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1
a
C
Copper(II) nitrate decomposes on heating. The reaction is endothermic.
2Cu(NO),(s) → 2CuO(s) + 4NO2(g) + 0,(9)
Sketch a reaction pathway diagram for this reaction to include the
activation energy
[3]
b Draw an energy cycle to calculate the standard enthalpy change for
this reaction, using enthalpy changes of formation.
[3]
Calculate the enthalpy change for this reaction using the following
enthalpy changes of formation.
AH, [Cu(NO, ),(s)] = -302.9 kJ mol-'
AH, [CuO(s)] =-157.3 kJ mol-!
AH [NO,(g)] = +33.2 kJ mol-!
[3]
d Copper(II) sulfate is soluble in water. A student dissolved 25.0 g of
copper(II) sulfate in 100 cm of water in a polystyrene beaker stirring
all the time. The temperature of the water fell by 2.9 °C.
i Calculate the enthalpy change of solution of copper(II) sulfate.
(specific heat capacity of water = 4.18 Jg1 °C ; relative
molecular mass of copper(II) sulfate = 249.7 g mol-')
[3]
ii Suggest one source of error in this experiment and explain how
the error affects the results.
[2]
[Total: 14]
Answers
This problem provides information about the decomposition of copper(II) nitrate to copper(II) oxide and dinitrogen monoxide; for example, it is endothermic, the enthalpies of formation and the chemical reaction, as well as copper (II) sulfate which when dissolved in water, exhibits a temperature decrease:
[tex]2Cu(NO_3)_2(s) \rightarrow 2CuO(s) + 4NO_2(g) + O_2(g)[/tex]
First of all, we can draw the reaction pathway as shown on the attached figure, by taking into account the positive enthalpy change as it is endothermic, so that the products turn out with higher energy than the reactants, for it to be positive. In addition, keep in mind that top point is the activation energy the reaction needs to take place.
Next, we calculate the enthalpy change for this reaction by using the general formula which subtracts the enthalpy of formation of products and reactants with each species' correct stoichiometric coefficient:
[tex]\Delta H=2\Delta _fH_{CuO}+4\Delta _fH_{NO_2}+\Delta _fH_{O_2}-2\Delta _fH_{Cu(NO_3)_2}[/tex]
So we plug in the given enthalpies of formation:
[tex]\Delta H=2(-157.3)+4(33.2)+(0)-2(-302.9)=424.0 kJ/mol[/tex]
Finally, we go over the calorimetry experiment, whereby the total heat absorbed by the copper(II) sulfate is calculated via the general heat equation, which includes the heat loss from the solution of water and the salt:
[tex]Q_{rxn}=-mC_w\Delta T\\\\Q_{rxn}=-(100+25)g*4.18\frac{J}{g\°C}*-2.9\°C=1515.25J[/tex]
By dividing the previous answer by the moles of salt:
[tex]n=25.0g*\frac{1mol}{249.7g}=0.100mol[/tex]
We can obtain the enthalpy change of solution of the copper salt:
[tex]\Delta _{dissolution}H=\frac{1,515.25J}{0.100mol} \\\\\Delta _{dissolution}H=15,134J/mol=15.1kJ/mol[/tex]
To conclude, it is important to note that one possible source of error is we are assuming the solution has the same specific heat to that of water and that is not necessarily true. Also, we are neglecting any heat transfer to and from the surroundings despite the polystyrene beaker is considered a heat isolator, which means the results cannot necesarilly be accurate and the enthalpy change could have turned out higher or lower in a rigoruous experiment.
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Related Questions
How do weak intermolecular bond strengths affect the melting and boiling point of a substance?
The melting point is lower, but the boiling point is higher.
Both the melting point and boiling point are lower.
The melting point is higher, but the boiling point is lower.
Both the melting point and boiling point are higher.
Answers
Considering the definition of intermolecular bond, the correct answer is second option: Both the melting point and boiling point are lower.
The molecules of covalent compounds can be held together through electrostatic interactions known as "intermolecular forces", which are characterized by holding more than one molecule together. Therefore, they are related to chemical bonds, which have the goal of making molecules stick together or separate.
In other words, intermolecular forces or bonds are those interactions that hold molecules together. These are electrostatic forces.
The presence of these forces explains, for example, the properties of solids and liquids.
They differ from intramolecular forces, because of these, they correspond to interactions that hold the atoms in a molecule together. In general, intermolecular forces are much weaker than intramolecular forces.
On the other side, the melting point is the temperature at which a substance goes from solid to liquid at a given pressure. Similarly, the boiling point is the temperature at which the substance passes from a liquid to a gaseous state.
Finally, the more intense the intermolecular forces, the higher the melting point and the boiling point of a substance because these are the forces that must be overcome to separate them.
In summary, the correct answer is second option: Both the melting point and boiling point are lower.
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CaOCl2 parent acid and base???
Answers
Answer:
this is not and reaction of acid and base.(CaOCL2)
Explanation:
Ca2, Cl, are base and O is a neutral.
so how can that be a acid and base reaction
Please help? It’s for chem
Answers
Answer:
O-H
Explanation:
It is polar covalent bond, because the hydrogen atom has electronegativity about 2.6, and the oxygen atom, electronegativity about 3.6. When the difference in electronegativity of the atoms is between 0.4 and 1.7, the result is a polar covalent bond.
what wouldn't be a redox reaction?
Answers
Answer:
Explanation:
Combination of oxidation and reduction reactions.
Where there is oxidation, there is reduction too.
Which polymer structure should be used if a strong and heat - resistant adhesive is required?
1. Linear
2. Branched
3. Networked
4 . Cross - linked
Answers
Cross-linked polymers are strong and heat - resistant hence they can be used for this purpose.
A polymer is obtained by the combination of small molecules called monomers. A polymer consists of a regular repeating unit of small molecules called monomers.
A cross-linked polymer is a polymer in which covalent bonds are used to join polymer chains together. Cross-linked polymers are strong and heat - resistant hence they can be used for this purpose.
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Based on properties of elements in the periodic table, which element is the best conductor of thermal energy?.
Answers
Answer:
Silver
Explanation:
Silver has the highest thermal conductivity of any element and the highest light reflectance.
How does the current flow affect pressure.
Answers
Answer:
when less water is flowing
When light waves pass through solids, the speed of the wave ___________.
remains the same
decreases
increases
Answers
It woukd decrease.
I am sure its correct you can trust me becuase I took the test.
Answer:
The speed of the wave decreases.
Explanation:
When light waves do pass through a medium, any solid, liquid, or gas, the speed of the waves actually decreases. Solids are more dense than liquids, so they decrease the speed of light even more.
(I did the quiz btw!!)
NaCl express your answer as an Ion
Does anyone know what the answer for this would be
Answers
Answer:
iconic compound
Explanation:
Distinguish between the first, second, and third ionization energies of an atom. b. How do the values of successive ionization energies compare
Answers
Answer:
The third ionization energy is the energy it takes to remove an electron from a 2+ ion. (That means that the atom has already lost two electrons, you are now removing the third.) And 2nd ionization energy is higher than 1st ionization energy, 3rd is higher than 2nd, and so forth.
hope it is helpful :)
What are the similarities and differences between living on Earth versus living in space?
find 5 points for each section
Answers
Answer:
Differences
• Space is everything in the universe beyond the top of Earth's atmosphere - The moon, Stars, Milky way, etc.
• In space, no one can hear you scream. This is because there is no air in space, i.e, it's vacuum.
• Earth is a planet on solar system. It is the only planet where life exists!!
• Earth is also called "blue sky" cause it has 75% water.
Similarities
•They need oxygen for survival: Man, animals in earth and space need oxygen for survival.
•Water is also need to stay alive.
•Food is very paramount to both man, animal s and organisms.
•Shelter, we all ned a place to lay our head in other to be safe.
•Air everywhere in the atmosphere.
•Water, air, food and shelter are available on earth but their availability differs in space.
•Astronaut need to bring everything one need in space with him or her from Earth. They often recycle the things they bring.
Hope it helps :)
The atmospheric conditions in earth and space is entirely different. Therefore the living in earth and space will be far different on many aspects such as adaptations, habits etc.
What are aliens?The living things that are believed to be exists in out of earth is called aliens. Some studies shows that there is a possibility to find exotic species living in space.
The study which deals with aliens is called exo-biology. The atmosphere thus, the presence gases, temperature, pressure, etc. will be different for space from that in the earth.
Hence, aliens may need not the presence of oxygen for living as well as the atmospheric conditions that maintains living in earth will not be there in space.
However, any living irrespective of earth or space need water and some kind of food to survive. Thus the presence of water in some planets opens the way to study the presence of livings there.
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A compound contains 36.48% Na, 25.41% S, and 38.11% O. Find it’s empirical formula
Answers
Answer:
we can use 100g of compounds as the basis.
Explanation:
PLEASE ANSWER NEED HELP!!!!!!!! PLEASE THE CORRECT ANSWER!!!!!!
Ivan has decided that he is going to work on having a more positive body image. What result should he hope for?
A.
He should feel good about his body and accept any flaws.
B.
He should look for compliments from friends and family about his body.
C.
He should love everything about his body and think he is very attractive.
D.
He should be happy with himself after following a strict diet and exercise routine.
PLEASE NO LINKS
Answers
Answer:
D
Explanation:
Hope it helps
The result he hope for he should be happy with himself after following a strict diet and exercise routine.
What is fitness?Fitness is defined as to be able to go about one's everyday activities without difficulty, without getting exhausted, and with enough energy to spare for leisure. Body composition, flexibility, muscular strength, muscular endurance, and cardiorespiratory endurance are the five facets of physical fitness. Physical activity can strengthen your bones and muscles, help you maintain a healthy weight, increase your ability to carry out daily tasks, and improve your cognitive health.
Exercise is defined as a bodily action that maintains or improves physical health and wellness overall. Exercise science is a field that investigates movement as well as the corresponding functional reactions and adaptations.
Thus, the result he hope for he should be happy with himself after following a strict diet and exercise routine.
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WILL MARK BRAINLIEST
Georgia completed an investigation about different forces and came up with an explanation. What does she need to support her explanation?
Problem
Conclusion
Question
Evidence
Answers
Georgia needs evidence
Evidence
5) When rain falls to the earth, it just doesn't sit there. Instead, the rain water starts moving. Some of the precipitation seeps into the ground to replenishing groundwater. However, most of
it flows downhill as runoff. Runoff is important in filling rivers and lakes, but it also changes the landscape by erosion and can be a powerful mover. Flowing water is a powerful force,
capable of moving boulders and carving out canyons. Runoff has an impact on streams and rivers, but it also has an impact on the ocean system. What can you infer about the impact of
runoff on Ocean life? Choose ALL that apply.
A) Runoff drops a lot of sediment in the ocean, decreasing salinity.
B) Runoff builds up the coastline, depositing sediment, disrupting habitats of marine wildlife.
Runoff can lead to overgrowth of algae that can cause oxygen deprivation and create a dead zone.
D) Runoff carries pollutants into the ocean, causing illness and death of vulnerable marine populations.
) Runoff can carry bacteria, viruses and other pathogens from pet and livestock waste that can harm shellfish and other marine organisms.
Answers
Answer: Rain evaporates and this same process happens over and over again.
Explanation:
if your going down a hill what type of energy are you making?
Answers
Answer:
Gravitational potential energy - into Kinetic energy
Explanation:
Which compound is an acidic oxide?
