The standard enthalpy of formation (Δ[tex]H_f[/tex]) is a measure of the energy released or consumed when one mole of a substance is created under standard conditions from its pure elements.
Standard enthalpies (Δ[tex]H_f[/tex]) of formation for given reaction is 978.3 kJ
What is Standard enthalpies of formation?The standard enthalpy of formation is defined as the enthalpy change when one mole of a substance in the standard state (1 atm of pressure and 298.15 K) is formed from its pure elements under the same conditions.
Given reaction ;
[tex]N_2O_4(g) + 4H_2 (g) - > N_2(g) + 4H_2O(g)[/tex]
To Find : Δ[tex]H_f[/tex]
Δ[tex]H_f[/tex] = ∑np Δ[tex]H_f[/tex] (products) – ∑np Δ[tex]H_f[/tex] (reactants)
Δ[tex]H_f[/tex] = [1(Δ[tex]H_f[/tex] [tex]N_2[/tex]) + 4(Δ[tex]H_f[/tex] [tex]H_2O[/tex])] – [1(Δ[tex]H_f[/tex] [tex]N_2O_4[/tex]) + 4(Δ[tex]H_f[/tex] [tex]H_2[/tex])]
Δ[tex]H_f[/tex] = [1(0) + 4(-241.8)] – [1(+9.16) + 4(0)]
Δ[tex]H_f[/tex] = [4(-241.8)] – [1(+9.16)] = 978.3 kJ
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A high temperature reaction vessel is charged with 0.5860 mol of iron powder and 35.1 L of oxygen gas at standard temperature pressure. On heating, the iron and oxygen react according to the balanced reaction below.
4Fe(s) + 3O2(g) ®️ 2Fe2O3(s)
After the reaction vessel is called, and assuming the reaction goes to completion, what volume of oxygen remains?
Answer: 25.1195 L
Explanation:
Given:
There are 0.5860 mol of Iron powder (Fe)
The volume of oxygen gas at STP is 31.5 L
The volume filled by a gas at STP is approximately 22.71 L
Therefore, the moles of oxygen gas at STP = Volume of oxygen gas at STP/ 22.71
= 35.1/22.71
= 1.5456 mol
The balanced chemical equation given for this reaction is:
4Fe(s) + 3O2 (g) ----> 2Fe2O3 (s)
Dividing the above equation by 2, yields:
2Fe(s) + 3/2O2(g) -------> Fe2O3 (s)
From the equation we see:
2 moles of Fe reacts with 3/2 mole of O2 to give one mole of Fe2O3
Thus, let x moles of O2 react with 0.5860 moles of Fe
0.5860/2=x/3/2
0.5860*3=4*x
x = 1.758/4
x =0.4395 mol
So the remaining moles of oxygen gas = 1.5456 - 0.4395
= 1.1061 mol
Therefore, the amount of oxygen gas, in litres, remaining is = 1.1061*22.71
= 25.1195 L
The electron configuration of an element is 1s^2 2s^2 2p^6. Describe what most likely happens when an atom of this element comes near an atom having seven valance electrons. (5 points)
Answer:
In some cases, they could bond to form covalent compounds. However, in most instances they will not interact.
Explanation:
Remember that elements desire to have a full octet (8 valence electrons). The configuration given represents an element with 8 valence electrons. I know this because the outermost shell (denoted by the 2 coefficient) has 8 electrons (2s²2p⁶ = 2 + 6 = 8). Therefore, this element is stable.
The other atom has 7 valence electrons. Since it is 1 electron away from having a full octet, it really wants 1 more electron. The original element is unlikely to give up an electron because that would prevent it from having a full octet. As such, when the atoms are close to one another, they will most likely not interact. The element with the full octet is most likely a noble gas, and these elements rarely form bonds. Noble gases can form bonds with halogens (elements with 7 valence electrons) but only if there are excess halogens and particular noble gases in the system.
The electron configuration of an element is 1s2 2s2 2p6 is Neon with atomic number 10. They either will form covalent bond with other element of does not from bond with any other element.
What is chemical bond?Chemical bond is defined as any of the interactions that allow for the grouping of atoms into molecules, ions, crystals, and other stable species that make up ordinary substances.
It can also be defined as a connection between atoms in molecules or compounds, as well as between ions and molecules in crystals.
There are basically four types of chemical bond.
Covalent bondIonic bondMetallic bondMolecular bondThus, the electron configuration of an element is 1s2 2s2 2p6 is Neon with atomic number 10. They either will form covalent bond with other element of does not from bond with any other element.
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Methane has a heat of fusion of 0.84 kJ/mol and a heat of vaporization of 9.2 kJ/mol. Estimate the value for the heat of sublimation.
9.00 kJ/mol
11.0 kJ/mol
8.00 kJ/mol
10.0 kJ/mol
12.0 kJ/mol
J BIJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ
2 HCl (g)
H2 (8)
Cl2 (8)
Is the model a correct representation of a chemical reaction taking place?
No, a chemical reaction always has more products than reactants.
Yes, the model shows atoms rearranging to produce a new compound.
No, a chemical reaction always produces more complex compounds.
Yes, the model shows atoms changing states of matter to form a product.
Yes. The model represents atoms rearranging to produce a new compound.
What chemical reactions?They are reactions involving the breakage of bonds and rearrangement of atoms in reactants to form products.
In the model, the bonds between hydrogen and chlorine were broken. Thereafter, each hydrogen and chlorine molecule linked up to form hydrogen chloride.
Thus, the model shows atoms rearranging to produce a new compound.
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A chemical reaction can be reversed if?
Question 18 options:
The energy of the products is less than the activation energy threshold.
The energy of the products exceeds the activation energy threshold.
The energy of the reactants exceeds the activation energy threshold.
The energy of the reactants is less than the activation energy threshold.
A chemical reaction can be reversed if the energy of the products exceeds the activation energy threshold.
What are reversible reactions?Reversible reactions are reactions which can proceed in two directions.
In reversible reactions, reactants can form products and products can also break down to form reactants.
For a chemical reaction to be reversed, the original reaction conditions leading to formation of products are reversed.
Therefore, a chemical reaction can be reversed if the energy of the products exceeds the activation energy threshold.
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The diameter of a hydrogen atom is 106 pm. Find the length in kilometers of a row of 4.34 x 1023 hydrogen atoms?
The length in kilometers of a row of 4.34 x 1023 hydrogen atoms is 4.34 x 10¹⁴ km.
Length of the entire hydrogen atoms
The length of the entire hydrogen atom is calculated as follows;
Length of the row = number x diameter of one
Length of the row = 4.34 x 10²³ x 10⁶ x 10⁻¹²
Length of the row = 4.34 x 10¹⁷ m
Length of the row = 4.34 x 10¹⁴ km
Thus, the length in kilometers of a row of 4.34 x 1023 hydrogen atoms is 4.34 x 10¹⁴ km.
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what are ways in controlling soil applicable in your community
Answer:
Some methods of controlling soil erosion.
1) Planting Vegetation. This method involves planting crops with deep roots that can hold the soil in place. ...
2)Contour Farming. ...
3)Applying Mulches. ...
4)Avoiding Overgrazing. ...
5)Reforestation. ...
6)Use Plastic Sheeting. ...
7)Applying Terraseeding Method
A scientist stores a very large number of particles in a container. In order to determine the number of particles, the scientist measures the temperature, pressure, and volume of the container and calculates the moles using the ideal gas law. In order for the calculated value to have the greatest accuracy, the scientist should make sure that (select all the apply)
A the temperature is high
B the volume is high
C the pressure is high
D the ideal gas law is always accurate, the conditions will not matter
When the temperature and the volume of the gas stored in the container are high then the number of the moles will be measured accurately. Thus, options A and B are correct.
What is the ideal gas law?The ideal gas law is the establishment of the relation between the elements like the moles, pressure, temperature, and the volume of the gas containing the particle.
The ideal gas states:
PV = nRT
With an increase in the temperature, the number of particles that collides increases as the kinetic energy increases. The particle of the container is more when the volume of the gas is more.
Therefore, in options A and B high temperature and volume increase the accuracy.
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ASAP PLS 100 POINTS Which statement best describes the role of oxygen in cellular respiration?
A. Oxygen molecules are a waste product of electron flow.
OB. Oxygen molecules form as ATP molecules are made.
OC. Oxygen molecules form as sugar molecules are broken down.
OD. Oxygen molecules are used to make water molecules.
Answer:
Option C
Explanation:
Oxygen molecules form as sugar molecules are broken down.
Sugar or carbohydrates are known as glucose or sucrose and malltose i.e C6H12O6 etc.
So they are broken down by cellular respiration and forms Oxygen for cells
URGENT!!! Based on the following reaction, how much water is produced when oxygen react with 1 mole of C₂H8?
C₂H8 (g) + 40₂ (g) →2CO2 (g) + 4H₂O(g)
Answer:
4 moles
Explanation:
For every mole of deuteriomethane consumed, 4 moles of water are produced.
So, the answer is 4 moles
For an atom electrons, how many energy sublevels are present in the principal energy level n = 4?
There are 4 energy sublevels are present in the principal energy level n = 4.
What is sublevels?Sub-level is a type of level that is lower than another level or it is a part or component of a big level. S, p, d and f are the four energy levels in which electrons are present.
So we can conclude that 4 energy sublevels are present in the principal energy level n = 4.
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The parent element 42 19 K decays by beta decay. Which daughter element will
form?
O A. Ca
OB. 1 Ar
O C. C
OD. K
Answer: A
Explanation:
This means that the atomic number decreases by 1 but the mass remains constant, meaning the atomic number of the new element is 20. This corresponds to calcium.
You have now identified whether crabs are able to see plankton they eat near the ocean floor. Based on your answer, explain how this information can be used to help the Australian Institute of Marine Biology further to understand the environment of the ocean floor (what other organisms live at the bottom? How are these able to see their food/ attract food to survive?
They are able to find out more organisms which are present at the bottom of the sea due to their accomplishment.
How this information can be used to help to understand the environment of the ocean floor?This information can be used to help the Australian Institute of Marine Biology further to understand the environment of the ocean floor because they are able to see the seas floor and can find out other creatures as well.
So we can conclude that they are able to find out more organisms which are present at the bottom of the sea due to their accomplishment.
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Which of the following stores chemical energy?
A. the bonds of a molecule
B. the nucleus of an atom
C. the density of a substance
D. the temperature of a substance
Answer:
A: The bonds of a Molecule
Explanation:
The reaction of a quantity of sulfur trioxide with water gives an acid with a volume of 2 l, containing 1.8 mol of the dissolved oxide.
a)Calculate the mass of ammonium sulfate that would be obtained by reacting with ammonia acid.
b)Calculate the CM of the solution with a volume of 100 ml of ammonia (aq) to be added for complete neutralization of the acid solution.
Answer :]
A.)Calculate the mass of ammonium sulfate that would be obtained by reacting with ammonia acid.
Correct me if i'm wrong :]
True or False?
The same carbon atoms are used repeatedly on Earth.
Answer:
True
Explanation:
had the same question
ICI(g) + Cl₂(g) → ICl3(s). The AG(f) of ICI(g) is -5.5 kJ/mol and the
AG(f)° of ICl3(s) is -22.59 kJ/mol
What is the AG of the reaction, in kJ/mol?
Answer:
KJ8RT898TGHO7-6734354546746R476
Explanation:
2C4H10+1302 -> 8CO2 + 10H₂O
If 2.46 g of H₂O are produced by a reaction, how many moles of H₂O are produced?
Answer:
.137 moles
Explanation:
need to know the molar mass of water which is 18.01528 g/mol
2.46 g of H₂O divided 18.01528 g/mol molar mass H₂O = moles of H₂O
2.46 divided by 18.01528 =
.137 moles
C4H10 is butane
butane is commonly used in cigarette lighters
2C4H10+1302 -> 8CO2 + 10H₂O is the burning of butane
burning butane with oxygen makes carbon dioxide and water
vsumhcwagovau
Question 17 of 30
For a reaction, AH = -286 kJ. When is the reaction spontaneous?
A. When TAS> 0
B. When TA S= -286 kJ
C. When TAS<-286 kJ
D. When TAS = 2(-286 kJ)
The reaction is spontaneous when TΔS is greater than zero (TΔS>0).
Spontaneous reactionA spontaneous reaction is determined by applying Gib's free energy formula as follows;
ΔG = ΔH - TΔS
A reaction is spontaneous when Gib's free energy is negative.
For the given example, the change in enthalpy is negative (-286 kJ), to obtain a negative Gib's free energy, the entropy must be positive.
Thus, the reaction is spontaneous when TΔS is greater than zero (TΔS>0).
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i) Explain why chlorine(1) oxide has a low melting point.
Answer:
Being a covalent compound, the intermolecular forces between the Cl2O molecules are weak and easily overcome. Therefore little heat energy, in terms of low boiling point is involved.
Potassium fluoride has a solubility of 92 g of KF in 100. g of H₂0 at 18 °C. Determine if
each of the following mixtures forms an unsaturated or saturated solution at 18 C:
a. adding 24 g of KF to 25 g of H₂O
b. adding 47 g of KF to 50. g of H₂O
c. adding 127 g of KF to 150. g of H₂O
a) In 25 grams of water, the solubility is 92/4 = 23 grams, so adding 24 grams will produce a supersaturated solution.
b) In 50 grams of water, the solubility is 92/2 = 46 grams, so adding 47 grams will produce a supersaturated solution.
c) In 150 grams of water, the solubility is 92(1.5) = 138 grams, so adding 127 grams will produce an unsaturated solution.
