Answer:
1.-213(kcal/mol)*5mol=1065kcal
2.100/213 mol
a. The energy released from 5.0 mol of methane is -1065 kcal/mol.
b. The number of moles of methane needed to give 100. kcal heat is 0.4694 moles.
What is combustion?Combustion is a chemical process in which the element reacts with oxygen to produce heat and light. Burning of wood.
The equation of combustion of methane:
CH₄ (g) + 2O₂(g) ------> CO₂ (g) + 2H₂O (l)
a) Enthalpy of the reaction is H = -213 Kcal/mol
This means 213 Kcal heat is released in the burning of one mole of CH4
H reaction = [ H products ] - [ H reactants ]
Hr = [ H(CO₂)g + 2H(H₂O)l ] - [ H(CH₄)g ] = -213 kcal/mol
For 5 moles of methane:
5CH₄(g) + 10O₂(g) -----> 5CO₂(g) + 10H₂O(l)
therefore, new Hr = 5 x -213 = -1065 kcal/mol
H reaction = -1065 kcal/mol
b) 213 kcal is released per mole of Methane
then, to release 100 kcal we need, 100 / (213) = 0.4694 moles
Thus, the energy released is -1065 kcal/mol, and the number of moles is 0.4694 moles.
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Which of the following contribute(s) to most of the mass of an atom?
Question 6 options:
A)
Neutrons only
B)
Protons and neutrons
C)
Protons and electrons
D)
Protons only
Question 7 (5 points)
In a certain chemical reaction, the bonds of the products contain more energy than the bonds of the reactants. For the reaction to occur, which of the following best describes what occurred?
Question 7 options:
A)
Energy was released, so the reaction is endothermic.
B)
Energy was released, so the reaction is exothermic.
C)
Energy was added, so the reaction is endothermic.
D)
Energy was added, so the reaction is exothermic
Question 8 (5 points)
A solution
Question 8 options:
A)
is a single-phase homogeneous mixture.
B)
must contain water.
C)
is always a liquid.
D)
can contain more than two phases.
Question 9 (5 points)
Which of the following is true of alloys?
Question 9 options:
A)
They can only be composed of metals.
B)
They must be held together by chemical bonds.
C)
They're liquid solutions.
D)
They must contain a metal.
Question 10 (5 points)
Which of the following best describes an atomic number? An element's identity is defined by its atomic number; this means it represents the number of
Question 10 options:
A)
electrons in the element.
B)
neutrons in its nucleus.
C)
protons plus neutrons in its nucleus.
D)
protons in its nucleus.
Answer:
1.
B) protons and newtrons
2.
D)
3.
C)
4.
A)
What does the presence of a polar covalent bond show about the electronegativity of its two atoms
Answer:
The electronegative of two atoms are not equal.
Explanation:
A field produced by a magnetic object that exerts a force on other magnetic materials or moving electrical charges is called alan a Magnetic field b Electric field Electrostatic field d All of the above
Answer: magnetic field
A field produced by a magnetic object that exerts a force on other magnetic materials or moving electrical charges is called a Magnetic field.
What is a magnetic field?The magnetic subject is the region around a magnet in which the effect of magnetism is felt. We use the magnetic area as a device to describe how the magnetic force is shipped inside the area around and inside something magnetic in nature.
Why magnetic area is important?The magnetic area is extremely critical to maintaining lifestyles in the world. without it, we'd be exposed to excessive amounts of radiation from the solar, and our environment would be unfastened to leak into space.
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Which element is a gas?
A.Br
B.C
C.B
D.Be
Answer:
A.Br
Explanation:
Bromine is the only gas from the choices provided. It belongs to the group of halogens, group 7.
It has atomic number of 35 and it belongs to the p-block on the periodic table.
C is carbon and carbon is a solid matter B is boron and boron is a metalloid Be is beryllium and silvery white metalOnly Bromine is the gas from the given choices. It is fuming liquid and when exposed, it becomes gaseous.
what is the name of CH3CH2CH2C(O)CH2CH3
Answer:
1-methoxypropane
Explanation:
What are the four main types of tissues in the human body?
epithelial
dermal
vascular
connective
muscle
nervous
Answer:
epithelium, muscle, connective tissue and nervous tissue.
Explanation:
Explanation:
Epithelial
Connective
Muscle
Nervous
How many total atoms are in 0.550 g of P2O5?
Answer:
Total atoms in 0.550g of =1.631x1022
Explanation:
answer is above
Your advisor has given you a tube of GMP that has been sitting in the freezer for many years and wants to know the concentration. There is one problem: the spectrophotometer in the lab has been 'optimized' for use with proteins and only measures at 280 nm. You decide to give it a try. After getting and absorbance reading of 0.2, what is the concentration of GMP in the tube (assuming a 1 cm path length).
