Answer:
(d) Why is the fuel cell in Question (c) described as an alkaline fuel cell? (e) Another type of fuel cell uses methanol instead of hydrogen.
Explanation:
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- Electrons always fill orbitals in the same order. Each s orbital holds 2 electrons, each set of p orbitals holds 6 electrons, each set of d orbitals holds 10 electrons, and each set of f orbitals holds 14 electrons. The order in which orbitals are filled, from first to last, is:
1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p
Beryllium has 4 electrons. What is the electron configuration of beryllium?
A.
2s^22p^2
B.
1s^22s^2
C.
2s^4
D.
4p^1
Answer:
[tex]1s^2\, 2s^2[/tex].
Explanation:
Electron orbitals in an atom (e.g., [tex]1s[/tex]) are denoted with:
A number, denoting the shell (principal energy level) of this orbital, andA letter, denoting the shape of this orbital ([tex]s[/tex], [tex]p[/tex], [tex]d[/tex], etc.)
There are two aspects to consider when finding the electron configuration of an atom:
The number of electrons that each type of orbitals could hold, andThe order in which the orbitals are filled.The [tex]s[/tex] orbital in each shell could hold up to [tex]2 \times 1 = 2[/tex] electrons (one [tex]s\![/tex] orbital per shell, with up to two electrons.)
The [tex]p[/tex] orbitals in each shell could hold up to [tex]2 \times 3 = 6[/tex] electrons (three [tex]p\![/tex] orbitals per shell, with up to two electrons in each orbital.)
The [tex]d[/tex] orbitals in each main shell could hold up to [tex]2 \times 5 = 10[/tex] electrons (five [tex]d\![/tex] orbitals per shell, with up to two electrons in each orbital.)
Refer to the order in which the orbitals are filled (Aufbau principle.)
The first orbital to be filled would be [tex]1s[/tex] (the [tex]s[/tex] orbital of the first shell,) accommodating up to [tex]2[/tex] electrons.The second orbital to be filled would be [tex]2s[/tex] (the [tex]s[/tex] orbital of the second shell,) accommodating up to [tex]2[/tex] electrons.All four electrons of Beryllium are thus assigned to the [tex]1s[/tex] and [tex]2s[/tex] orbitals. In a ground-state Beryllium atom, orbitals [tex]2p[/tex] and beyond would contain no electrons.
Notation:
Two electrons in the [tex]1s[/tex] orbital: [tex]1s^{2}[/tex] (the superscript denotes the number of electrons in this orbital (or group of orbitals).)Two electrons in the [tex]2s[/tex] orbital: [tex]2s^2[/tex].Write the non-empty orbitals in the order by which they are filled:
[tex]1s^2\, 2s^2[/tex].
An allele is a form of a gene? true or false
Answer:
true
Explanation:
Which property increases as you move down a column in the periodic table?
A) atomic size
B) ionization energy
C) nonmetallic character
D) none of the above (all increase as you move down a column).
Answer:
A) atomic size
Explanation:
Which of the following is a conductor?
a) Glass
b) Wood
c) Gold
d) Oil
the answer is gold cause oil wood and glass are electrical insulators
cosity a letter to our mother
who is in lagos Nigeria telling
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in the school and at
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Question 6 of 10
What could make AG become negative at a given enthalpy and entropy?
A. Changing the temperature
B. Changing the concentrations
C. Changing the pressure
D. Changing the volume
SUBMIT
Answer:
A via A P E X
The entity that would make ΔG to become negative at a given enthalpy and entropy is Changing the temperature (Option A)
Gibbs free energyΔG = ΔH – TΔS
Where
ΔG is the Gibbs free energy ΔH is the enthalpy changeT is the temperature ΔS is the change in entropyNOTE
ΔG = +ve (non spontaneous)
ΔG = 0 (equilibrium)
ΔG = –ve (spontaneous)
From the Gibbs free energy equation, we can see that the entities that makes us the equation are
Enthalpy, ΔHEntropy, ΔSTemperature, TThus, we can conclude that the correct answer to the question is: changing the temperature (Option A) since the equation has nothing to do with neither concentration, pressure nor volume
Learn more about Gibbs free energy:
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What is most likely oxidation state of aluminum (AI)?
An electromagnet is the most powerful type of magnet there is. It is a magnet with a current running through it that can be turned on and off. Why might it be useful to be able to turn the electromagnet on and off?(1 point) 1
to not waste electricity
to control the strength of the magnet
to reduce wearing out of the magnet over time
to latch onto and let go of objects
What does electric current measure?(1 point) 2
how quickly electrical energy moves in a circuit
how frequently electrical energy moves in a circuit
how much electrical energy moves in a circuit
how well electrical energy moves in a circuit
How is a magnetic field produced?(1 point) 3
when an object has an electric charge
when electrons move through a circuit
when a current runs through a conductor
when an electromagnetic field interacts with a magnet
Which statement best describes how an electromagnetic motor works?(1 point) 4
Electrons are moved through a magnet, creating a circuit. That circuit interacts with a current, moving the conductor in the orientation of the field.
Electrons are moved through a circuit, creating a current. That current interacts with a magnet, moving the conductor in the orientation of the field.
Electrons are moved through a current, creating a circuit. That circuit interacts with a magnet, moving the conductor in the orientation of the field.
Electrons are moved through a magnet, creating a current. That current interacts with a circuit, moving the conductor in the orientation of the field.
Electromagnetism in Use Quick Check
5 of 5Items
Item 5
Use the image to answer the question.
A diagram shows a wire carrying a current in vertical direction. The magnetic field drawn using compass needles around the wire are concentric circles in a plane perpendicular to the direction of current.
What are the particles demonstrating in this image?
(1 point) 5
electric field
electromagnetic field
electromagnetic motor
magnetic field
Answer:
1. to latch onto and let go of eggs
2. how quickly electrical energy moves in a circuit
3. when a current runs through a conductor
4. Electrons are moved through a circuit, creating a current. That current interacts with a magnet, moving the conductor in the orientation of the field.
5. electromagnetic field
Potassium iodide, KI, is used as an expectorant. How many grams are in 0.300 mole of potassium iodide?
Answer: 49.8 g
Explanation: molar mass M(KI) = 39.1+ 126.9 = 166 g/mol
Mass m= n·M= 0.3 mol· 166 g/mol
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
How many moles of CO2 can form from 17.5 moles of octane?
Answer:
140 mol CO₂.
Explanation:
2 C₈H₁₈ + 25 O2 → 16 CO₂ + 18 H₂OIn order to convert from moles of octane (C₈H₁₈) into moles of CO₂, we can use a conversion factor with the stoichiometric coefficients of the balanced reaction:
17.5 mol C₈H₁₈ * [tex]\frac{16molCO_2}{2molC_8H_{18}}[/tex] = 140 mol CO₂140 moles of CO₂ can be produced from 17.5 moles of octane.
What is true about a car with constant velocity?
A. It has a zero acceleration
B.It has a changing direction
C.postive acceleration
D. Negative acceleration
Answer:
Explanation:
c it’s see it
A student prepared a stock solution by dissolving 20.0 g of NaOH in enough water to make 150. mL of solution. She then took 15.0 mL of the stock solution and diluted it with enough water to make 65.0 mL of a final solution. What is the concentration of NaOH for the final solution
Answer:
[tex]0.769\ \text{M}[/tex]
Explanation:
Mass of stock solution = 20 g
Molar mass of NaOH = 40 g/mol
Volume of stock solution = 0.150 mL
[tex]M_2[/tex] = Concentration of NaOH for the final solution
[tex]V_1[/tex] = Amount of stock solution taken = 15 mL
[tex]V_2[/tex] = Total volume of solution = 65 mL
Molarity is given by
[tex]M_1=\dfrac{\text{Mass}}{\text{Molar mass}\times \text{Volume}}\\\Rightarrow M_1=\dfrac{20}{40\times 0.15}\\\Rightarrow M_1=\dfrac{10}{3}[/tex]
We have the relation
[tex]M_1V_1=M_2V_2\\\Rightarrow M_2=\dfrac{M_1V_1}{V_2}\\\Rightarrow M_2=\dfrac{\dfrac{10}{3}\times 15}{65}\\\Rightarrow M_2=0.769\ \text{M}[/tex]
The concentration of NaOH for the final solution is [tex]0.769\ \text{M}[/tex].