Write the ion symbol for an atom with the given number of protons and electrons.
55 protons and 54 electrons
The element is identified with the number of protons, and the element with 55 protons is Cs.
Since there are 54 electrons, the overall charge is +1, so the answer is [tex]\boxed{\text{Cs}^{+}}[/tex]
The ion symbol for an atom with 55 protons and 54 electrons is [tex]Cs^+[/tex]. In chemistry, a "ion" is a term used to describe an electrically charged particle.
An electrically charged particle is referred to as a "ion" in chemistry. It can be negatively charged (referred to as an anion) or positively charged (referred to as a cation). Ions are created when there is an imbalance between the number of protons and electrons in an atom, which happens when atoms gain or lose electrons. Ions are essential in many chemical processes and are in charge of an electrolytic solution's conductivity. Electric current can flow because in solution, ions are free to travel and carry electrical charges. Ions play an important role in cellular communication and the transport of chemicals through cell membranes in biological systems.
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Does a displacement reaction take place in 'magnesium + lead nitrate'? and if so why?
Answer:
Maybe or maybe not (not sure)
Explanation:
A displacement reaction is a type of reaction where one element is displaced by another from a compound.
In the case of magnesium and lead nitrate, magnesium is more reactive than lead. Therefore, it will displace lead from lead nitrate to form magnesium nitrate and lead.
The reaction can be represented as:
Mg(s) + Pb(NO3)2(aq) → Mg(NO3)2(aq) + Pb(s)
Another answer could be;
A displacement reaction does not take place in 'magnesium + lead nitrate' because magnesium is more reactive than lead.
Calculate the number of moles of hydrogen chloride produced from 10 moles
of hydrogen.
H₂(g) + Cl₂(g) → 2HCl(g)?
Answer:
20 moles HCl
Explanation:
To find the final answer, you need to use the mole-to-mole ratio (from the equation) to convert from moles H₂ to moles HCl. Make sure to arrange the ratios in a way that allows for the units of H₂ to cancel out.
1 H₂ (g) + Cl₂ (g) --> 2 HCl (g)
10 moles H₂ 2 moles HCl
------------------- x --------------------- = 20 moles HCl
1 mole H₂
What bonds break in the combustion of butane?
The specific heat of aluminum is approximately
0.90 J/g °C. How much heat energy would be
required to raise the temperature of a 50 g
sample of aluminum from 20 °C to 100 °C?
Answer:
3600J
Explanation:
Q = mc∆T
= 50 x 0.9 x (100 - 20)
= 3600J
What is known about a reaction with a positive enthalpy?
A. Heat is given off as a product of the reaction.
B. The reaction has a large activation energy.
OC. Heat is required to make the reaction occur.
OD. The reaction will never be spontaneous.
Answer: C
Explanation:
In endothermic reactions, enthalpy is positive, and in exothermic reactions, enthalpy is negative, So, if enthalpy is positive, then it is an endothermic reaction, and hence is required for the reaction to occur.
The element __ is the most similar to oxygen in chemical and physical properties.
Answer:
the element air is the most similar to oxygen in chemical. and physical properties
Which law states that at constant temperature the pressure of a given amount of gas is inversely proportional to the volume of the gas?
A.
Combined gas law
B.
Gay-Lussac’s law
C.
Charles’s law
D.
Boyle’s law
E.
Ideal gas law
Boyle’s law states that at constant temperature the pressure of a given amount of gas is inversely proportional to the volume of the gas. Hence, option D is correct.
What is Boyle’s law?The volume of a gas at a constant temperature varies inversely with the pressure exerted on it.
Boyle's law states " The pressure of a gas is inversely proportional to the volume occupied by the gas when the temperature(in kelvins) is held constant ".
[tex]P[/tex] ∝ [tex]\frac{1}{V}[/tex]
[tex]PV =CONSTANT[/tex]
This means that with an increase in the volume of gas the pressure exerted by the gas decreases or vice versa. Here variables were pressure and volume.
[tex]P[/tex] ∝ [tex]\frac{1}{V}[/tex]
Boyle’s law states that at constant temperature the pressure of a given amount of gas is inversely proportional to the volume of the gas. Hence, option D is correct.
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What types of intermolecular forces are important in controlling bio-molecular structure of proteins?
- H-bonding
- Van der Waals
- Dipole Dipole
- All of the above
- None of the above
Answer:
What types of intermolecular forces are important in controlling bio-molecular structure of proteins?
hydrogen bond
option a H - bondinghope it's helpful thanks