Calculate the standard enthalpy change associated with this reaction at 25 °C using the
following enthalpies of formation:
CH4 ∆Hf = -62.7 kJ·mol–1, CO2 ∆Hf = -393.5 kJ·mol–1, H2O ∆Hf = -285.8 kJ·mol–1.
The standard enthalpy change associated with the given reaction at 25 °C using the following enthalpies of formation will be − 902.4 kJ
What is Standard Enhalpy change ?The standard enthalpy change of formation of a compound is the enthalpy change which occurs when one mole of the compound is formed from its elements under standard conditions, and with everything in its standard state.
According to the balanced chemical equation ;
CH₄(g) + 2O₂(g) ⟶ CO₂(g) + 2H₂O(l)
Now,
ΔH⁰ = ΔH⁰f(products) − ΔH⁰f(reactants)
= [ΔH⁰(CO₂) +ΔH⁰(H₂O)] − [ΔH⁰(CH₄) + 2ΔH⁰(O₂)]
= [−393.5 + 2 x (−285.8)] − [−62.7 + 2 x 0]
= − 902.4 kJ
Hence, The standard enthalpy change associated with the given reaction at 25 °C using the following enthalpies of formation will be − 902.4 kJ
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nts
S + 6 HNO3 → H₂SO4 + 6 NO₂ + 2 H₂O
In the above equation, how many grams of water can be made when 19.7 moles of HNO3 are
consumed?
Round your answer to the nearest tenth. If you answer is a whole number like 4, report
the answer as 4.0
Use the following molar masses. If you do not use these masses, the computer will mark
your answer incorrect.:
Molar
Mass
Element
Hydrogen 1
Nitrogen 14
Sulfur 32
Oxygen 16
Answer:
118.2 g H₂O
Explanation:
To find the mass of water, you need to (1) convert moles HNO₃ to moles H₂O (via mole-to-mole ratio from reaction coefficients) and then (2) convert moles H₂O to grams H₂O (via molar mass).
The molar mass of water can be found by combining the element's molar masses times their quantities. The ratios/conversions should be arranged in a way that allows for the cancellation of units (desired unit should be in the numerator).
Molar Mass (H₂O): 2(1 g/mol) + 16 g/mol
Molar Mass (H₂O): 18 g/mol
S + 6 HNO₃ ---> H₂SO₄ + 6 NO₂ + 2 H₂O
^ ^
19.7 moles HNO₃ 2 moles H₂O 18 g
-------------------------- x ----------------------- x --------------------- = 118.2 g H₂O
6 moles HNO₃ 1 mole H₂O
Help please! Thank you!
Answer:
KCl
Explanation:
Ionic compounds are formed between atoms with very different electronegativity (EN) values. The elements with the highest EN values are on the top-right of the periodic table.
Ionic compounds are also generally between a metal and nonmetal. Nonmetals are located in the p-block (the right) of the periodic table and metals are pretty much everywhere else.
That being said, water (H₂O), CO, and CO₂ contain elements that have too similar of EN values to ionically bond.
However, the elements in KCl have different enough EN values to undergo ionic bonding by donating/receiving electrons from each other.
a prescriber has ordered childrens motrin 400 mg po q6h for a child who weighs 60 kg. how many mg/kg is the child receiving
Answer:
6.67 mg/kg per dose ( 26.67 mg/kg per day)
Explanation:
400 mg / 60 kg = 6 2/3 mg/kg per dose
per DAY is four times this number
number 3 pls and thank u
The statement which is not true is as follows:
The repulsive force between electrons on different atoms does not matter at all.Thus, the correct option is C.
What is Equilibrium?An equilibrium may be defined as the condition in which both the reactants and products are present in concentrations that have no additional propensity to alter with time so that there is no noticeable transformation in the possessions of the system.
The causation of repulsive force was thought to be made by the overlap of atomic orbitals and in between the electrons of diverse atoms, it matters a lot.
The equilibrium distance between nuclei of two covalently bonded atoms is called the bond length of that atom. It is the atomic separation at equilibrium.