Answer:
2.22 × 10^-5M
Explanation:
From Beer-Lambert's law;
A=εcl
Where A = absorbance of GMP= 0.2
ε= molar extinction coefficient of GMP = 9000 M-1cm-1
c= concentration of GMP= the unknown
l= path length = 1 cm
c= A/εl = 0.2/ 9000 M-1cm-1 × 1 cm
c= 2.22 × 10^-5M
Is it true or false that the Temperature is a direct measurement of the energy stored in a substance?
What would happen if I throw nail polish remover into the fireplace
Answer:
Your house could catch fire because while Nail Polish Remover itself isn't particularly flammable, the vapors it gives off are. Because of this, sparks could occur if nail polish is used near open flame or was tossed in, and then the sparks could catch onto something else and grow. I would not recommend trying this.
Explanation:
20 POINTS A group of students is conducting a density experiment with two blocks. Block 1 has more mass and less volume than Block 2. Based on this information, the student can correctly conclude that *
both blocks have densities less than water's density
both blocks have densities greater than water's density
Block 1 has a higher density than Block 2
Block 1 has a lower density than Block 2
Answer:
Block 1 has a higher density then block 2
Explanation:
Answer:
Yep, the correct answer is C. Block 1 has a higher density than block 2.
Explanation:
Chemical equation to show cdso4 dissolves in water
no se bb si quieres salimos tu sabes
Which element has an outer(ending) electron configuration of s2p4?
The question is in complete, the complete question is:
Which element has an outer electron configuration of s 2 p4 ?
(A) Ca (B) Cr (C) Ge (D) Se
Answer:
(D) Se
Explanation:
The outer electronic configuration of an atom reflects the group to which it belongs in the periodic table. Each group has its unique outermost electron configuration and number of electrons found in the outermost shell of the atoms of elements in the group.
s 2 p4 is the unique outermost electron configuration of group 16 elements. Group 16 elements have six electrons in their outermost shell. If we consider the options, only Se is a member of group 16. Hence it is only Se that has the outermost electron configuration s 2 p4 .
An element which has an outer (ending) electron configuration of [tex]s^2p^4[/tex] is: Oxygen.
Electron configuration can be defined as a formula that is used to denote the distribution of the atoms of a chemical element in an atomic orbital.
Basically, electron configuration uses four (4) main letters to illustrate the distribution of atoms in an atomic orbital:
spdfThe electron configuration of [tex]s^2p^4[/tex] indicates that the chemical element is in Group 6 and has six (6) electrons in its outermost shell.
Hence, a chemical element such as Oxygen (O) or Selenium (Sn) in Group 6 of the periodic table would have an electron configuration of [tex]s^2p^4[/tex].
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in addition to Earthquake, hurricane, which of the following could be categorized as a "disaster" risk?
Answer:
I think its a World War.
Explanation:
This is just what my sister told me, since the cost for the war could make a country poor and the damage it could cause could lead a country to disaster.
i think d answer is tsunami
what is the hybridization of NO2
Answer: Explanation:
If we apply the hybridization rule then it states that if the sum of the number of sigma bonds, lone pair of electrons and odd electrons is equal to three then the hybridization is sp2.
how many orbitals are in 6s sublevel
The azimuthal quantum number and magnetic quantum number corresponds to the s orbital is zero. Hence, there is only one m value and thus contains one orbital only.
What are quantum numbers ?The quantum numbers are numbers used to describe the position of an electron within an orbital. The principal quantum number n indicates the main energy level. The azimuthal quantum number l indicates the shape and type of orbital which have values from 0 to n-1.
The magnetic quantum number m indicates the number of orbitals for a sublevel. m can have values from + l to -l. The fourth quantum number s is called spin quantum number. For an electron the spin quantum number can be +1/2 or -1/2.
The n value for the 6s sublevel is 6. The azimuthal quantum number , l for an s orbital is zero. So its m quantum number has only one value that is zero. Hence, there is only one orbital in 6s sublevel.
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Which of the following situations best describes an ionic bond?
Two atoms each give up an electron, and an electrostatic force attracts them.
One atom gains an electron while the other atom loses an electron, and an
electrostatic force attracts them.
One atom gains an electron while the other atom loses an electron, and an
electrostatic force repels them.
Two atoms gain electrons and an electrostatic force attracts them.
The situation which best describes the ionic bond is “ One atom gains an electron while the other atom loses an electron, and an electrostatic force attracts them”.
What is an ionic bond?
An ionic bond is formed between two atoms by donating an electron from the electropositive atom and withdrawal of that electron by the second atom which is electronegative and thereby attaining stability by making their valency completed.
The electron loss-gain interaction make an electrostatic force of attraction between them, where the electrons from the electropositive atom is attracted towards the electronegative atom.
Thus the two atoms are bound together by the electrostatic force of attraction created by the electron donation. Hence, option b is correct.
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If 2.1 mL of 70.0% alcohol is added to 6.7 mL of water, what is the percent alcohol (%v/v) in the new mixture?
Answer:
Since we are adding more water to an alcohol solution,
the volume of alcohol in the alcohol will be the same but the volume percent of alcohol will decrease
Initial Volume of Alcohol in the solution:
We are given that 70% of the 2.1 mL solution is alcohol
So, Finding 70% of 2.1
70/100 * 2.1 = 1.470 mL alcohol
Volume of Water in the Solution:
In our initial solution, we have (2.1 - 1.47) mL water
and we add an additional 6.7 mL water in the solution
Hence,
the total amount of water in the solution = (2.1- 1.47) + 6.7
Total amount of water in the solution = 0.63 + 6.7
Total amount of water in the solution = 7.33 mL
Volume of the final solution = 8.8mL
Percent Alcohol in the new mixture:
Now that we know the volume of alcohol and the volume of water in our mixture, we can now find the percent composition of alcohol
Percent of alcohol (%v/v) = Amount of alcohol / 100mL of solution
Percent of alcohol = (1.47 / 8.8) * 100
Percent of alcohol = 0.167 * 100
Percent of alcohol = 16.7
Therefore, in a 100mL solution, we will have 16.7 mL alcohol
sharpining a pencil leaves behind pencil shavings. Is sharpining a pencil a physical change a physical or chemical? Explain
Answer:
A physical change
Explanation:
Cause when sharpening a pencil the led stays as led and only changes the height of it not the composition of it
How is the term stable used in the text?
Answer:
When something is stable, it's fixed and steady. If you needed advice, you'd probably go to your most stable friend, the one least likely to act crazy or be easily upset.
Explanation:
Whether you're talking about an object or a person, the adjective stable implies reliability and strength. You can describe a government as stable, or a relationship, or a desk. A completely different meaning of stable is the noun "building used for housing horses or other animals." Both senses of the word come from the Latin stabilis, "firm or steadfast."
What’s it called when a sound wave is slowed down by a new medium?
Answer:
Refraction of waves involves a change in the direction of waves as they pass from one medium to another. ... Sound waves travel slower in cooler air than they do in warmer air.
Explanation:
if two successive terms of the fibonacci sequence are both odd, is the next term is even or odd? why?
Answer:
Even because you always add the previous two terms in the sequence. Since they are both odd, the next term will be even. (odd+odd = even)
Explanation:
Question 1 of 10 What is molarity a measurement of? O A. The volume of liquid containing a dissolved substance B. The grams of a substance dissolved in a liquid O c. The concentration of a substance dissolved in a liquid O D. The number of moles of a dissolved substance
To do this measure called molarity is commonly used. Molarity (M) is defined as the number of moles of solute (n) divided by the volume (V) of the solution in liters. It is important to note that the molarity is defined as moles of solute per liter of solution, not moles of solute per liter of solvent.
so the answer is D.
hope this helps have a great day....!
According to the concept of molar concentration, molarity is defined as the number of moles of a dissolved substance.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.
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Which is the electron configuration for boron?
A.1s22s3
B.1s22s23s
C.1s'2s²2p?
D.1s22s²2p?
Answer:
electron configuration for boron is 1s22s22p1
hope this helps :)
Explanation:
Liquid hexane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 17. g of hexane is mixed with 101. g of oxygen. Calculate the maximum mass of carbon dioxide that could be produced by the chemical reaction. Be sure your answer has the correct number of significant digits.
Answer:
52g of carbon dioxide
Explanation:
Liquid hexane + gaseous oxygen --> Carbon dioxide + gaseous water
The balance chemical equation is given as;
C6H12 + 9O2 --> 6CO2 + 6H2O
From the stochiometry of the reaction;
1 mol of hexane (86g) would consume 9 mol of oxygen (144g) to form 4 mol of carbon dioxide (264g)
The limiting reactant in this equation is hexane as it would run out before oxygen. This means hexane determines how much of the carbon dioxide is formed.
86g of hexane = 264g of crbon dioxide
17g of hexane = xg of carbon dioxide
x = 17 * 264 / 86 = 52g of carbon dioxide
9) Which must be a mixture of substances?
A) solid
B) liquid
C) gas
D) solution
Answer:
D
Explanation:
Please answer 3 and 2
Answer:
3 is c but im unable to see the 2nd questions picture
Explanation:
18. Which two particle diagrams each represent a sample of one substance? Key O = atom of oxygen = atom of hydrogen 0 = atom of chlorine 8 OO 1 நம் மும் 20 2000 (1) I and III (3) II and IV (2) II and III (4) I and II
Answer:
1 and 11
Explanation:
Answer:1 and 11
Explanation:
If two atoms are the same element, which statement can never be true?
1: they can have different number of protons.
2:they can have different number of electrons.
3:they can have different number of neutrons
Answer:
The answer is number 3: They can have different number of neutrons
Explanation:
What formations are created by sand deposition by waves?
Cirques
Dunes
Horns
Spits
Answer:
Spits
Explanation:
Deposit by waves include beaches. They may shift along the shoreline due to longshore drift. Other wave deposits are spits, sandbars and barrier islands
Answer: D
Explanation: