Answer:
0.15 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities.
From the question we have
[tex]n = \frac{9.3 \times {10}^{22} }{6.02 \times {10}^{23} } \\ = 0.154485...[/tex]
We have the final answer as
0.15 molesHope this helps you
Why is K lighter than Na
Answer:
Basically, in the case of sodium and potassium the increase in shell size outweighs the pull of the core on the outer shell electron and so potassium is less dense than sodium. When we more from Na to K, effect of increase in volume is more pronounced as compared to effect of increase in atomic mass.
Circle the word that correctly completes each sentence as it relates to a battery (voltaic cell). a. The positive electrode is the (cathode anode b. The cathode / anode) is the site of the oxidation half-reaction. c. Electrons flow out of the cathode / anode) and into the (cathode 1 anode). d. The metal piece that is used for the cathode anode) is the reducing agent. g
Answer:
a) anode
b) anode
c) cathode
d) anode
HELP!!!!!!
I DON'T KNOW THE ORDER!!
Answer:
for 1 solid its freezing.
for 2 solid and liquid its melting
for 6 liquid to gas its evaporation and for 5 gas to liquid its condensation.
Explanation:
hope this helped :)
Answer:
solid->liquid= melting
liquid->solid= freezing
gas->liquid= consendation
liquid->gas= evaporation
A pure substance made of two two or more elements that are chemically combined is a(n)
Answer:
A pure substance made up of two or more elements that are chemically combined is a compound
Explanation:
How many moles of mercury are 4.000 x 1022 atoms of mercury?
Answer:
0.06642 moles of mercury
Explanation:
Step 1: Given data
Moles of mercury: 4.000 × 10²² atoms
Step 2: Calculate the number of moles of mercury that correspond to 4.000 × 10²² atoms of mercury
To convert atoms to moles, we need to consider the Avogadro's number: there are 6.022 × 10²³ atoms of mercury per mole of mercury.
4.000 × 10²² atoms × (1 mol/6.022 × 10²³ atoms) = 0.06642 mol
which of the following is an example of a decomposition reaction
Answer:
Examples of decomposition reactions include the breakdown of hydrogen peroxide to water and oxygen, and the breakdown of water to hydrogen and oxygen.
A.) What is the mass in g of 5 mols of Mg?
B.) If you are given 7.4 *10^23 atoms of Cu, how many mols of Cu do you have?
Answer:
Mass of Mg = 120 g
1.23 moles of Cu
Explanation:
A)
Given data:
Number of moles of Mg = 5 mol
Mass of Mg = ?
Solution:
Number of moles = mass/molar mass
Molar mass of magnesium is 24 g/mol.
5 mol = mass/ 24 g/mol
Mass = 5 mol × 24 g/mol
Mass = 120 g
B) Given data:
Number of atoms of Cu = 7.4 ×10²³ atom
Number of moles of Cu = ?
Solution:
Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
7.4 ×10²³ atom × 1 mol / 6.022 × 10²³ atom
1.23 moles of Cu
How much heat energy is required to melt 25.0 g of Aluminum at its melting point, 658°C? (The Hf of Al is 94.4 joules/gram)
Answer:
2360J
Explanation:
Given parameters:
Mass of aluminum = 25g
Melting point = 658°C
Latent heat of melting = 94.4j/g
Unknown:
Amount of heat require for melting = ?
Solution:
The amount of heat required for this melting will be the product of the mass of the aluminum and the latent heat of melting;
H = m L
m is the mass
L is the latent heat of melting
Insert the parameters and solve;
H = 25 x 94.4 = 2360J
It is cold and wet outside. Pam is wearing a wool hat and fur lined boots to help keep her warm. These pieces of clothing are good__.
Question 18 options:
A. conductors
B. heaters
C. insulators
D. thermometers
Answer:
c insulators
Explanation:
Answer:
C: Insulators
Explanation:
Hope This Helps :)
Which of the following statements is true about covalent bonds?
a) The shared electrons provide both atoms with an octet.
b) Sometimes electrons are gained to provide an atom with an octet.
OC) Hydrogen will share its one electron to obtain an octet
O d) The shared electrons are attracted by the nuclei of both atoms.
e) both a and d.
Answer:
the answer is D.)
Explanation:
Given the enthalpies of reaction
S(s)+O2(g)→SO2(g) ΔH = -297 kJ
2S(s)+3O2(g)→2SO3(g) ΔH=-791kJ
Calculate the enthalpy change (ΔH) for the following reaction using the data above and Hess's Law:
2SO2+O2⟶2SO3
2SO₂+O₂⇒2SO₃ ΔH=-197 kJ
Further explanationBased on the principle of Hess's Law, the change in enthalpy of a reaction will be the same even though it is through several stages or ways
Reaction
2SO₂+O₂⇒2SO₃
Given :
1. S(s)+O₂(g)→SO₂(g) ΔH = -297 kJ
Reverse
SO₂(g) ⇒S(s)+O₂(g ΔH = +297 kJ (sign change to +) x 2
2SO₂(g) ⇒2S(s)+2O₂(g ΔH = +594 kJ
2.2S(s)+3O2(g)→2SO3(g) ΔH=-791kJ
Add both reactions and remove/subtract the same compound for different sides
1. 2SO₂(g) ⇒2S(s)+2O₂(g) ΔH = +594 kJ
2.2S(s)+3O₂(g)→2SO₃(g) ΔH=-791kJ
--------------------------------------------------------+
2SO₂+O₂⇒2SO₃ ΔH=-197 kJ
To prepare 380 mL of 0.500 M NaCl (MW = 58.5 g/mol), how many grams of sodium chloride is required?
11.12 grams of sodium chloride is required to prepare 380 mL of 0.500 M NaCl (MW = 58.5 g/mol).
HOW TO CALCULATE MASS:
The mass of a substance can be calculated by multiplying the number of moles of the substance by its molar mass. However, the number of moles of sodium chloride must first be calculated by multiplying the molarity by its volume. Molarity = no. of moles ÷ volume 0.500M = n ÷ 0.380Ln = 0.5 × 0.380n = 0.19molmass of NaCl = 58.5g/mol × 0.19molMass of NaCl = 11.12gTherefore, 11.12 grams of sodium chloride is required to prepare 380 mL of 0.500 M NaCl (MW = 58.5 g/mol).Learn more about how to calculate mass at: https://brainly.com/question/14948089?referrer=searchResults
How many atoms are in 15.6 grams of silicon?
Answer:
3.34 x 1023 atoms
Explanation:
What is the molar mass of AlCl3?
A. 62.43 g/mol
B. 116.39 g/mol
C. 124.86 g/mol
D. 133.33 g/mol
E. 187.29 g/mol
Answer:
133.33 g/mol
Explanation:
Molar mass:
Molar is the sum of all the atomic masses of the atoms of the elements present in a compound.
Molar mass of AlCl₃:
Atomic mass of Al = 26.98 amu
Atomic mass of chlorine = 35.45 amu
There are 3 atoms of chlorine present.
35.45×3 = 106.35
Molar mass of AlCl₃ = 26.98 + 106.35 = 133.33 g/mol
The molar mass of AlCl₃ is 133.33 g/mol.
What is molar mass?Molar mass of many compounds can be calculated by dividing the mass of the compound by the number of moles of the compound.
Atomic mass of Al = 26.98 amu
Atomic mass of chlorine = 35.45 amu
There are 3 atoms of chlorine present.
35.45 × 3 = 106.35
Molar mass of AlCl₃ = 26.98 + 106.35 = 133.33 g/mol
Thus, the molar mass of AlCl₃ is 133.33 g/mol.
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Which of the following properties of a photon are required to calculate the energy emitted by an electron returning to its ground state?
A. wavelength
B. frequency
C. either A or B
D. both A and B
Answer:
C. either A or B
Explanation:
To calculate the energy of a photon returning to its ground state, we required either the frequency or the wavelength. Often times, not both.
The wavelength of a photon can be derived by;
E = hf
or
E = [tex]\frac{hc}{wavelength}[/tex]
h is the Planck's constant
c is the speed of light
f is the frequency
When NaCl is dissolved in water, it separates into Na+ and CI-ions, which are also dissolved in water. How would the phase of the NaCl, the Na+, and the CI-
be written in the reaction equation?
A. (g)
B. (1)
C. (aq)
D.(s)
Answer:
C aq
Explanation:
Means desolves in water
When NaCl is dissolved in water, it separates into its constituent ions Na+ and Cl- ions. The phase of the ions are written as (aq) and that of NaCl is written as (s) .
What is NaCl ?Sodium chloride is an ionic compound formed by the transfer of electrons from the metal sodium to the nonmetal chlorine. It is used as the common table salt.
Na contains one valence electron and Cl contains 7 valence electrons. Hence, Na can donate that electron to Cl to achieve octet in both. When Na loss an electron it forms Na+ and Cl gains the electron to form Cl-. These two ions are then attracts to form the NaCl.
When NaCl is dissolved in water the bond between these two ions weaken and the ions gets released into the solution. The ions in the solution is indicated with the phase aqueous (aq) and the undissolved NaCl is in solid (s) state.
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What is Scrooge’s “business” according to his interaction with the men? Why does he feel this way
Answer:
Ebenezer Scrooge's business is to take care of his own establishment and thus, refused to donate/ contribute any to the charity.
He feels this way because he thinks that it is not one's business to interfere in another's business.
Explanation:
Charles Dickens's play "A Christmas Carol," tells the story of the protagonist Ebenezer Scrooge and his 'hatred' of the Christmas festival. But it was during this time of the year that he got 'inspired' by the ghost of his late partner c um friend Marley, teaching him a life lesson that changed Scrooge for the better.
When the two gentlemen came to visit the workplace of Scrooge expecting some donation for charity, Scrooge refused to give a single penny. According to him, the suffering of the people and their need is none of his business. He exclaims "I don’t make merry myself at Christmas and I can’t afford to make idle people merry. I help to support the establishments I have mentioned—they cost enough; and those who are badly off must go there." Rather, his business is to take care of his company, which "occupies [him] constantly" and thus, it's not his business to "not to interfere with other people’s".
he felt this way because he thinks that it is "unfair" and unbecoming to get involved in someone's business.
A negative ion is known as a(n) *
ionic radius.
valence electron.
cation.
anion.
Answer:
Positively charged ions are called cations; negatively charged ions, anions
If the % acetic acid listed on a vinegar bottle is 4%, what is the implied uncertainty of the acetic acid concentration
Answer:
This question appears incomplete
Explanation:
This question appears incomplete because the data provided only makes it possible to calculate the certainty of the acetic acid content per total volume of the vinegar. Thus, the 4% means for every 100 mL of the vinegar, there is 4 mL of acetic acid present. To calculate the volume of acetic acid in any other volume of vinegar, the formula will be
volume of acetic acid = 4/100 × total volume of vinegar
The polar bear runs at a speed of 8.3 m/sec, how long will it take it to run 200
meters?
Answer:speed of 6.5 meters per second, what is the distance she covers in that time? ... backstrokes at an average speed of 8 meters per second, how long will it take ... 200m smis. 255. 7. Lauren's SUV was detected exceeding the posted speed limit ... Suppose the polar bear was running on land instead of swimming. ... V = 8.3mls.
Explanation:
[tex]\mathfrak{\huge{\pink{\underline{\underline{AnSwEr:-}}}}}[/tex]
Actually Welcome to the Concept of the Kinematics.
Since, we know that,
Time = Distance / Speed
so here, Speed = 8.3 m/s and Distance= 200m
so we get as, T = 200/8.3 => 24.09 seconds.
Hence, time taken will be => 24.09 seconds.
Which are characteristics of metals that result from their bonding? Check all that apply.
ANSWER: Conduct Electricity and Are Malleable, 2 and 4
Answer:
Conduct Electricity and Are malleable
Explanation:
Answer:
conduct electricity
are malleable
Explanation:
Metals conduct electricity because they have “free electrons.” Unlike most other forms of matter, metallic bonding is unique because the electrons are not bound to a particular atom. This allows the delocalized electrons to flow in response to a potential difference.
And since metals don't tightly hold on to electrons during metallic bonding, they are easily replaced. In metallic bonding, electrons are delocalized and move freely among nuclei. When a force is exerted n the metal, the nuclei shift, but the bonds do not break, giving metals their characteristic malleability.
Which unit is used to express a amount of thermal energy
Answer:
Joule
Explanation:
Answer:
The calorie
Explanation: as the amount of thermal energy necessary to raise the temperature of one gram
What is the wavelength, in nanometers, of light with a frequency of 1.90x10^15 Hz?
Answer:
1.58×10² nm
Explanation:
Given data:
Frequency of light = 1.90 ×10¹⁵ Hz
wavelength of light = ?
Solution:
Speed of light = wavelength × Frequency
Speed of light = 3×10⁸ m/s
3×10⁸ m/s = λ × 1.90 ×10¹⁵ Hz
Hz = s⁻¹
λ = 3×10⁸ m/s / 1.90 ×10¹⁵s⁻¹
λ = 1.58×10⁻⁷ m
meter to nm:
1.58×10⁻⁷ m ×10⁹ nm/ 1m
1.58×10² nm
Question 9 (5 points)
What is a boundary where cold air and warm air meet?
a
air pressure
b
air mass
C
front
d
precipitation
Answer:
A. air pressure,this is answer.
Assuming that seawater is an aqueous solution of NaCl, what is its molarity? The density of seawater is 1.025 g/mL at 20 ∘C, and the NaCl concentration is 3.50 mass %.
Answer:
0.6139M
Explanation:
A 3.50% by mass of NaCl means there are 3,50g of NaCl in 100g of solution. To find molarity we need to convert the mass of NaCl to moles and mass of solution to liters as follows:
Moles NaCl -molar mass: 58.44g/mol-:
3.50g NaCl * (1mol / 58.44g) = 0.05989 moles of NaCl
Liters solution:
100g solution * (1mL / 1.025g) * (1L / 1000mL) = 0.09756L of solution
Molarity -Ratio of moles and liters-:
0.05989 moles of NaCl / 0.09756L of solution =
0.6139M2 C2H2 + 5 O2
2 H2O + 4 CO2
what reaction type
Answer:
Combustion reaction
General Formulas and Concepts:
Chemistry
Synthesis Reactions: A + B → ABDecomposition Reactions: AB → A + BSingle-Replacement Reactions: A + BC → AB + CDouble-Replacement Reactions: AB + CD → AD + BCExplanation:
Step 1: Define
2C₂H₂ + 5O₂ → 2H₂O + 4CO₂
Step 2: Identify
Any organic molecule reacting with oxygen to produce water and carbon dioxide is a combustion reaction.
We also see from the RxN that is is a double replacement reaction.
Answer:
Answer: 0.4 g
Explanation:
1) Balanced chemical equation:
2) 2C2H2 + 5 O2 → 4CO2 + 2 H2O
3) mole ratios:
2 mol C2h2 : 5 mol O2
4) Convert 0.13 g C2H2 into number of moles
n = mass in grams / molar mass
molar mass C2H2 = 2 *12g/mol + 2*1 g/mol = 26 g/mol
n = 0.13 g / 26 g/mol = 0.005 mol
5) Set the proportion with the unknown
5 mol O2 x
----------------- = ---------------
2 mol C2H2 0.005 mol C2H2
x = 0.005 mol C2H2 * 5 mol O2 / 2 mol C2H2 = 0.0125 mol O2
6) Convert 0.0125 mol O2 to grams
mass = number of moles * molar mass
molar mass of O2 = 32 g/mol
mass = 0.0125 mol * 32 g/mol = 0.4 g
Answer: 0.4 g
Explanation:
HELP
1. A chemical needs 0.22 moles CaO for a chemical reaction. How many grams of CaO do they need to obtain that amount?
2. What is the mass of 0.83 moles of NaCl?
3. For an acid-base titration, 0.5 moles of H2SO4 will be needed. How many grams of H2SO4 were needed for the Laboratory Activity?
Answer:
Explanation:
1.
Given parameters:
Number of moles of CaO = 0.22moles
Unknown:
Mass of CaO = ?
Solution:
Mass, number of moles and molar mass are related using the expression below;
Mass = number of moles x molar mass
Molar mass of CaO = 40 + 16 = 56g/mol
Insert the parameters and solve;
Mass = 0.22 x 56 = 12.32g
2
Given parameters:
Number of moles of NaCl = 0.83moles
Unknown:
mass of NaCl = ?
Solution:
Also,
Mass = number of moles x molar mass
Molar mass of NaCl = 23 + 35.5 = 58.5g/mol
Now insert the parameters and solve;
mass = 0.83 x 58.5
mass = 48.6g
3.
Given parameters:
Number of moles of H₂SO₄ = 0.5moles
Unknown:
mass of H₂SO₄ = ?
Solution:
Mass = number of moles x molar mass
Molar mass of H₂SO₄ = 2(1) + 32 + 4(16) = 98g/mol
Insert the parameters and solve;
Mass = 0.5 x 98 = 49g
Calculate the standard cell potential, ∘cell, for the equation Co(s)+F2(g)⟶Co2+(aq)+2F−(aq) Use the table of standard reduction potentials. ∘cell=
Answer:
3.15 V
Explanation:
Step 1: Write the balanced cell reaction
Co(s) + F₂(g) ⟶ Co²⁺(aq) + 2 F⁻(aq)
Step 2: Identify both half-reactions:
Cathode (reduction): F₂(g) + 2 e⁻ ⟶ 2 F⁻(aq) E°red = 2.87 V
Anode (oxidation): Co(s) ⟶ Co²⁺(aq) + 2 e⁻ E°red = -0.28 V
Step 2: Calculate the standard cell potential
We will use the following expression.
E°cell = E°red,cathode - E°red,anode
E°cell = 2.87 V - (-0.28 V) = 3.15 V
Given E°cell > 0, the reaction is spontaneous.
Taking into account the definition of standard cell potential, E°cell has a value of 3.15 V.
The balanced cell reaction is:
Co(s) + F₂(g) ⟶ Co²⁺(aq) + 2 F⁻(aq)
First of all, it must be taken into account that oxidation is a reaction where an atom, ion or molecule loses electrons while reduction corresponds to the gain of electrons from an atom, ion or molecule.
Both oxidation and reduction depend on the change in the oxidation state of the atom, that is, on the difference in the charge of the atom in a reaction.
The oxidation and reduction reactions always occur simultaneously for what are generally known as oxidation-reduction reactions or redox reactions.
So, the anode corresponds to the negative electrode which normally oxidizes in the electrolytic chemical reaction while the cathode corresponds to the positive electrode which normally reduces its oxidation state when it receives electrons.
Si, in this case, the both half-reactions will be:
Cathode (reduction): F₂(g) + 2 e⁻ ⟶ 2 F⁻(aq) E°red = 2.87 V Anode (oxidation): Co(s) ⟶ Co²⁺(aq) + 2 e⁻ E°red = -0.28 V
The potential of an Ecel cell is a measure of the difference in electronic energy between the two electrodes. The electronic energy of each electrode is related to the force with which the reaction occurs at the electrode-solution interface. The unit in which it is measured is the volt.
In electrochemistry, because a cell reaction is made up of two half-cell reactions, each of which has a characteristic electrode potential, the potentials measure the driving force of the two half-reactions.
The cell potential is obtained by subtracting the potentials of both half cells as shown below:
E°cell= Ecatode - Eanode
So, in this case, the Ecell is calculated as:
E°cell = 2.87 V - (-0.28 V) = 3.15 V
In summary, E°cell has a value of 3.15 V.
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Answer:
Chemical change
Explanation:
The rusting of iron/a nail is a chemical change
Iron (Fe) and Oxygen (O) combine to create the compound Iron Oxide (Fe2O3), which is rust.
2. Click on the bucket to raise the temperature of the container to approximately 400 K (127°C). What happened to the pressure?
Answer:
Increased, 7.5-8.3
Decreases, 3.5-4.3
Gay Lussacs law
Explanation:
There are so many laws for ideal gas at constant temperature , at constant pressure, the law at constant volume is called Gay-Lussac's law. Therefore, on increasing temperature to approximately 400 K (127°C), the pressure will also increase.
What is Gay-Lussac's law?According to this law, pressure is directly proportional to temperature. This gas law is valid only to ideal gas not on the vanderwaal gas. Since it is mentioned in the question that volume is constant we can apply Gay-Lussac's law over here.
Mathematically
P₁T₂=P₂T₁
Since according to this law, pressure is directly proportional to temperature, so on increasing temperature to approximately 400 K (127°C), the pressure will also increase.
Therefore, on increasing temperature to approximately 400 K (127°C), the pressure will also increase.
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