Equilibrium occurs when the attractive and repulsive forces neglected the effect of each other in a specific state.
Therefore, it is well described above.
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TUTOR Determining Molecular Weight
What is the molecular weight of Cr3(ASO4)2? amu
The molecular weight of Cr3(AsO4)2 is 433.827.
Is molecular weight the same As molar mass?Furthermore, the primary distinction between each is that molar mass gives the mass of a mole of a selected substance. While molecular weight is the mass of a molecule of a particular substance. At an equal time as the definition and devices are splendid for molar mass and molecular weight, the value is the same.
The sum of the atomic hundreds of all atoms in a molecule is based totally on a scale wherein the atomic loads of hydrogen, carbon, nitrogen, and oxygen are 1, 12, 14, and 16, respectively.
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Calculate the number of Pt atoms in the cube and find the radius in picometers of a Pt atom. Be sure your answer has the correct number of significant digits. Full questions are in pictures...Thank you!
V cube = 2.2³ = 10.648 cm³
V Pt atoms = 0.75(75%) x 10.648 = 7.986 cm³
Part 1
mass of a single Pt atom = 3.24 x 10⁻²² g
mass Pt atoms = ρ x V = 21.45 g/cm³ x 7.986 cm³ = 171.3 g
the number of Pt atoms = 171.3 : 3.24 x 10⁻²² = 5.287 x 10²³
Part 2
4/3πr³=7.986 cm³
r = 1.24 cm = 1.24 x 10¹⁰ pm
just need help with one question pls
Answer:
A large absorption at 2950 cm⁻¹ indicates that there is likely an sp³C-H functional group somewhere in the molecule. The "sp³" designation means that this is a single bond because these atoms have 4 orbitals available (s + p + p + p) for hybridizing, meaning only single bonds are possible.
Calculate the moles for C. and D. in the attached picture:
The moles of nitrogen (iv) oxide produced in C and D are 0.284 moles and 68.32 moles respectively.
What is the mole ratio of the reaction?The mole ratio of the given reaction shows that 2 moles of dinitrogen (v) oxide produces 4 moles of nitrogen (iv) oxide when it decomposes.
B of dinitrogen (v) oxide in 15.4 g is calculated below:
Molar mass of dinitrogen (v) oxide = 108 g/mol
Moles of dinitrogen (v) oxide = 15.4/108 = 0.14 moles
Moles of nitrogen (iv) oxide produced = 0.142 * 2 = 0.284 moles
Moles of dinitrogen (v) oxide in 3.69 kg is calculated below:
Molar mass of dinitrogen (v) oxide = 108 g/mol
Mass = 3.69 kg = 3690 g
Moles of dinitrogen (v) oxide = 3690/108 = 34.16 moles
Moles of nitrogen (iv) oxide produced = 34.16 * 2 = 68.32 moles
Therefore, the moles of nitrogen (iv) oxide produced in C and D are 0.284 moles and 68.32 moles respectively.
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What does Gay Lussacs law state and explain
Answer:
'Gay-Lussac's law is a gas law that states the pressure of a gas varies directly with temperature when mass and volume are kept constant. As the temperature increases, the pressure will also increase.'
Answer:
Gay Lussac’s law says that the pressure created by a gas is proportional to the temperature of the gas when the mass is constant or the same
so, when pressure increases so does the temperature and when pressure decreases so does the temperature
What is the ph of a peach with a [ –oh] = 3.2 × 10 –11 m?
The properties of an element depend on the electron structure within its atoms. The electrons are arranged in different
orbitals, at different energy levels and sublevels. Match each sublevel to the maximum number of electrons it can
accommodate?
S=2, p=6, d=10, and f=14 the maximum number of electrons it can
accommodate.
What are orbitals?The probability of finding an electron around the nucleus.
The principal number (n), is the number of the shell, it goes from 1 to 7 and is represented by the letter K, L, M, N, O, P, Q. The maximum number of electrons in the shells are, K = 2, L = 8, M = 18, N = 32, O = 32, P = 18, Q =8.
The secondary number (l) is the subshells, and it goes from 0 to 4 and is represented, in order, for the letter, s, p, d, f. The maximum number of electrons permitted in each subshell is s = 2, p = 6, d = 10, f = 14.
The magnetic number (ml), is represented by orbitals, and it goes from -l to +l, passing by 0. The maximum number of electrons is 2 for each one.
The spin number (ms) refers to the rotation of the electron, and it can be +1/2 or -1/2.
Hence, S=2, p=6, d=10, and f=14 the maximum number of electrons it can
accommodate.
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i hope someone can help me here please don't answer nonsense!
Answer:
4560 torr
Explanation:
PV = K
4 x 1.5 = k
k = 6
V = k / p
V = 6 / 1
V = 6
atm to torr = 1 to 760
760 x 6 = 4560
What is the best definition of the enthalpy of vaporization, ^ Hvap?
A. The change in the disorder of a system when a liquid changes to a
gas
B. The change in the disorder of a system when a molecule forms
from its atoms
C. The energy needed to raise the temperature of a liquid to the
boiling point
D. The energy needed to change a liquid into a gas
Answer: D. The energy needed to change a liquid into a gas
How many moles of N are in
0.227g N₂0?
Answer:
0.217 ×2. =9.86×10moles
44
Air pressure is measured in pascals. For a professional American football game, the ball should be inflated to about 90,000 pascals. Scientists studied the effects of air temperature on the pressure inside American footballs by taking these steps:
1. Prepare 100 footballs.
2. Measure each football's air pressure.
3. Divide footballs into 10 groups.
4. Place the groups in different lockers cooled to different air temperatures.
5. After 12 hours, remove the footballs from lockers.
6. Measure each football’s pressure again.
7. Compare the new pressures to the starting pressures.
What two terms best describe the variable "air pressure inside the football" in this experiment?
independent, qualitative
independent, quantitative
dependent, qualitative
dependent, quantitative
The variable "air pressure inside the football" in this experiment is quantitative and dependent variable. Hence, option D is correct.
What is the dependent variable?The dependent variable is the variable that is being measured or tested in an experiment.
In the experiment, the scientist filled the footballs with fix quantity of pressure which was then kept for 12 hours. After 12 hours the pressure inside the footballs was again measured. Pressure here is a quantitative variable.
Since the air temperature is an independent variable. The pressure being the dependent variable depends upon the temperature of the air.
Independent variable; The variable which does not depends upon any other variable.
Dependent variable; The variable which depends upon the independent variable or varies with the change independent variable.
Qualitative variables are variables which cannot be expressed in form of numbers. They generally convey the characteristic, category, quality or type.
Whereas Quantitative variables are the variables which can be expressed in the form of numbers. These are the variables which exist along the continuous sequence.
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A group of students is comparing the graphs of strong acid-strong base and weak acid-strong base titration curves, where the base is the titrant. Which statement inaccurately describes a difference between the two curves?
A. The initial pH for the weak acid-strong base curve is higher than the initial pH for the strong acid-strong base curve.
B. At the equivalence points, the pH of the weak acid-strong base is greater than the pH of the strong acid-strong base.
C. At the half-equivalence points, the pH of the weak acid-strong base is greater than the pH of the strong acid- strong base.
D. The steep-rise interval in the weak acid-strong base curve is more pronounced than in the strong acid-strong base curve.
The initial pH for the weak acid-strong base curve is higher than the initial pH for the strong acid-strong base curve. Hence, option A is correct.
What is a weak acid?Weak acids are acids that don't completely dissociate in solution.
A weak acid is an acetic acid. It has a of 1.8⋅[tex]10^{-5}[/tex]. Calculate how much it will dissociate in water. Since acetic acid is a weak acid so large part will not dissociate completely.
[tex]k_a=\frac{[CH_3COO^-]H^+]}{[CH_3COOH]}[/tex]
B is not true, it shows the titration curve for weak/strong acid titrated with a strong base. When choosing an indicator for colourimetric titration select one so that the pH jump at the equivalence point contains the interval p±1. Phenolphthalein has a p≈9, so to decide if it is a suitable indicator check if the pH jumps from 8 to 10 at the equivalence point.
C is not true either because of the very slow reaction.
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A student combined equal amounts of two solutions. One solution had a pH of 2 and the other had a pH of 12. Which would
most likely be the resulting pH?
1
3
6
11
Answer:
the answer is 6. 2 goes into 12 6 times resulting in the answer 6
Hazmat Poison gas is in what class?
HAZMAT Class 6 Toxic and infectious substances.
Answer:
CLASS 2 Gases
Explanation:
Hope this helps
The average atomic mass of carbon is 12.01 amu. Based on the atomic
masses of the two isotopes of carbon, how do the relative abundances of the
isotopes compare?
Isotope
Atomic mass (amu)
C-12
12.000
C-13
13.003
OA. There is a slightly larger percentage of C-12 than C-13.
OB. There is a very large percentage of C-12.
OC. There is a very small percentage of C-12.
OD. They are about the same.
Answer: There is a very large percentage of C-12.
Explanation:
The atomic mass is must closer to that of C-12 than of C-13, meaning that there is a much larger percentage of C-12.
The table shows the total number of electrons in Atom A and Atom B.
Atom Number of Electrons
10
B
12
Which statement is correct? (5 points)
O A will give up two electrons to form bonds.
• B will give up two electrons to form bonds.
• Both A and B will be chemically unreactive.
• Both A and A B will gain electrons to become stable.
Answer:
The answer is "B will give up two electrons to form bonds".
Explanation:
To first solve this multiple choice question, we need to identify the Atoms, A and B.
We can do this by looking at their amount of electrons.
For instance,
A = Neon = 10 Electrons
B = Magnesium = 12 Electrons
With this information we can then look at both elements charges to see what they need to form a bond.
In this case Neon doesn't want to form a bond, since they're in a complete octet, however Magnesium does not have a complete octet. So, it wants to give up two electrons to form a bond (2+ charge shows us that).
This then shows us that Option 2, "B will give up two electrons to form bonds" is correct.
Answer:
B will give up two electrons to form bonds
Explanation:
For each substance that can move across the dialysis membrane, determine whether it will move into the blood, out of the blood,
or in both directions,
Moves into the blood
Moves out of the blood
Moves in both directions
water
Ducose
urea
Na, K, and Ca ions
The movements of the substance across the dialysis membrane are as following: water: Moves in both directions.
Glucose: Moves into the blood.
Urea: Moves out of the blood.
Na, K, and Ca ions: Moves in both directions.
What is dialysis?Dialysis is a process of filtration and purification of blood by a machine. This machine helped those people whose kidney stop working and doesn't purify the blood.
Thus, the correct options are: water: Moves in both directions.
Glucose: Moves into the blood.
Urea: Moves out of the blood.
Na, K, and Ca ions: Moves in both directions.
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Predict the shape of the molecule.
Number of electron pairs = \frac{1}{2}[V+N-C+A]
2
1
[V+N−C+A]
V = number of valence electrons present in central atom
N = number of monovalent atoms bonded to central atom
C = charge of cation
A = charge of anion
SbCl_5SbCl
5
:
In the given molecule, antimony is the central atom and there are five chlorine as monovalent atoms.
The number of electron pairs are 5 that means the hybridization will be sp^3dsp
3
B and geometry of the molecule will be trigonal bipyramidal.
pls this this solutions
How many taste buds are present on the tongue? Name them.
there are five Taste bud present tongue they are -
SWEET SALT SOUR BITTER UMAMI ______________________out of the four type of papillie present on tongue the fungiform circumvallate and folite papillie contain numerous small taste but few such type of Taste but also occur in the mucous membranes of soft palate tonsils and epiglottis all of these days but received taste is normally
each Taste bud is an oval structures formed due to modification of epithelial cells which are situated erect and vertically on the surface long sensory cells and supporting cells are found in this bird is sensory cell is spindle shaped in which a sensory here is found at its free in the century fibre of the facial and vagus cranial nerves are wrapped around the basal and of the gustatory cells each test but open on the epithelial surface through minute taste pore
____________________Choose the correct option.
1. A chain of small chemical units combined to form a large single unit is called ______
a) Polymer
b) Poly
c) Polythene
d) None of the above
2. Polythene and PVC are examples of
a) Bio degradable substance
b) Thermosetting plastics
c) Thermoplastics
d) Rayon
3. Plastics which when moulded once, cannot be softened by heating. Such plastics are called __ a) Polythene
b) Thermoplastics
c) Polyster
d) Thermosetting plastics
4. Polycot is made by mixing two types of fibres namely
a) Silk + Cotton
b) Polythene + cotton
c) Silk + Polyester
d) Polyester + Cotton
5. The 4 R Principle is
a) Reduce, Reuse, Recycle, Recover
b) Remember, reduce, Recycle, Rejoice
c) Repeat, Rejoice, recycle, reduce
d) None of the above
6. _____________ is an example of natural polymer
a) Rayon
b) Cellulose
c) Nylon
d) All of the above
7. Which of the following is Non-biodegradable ?
a) Woolen clothes
b) Plastic bag,
c) Cotton cloth
d) Wood
8. Bakelite and Melamine are examples of
a) Thermosetting plastics
b) Silk
c) Nylon
d) Rayon
9. Fire proof plastic uniform worn by fire fighters has a coating of _____ to make it fire resistant. a) Nylon
b) Rayon
c) Melamine plastic
d) silk
The coating on modern non- stick cookware and electric iron is of
a) Terrycot
b) Rayon
c) Polyester
d) Teflon
What best describes the reason why neap tides occur?
A. Neap tides occur in the fall and winter months when the Sun and Moon align obliquely to each other.
B. Neap tides occur when the angle between the Earth and Sun is 90° offsetting the attraction of the Moon.
C. Neap tides occur during the change of tide when there is no movement of water.
D. When the Sun and Moon are at right angles, the combined gravity is weaker producing modest tides.
Answer:
Explanation:
A
Question 21
A sample of rainwater has a pH of 3.5. What ion is sure to be present in relatively
large concentration in this rain sample?
H3O+
SO4²-
OH
HSO4
A sample of rainwater with a pH of 3.5 is sure to contain a large concentration of [tex]H_3O^+[/tex]
pH scaleA pH value of 7 downward is said to be acidic. Upward of 7 is said to be basic. A pH of 7 on the dot is said to be neutral.
An acid is defined as a substance that produces [tex]H_3O^+[/tex] as its only positively charged ion in solution.
Thus, rainwater with a pH of 3.5 is acidic and will contain a high concentration of [tex]H_3O^+[/tex].
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Guillaume Amontons first took a stab at measuring absolute zero in 1702. What would be the most reasonable way it would have been done then
The most reasonable way to measure absolute zero would have been to extrapolate the ideal gas law.
What is Absolute zero?This is referred to the temperature at which a thermodynamic system has the lowest form of energy.
Guillaume Amontons used gas equation to prove that absence of heat was theoretically possible which would have involved only extrapolating the ideal gas law.
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A. What is the theoretical yield in grams for this reaction under the given conditions?
B. What is the percent yield for this reaction under the given conditions?
The theoretical yield of NH3 is 10.03 g while the percentage yield of NH3 is 22%.
What is the theoretical yield?The theoretical yield is defined as the yield of the product as obtained from the stoichiometry of the reaction.
Given that the reaction equation is; N2 + 3H2 ------> 2NH3
Number of moles of N2 = 9.80 g/28 g/mol = 0.35 moles
Number of moles of H2 = 1.77 g/ 2 g/mol = 0.885 moles
If 1 mole of N2 reacts with 3 moles of H2
0.35 moles reacts with 0.35 moles * 3 moles / 1 mole
= 1.75 moles
Hydrogen is the limiting reactant
Thus;
3 moles of H2 yields 2 moles of NH3
0.885 moles yields 0.885 moles * 2 moles/3 moles
= 0.59 moles
Theoretical yield of NH3 = 0.59 moles * 17 g/mol = 10.03 g
Percent yield = 2.21/10.03 * 100/1
= 22%
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