Aaluminium oxide
carbon dioxide
copper(II) oxide
magnesium oxide
Answers
Answer:
Carbon dioxide
Explanation:
Metal oxides are basic and Non metal.oxides are acidic.
Al, Be, Zn,Sn ,Pb oxides are amphoteric so they show both acidic and basic properties.
From the above answers Al, Cu and Mg are metals so their oxides are acidic while Carbon is a non metal.so CO2 is an acidic oxide
blank are produced when atoms if the elements in group 7A blank an electron
Answers
Answer:
Halide ions are produced when atoms of elements in Group 7A gain an electron.
Explanation:
4. One gram of of ............... contains one type of atoms. a. iron b. ammonia c. hydrogen chloride d. water
Answers
Answer: hydrogen chloride.
Explanation:
Someone know the answer for that question
Answers
C2H4NH Lewis structure
Answers
How many deciseconds are
in 554 seconds?
Give your answer in standard form.
Answers
Answer:
5540
Explanation:
Answer:
5,440
Explanation:
10 deciseconds = 1 seconds
554 seconds = 5,440 seconds
What has more atoms, a mole of carbon or a mole of fluorine?
A mole of carbon
A mole of Florine
They have the same number of atoms
Answers
Answer:
They have the same number of atoms
Explanation:
The mole (symbol: mol) is the base unit of amount of substance.
Think of mole meaning like inch. An inch of grass is the same as an inch of a flower. Mole is the standard measuring unit of atoms.
-Rutherford's experiment was important because it showed that:
A) Radioactive elements give off alpha particles.
b) A zinc sulfide screen glows when struck by a charged particle.
C) The mass of the atom is uniformly distributed throughout the atom
d) An atom is mostly empty space
Answers
Answer: D
Explanation:
i need help!!!!! limited time! please Explain the energy transformation that occurs when food is digested.
Chemical energy transforms into mechanical energy.
Electrical energy transforms into mechanical energy.
Mechanical energy transforms into chemical energy.
Thermal energy transforms into electrical energy. I RLLY NEED HELP pls
Answers
Answer:
thermal energy
Explanation:
please mark me as brainlists
What is infrared energy? simplify it
Answers
Answer:
It is a type of radiant energy that's invisible to human eyes but that we can feel as heat.
can someone help me with this
Answers
Answer: 5. Positive
6. Negative
9. Oxygen carbon hydrogen nitrogen
Explanation:
How much heat is absorbed when 25 g of water increases by 45 K?
Answers
4709.25 joules of heat are absorbed when 25 grams of water increases temperature by 45 K.
Let suppose that temperature change experienced by water is entirely sensible. Then, we can estimated the heat absorbed by the water sample ([tex]Q[/tex]), in joules, through this expression:
[tex]Q = m\cdot c \cdot \Delta T[/tex] (1)
Where:
[tex]m[/tex] - Mass of the water sample, in grams.[tex]c[/tex] - Specific heat of water, in joules per kilogram-Kelvin.[tex]\Delta T[/tex] - Temperature change, in Kelvin.If we know that [tex]m = 25\,g[/tex], [tex]c = 4.186\,\frac{J}{g\cdot K}[/tex] and [tex]\Delta T = 45\,K[/tex], then the heat absorbed by the water sample is:
[tex]Q = (25\,g)\cdot \left(4.186\,\frac{J}{g\cdot K} \right)\cdot (45\,K)[/tex]
[tex]Q = 4709.25\,J[/tex]
4709.25 joules of heat are absorbed when 25 grams of water increases temperature by 45 K.
We kindly invite to check this question on sensible heat: https://brainly.com/question/11325154
Name the elements that make the phone vibrate.
Answers
Answer:
someone calling you, notifications or apps
Explanation:
determine the element of lowest atomic number that contains a complete d subshell in the ground state.
Answers
Answer:
The element with the lowest atomic number that contains a complete d-subshell in the ground state is copper.Source:
Determine the element of lowest atomic number that contains a complete d subshell in the ground... - Study.com