuric acid can be given as:

Moles = Molarity × Volume

Given, the molarity of acid ([tex]\rm H_2SO_4[/tex]) = 0.355 M

Volume of acid = 28.2 ml = 0.0282 L

Volume of base (NaOH) = 25 ml = 0.025 L

Moles of [tex]\rm H_2SO_4[/tex] = 0.355 × 0.0282 mol

Moles of [tex]\rm H_2SO_4[/tex] = 10.011  mol.

Since, 1 mole [tex]\rm H_2SO_4[/tex] = 2 moles NaOH

10.011 moles [tex]\rm H_2SO_4[/tex] = 10.011 × 2 moles NaOH

10.011 moles [tex]\rm H_2SO_4[/tex] = 20.022 moles NaOH.

The neutralization of 0.355 M [tex]\rm H_2SO_4[/tex] requires 20.022 moles NaOH. The strength of the NaOH solution will be:

Molarity = [tex]\rm \dfrac{Moles}{Volume\;(L)}[/tex]

Molarity of NaOH = [tex]\rm \dfrac{20.022}{0.025}[/tex]

Molarity of NaOH = 0.801 [tex]\rm \times\;10^-^3[/tex] M.

The molarity of the NaOH solution used in the neutralization reaction has been 0.801 [tex]\rm \times\;10^-^3[/tex] M. Thus, option A is correct.

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Can someone answer 3’for me please?

Answers

The correct is B, the ball in her hands has potential energy. When it falls, the potential energy changes to kinetic energy.
b is the correct answer

The red outlined elements have what major characteristics in common?
1 point
Metals, Nonmetals, and Metalloids

Answers

One major characteristic they have in common is they are metals.

c. What might have happened in Kush and Egypt if Kush had developed iron
weapons?

Answers

Answer:

Kush would have been able to fight better and probably would have never been invaded by Egypt, and they could have beaten the Assyrians when they tried to takeover Egypt. And the 25th dynasty would have continued.

Explanation:

that is my explanation and answer^

GIVE 6 GIVING AWAY 100 IN A ROW HOPE YALL ENJOY MAKE SURE TO TELL PEOPLE ABOUT MY GOOD WORK TY

Answers

Answer:

YOURE AMAZING THANK YOU THANK YOU THANK YOU

Explanation:

When chemists work with solid materials, we simply weigh out amounts of solid reagents and calculate mole amounts when thinking about stoichiometry. However, when we dissolve a solid (also known as a solute) in a solvent to form a solution, the solute becomes evenly distributed throughout the solution and we need to know how many moles of solute are present in a particular volume of solution.a) A solution is created by dissolving 13.5 grams of ammonium chloride in enough water to make 315 mL of solution. How many moles of ammonium chloride are present in the resulting solution?b) What is the molarity of the solution described above?c) To carry out a particular reaction, you determine that you need 0.0500 moles of ammonium chloride. What volume (mL) of the solution described above will you need to complete the reaction without any leftover NH4Cl?

Answers

Answer:

See the answers below

Explanation:

13.5 g of NH4Cl was dissolved in 315 mL of water.

Moles of NH4Cl present in the solution = mass/molar mass

Molar mass of NH4Cl = 54.49 g/mol

a) Moles of NH4Cl = 13.5/54.49

            = 0.25 mole

b) Molarity of solution = moles of solute/volume of solution

moles of NH4Cl = 0.25

volume of solution = 315 mL = 0.315 L

molarity = 0.25/0.315

             = 0.79 M

c) moles required = 0.0500 mole

molarity = 0.79 M

molarity = moles x volume

volume = molarity/moles

         = 0.79/0.0500

         = 15.8 L = 15,800 mL

What is electron affinity? ​

Answers

Answer:

The ability of an atom to accept an electron.

Explanation:

Electron affinity is measured by observing the energy change of a substance when an electron is added to it in its neutral gas form. For example, elements that are on the far right of the periodic table (excluding noble gases) are more likely to accept electrons rather than give them up. This is why Fluorine has the highest electron affinity of all atoms on the periodic table.

During homogeneous catalysis, if a catalyst is present in the liquid phase, which phase must the reactants be in?

Answers

Answer:

The reactants must be in the liquid phase.

Explanation:

Homogeneous means that something is of the same nature.

In the context of catalysis, it means that the catalyst and the reactants are in the same phase.

If the catalyst is in the solid phase, the reactants are solids are well.

If the catalyst is in the liquid phase, then the reactants are also in the liquid phase.

And so on.

The list identifies various properties of four elements:

Element 1 is a gas at room temperature.
Element 2 is a solid which conducts electricity.
Element 3 is a gas with an effective nuclear charge of +7.
Element 4 is malleable and can take the form of a shiny solid sheet.

Based on this list, which elements are metals?

A. Elements 1 and 3
B. Elements 1 and 4
C. Elements 2 and 3
D. Elements 2 and 4

Answers

Answer: D

Explanation: I guessed it and got it right

A fundamental object that is difficult to divide into smaller bits is known as an element. Therefore option D is correct.

What is element ?

An element is a species of atoms, including the pure material made entirely of that species, that have a specific number of protons in their nuclei. Chemical elements, in contrast to chemical compounds, cannot be reduced by any chemical process into simpler molecules.

An element is a material that cannot be broken down by non-nuclear processes in chemistry and physics. A discrete component of a larger system or collection is referred to as an element in computers and mathematics.

Metals, nonmetals, and metalloids are the Periodic Table's three main groupings. Each group's constituent elements share comparable physical and chemical characteristics. Among the physical characteristics used to separate the three groups are, A substance's capacity to reflect light is referred to as luster.

Thus, option D is correct.

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4. Look at the equation below and determine what fitsI in the empty box.
14 C --> 4 N+
?
re
c. en TH
What belongs in the empty box?
A.
В.
e
D.

Answers

Answer:

Beta particles

Explanation:

A beta emission is said to occur when a neutron is converted into a proton. When a beta emission takes place, the daughter nucleus increases it's atomic number by 1. A neutrino is also produced.

Since the mass number remain the same but the daughter nucleus has it's atomic number increased by 1, then the particle is a beta particle.

A metal is found that has a mass of 27g and will displace 6mL of water. Calculate its density and identify the metal.

Answers

The density of metal = 4.5 g/ml, and the metal = Titanium

Further explanation  

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

Density formula:  

[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]

ρ = density  

m = mass  

v = volume  

mass of metal=27 g

volume = 6 ml

The density :

[tex]\tt \rho=\dfrac{27}{6}\\\\\rho=4.5~g/ml[/tex]

The metal with a density of 4.5 g/ml is Titanium

Which model of the solar system is shown here?

Answers

Answer: C

Explanation: hope this helps

The model of the solar system that is shown here is:

C. Geometric model

Model for description of earth and other entites

Geometric model:

In astronomy, the geocentric model is a superseded description of the Universe with Earth at the center. Under the geocentric model, the Sun, Moon, stars, and planets all orbit Earth.

Characteristics:

the Earth is the focal point of the universe and it is fixed,the planets, the Sun, and the stars spin around the Earth,the circle and the circle are "awesome" shapes, so all movements overhead ought to follow roundabout ways, which can be credited to objects being appended to circular shells.

Thus, option C is correct.

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Calculate the molar mass of Ga(NO3)3
255.732 g/mol
159.738 g/mol
227.718 g/mol
131.727 g/mol

Answers

Answer:

255.732 g/mol

Explanation:

Molar mass of Ga(NO3)3 = 255.7322 g/mol. This compound is also known as Gallium(III) Nitrate.

What is the electron configuration for N (nitrogen)?
A. 1s22s23s23p1
B. 1s21p5
C. 1s22s22p3
D. 1s22s22p23s1

Answers

Explanation:

₇N = 1s² 2s² 2p³

Group = 15period = 2atomic mass = 14Hydride of Nitrogen = Ammoniavalency = 3

Therefore,

Option C is correct ✔

PLEASE HELP I WILL GIVE BRAINLIEST!!!!!

What is a main difference between a mixture and a pure substance?
OAmixture is only a liquid, but a pure substance can be in any state.
OAmixture looks the same throughout, but a pure substance does not.
OAmixture can vary in composition, but a pure substance has a set composition.
O Amixture can be made up of a single compound, but a pure substance cannot

Answers

Answer:

I think the answer is c!

Explanation:

Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components. A chemical substance is composed of one type of atom or molecule. hope this helps you!

Which is stronger, the strong force (SF) or the electromagnetic force (EMF)? Describe how they battle each other in the nucleus. What would happen if their strengths were reversed?

Answers

Answer:uclear Force that holds together the nucleus of an atom. electromagnetic force. ... They are unstable because the Strong Force that would hold them together if the protons and neutrons were closer is weakened because the protons and neutrons get too far apart.

Explanation:

Electron transfer between redox centers in proteins is controlled by quantum tunneling. We can model the region between two redox centers as an energy barrier which the electron must cross. If the distance between the redox centers is 0.681 nm and the energy of the electron is 0.5540.554eV lower than the height of the barrier, what is the probability that the electron will successfully cross to the next redox center

Answers

Answer:

5.61 e⁻³

Explanation:

Given that:

The barrier length = 0.681 nm = 6.81 × 10⁻¹⁰

The difference between the height of the barrier & the energy of the electron is;

[tex]V - E = 0.554 \ eV (1.6 \times 10^{-19} )[/tex]

= 8.864 × 10⁻²⁰ V

where;

m = 9.1 × 10⁻³¹ kg

The probability[tex]P = e^{-2 \ kd}[/tex]

[tex]k = 2 \pi \sqrt{\dfrac{2m (V-E)}{h^2} }[/tex]

[tex]k = 2 \pi \times \dfrac{\sqrt{2 \times 9.1 \times 10^{-31} \times 8.864 \times 10^{-20}}}{6.63 \times 10^{-34}}[/tex]

k = 3.806 × 10⁹

[tex]P = e^{-2 \ kd}[/tex]

[tex]P = e^{2 \times 3.806 \times 10^9 \times 6.81 \times 10^{-10}}[/tex]

P = 0.005606

P = 5.61 × 10⁻³

P = 5.61 e⁻³

The combustion of ethyne, shown below unbalance, produces heat which can be used to weld metals:
C2H2 (g) +502 (g) →2CO: (g) +H20 (g) AH reaction= -1544kJ
How much ethyne gas (in g) would you need to react with excess oxygen according to this reaction in order to raise the temperature of 325 g of high carbon steel from 165'C to its melting point, 1540 C? The heat capacity of high carbon steel is 0.490 J/g'C. (Assume a complete reaction and that all heat is transferred from the reaction to the metal with no loss.)
a. 7.37g
b. 1.84 g
c. 4.13 g
d 3.69 g

Answers

Answer:

3.69 g

Explanation:

Given that:

The mass m = 325 g

The change in temperature ΔT = ( 1540 - 165)° C

= 1375 ° C

Heat capacity [tex]c_p[/tex] = 0.490 J/g°C

The amount of heat required:

q = mcΔT

q =  325 × 0.490 × 1375

q = 218968.75 J

q = 218.97 kJ

The equation for the reaction is expressed as:

[tex]C_2H_{2(g)} + 5O_{2(g)} \to 2CO_{2(g)} + H_2O_{(g)} \ \ \ \ \ \Delta H^o_{reaction} = -1544 \ kJ[/tex]

Then,

1 mole of the ethyne is equal to 26 g of ethyne required for 1544 kJ heat.

Thus, for 218.97 kJ, the amount of ethyne gas required will be:

[tex]= \dfrac{26 \ g}{1544 \ kJ} \times 218.97 \ kJ[/tex]

= 3.69 g

WILL BE MARKED BRAINLIEST IF U ANSWER CORRECT


PLUS 30 PT

Why does DNA dissolve in water?



Why is salt added to solution of DNA and water?



How does ethanol help the precipitate form?



After a pellet is formed, is the DNA in the pellet or the supernate?

Answers

Explanation:

Because of this, DNA and RNA can easily dissolve in water. ... Adding ethanol helps the Na+ and PO3- ions come together, because ions travel easier in ethanol than water. The supernate is removed and new ethanol is added in the second washing. This removes any residual salt that remained on the pelleted DNA.

Answer:

DNA is polar due to its highly charged phosphate backbone. Its polarity makes it water-soluble (water is polar) according to the principle "like dissolves like". ... This fact makes water a very good solvent for charged compounds like salts.

Your DNA's sugar phosphate backbone is charged. By adding salt, we help neutralize the DNA charge and make the molecule less hydrophilic, meaning it becomes less soluble in water. The salt also helps to remove proteins that are bound to the DNA and to keep the proteins dissolved in the water.

It is well known that Ethanol has a lower dielectric constant than water, making it to promote ionic bond formations between the Na+ (from the salt) and the PO3- (from the DNA backbone), further, causing the DNA to precipitate.

Explanation:

Ideally DNA needs to be precipitated with pellet and should not remain in supernatant. DNA is acidic in nature and therefore, needs optimum salt concentration in the buffer to be pelleted from a solution. At very low salt concentration or without salt DNA would remain in supernatant.

Which is the correctly balanced equation?

A) Cl2 + 2NaI = 2NaCl + I2

B) NaOH +HCl = NaCl + H2O2

C) 2HgO = Hg + O2

D) 2Li + H2O = 2LiOH + H2


PLS HURRY, TAKING TEST, NEED HELP NOW

Answers

Answer:

A) Cl2 + 2NaI = 2NaCl + I2

No help hat 2................ 2................

Which scenario is likely to result in the most diverse offspring?

1 point
Sexual reproduction between two individuals from different continents
Sexual reproduction between two individuals in the same population
Asexual reproduction by binary fission
Asexual reproduction by budding

Answers

Sexual reproduction between two individuals from different continents is the answer. The other 3 offsprings wouldn’t be as diverse

Answer:   i think it is binary fission

 

Explanation:

A student makes observations of a tree in a nearby forest. Which of the following observations of the
tree's characteristics would be useful in determining its identity with a dichotomous key?
A
It contains the nests of several birds.
B
Its leaves are long and narrow.
с
Its branches were recently cut.
D
It provides shade for ground brush.

Answers

The answer should be B

The observations of the tree's characteristics would be useful in determining its identity with a dichotomous key is its leaves are long and narrow. The correct option is B.

What is an observation?

Observation is a process of recognizing and recording an event or fact that frequently involves measuring it with tools. Recognizing and recording an event, or fact frequently involves measuring with tools. Field notes are written observations made while participating in field observations or immediately afterward.

They are crucial for understanding phenomena that have been seen in the field. Field notes frequently take the form of scratch notes, diaries, and notebooks. In the scientific field, observation is a crucial step.

Therefore, the correct option is B. Its leaves are long and narrow.

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How many atoms are in 2.37 moles of Krypton

Answers

Answer:

1.43 × 10²⁴ atoms Kr

General Formulas and Concepts:

Chemistry - Atomic Structure

Using Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Explanation:

Step 1: Define

2.37 mol Kr

Step 2: Convert

[tex]2.37 \ mol \ Kr(\frac{6.022 \cdot 10^{23} \ atoms \ Kr}{1 \ mol \ Kr} )[/tex] = 1.42721 × 10²⁴ atoms Kr

Step 3: Check

We are given 3 sig figs. Follow sig fig rules and round.

1.42721 × 10²⁴ atoms Kr ≈ 1.43 × 10²⁴ atoms Kr

How high of a Frequency would a photon have to be for it to have an energy of 4 joules

Answers

The frequency of photon=6.03 x 10³³ /s

Further explanation

Radiation energy is absorbed by photons

The energy in one photon can be formulated as

[tex]\large{\boxed{\bold{E\:=\:h\:.\:f}}}[/tex]

Where

h = Planck's constant (6,626.10⁻³⁴ Js)

f = Frequency of electromagnetic waves

Energy of photon = 4 J

So the frequency :

[tex]\tt f=\dfrac{E}{h}\\\\f=\dfrac{4}{6.626.10^{-34}}\\\\f=6.03.10^{33}/s[/tex]

How many moles are in the 100,000g of CuSO4 • 5H2O ?

Answers

Answer:

try (107.87 amu)

Explanation:

The only sure evidence for a chemical reaction is

Answers

Answer:

that one or more new substances are produced. Temperature Changes Chemical reactions can release energy or absorb energy.

Explanation:       .

Percent yield is very important in terms of money. The higher the percent yield, the more of a product you can make. If you are working for a drug company and your theoretical yield is 120 kg, but you actually made 105 kg, what is your percent yield?
A. 8.75%
B. 114%
C. 87.50%
D. 15.00%

Answers

Answer:

87.5 %

Explanation:

Step 1: Given data

Theoretical yield: 120 kgReal yield: 105 kg

Step 2: Calculate the percent yield

When working with chemical reactions, we can determine the efficience in obtaining a product measuring the percent yield. The theoretical yield is the maximum amount of product that we could obtain according to the stoichiometry, whereas the real yield is the amount of product that we actually obtain when we carry out the process. We can calculate the percent yield usign the following expression.

%yield = real yield / theoretical yield × 100%

%yield = 105 kg / 120 kg × 100%

%yield = 87.5 %

At what temperature is water a gas

Answers

Answer:

212 degrees Fahrenheit

Explanation:

When liquid water reaches a low enough temperature, it freezes and becomes a solid—ice. When solid water is exposed to enough heat, it will melt and return to a liquid. As that liquid water is further heated, it evaporates and becomes a gas—water vapor.

Based on the activity series provided, which reactants will form products? F > Cl > Br > I CuI2 + Br2 Right arrow. Cl2 + AlF3 Right arrow. Br2 + NaCl Right arrow. CuF2 + I2 Right arrow.

Answers

Answer: Cul2 + Br2 ->

Explanation:

Answer:

i believe the answer is a

Explanation:

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