Answer: I don't know how to add a picture, so I might not explain this well.
Explanation: You put Na in the first box. Then you put F in the center of the second box because it gained one electron from Na. Then in the third box you put Na [+] because it lost one electron so it's now an cation(has a positive charge) because it lost a valence electron. In the last box you would put F [-] because it gained one electron so it's now an anion( has a negative charge) because it gained a valence electron. F now has 8 valence electrons and Na has 8 as well therefore they're both balanced.
The final method of sodium fluoride is NaF. An ionic compound is formed with the aid of the complete transfer of electrons from a steel to a nonmetal and the ensuing ions have achieved an octet.
what is the ionic compound for sodium fluoride?The chemical formula of sodium fluoride is NaF and its molar mass is 41.99 g/mol. it's miles an easy ionic compound, made from the sodium (Na+) cation and fluoride (F-) anion. The strong salt exists as cubic crystals just like the crystal structure of sodium chloride (NaCl).
what is sodium fluoride?Sodium fluoride is synthetic via the response of hydrofluoric acid with sodium carbonate or sodium hydroxide with the formula NaF. The most inexpensive chemical to be had for fluoridation is sodium fluorosilicate, formerly referred to as sodium silicofluoride.
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The radioactive isotope used for carbon dating is
1. Carbon 12
2. Carbon 13
3. Carbon 15
4. Carbon 14
Carbon 14 would be your answer, however if it's more than one answer it would also be Carbon 12, so yeah. Your best bet would be Carbon 14.
If a had a number that was 12.47, what would be the answer rounded to 2 sig figs?
12
Explanation:
Look at the number directly after the number you want to keep. I'm your case you want to keep the first two numbers and the number directly after is 4 so there is no need to round up. Keep your 12 without a decimal.
A tank originally had 12.0 atm, was 3.9L at 25C. If the tank is heated to 591C what is the new pressure ?
Answer:
34.79 atm.
Explanation:
The following data were obtained from the question:
Initial pressure (P1) = 12 atm
Initial temperature (T1) = 25 °C
Final temperature (T2) = 591 °C
Final pressure (P2) =...?
Note: the volume of the tank is constant.
Next, we shall convert celsius temperature to Kelvin temperature. This can be obtained as follow:
Temperature (K) = Temperature (°C) + 273
T(K) = T (°C) + 273
Initial temperature (T1) = 25 °C
Initial temperature (T1) = 25 °C + 273 = 298 K.
Final temperature (T2) = 591 °C
Final temperature (T2) = 591 °C + 273 = 864 K.
Finally, we shall determine the new pressure as follow:
Initial pressure (P1) = 12 atm
Initial temperature (T1) = 298 K.
Final temperature (T2) = 864 K.
Final pressure (P2) =...?
P1/T1 = P2/T2
12/298 = P2/864
Cross multiply
298 x P2 = 12 x 864
Divide both side by 298
P2 = (12 x 864)/298
P2 = 34.79 atm.
Therefore, the new pressure is 34.79 atm.
It's urgent! Any kind soul please help me ASAP!
Answer:
a white precipitate of barium chloride is formed as displacement reaction takes place.
Ethylene, a gas found in nature, is commonly used to ripen bananas and other fruits. Which compound is ethylene?
H2C — CH2
НО
НО
Н
Н
0
С — С
Н
Н
ОН — СЕ С — Н
Answer:
C2H4
Explanation:
cause the compound of ethylene is C2H4
Ethylene is a hydrocarbon gas with the chemical formula C₂H₄. It is a simple molecule that consists of two carbon atoms and four hydrogen atoms and is also known as ethene. The skeletal structure is CH₂=CH₂.
What is ethylene ?Ethylene is a colorless and odorless gas that is the simplest member of the olefin class of hydrocarbons, with the chemical formula C₂H₄. It is an important organic compound and is widely used in industry.
Ethylene is primarily used to produce polyethylene, which is one of the most common plastic materials in the world. It is also used as a fuel in some industrial processes, as a refrigerant, and as a precursor to other chemicals.
It is an important plant hormone and is involved in various physiological processes such as fruit ripening, senescence, and abscission. Ethylene is naturally produced by plants, but it can also be produced artificially and is commonly used in agriculture to ripen fruits and vegetables.
Thus, the ethylene compound is CH₂=CH₂.
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Choose all of the orbitals that can form a σ bond to the orbital displayed below (side-by-side, in the orientation shown).
Answer:
s orbital
Explanation:
The orbital shown is a py orbital. py orbitals overlap side by side with s orbital to form a sigma bond. Looking at the direction of the Px and py orbitals, overlap of these with a py orbital can only lead to the formation of a pi bond.
However, the s orbital being spherically symmetric overlaps with py orbital in such a manner that a sigma bond is formed. The s orbital overlaps with one of the lobes of the py orbital.
Sigma bonds are formed by end to end overlap of atomic orbitals. It is the strongest type of covalent bond.
What do we call matter made you of only one kind of atom?
And Atoms have weight and take up space
Answer:
Matter is any substance, if it is made up of only one kind of atom, then it is an element. Elements consists of atoms with the same weight and same number of protons in the nuclei.
What is the unit charge on each subatomic particles
Answer:
Protons, Electrons, Neutrons
Explanation:
Neutron: 0 or Neutral
Electron: -1 or Negative
Proton: +1 or Positive
For proton and neutron look at neutr for neutral and p for positive
Answer:
❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️
The answer is Protons, Electrons, Neutrons
There is three of them.....
Hope this will help you
❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️
Explanation:
Match each term below with its definition or description.
1 The point in a titration when the added amount of standard reagent is equal to the amount of analyte being titrated.
2 The analyte is titrated with the standard reagent and the volume of standard solution required to complete the reaction is measured.
3 A reagent that is pure and stable, which can be used directly after weighing.
4 The analyte that is being analyzed in the titration.
5 Standard reagent is added in excess to ensure complete reaction with the analyte. The excess reagent is then titrated with a second standard reagent.
6 A solution, whose concentration is known, often made from a reagent of known purity.
7 The standard reagent of known concentration that is added from a buret to the analyte solution.
8 The analyte does not react directly with the titrant so it is converted to another form which will react with the titrant.
9 The point in a titration when a change in the analyte solution is observed, indicating equivalency.
10 It is added to the analyte solution and aids in the observation of the completion of the reaction.
a) End Point
b) Indicator
c) Direct Titration
d) Back Titration
e) Indirect Titration
f) Primary Standard
g) Standard Solution
h) Titrand
i) Equivalence Point
j) Titrant
Answer:
1. Equivalence point
2. Direct titration
3. Primary standard
4. Titrand
5. Back titration
6. Standard solution
7. Titrant
8. Indirect titration
9. End point
10. Indicator
Explanation:
1. The equivalence point is the tiration point at which the quantity or moles of the added titrant is sufficient or equal to the quantity or moles of the analyte for the neutralization of the solution of the analyte.
2. Direct titration is a method of quantitatively determining the contents of a substance
3. A primary standard is an easily weigh-able representative of the mount of moles contained in a substance
4. A titrand is the substance of unknown concentration which is to be determined
5. The titration method that uses a given amount of an excess reagent to determine the concentration of an analyte is known as back titration
6. A standard solution is a solution of accurately known concentration
7. A titrant is a solution that has a known concentration and which is titrated unto another solution to determine the concentration of the second solution
8. Indirect titration is the process of performing a titration in athe reverse order
9. The end point is the point at which the indicator indicates that the equivalent quantities of the reagents required for a complete reaction has been added
10 An indicator is a compound used to visually determine the pH of a solution.
The titration has been the neutralization reaction in which the titrand and the titrant react to form the salt and the water and help in the determination of the qualitative and quantitative properties.
What is an Endpoint?In a titration reaction, the endpoint has been the point at which the equivalent amount of reagent has been completely neutralized.The Indicator has been the chemical that changes to indicate the endpoint of the reaction.Direct titration involves the reaction for the quantitative determination of the substances.The back titration can be given as the reaction in which the excess reagent is used to titrate the second standard reagent in the reaction.Indirect titration can be given as the reaction of the analyte to convert to another form and then the analysis with the titrant.The primary standard has been the known concentration of the pure and stable weighing reagent.The standard solution has been the solution of the known concentration in the reaction.Titrand has been the unknown sample that has to be analyzed.The equivalence point is the concentration point at which the quantity of titrant added to the titrand has been equal.Titrant has been the known concentration of sample that has been added to equivalent the unknown sample.Learn more about titration here:
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Suppose a 22.092 g sample of a 1:1 mixture of acetylferrocene and ferrocene was separated by column chromatography, and the recovered fractions weighed 9.017 g (acetylferrocene) and 8.075 g (ferrocene), what was the percent recovery of acetylferrocene?
Answer:
81.6%
Explanation:
mass of acetylferrocene and ferrocene mixture = 22.092 g
mass ratio acetylferrocene and ferrocene mixture = 1 : 1
The sum of the ratios = 2, therefore the mass of each compound will be half the mass of the mixture
mass of each compound in the sample mixture = 1/2 * 22.09 2= 11.046 g
mass of recovered acetylferrocene = 9.017 g
percentage recovery = mass recovered/mass in sample * 100%
percentage recovery of acetylferrocene = (9.017 g / 11.046 g) * 100%
percentage recovery of acetylferrocene = 81.6%
Which two features of Earth's crust involve tension?
O A. Convergent boundaries
B. Reverse faults
c. Divergent boundaries
O D. Normal faults
Answer:
The correct options are;
C. Divergent plate boundary
D. Normal faults
Explanation:
Tensile stress tends to pull objects part by acting axially upon the object to pull the object on a cross section perpendicular to the objects cross-section
The most common stress in convergent plate boundaries is compression stress
The most common stress in divergent plate boundaries is tensile stress
In the presence of tensile stress, normal faults results in the raising of mountains due to their enormous forces
Therefore, the features of Earth's crust involving tension are divergent plate boundary and normal faults.
Answer:c and d
Explanation:
Characteristic 1: a scar due to an injury
Characteristic 2: the shape of a person's face
Which characteristic is a trait that can be inherited? Explain your answer.
Answer:
Only characteristics that are coded for by genes can be inherited. The shape of a person's face is inherited because this characteristic is coded for by genes. Characteristics that are due to environmental factors cannot be inherited. A scar due to an injury cannot be inherited because this characteristic is a result of an environmental factor.
Explanation:
sample response
The lewis representation above depicts a reaction between hydrogen (blue) and a main-group element from group (red). in this representation, each y atom needs 1 electron(s) to complete its octet, and gains these electrons by forming 1 bond(s) with atoms of h . there are 1 unshared electron pair(s) and 1 bonding electron pair(s) in the product molecule. the bonds in the product are .
The question is incomplete, the complete question is;
The Lewis representation above depicts a reaction between hydrogen (blue) and a main-group element from group______ (red).
In this representation, each Y atom needs ______ electron(s) to complete its octet, and gains these electrons by forming______ bond(s) with atoms of H .
There are ______ unshared electron pair(s) and _______bonding electron pair(s) in the product molecule.
The bonds in the product are _________ (Ionic or Covalent)
Answer:
1) 16
2) 2 electrons
3) 2 bonds
4) 2 unshared pairs of electrons
5) 2 bonding pairs of electrons
6) The bonds in the product are covalent
Explanation:
Group sixteen elements have six electrons on their outermost shell. These include two unshared pairs of electrons and two unpaired electrons. These two unpaired electrons can now be covalently bonded to two hydrogen atoms to give H2Y. The compound H2Y has two lone pairs and two bond pairs of electrons.
H2Y can be a general formula for all hydrides of group 16. They are all very similar in structure but gradually differ in physical and chemical properties according to the graduated variation observed down the group.
The molecule has been [tex]\rm H_2Y[/tex], where the two bonds have been formed for the sharing of 2 electrons pair between the H and Y atom.
The Lewis representation above depicts a reaction between hydrogen (blue) and a main-group element from group ______ (red).
The main group element that has the ability to form [tex]\rm H_2Y[/tex] type of structure has been Group 16.
In this representation, each Y atom needs ______ electron(s) to complete its octet, and gains these electrons by forming______ bond(s) with atoms of H .The atom required 2 electrons to complete its octet, and in order to gain two electrons, the atom form 2 bonds with the H, resulting in [tex]\rm H_2Y[/tex].
There are ______ unshared electron pair(s) and _______ bonding electron pair(s) in the product molecule.The atom forms bond with the two H atoms, thus there has been the presence of two unshared electrons pair. The bonding electrons pair are also two in the molecule.
The bonds in the product are _________ (Ionic or Covalent)The bond has been formed with the sharing of the electron pair. Thus it has been a covalent bond.
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May I know how to balance this
Answer:
C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O
Explanation:
Let's start by counting how many molecules we have on each side.
Reactants
C - 5
H - 12
O - 2
Products
C - 1
O - 3
H - 2
We have to balance both sides. Since we have 5 carbon atoms on the reactants side and 1 carbon atom on the products side, we'll start with that. Write 5 as the coefficient for CO₂ to balance the carbons.
C₅H₁₂ + O₂ → 5CO₂ + H₂O
Now that the carbons are balanced, let's look at the hydrogens. There's 12 on the reactants side and 2 on the products side. To balance the hydrogens, we have to write 6 as the coefficient for H₂O.
C₅H₁₂ + O₂ → 5CO₂ + 6H₂O
Now the hydrogens are balanced. All that's left to do is balance the oxygens. Let's start by counting how many atoms we have on each side.
Reactants
C - 5
H - 12
O - 2
Products
C - 5
H - 12
O - 16
So, to balance the number of atoms on both sides, write 8 as the coefficient for O₂.
C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O
Lastly, let's check to make sure everything is balanced.
Reactants
C - 5
H - 12
O - 16
Products
C - 5
O - 16
H - 12
Both sides are balanced. Therefore, the balanced chemical equation is: C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O.
Hope that helps.
Answer:
[tex]\boxed{C_{5}H_{12} + 8O_{2} -->5CO_{2} + 6H_{2}O}[/tex]
Explanation:
Part 1: Count the number of atoms on each side per element
To start, count the number of atoms per element on both sides of the equation.
Left Side
C - 5 atoms
H - 12 atoms
O - 2 atoms
Right Side
C - 1 atom
H - 2 atoms
O - 3 atoms
Part 2: Balance carbon atoms
Now, with this information, you can begin finding out how to properly balance both sides of the equation.
You need 5 carbon atoms on the left, so place a coefficient of 5 in front of the [tex]CO_{2}[/tex] product. This will balance the carbons. Do not place a coefficient in front of the [tex]C_{5}H_{12}[/tex] reactant - none are necessary!
Then, you can update your counts for your atoms.
Left Side
C - 5 atoms
H - 12 atoms
O - 2 atoms
Right Side
C - 5 atoms
H - 2 atoms
O - 11 atoms
The updated equation will look like this:
[tex]\boxed{C_{5}H_{12}+O_{2} --> 5CO_{2} + H_{2}O}[/tex]
Part 3: Balance hydrogen atoms
Now, balance the hydrogen atoms. Place a coefficient of 6 in front of the [tex]H_{2}O[/tex] product. This will balance the hydrogen atoms.
Once again, update the atom counts:
Left Side
C - 5 atoms
H - 12 atoms
O - 2 atoms
Right Side
C - 5 atoms
H - 12 atoms
O - 16 atoms
The updated equation will look like this:
[tex]\boxed{C_{5}H_{12} +O_{2}--> 5CO_{2} +6H_{2}O}[/tex]
Part 4: Balance oxygen atoms
To fully balance the equation, place a coefficient of 8 in front of the [tex]O_{2}[/tex] reactant. This will equalize the amount of oxygen atoms on both sides of the equation.
The updated equation will look like this:
[tex]\boxed{C_{5}H_{12} + 8O_{2} --> 5CO_{2} + 6H_{2}O}[/tex]
Part 5: Check the equation and atom counts
Now, update the atom counts one last time to make sure they are equal.
Left Side
C - 5 atoms
H - 12 atoms
O - 16 atoms
Right Side
C - 5 atoms
H - 12 atoms
O - 6 atoms
They are equal, so you may proceed.
Part 6: Check if reductions are necessary
If the equations coefficients can all be divided by a common divisor (i.e., 3), follow up with that step. However, any equation that has a reactant or product without a coefficient, skip this step entirely.
This equation falls into that category, so you may proceed past it.
Your final equation will look like this: [tex]\boxed{C_{5}H_{12} + 8O_{2} -->5CO_{2} + 6H_{2}O}[/tex]
During which two minute time period is the temperature of the water changing fastest? Select one: a. 0-2 minutes b. 2-4 minutes c. 4-6 minutes d. 6-8 minutes Clear my choice
Answer:
b. 2-4
Explanation:
Look at the slope of the line, between 0-2 and 4-6 the slope is only 10, but between 2-4 the slope is 20, so that's when the temperature is changing the fastest. In the same time it took for the water to increase by 20 degrees between 0-2 and 4-6, the temperature of the water increased by 40 degrees between 2-4 so that's when the change is the fastest.
How many valence electrons do the alkaline earth metals have?
O A. 6
O B. 2
O C. 4
O D. 8
Answer:
[tex]\boxed{2}[/tex]
Explanation:
Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.
2 valence electrons do the alkaline earth metals have. Therefore, option B is correct.
Alkaline earth metals are the elements in Group 2 of the periodic table, which includes beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
In general, elements in Group 2 have two valence electrons. Valence electrons are the electrons located in the outermost energy level (or shell) of an atom. For the alkaline earth metals, the outermost energy level is the second energy level, which can hold up to 8 electrons.
Only the two electrons in the s sublevel of the second energy level are considered valence electrons. These two valence electrons are involved in chemical reactions and bonding.
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Plz solve mcqs#04 with full detailed.note
Answer:
The correct option is;
(B) 1 s², 2s², 2p⁶, 3s², 3p³
Explanation:
The electron configuration is the outline of the electron arrangement about a nucleus
In the systemic pattern of electron arrangement within an atom, there are, s, p, d, f orbitals
The maximum number of electrons in an s, p and d orbital = 2, 6, and 10 respectively
Based on Aufbau's principle the electrons are arranged based on the order of their energy level
The charge is presented by the number of electrons in the outermost shell, an element able to form an ion of charge of -3 will gain 3 electrons to complete its outermost shell
Among the options given, option B is the only option that has the capacity to take the electrons to complete the number of electrons in the p orbital outermost shell to 6 from 3, that is 3p³ + 3e⁻→ 3p⁶.
Why are the oxidation and reduction half-reactions separated in an
electrochemical cell?
Answer:
Electrochemical cells typically consist of two half-cells. The half-cells separate the oxidation half-reaction from the reduction half-reaction and make it possible for current to flow through an external wire.
Explanation:
A molecule of chlorine has atoms of the same element, and a molecule of carbon dioxide has different kinds of atoms. Based on this information, chlorine is and carbon dioxide is .
Answer:
chlorine is element and carbon dioxide is compound
Answer:
The correct answer would be that Chlorine is an Element and Dioxide is an Compound.
Which of these is an example of something a civil engineer would deal with?
A. The rebuilding and redesign of the dam in Louisiana after
Hurricane Katrina
B. A gauge that reads the strength of an earthquake
C. The new hybrid cars that are more environmentally friendly and
reduce oil consumption
D. The design of the Discovery space shuttle
Answer:
A
Explanation:
civil deals with desighning, construction work of natural or physical environment and a fits guess
A nursing home is installing their own bulk oxygen system due to their large volume of consumption. OSHA regulation 29 CFR 1910.104(b)(2)(iii) requires owners of bulk oxygen systems to provide noncombustible surfacing in areas where liquid oxygen might leak during operation of the system or during the filling of a storage container. If the nursing home provides an asphalt surface in areas where oxygen could potentially leak, will it be in compliance with the workplace regulation regarding oxygen? Explain your answer
Answer:
NO! It would be in violation of the workplace regulation regarding oxygen.
Explanation:
Bulk oxygen systems convey liquified oxygen which is of geat use and importance in institutions like a nuirsing home.
Liquified oxygen is gaseos oxygen that has been condensed under high presures into liquid form. It is transported via a complex system of vaporizers, storage tanks and pipes around the facility it is needed. Liquified oxygen is oxygen- rich.
Asphalt is a petroleum derivative that is often used to in coating surfaces and tarring roads.
Its primry constituent is Carbon with minor constitunets like sulphur, nirogen, oxygen. As a petrolem derivative, it is very combustible.
In the event of an oxygen leak on an asphalt surtface, oxygen acting as an oxidizing agent can combine with asphalt in the presence of air, to cause a large fire.
Hence, asphalt surfacing in areas of oxygen leaks, would not be in compliance with the workplace regulation as it has the potential of causing a fire in the nursing home.
For a system, H2(g) + I2(g) ⇌ 2 HI(g), Kc = 62.9 at 750 K. 2.80 moles of HI were placed in a 10.0-liter container, brought up to 750 K, and allowed to come to equilibrium. Which situation described below is true, at equilibrium?
a. [HI] = 2 × [H2]
b. [HI] = [H2]
c. [HI] < [H2]
d. [HI] > [H2]
e. [H2] > [I2]
Answer:
d. [HI] > [H2]
Explanation:
The explanation at equilibrium is shown below:-
Data provided [tex]H_2(g) + I(g) \rightleftharpoons 2HI_(g)[/tex]
Initial concentration - - [tex]\frac{2.80}{10}[/tex] = 0.280 M
At equilibrium x x 0.280 - 2x
[tex]K_c = \frac{(HI)^2}{(H_2)(I_2)} = 62.9[/tex]
[tex]= \frac{(0.280 - 2x)^2}{x^2} = 62.9\\\\4x^2 - 1.12x + 0.0784 = 62.9x^2[/tex]
After solve the above equation we will get
x = 0.0282 M
Therefore at equilibrium
[tex][H_2] = [I_2] = x = 0.0282M\\\\[/tex]
[tex][HI] = 0.280 - 2x = 0.2236 M[/tex]
Hence, the correct option is d.
why ammonium is not a molecular ion
Answer:
See below
Explanation:
Ammonium [tex](NH_{4}^+)[/tex] is not a molecular ion because it is just a poly-atomic ion. A molecular ion has a "negative or positive charge" as a whole but the positive charge on here is not on the whole. So, it is a poly-atomic ion and not molecular ion.
The electron configurations of two unknown elements x and y are shown. X: 1s2 2s2 2p6 Y: 1s2 2s2 2p6 3s2 3p6 Which statement is most likely correct about the two elements? A) They will react because X can give up two electrons B) They will react because X and Y can share two pairs of electrons to become stable C) They will not react because both have a complete outermost shell and are stable D) They will not react because both will give up one electron. to become stable.
Answer:
B) They will react because X and Y can share two pairs of electrons to become stable
Explanation:
The electron configurations of two elements x and y are given :
X: 1s2 2s2 2p6
Y: 1s2 2s2 2p6 3s2 3p6
The statement that is true for both the elements is that, they both will react as they both can share two pairs of electrons to become stable.
To become stable the outermost shell or p orbital should have 8 electrons, so element X can gain 2 atoms to become stable.
Element Y can also react as it can also share two atoms to fulfill its 3p orbital and will stable.
Hence, the correct option is "B".
Why do you think the landscape varies so much throughout the United States?
Answer:
hi there
you're answer would be:
The landscape varies greatly throughout the United States due to geology and weather. Things like volcanoes, the Ice Age, floods, rain, winds and drought have made an impact on the land.
hope this answer correct
A 35 gram of saturated solution is distilled out completely. If the solubility of the solute is 110, find the amount of residue solute snd distilled water
Answer:
3850g
Explanation:
Solubility is the amount of solute dissolved in a solvent.
Solubility is mass of solute÷mass of solvent
The solvent is 35grams
Solute?