Why do atoms connect to eachother?
Answer:
To keep from falling apart
Explanation:
.) Neon and HF have approximately the same molecular masses. a.)Explain why the boiling points of Neon and HF differ b.)Compare the change in the boiling points of Ne, Ar, Kr, and Xe with the change of the boiling points of HF, HCl, HBr, and HI, and explain the difference between the changes with the increasing atomic or molecular mass.
Answer:
See explanation
Explanation:
a) The magnitude of intermolecular forces in compounds affects the boiling points of the compound. Neon has London dispersion forces as the only intermolecular forces operating in the substance while HF has dipole dipole interaction and strong hydrogen bonds operating in the molecule hence HF exhibits a much higher boiling point than Ne though they have similar molecular masses.
b) The boiling points of the halogen halides are much higher than that of the noble gases because the halogen halides have much higher molecular masses and stronger intermolecular forces between molecules compared to the noble gases.
Also, the change in boiling point of the hydrogen halides is much more marked(decreases rapidly) due to decrease in the magnitude of hydrogen bonding from HF to HI. The boiling point of the noble gases increases rapidly down the group as the molecular mass of the gases increases.
d. If you were to open the carbonated drink bottle after shaking, what would you expect to happen and why? If you were to open the water bottle after shaking, what would you expect to happen and why?
Shaking causes small bubbles, which helps the soda's carbon dioxide escape faster. The gas will gradually escape from the liquid as bubbles once the can is opened, and the soda will become "flat." The dissolved gas takes a long time to escape if the liquid is treated gently.
A voltaic cell is assembled by using two 30-mL beakers. In one beaker, Ag metal is used as the electrode with 10 mL of 1 M AgNO3. In the other beaker, Zn metal is used as the electrode with 10 mL of 1 M ZnSO4. The beakers are connected with a salt bridge and the measured cell potential, Eocell, is 1.50 V. The Zn electrode is negative (anode). Which reaction takes place at the Zn electrode
Answer:
Reaction that takes place at the Zn electrode is oxidation:
Zn ⇄ Zn²⁺ + 2e⁻
Explanation:
This excersise explains the structure of a typical battery, that is useful to study electrochemistry.
AgNO₃ → Ag⁺ + NO₃
ZnSO₄ → Zn²⁺ + SO₄⁻²
Generally batteries contains 2 electrodes, where we have 2 conductive metallic. Batteries work to obtain electricity from a chemistry reaction which is always a redox type. One electrode releases electrons while the other catch them. Electrons travel from the anode to cathode, so in the anode, the e⁻ are released.
Reaction that takes place at the Zn electrode is oxidation:
Zn ⇄ Zn²⁺ + 2e⁻
Oxidation state is increased, electrons are free to go to cathode, where the other element decreases the oxidation state:
Ag⁺ + e⁻ ⇄ Ag
In the middle of the battery, the salt bridge (generally KCl) contributes the redox with more charges. Cl⁻ for the anode and K⁺ for the cathode.
Note that the same amount of electrons travel from anode to cathode, because in this example, Ag gained 1 mol and Zn released 2 moles.
The scheme for the battery is:
⁻ Zn(s) / Zn²⁺ (aq) // Ag⁺ (aq) / Ag (s) ⁺
1 M 1 M
Where the first place represents the anode, // represents the salt bridge and then, the cathode. Below, we write the molar concentration of each salt.
Calculate the pH of a 0.10 M NH4Cl solution.
Answer:
Answer: pH = 2.72
Explanation:
Calculate the pH of 0.010 M HNO2 solution. The K, for HNO2 is 4.6 x 104
PDF on Unit operation 1 and 2
What is the molecular geometry of COF2?
Answer:
trigonal planar
Explanation:
In the oxidation of iron; how many grams of iron (III) oxide will be produced from 6.20 mol of Fe?
4Fe(s) + 3O2(g) --> 2Fe2O3(s)
Answer:
496 g of Fe₂O₃.
Explanation:
The balanced equation for the reaction is given below:
4Fe + 3O₂ —> 2Fe₂O₃
From the balanced equation above,
4 moles of Fe reacted to produce 2 moles of Fe₂O₃.
Therefore, 6.20 moles of Fe will react to produce = (6.20 × 2)/4 = 3.1 moles of Fe₂O₃
Finally, we shall determine the mass of 3.1 moles of Fe₂O₃. This can be obtained as follow:
Mole of Fe₂O₃ = 3.1 moles
Molar mass of Fe₂O₃ = (56 × 2) + (3×16)
= 112 + 48
= 160 g/mol
Mass of Fe₂O₃ =?
Mass = mole × molar mass
Mass of Fe₂O₃ = 3.1 × 160
Mass of Fe₂O₃ = 496 g
Therefore, 496 g of Fe₂O₃ were produced from the reaction.
Someone please help me and thank you
Answer:
what grade is this?
C3H8(g) + 5O2(g) ⟶ 3CO2(g) + 4H2O(g) H = -2220 kJ If 865.9 g of H2O is produced during this combustion, how much heat is generated? Do not include the negative sign in your answer. Express the answer to the nearest whole number, or round to the nearest ones place. The molar mass of H2O is 18.02 g/mol.
Answer:
3 × 10⁴ kJ
Explanation:
Step 1: Write the balanced thermochemical equation
C₃H₈(g) + 5 O₂(g) ⟶ 3 CO₂(g) + 4 H₂O(g) ΔH = -2220 kJ
Step 2: Calculate the moles corresponding to 865.9 g of H₂O
The molar mass of H₂O is 18.02 g/mol.
865.9 g × 1 mol/18.02 g = 48.05 mol
Step 3: Calculate the heat produced when 48.05 moles of H₂O are produced
According to the thermochemical equation, 2220 kJ of heat are evolved when 4 moles of H₂O are produced.
48.05 mol × 2220 kJ/4 mol = 2.667 × 10⁴ kJ ≈ 3 × 10⁴ kJ
As mentioned, every step in the Fischer esterification mechanism is an equilibrium. As such, the reaction conditions are chosen in such a way to drive reaction to completion. a. For the reaction you have chosen, calculate the number of moles of carboxylic acid and the number of moles of alcohol given using the starting volumes given in the experiment
Answer:
Hello your question lacks some required information attached below is the missing information
answer :
number of moles
Acetic acid = 0.061199 mole
Alcohol = 0.027320 mole
Explanation:
The starting volumes : 2.5mL of either alcohol and 3.5mL of either acid
for the purpose of this solution I will take 2.5 mL of 1-butanol and 3.5 mL of acetic acid
mass of 1-Butanol = 2.5 mL * 0.81 g/mol = 2.025 g
∴ number of moles of 1-butanol = 2.025g / 74.12 g/mol = 0.027320 mole
mass of acetic acid = 3.5 mL * 1.05 g/mol = 3.675 g
∴ number of moles of Acetic acid = 3.675 g/ 60.05 g/mol = 0.061199 mole
Reaction equation
CH3-CH2-CH2-CH2-OH + CH3-COOH + H+ (cat) ↔ CH3-CH2-CH2-CH2-O-CO-CH3 + H2O
What lives in the arctic tundra biome? Choose all that apply.
Use this website to answer the question: https://thewildclassroom.com/biomes/artictundra-2/
Question 6 options:
caribou
reptiles
amphibians
lots of insects
muskox
reindeer
Answer: Animals found in the Arctic tundra include herbivorous mammals (lemmings, voles, caribou, arctic hares, and squirrels), carnivorous mammals (arctic foxes, wolves, and polar bears), fish (cod, flatfish, salmon, and trout), insects (mosquitoes, flies, moths, grasshoppers, and blackflies), and birds (ravens, snow buntings
The lives in Artic tundra biome is caribou.
What is arctic tundra biome?Artic tundra biome is the northernmost biome, which covers the land of the arctics with the ice caps.
Climate of this Artic tundra biome is almost cold means the temperature in winter season of this region is about -34 degree celsius. In this region small animals like Norway lemmings as well as large animals like caribou are present which have high amount of fat to rescue from the cold.
Hence, option (a) is correct.
To know more about Artic tundra biome, visit the below link:
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What class of chemicals is responsible for ozone depletion?
True or false solar power take power from wind and uses it to make electricity
Theses are all the points
I have left
Would you rather Go to jail for the rest of your life or go to prison for the rest of you life?
Answer:
I honestly don't know but I hope you get more points! ;D
Explanation:
g Consider a pure sample of a radioactive isotope with a mass number of (46 A). If the sample has mass of (25.0 B) micrograms and the isotope has a half-life of (4.50 C)x106 years, determine the decay rate for the sample. Give your answer in decays/second and with 3 significant figures.
This question is incomplete, the complete question is;
g Consider a pure sample of a radioactive isotope with a mass number of (46 + A). If the sample has mass of (25.0 + B) micrograms and the isotope has a half-life of (4.50 + C)x10⁶ years,
determine the decay rate for the sample. Give your answer in decays/second and with 3 significant figures.
A = 1, B = 1, C = 11.
Answer:
the decay rate for the sample is 469,625.898 decay/s
Explanation:
Given the data in the question;
[tex]T_{\frac{1}{2}[/tex] = ( 4.50 + C ) × 10⁶ years
C = 11
[tex]T_{\frac{1}{2}[/tex] = ( 4.50 + 11 ) × 10⁶ years
[tex]T_{\frac{1}{2}[/tex] = 15.50 × 10⁶ years
[tex]T_{\frac{1}{2}[/tex] = 15.50 × 10⁶ × 365 × 24 × 60 × 60
λ = 0.693 / [tex]T_{\frac{1}{2}[/tex]
so
λ = 0.693 / ( 15.50 × 10⁶ × 365 × 24 × 60 × 60 )
also
N = ( 25.0 + B )
B = 1
N = ( 25.0 + 1 )
N = 26 × 10⁻⁶
isotope with a mass number of ( 46.0 + A ) , A=1
= ( 46.0 + 1 ) = 47
N = 26 × 10⁻⁶( 1/47 )( 1 / 1.67 × 10⁻²⁷ ) = 3.31252 × 10²⁰
R = λN
so
R = (0.693 / ( 15.50 × 10⁶ × 365 × 24 × 60 × 60 )) × (3.31252 × 10²⁰)
R = 1.41773 × 10⁻¹⁵ × (3.31252 × 10²⁰)
R = 469,625.898 decay/s
Therefore, the decay rate for the sample is 469,625.898 decay/s
#7 which of the following decreases the rate of solubility of solid molecules in a solution?
Answer:
7. Option D
Explanation:
Solubility increases with the increase in temperature of the solution. It is so because the increase in temperature leads to increase in kinetic energy which then breaks the solute particles held together by intermolecular attractions.
Hence, option D is correct
what is an optical property
Answer:
The optical properties of a material define how it interacts with light. The optical properties of matter are studied in optical physics, a subfield of optics. Wiki.pedia
Explanation: