A scientist measures the standard enthalpy change for the following reaction to be 67.9 kJ:
Fe2O3(s) + 3 H2(
92Fe(s) + 3 H2O(9)
Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation
of H2O(g) is
kJ/mol.

Answers

Answer 1

Answer: The standard enthalpy of formation  of [tex]H_2O(g)[/tex] is  -252.1 kJ/mol.

Explanation:

The balanced chemical reaction is,

[tex]Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(g)[/tex]

The expression for enthalpy change is,

[tex]\Delta H=[n\times H_f_{products}]-[n\times H_f_{reactantss}][/tex]

Putting the values we get :

[tex]\Delta H=[2\times H_f{Fe}+3\times H_f{H_2O}]-[1\times H_f{Fe_2O_3}+3\times H_f{H_2}][/tex]

[tex]67.9kJ=[(2\times 0)+(3\times H_f{H_2O})]-[(1\times -824.2kJ/mol)+3\times 0kJ/mol)][/tex]

[tex]H_f{H_2O}=-252.1kJ/mol[/tex]

Thus standard enthalpy of formation  of [tex]H_2O(g)[/tex] is  -252.1 kJ/mol.


Related Questions

what is your experience about water pollution​

Answers

Answer:

water pollution is a process in which water gets polluted due to discharge of city sewage and industrial waste. I was suffering through the water born disease when I drank the contaminated water. The sources of water becomes dirty. It makes environment unbalanced. People suffer from different water born disease when they drink polluted water.

Which has greater heat capacity—iron, tin, or bismuth? Why do you say this?

Answers

Answer:

Bismuth, because when three cubes of the same mass were heated and dropped into the same temperature water, the water the bismuth cube was dropped in heated up much less than the water with iron or tin.

REWRITE THIS IN YOUR OWN WORDS PLEASE, THANK YOU.

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The greatest heat capacity is possessed by iron.

The heat capacity of materials increases as the number of particles in the material or density of the material increases.

This means that the denser a material is, the higher its heat capacity because it has more particles that absorbs heat.

The heat capacity is the quantity of heat required to raise the temperature of 1 gram of a material by  1°C.

The heat capacities of iron, tin and bismuth are: 0.45 J/g °C, 0.213 J/g °C and 0.123 J/g °C.

This follows from the decreasing densities of the metals in the order; iron > tin > bismuth.

Hence iron has the greatest heat capacity among the three elements.

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What is the pressure, in mmHg, of a 4.00 g sample of O2 gas, which has a temperature of 37.0 °C, and a volume of 4400 mL?

Answers

Answer:

549.48 mmHg

Explanation:

We'll begin by calculating the number of mole of oxygen in 4 g. This can be obtained as follow:

Molar mass of O₂ = 2 × 16 = 32 g/mol

Mass of O₂ = 4 g

Mole of O₂ =?

Mole = mass /molar mass

Mole of O₂ = 4/32

Mole of O₂ = 0.125 mole

Next, we shall convert 37.0 °C to Kelvin temperature. This can be obtained as follow:

T(K) = T(°C) + 273

T (°C) = 37.0 °C

T(K) = 37.0 °C + 273

T(K) = 310 K

Next, we shall convert 4400 mL to L.

1000 mL = 1 L

Therefore,

4400 mL = 4400 mL × 1 L / 1000 mL

4400 mL = 4.4 L

Next, we shall determine the pressure. This can be obtained as follow:

Number of mole (n) = 0.125 mole

Temperature (T) = 310 K

Volume (V) = 4.4 L

Gas constant (R) = 0.0821 atm.L/Kmol

Pressure (P) =?

PV = nRT

P × 4.4 = 0.125 × 0.0821 × 310

Divide both side by 4.4

P = (0.125 × 0.0821 × 310) / 4.4

P = 0.723 atm

Finally, we shall convert 0.723 atm to mmHg.

1 atm = 760 mmHg

Therefore,

0.723 atm = 0.723 atm × 760 mmHg / 1 atm

0.723 atm = 549.48 mmHg

Thus, the pressure is 549.48 mmHg

Convert 467.00 g AlCl3 to mol AlCl3.

Answers

Answer:

467.000g AICI3 to mol AICI3

Explanation

Answer:

7.49959 mol i hope this is right

need help i only have 5 more minutes left

Answers

Answer:

Bleach, seawater, blood, water, coffee, orange, lemon

Explanation:

The pH is a measurement in chemistry defined as the -log [H⁺]. pH is used in quality control of materials. The pH is a scale from 1 (Acids) to 14 (Bases). The pH of 7 is for neutral solutions

Based on the information of the image, the most basic is bleach, then the seawater, the blood, water (Neutral), coffee, orange and, the most acidic is lemon.

The order is:

Bleach, seawater, blood, water, coffee, orange, lemon

A mixture of gaseous reactants is put into a cylinder, where a chemical reaction turns them into gaseous products. The cylinder has a piston that moves in or out, as necessary, to keep a constant pressure on the mixture of . The cylinder is also submerged in a large insulated water bath. (See sketch at right.) From previous experiments, this chemical reaction is known to release of energy. The position of the piston is monitored, and it is determined from this data that the system does of work on the piston during the reaction.

Answers

Answer:

It is exothermic in nature.

Explanation:

(1) The reaction is exothermic in nature because it releases heat energy.

(2)  Yes, the temperature of the water go up as the reaction releases heat energy and the temperature cool down as the heat energy is completely removed from the water.

(3)  The piston move in when the pressure in the cylinder decreases and the piston move out when increase of pressure occur.

 (4)  As the outside movement of piston occurs, so we can say that the gas mixture does work on its surroundings.

 (5)   The system released 244 kJ of energy, in which only 150 kJ went into the water, then the difference must be the work done by the system on its surroundings.

 W = (244 - 150) kJ = 94 kJ

Which example is a mixture? alcohol water mercury orange soda

Answers

Answer:

water is an example of mixture

I don’t know how to do that cause that’s what I’m having trouble with

Click on an olive tree and read about it. Based on what you read, do you think the climate of Barcelona is very wet or rather dry? Explain.

Answers

Answer:

In the Autumn, Spring, and Winter, It is wet. In the Summer it is dry.

Explanation:

By which method the following mixture can be separated?(i)mixture of colours (ii) Minerals oil.​

Answers

Answer:

mixture of colours answer

If carbon is in an animal is it:
A. Abiotic matter
B. Biotic matter
C. Energy storage molecules
D. Carbon dioxide

I WILL MARK BRAINLIEST IF YOU HELP!
Do not guess or give me a file or I will report you!!​

Answers

Answer:

It is A

Explanation:

Abiotic matter

1.2 What type of bonding occurs when hydrogen form a diatomic molecule?​

Answers

Answer:

I think it is covalent bonding...

Explanation:

The bonding is covalent in homonuclear diatomic molecules. Each atom in the molecule has the same electronegativity, which means electrons are shared equally between the two. The electronegativity of the atoms in heteronuclear diatomic molecules varies, and these molecules have polar covalent bonds. A dipole is formed when a molecule interacts with another molecule. (i think it's covalent bonding but i might be wrong)

hope this helps...

A covalent bond! A hydrogen molecule forms from two hydrogen atoms, each with one electron in a 1 s orbital. The two hydrogen atoms are attracted to the same pair of electrons in the covalent bond. A covalent bond is the force of attraction that holds together two atoms that share a pair of electrons. The shared electrons are attracted to the nuclei of both atoms. Covalent bonds form only between atoms of nonmetals. The two atoms may be the same or different elements. If the bonds form between atoms of different elements, a covalent compound forms.

An orgo lab student named Bob wanted to synthesize an isoamyl acetate ester because it smells like bananas and he really likes to sniff it. He heated 7.50 grams of isoamyl alcohol (3-methyl-1-butanol) with 22.5 grams of acetic acid (ethanoic acid) and 4.50 grams of sulfuric acidto prepare his favorite ester. Based on these numbers, how many grams of isoamyl acetateshould he theoretically obtain

Answers

Answer:

The answer is "11.07 g".

Explanation:

Isoamyl alcohol is a reagent restriction

Isoamyl alcohol Moles: 

[tex]= \frac{7.5}{88.15} \\\\ =0.085[/tex]

Moles only with the shape of isoamyl acetate are equivalent to numbers.

Isoamyl acetate grams:

[tex]= 0.085 \times 130.19\\\\ = 11.07 \ g[/tex]

Can somebody please help me!!

Answers

Answer:

acceleration

pls dont report me

What occurs during a decomposition reaction?

Answers

Answer:

Hello

The chemical bonds between the atoms of the decomposing compound are broken, and then rearranged between the atoms in new ways to make the products.

Explanation:

The chemical bonds between the atoms of the decomposing compound break, and new substances are formed as new chemical bonds form between the atoms of the elements of the decomposed compound.

Have a nice day!

For each of the following, predict the complete, balanced chemical equation for the reaction that occurs when they are mixed. Make sure to label the states.
1. HNO3 & NaOH
2. Sr(OH)2 & HI
..

Answers

Answer:

1. The balanced chemical reaction is:

[tex]HNO_3(aq)+NaOH(aq)\rightarrow NaNO_3(aq)+H_2O(l)[/tex]

2. The balanced chemical reaction is:

[tex]2HI(aq)+Sr(OH)_2(aq)\rightarrow SrI_2(aq)+2H_2O(l)[/tex]

Explanation:

Hello there!

In this case, according to the given chemical reactions, it is necessary to keep in mind the cations and anions are switched around as a result of the bonds rearrangement in these neutralization reactions; therefore, we can proceed as follows:

1. The balanced chemical reaction is:

[tex]HNO_3(aq)+NaOH(aq)\rightarrow NaNO_3(aq)+H_2O(l)[/tex]

Because all atoms are in the same amount at each side of the equation and the resulting salt is soluble.

2. The balanced chemical reaction is:

[tex]2HI(aq)+Sr(OH)_2(aq)\rightarrow SrI_2(aq)+2H_2O(l)[/tex]

Because all atoms are in the same amount at each side of the equation and the resulting salt is soluble.

Best regards!

The isomerization reaction, ch3nc → ch3cn, is first order and the rate constant is equal to 0.46 s-1 at 600 k. what is the concentration of ch3nc after 7.0 seconds if the initial concentration is 0.30 m?

Answers

Answer:

y=meme3squared

Explanation:

YEEEEEEEEEEEEEEEE

Section I: Experimental Overview

Provide background information.

Include the hypothesis(es).

Summarize the procedures.



Section II: Data and Observations

Summarize the data you collected in the lab guide.

Include information from data tables.

Include any written observations that are relevant.



Section III: Analysis and Discussion

Discuss any important calculations or formulas used.

Identify key results, what the results indicate, and any trends in the data.

Include graphs (if constructed) that display trends in the data.

Provide possible reasons for any problems with the experiment, or unexpected data.



Section IV: Conclusions

Identify if the hypothesis(es) was (were) supported or refuted.

Provide logical reasoning based on data.

Explain how the experiment could be improved.


To help you write your lab report, you will first answer the questions listed below by reflecting on the experiment you have just completed. Then you will use the answers to these questions to write the lab report that you will turn into your teacher.

You can upload your completed report with the upload tool in formats such as , Microsoft Word, or PDF. Alternatively, your teacher may ask you to turn in a paper copy of your report or use a web-based writing tool.

Questions



Section I: Experimental Overview



What is the purpose of the lab, the importance of the topic, and the question you are trying to answer?































What is your hypothesis (or hypotheses) for this experiment?



















What methods are you using to test this (or each) hypothesis?








Section II: Data and Observations

Locate the data and observations collected in your lab guide. What are the key results? How would you best summarize the data to relate your findings?































Do you have quantitative data (numerical results or calculations)? Do you have qualitative data (written observations and descriptions)? How can you organize this date for your report?














Section III: Analysis and Discussion



What do the key results indicate?





























If you constructed graphs, what trends do they indicate in your data?

Answers

Answer:

If you constructed graphs, what trends do they indicate in your data?

A study was created to test the effects of fear in children. The hypothesis of the experimenters was that if babies were exposed to fuzzy bunnies and at the same time a loud cymbal was struck close behind them, then that child would be afraid of all fuzzy things. Another group of children would be exposed to bunnies without any loud noises. The study was carried out as planned and as a result, hundreds of young children developed fear of all cute furry bunny rabbits.

Dependent Variable: ______________________

Control Group: ____________________________

Independent Variable: _____________________

Experimental Group: _______________________

Answers

Answer:

Dependent variable: the children's fear of rabbits

Control: the group that was NOT exposed to loud noises

Independent variable: the loud noises

Experimental Group: the group that was exposed to loud noises

Organelles that use energy from sunlight to produce food are called mitochondria
O True
O False​

Answers

Answer:

Organelles that use energy from sunlight to produce food are called mitochondria.

False

Pls help ASAP ! Identify the following reaction: H2 + O2 → H2O
Group of answer choices

synthesis reaction

decomposition reaction

single replacement reaction

double replacement reaction

Answers

Answer:

Synthesis Reaction

Explanation:

Here we see H2 and O2 are being combined H2O. Synthesis reactions are where we see a combination to make a single product.

So here it'd be A + B =AB

2Na(s)+Cl2(g)→2NaCl(s)

Decomposition would be the break down of a compound into 2, the opposite of synthesis.

AB = A + B

2HgO(s)→2Hg(l)+O2(g)

Single replacement is where  1 element replaces another in a reaction, or switches place with 1 element.

AY + B = A + BY

2 HCl(aq) + Zn(s) → ZnCl2(aq) + H2(g)

Double replacement is similar but 2 elements are switch/replaced.

AY + BX = AX + BY

CuCl2(aq) + 2 AgNO3(aq) → Cu(NO3)2(aq) + 2 AgCl(s)

what is the xonclusion of separating acetone and water by simple and fractional distillation

Answers

Answer:

In conclusion, acetone was determined to be the unknown used in the simple distillation and acetone- water was separated successfully by fractional distillation. Introduction Distillation is the chief technique used to separate and purify liquids.

A company claims that its weight-loss product is the safest. Why might this
be a biased claim?
A. The company is trying to get you to buy its product.
B. The company has lots of scientific information about the product
C. The company is very successful.
D. The company has studied the product more than anyone.​

Answers

The answer could either be C or A.

what changes would you see in the colour of litmus paper in lemon,ash and blood​

Answers

Answer:

Colour of litmus papers in lemon:

Blue litmus- Red

Red litmus- No change

Really sorry but don't know about others

Litmus paper indicator shows following color  changes for lemon it is, blue litmus to red, for ash and blood  it is red litmus to blue  indicating their acidic nature in case of lemon and alkaline nature in case of ash and blood.

What is an indicator?

Indicator is defined as a chemical substance which is chemically a weak acid or a weak base which changes it's color depending upon the concentration of hydrogen ions present in the solution.They dissociate slightly in water to produce ions.

These are generally derived from plant pigments and are of slightly acidic or basic in nature.There are three types of indicators:

1) natural indicators

2) synthetic indicators

3) olfactory indicators.

These are mainly used in determination of end point of titrations. Every indicator has it's pH range in which it can perform effectively.These are usually organic compounds.

Learn more about indicators,here:

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Please help it’s for 100 points

Has your cell phone ever not had enough battery when you really needed it? What did you do?

Answers

Answer:

Yes

Explanation:

There are some times when I will need my cell phones but it will have not battery. At this point, I look for a means to charge it or I could probably use power bank to charge. I always have an extra battery, so when the other battery is flat, I will replace it with the second charged one. But when both batteries are flat, I will look for a means to charge it using generator or wait till I have access to power supply.

Q) Briefly describe how body systems work all together

Answers

Answer:

Your bones and muscles work together to support and move your body. Your respiratory system takes in oxygen from the air. ... Your circulatory system carries oxygen, water, and nutrients to cells throughout your body. Wastes from the cells are eliminated by your respiratory system, your excretory system, and your skin.

Explanation:

why does oxygen and carbon dioxide travel within the seed and the egg

Answers

Answer: Inside the egg, oxygen is used by the chick as a source of energy and is turned into carbon dioxide. The carbon dioxide then leaves through the egg's shell. Oxygen enters through the egg's shell. Inside the egg, oxygen reacts with molecules from the yolk to release energy for the growth of the chick.

explain hydrophobic and hydrophylic​

Answers

Answer:

hydrophobic: tending to repel or fail to mix with water.

hydrophylic​: having a tendency to mix with, dissolve in, or be wetted by water.

Hope it helps!!!

Does all of the liquid water in the atmosphere fall as rain? Why or why not?

Answers

Most of the condensed water in clouds does not fall as precipitation because their fall speed is not large enough to overcome updrafts which support the clouds. ... Water droplets may grow as a result of additional condensation of water vapor when the particles collide.

Which cross section below best shows the locations of high air pressure and low air pressure near a beach on a hot, sunny, summer afternoon?

Answers

Locations of high air pressure is the beach whereas the location of low air pressure is in the sea on a hot, sunny, summer afternoon.

Where is low and high air pressure exists?

Areas where the air is warmed have lower pressure because the warm air rises in the air. These areas are known as low pressure systems. Places where the air pressure is high, are called high pressure systems. These are places where air is cold.

So we can conclude that Locations of high air pressure is the beach whereas the location of low air pressure is in the sea on a hot, sunny, summer afternoon.

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Why is NH3 not considered a base under the Arrhenius definition of acids and bases?

SELECT AN ANSWER

a. It does not react with acids.
b. NH3(aq) does not contain OH- ions.
c. NH3 is considered a base under the Arrhenius definition, but not under the Bronsted-Lowry definition.
d. It does not cause a color change when mixed with an acid-base (pH) indicator.

Answers

Answer:

b. NH3(aq) does not contain OH- ions.

Explanation:

According to Arrhenius in his definition, a base is a substance that has the ability to increase the hydroxyll ion (OH-) of an aqueous solution. In other words, Arrhenius bases dissociates into OH- when dissolved in water.

According to this question, ammonia (NH3) will not be considered an Arrhenius base because it does not contain OH-. This means that ammonia (NH3) cannot dissociate into hydroxyll ion when dissolved in water.

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