Solubility of solute is 110
110=x/35
= 110 × 35
The amount of residue solute is 3850g
g When a 2.75g sample of liquid octane (C8H18) is burned in a bomb calorimeter, the temperature of the calorimeter rises from 22.0 °C to 41.5 °C. The heat capacity of the calorimeter, measured in a separate experiment, is 6.18 kJ/°C. Determine the ΔE for octane combustion in units of kJ/mol octane.
Answer:
The correct answer is 5021.25 kJ/mol octane
Explanation:
The heat absorbed by the calorimeter is given by:
heat absorbed = Ccal x ΔT
Given:
Ccal = 6.18 kJ/ºC (heat capacity of calorimeter)
ΔT= Final temperature - initial temperature = 41.5ºC-22.0ºC = 19.5ºC
We first calculate the heat absorbed:
heat absorbed = 6.18 kJ/ºC x 19.5ºC = 120.51 kJ
The change in internal energy (ΔE) is equal to the heat absorbed by the calorimeter. In order to determine ΔE in kJ/mol we have to divide the heat into the number of moles of octane (C₈H₁₈) burned in the calorimeter.
Molecular weight (C₈H₁₈) = (12 g/mol x 8) + (1 g/mol x 18) = 114 g/mol
Moles of C₈H₁₈= mass/molecular weight= (2.75 g)/(114 g/mol)= 0.024 moles
Finally, we calculate ΔE:
ΔE = heat absorbed/moles of octane = (120.51 kJ)/(0.024 mol octane) = 5021.25 kJ/mol octane
Question 18 of 25
How is the atomic number related to core electrons?
O A. The atomic number is equal to the number of core electrons.
O B. The atomic number minus the period number is the number of
core electrons.
O C. The atomic number plus the group number is the number of core
electrons.
O D. The number of valence electrons plus core electrons is the atomic
number
Answer:
D
Explanation:
If the atom is neutral, the sum of the core and valence electrons is the same as the number of protons, which is the atomic number of the element. So if the sum of the core and valence electrons in a neutral atom equals 25 , that is the number of protons in the atomic nucleus, and the atomic number of the element.
The number of valence electrons plus core electrons is the atomic number.
How is the atomic number related to the variety of electrons?The variety of protons, neutrons, and electrons in an atom may be determined from a set of easy guidelines. The wide variety of protons within the nucleus of the atom is equal to the atomic quantity (Z). The quantity of electrons in an impartial atom is identical to the number of protons.
What's an atomic number associated with?The variety of protons in a nucleus is called the atomic variety and usually equals the number of electrons in orbit approximately that nucleus (in a nonionized atom). For this reason, all atoms which have an equally wide variety of protons and the atomic range are atoms of the equal element.
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Answer:
In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.
i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.
This type of reaction is called neutralization.
ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.
So, the color change of the mixture at the end point is from pink to colorless.
iii) same explanation from question i,
HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
iv) no. of moles = volume (in dm3) x concentration
hence,
no. of moles of NaOH used = 25/1000 x 0.1
= 0.0025 mol
From the equation in (iii), since the mole ratio of HCl : NaOH = 1:1, meaning 1 mole of HCl reacts completely with 1 mole of NaOH.
This also means that the no. of moles of NaOH reacted equals to the no. of moles of HCl needed to react with it, which is 0.0025 mol.
Given the concentration of HCl in solution P is 0.1 mol /dm3. (pls correct me if I misunderstood your comment),
if v is the volume of HCl needed,
0.0025 = 0.1 v
v = 0.025 dm3
also = 25 cm3
Answer:
In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.
i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.
This type of reaction is called neutralization.
ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.
So, the color change of the mixture at the end point is from pink to colorless.
Explanation:
A number should be rounded up if
it is the first digit
b. the number after it is between 0 and 4
the number after it is between 5 and 9
d. it is the last digit
Please select the best answer from the choices prou
Answer:
C.) The number after it is between 5 and 9
Explanation:
If the digit to the right is less than five, you must leave the digit you want to round to as it is.
But, if the digit to the right is greater than or equal to five, you must increase the value of the digit you're rounding to by one. And any remaining digits before the decimal point become zeros, and any that are after the decimal point are dropped.
Hope this helps you out! : )