Answer:
E = 5×10⁻¹⁹ J
Explanation:
Given data:
Wavelength = 400 nm (400×10⁻⁹ m)
Energy of wave = ?
Solution:
Formula:
E = h c/λ
c = 3×10⁸ m/s
h = 6.63×10⁻³⁴ Js
Now we will put the values in formula.
E = 6.63×10⁻³⁴ Js × 3×10⁸ m/s /400×10⁻⁹ m
E = 19.89×10⁻²⁶ J.m / 400×10⁻⁹ m
E = 0.05×10⁻¹⁷ J
E = 5×10⁻¹⁹ J
Which of the compounds of H3PO4, Mg(OH)2, LiOH, and HCl, behave as acids when they are dissolved in water?A. Mg(OH)2 and LiOH.B. B H3PO4 and HC.C. Only HCl.D. Only LiOH.
Answer:
B. H3PO
Explanation:
The pH, texture, reactivity, and conductivity should be seen while determining acid or base. Among given option, H₃PO₄ is the acid when dissolved in water.
What are acid and base?Acid is a substance that has sour taste, pH lies in the range of 0-7 and give hydronium ion when dissolved in water. Acid turns blue litmus red. Whereas base has bitter, its pH is between 7-14 and it turns red litmus blue. It give hydroxide ion when dissolved in water.
Extensive properties, such as mass and volume depend on the amount of substance present and are not useful in the identification of a substance. Measuring mass and volume is not useful While determining acid or base. Out of given compounds, H₃PO₄ is the acid when dissolved in water.
Therefore, H₃PO₄ is the acid when dissolved in water.
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Why is the following electron configuration not possible?
1-9-1
Answer: because its noy
Explanation:
What is the chemical name of the compound NH4SCN?
Its called "Ammonium thiocyanate" Have a great day!! <3
Answer:
it is called Ammonium Thiocyanate or Thiourea
Explanation:
it is made made up of 2 nitrogen atoms, 4 hydrogen atoms, 1 sulfur atom and 1 carbon atom. stay safe and have a great day! TPWK
What is the mole fraction of water in a solution that contains 8.0 mol of ethanol (C2H5OH) and 1.6 mol of water?
Answer:
the mole fraction of water in a solution is 0.17
Explanation:
The computation of the mole fraction of water in a solution is shown below:
Given that
Ethanol be 8.0 mol
And, the water be 1.6 mol
Based on the above information, the mole fraction of water in a solution is
= Water ÷ (Water + ethanol)
= 1.6 mol ÷ (1.6 mol + 8.0 mol)
= 1.6 mol ÷ 9.6 mol
= 0.17
Hence, the mole fraction of water in a solution is 0.17
How many valence electrons are found in P3- ?
Answer:
5 valence elctrons
Explanation:
the outer most orbitals, 3s2 and 3p3 contains 5 electrons, thus valences electrons for P is 5
What two options are homogeneous mixture
Answer:
vinegar and soap
Explanation:
Answer:
vinegar and soap
Explanation: just took the test
What does this image represent?
Amine group
Carbonyl group
Ether group
Hydroxyl group
Answer:
ether group
Explanation: I looked it up
Using the van der Waals equation, calculate the pressure for a 1.25 mol sample of xenon contained in a volume of 1.000L at 75°C; a = 4.194 L2 atm/mol2 and b = 0.05105 L/mol for Xe. Compare these results to that predicted by the ideal gas law.
Answer:
ABC
Explanation:
hrdjyt
Calculate the pH during the titration of 20.00 mL of 0.1000 M trimethylamine, (CH3)3N(aq), with 0.2000 M HClO4(aq) after 9.48 mL of the acid have been added.
Complete Question
Calculate the pH during the titration of 20.00 mL of 0.1000 M trimethylamine, (CH3)3N(aq), with 0.2000 M HClO4(aq) after 9.48 mL of the acid have been added.Kb of trimethylamine = 6.5 x 10-5.
Answer:
The pH is [tex]pH = 9.84[/tex]
Explanation:
From the question we are told that
The volume of trimethylamine, (CH3)3N(aq) is [tex]V_{t} = 20.00mL[/tex]
The concentration of trimethylamine is [tex]C_t = 0.1000 \ M[/tex]
The volume of HClO4(aq) is [tex]V_{h} = 9.48 mL[/tex]
The concentration of HClO4(aq) is [tex]C_h = 0.200 M[/tex]
The Kb value is [tex]K_b = 6.5 * 10^{-5}[/tex]
Generally the the pOH of this reaction is mathematically represented as
[tex]pOH = pK_b + log [\frac{N_h}{N_b} ][/tex]
Here [tex]N_h[/tex] is the number of moles of acid which is evaluated as
[tex]N_h = C_h * V_h[/tex]
=> [tex]N_h = 0.200 * 9.48[/tex]
=> [tex]N_h = 1.896[/tex]
Here [tex]N_t[/tex] is the number of moles of acid which is evaluated as
[tex]N_t = C_t * V_t[/tex]
=> [tex]N_t = 0.100 * 20[/tex]
=> [tex]N_t = 2[/tex]
So
[tex]pOH = -log(K_b) + log [\frac{N_h}{N_b} ][/tex]
[tex]pOH = -log(6.5*10^{-5}) + log [\frac{1.896}{2} ][/tex]
=> [tex]pOH = 4.1639[/tex]
Generally the pH is mathematically represented as
[tex]pH = 14 - pOH[/tex]
=> [tex]pH = 14 - 4.1639[/tex]
=> [tex]pH = 9.84[/tex]
Calculate the volume in milliliters of 1.57 M potassium hydroxide that contains 10.3 g of solute.
Answer:
[tex]V = 0.117 \ L[/tex]
General Formulas and Concepts:
Chem
Reading a Periodic TableWriting compounds and polyatomic ionsMolarity = moles of solute / liters of solutionExplanation:
Step 1: Define
1.57 M KOH (potassium hydroxide)
10.3 g KOH
Step 2: Define conversions
Molar Mass of K - 39.10 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of H - 1.01 g/mol
Molar Mass of KOH - 39.10 + 16.00 + 1.01 = 56.11 g/mol
Step 3: Convert
[tex]10.3 \ g \ KOH(\frac{1 \ mol \ KOH}{56.11 \ g \ KOH} )[/tex] = 0.183568 mol KOH
Step 4: Solve for Volume
Substitute: [tex]1.57 \ M=\frac{0.183568 \ mol}{x \ L}[/tex]Move x: [tex]x1.57 \ M=0.183568 \ mol[/tex]Isolate x: [tex]x=\frac{0.183568 \ mol}{1.57 \ M}[/tex]Evaluate: [tex]x=0.116922 \ L[/tex]Step 5: Check
We are given 3 sig figs. Follow sig fig rules.
[tex]0.116922 \ L \approx 0.117 \ L[/tex]
given that the only known ionic charges of lead are pb(ii) and pb(iv), how can you explain the existence of the pb2o3 salt
Answer:
See Explanation
Explanation:
Pb2O3 is better formulated as PbO.PbO2. It is actually a mixture of the two oxides of lead, lead II oxide and lead IV oxide.
This implies that this compound Pb2O3 (sometimes called lead sesquioxide) is a mixture of the oxides of lead in its two known oxidation states +II and +IV.
Hence Pb2O3 contains PbO and PbO2 units.
In the reaction of aluminum metal and oxygen to make aluminum oxide, how many grams of oxygen gas will react with 2.2 moles aluminum metal?
Answer:
52.8 g of O2.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
4Al + 3O2 —> 2Al2O3
From the balanced equation above,
4 moles of Al reacted with 3 moles of O2 to produce 2 moles of Al2O3
Next, we shall determine the number of mole of O2 needed to react with 2.2 moles of Al. This can be obtained as follow:
From the balanced equation above,
4 moles of Al reacted with 3 moles of O2.
Therefore, 2.2 moles of Al will react with = (2.2 × 3)/4 = 1.65 moles of O2.
Thus, 1.65 moles of O2 is needed for the reaction.
Finally, we shall determine the mass of O2 needed as shown below:
Mole of O2 = 1.65 moles
Molar mass of O2 = 2 × 16= 32 g/mol
Mass of O2 =?
Mole = mass/Molar mass
1.65 = mass of O2 /32
Cross multiply
Mass of O2 = 1.65 × 32
Mass of O2 = 52.8 g
Therefore, 52.8 g of O2 is needed for the reaction.
Which numerical setup can be used to calculate the
atomic mass of the element bromine?
Answer:
From the numerical steps highlighted under explanation, the average atomic mass of bromine is 79.91 u
Explanation:
The steps to be taken will involve;
1) Find the number of isotopes of bromine.
2) Identify the atomic mass and relative abundance of each of the isotopes.
3) Multiply the atomic mass of each of the isotopes by their corresponding values relative abundance value.
4) Add the value in step 3 above to get the average atomic mass of bromine.
Now;
Bromine has 2 isotopes namely;
Isotope 1: Atomic mass = 78.92amu and a relative abundance of 50.69%.
Isotope 2: Atomic mass = 80.92amu and a relative abundance of 49.31%.
Using step 3 above, we have;
(78.92 × 50.69%)
And (80.92 × 49.31%)
Using step 4 above, we have;
(78.92 × 50.69%) + (80.92 × 49.31%) ≈ 79.91 u
The atomic mass of bromine has been calculated as 79.9062 amu.
The relative atomic mass of the element has been given as the mass of each isotope with respect to their abundance.
The atomic mass has been given as:
[tex]amu=\sum mass\;\times\;\% Abundance[/tex]
The available isotopes of Bromine have been:
Isotope 1 = 78.92 amu, and 0.5069 % abundance
Isotope 2= 80.92 amu, and 0.4931 % abundance
Submitting the values for the atomic mass unit of bromine ([tex]amu_{\text{Br}}[/tex]):
[tex]amu_{\text {Br}}= (78.92\;\times\;0.5069)\;+\;(80.92\;\times\;0.4931)\\amu_{\text{Br}}=40.0045\;+\;39.9016\\amu_{\text{Br}}=79.9062[/tex]
The atomic mass of bromine has been calculated as 79.9062 amu.
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For a particular reaction, the change in enthalpy is â9kJmole and the activation energy is 13kJmole. The enthalpy change (ÎH) and activation energy (Ea) for the catalyzed reaction could be which of the following? a. â9kJmole,5kJmole. b. â9kJmole,19kJmole.c. â14kJmole,5kJmole.d. â14kJmole,â13kJmole.
Answer:
The answer is Option a, that is "−9kJmole,5kJmole".
Explanation:
Please find the complete question in the attached file.
In the question, it uses the catalyst inside a process, which does not modify the process eigenvalues, however, it decreases the active energy with an enthalpy of -9kJmole, and also the power for activating decreases around 13 to 5 kJ mole, that's why the choice a is correct.
How is filtration done?
What is the difference between residue and filtrate?
Answer:
residue is whatever remains after something else has been removed while filtrate is the liquid or solution that has passed through a filter, and which has been separated from the filtride.
filtration id done by placing a filter paper on the beaker or container then pour the filtride then let it settle and it will pass through and you will have the fitrate and residue
Explanation:
Help ASAP
Please and thank you
Answer: C
Explanation: Everything else is true.
Identify the titration curve for a monoprotic weak acid titrated with a strong base.
Answer:
Titration is a technique to determine the concentration of an unknown solution. As illustrated in the titration setup above, a solution of known concentration (titrant) is used to determine the concentration of an unknown solution (titrand or analyte).
Typically, the titrant (the solution of known concentration) is added through a burette to a known volume of the analyte (the solution of unknown concentration) until the reaction is complete. Knowing the volume of titrant added allows us to determine the concentration of the unknown analyte. Often, an indicator is used to signal the end of the reaction, the endpoint. Titrant and analyte is a pair of acid and base. Acid-base titrations are monitored by the change of pH as titration progresses.
Let us be clear about some terminologies before we get into the discussion of titration curves.
X-rays are often used in medical settings to create images of the body's internal structures such as bones. This is made possible by the
fact that X-rays are able to pass through the body's softer tissues without being absorbed.
Radio waves are also able to pass through the body's softer tissues without being absorbed. Why are radio waves not used to generate
medical images?
OA. The electrons in most atoms are not in high enough energy states to absorb the photons of radio waves.
OB. Radio waves tend to bend too much when they encounter solid materials to be used for generating accurate images,
OC
The frequency of most radio waves is too low to allow them to pass through bones or other solid materials.
OD.
Radio waves carry so little energy that they tend to pass through most atoms without an interaction taking place.
Answer:D
Explanation:I did it on study island.
Radio waves are not used to generate medical images because as per the electromagnetic spectrum ,the radio waves carry little energy that they pass through most atoms without interaction.
What is an electromagnetic spectrum?The electromagnetic spectrum consists of radiation which consists of waves made up of electromagnetic field which are capable of propogating through space and carry the radiant electromagnetic energy.
The radiation are composed of electromagnetic waves which are synchronized oscillations of electric and magnetic fields . They are created due to change which is periodic in electric as well as magnetic fields.
In vacuum ,all the electromagnetic waves travel at the same speed that is with the speed of air.The position of an electromagnetic wave in an electromagnetic spectrum is characterized by it's frequency or wavelength.They are emitted by electrically charged particles which undergo acceleration and subsequently interact with other charged particles.
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Which statement describes how phase changes
can be diagrammed as a substance is heated?
A. The phase is on the y-axis and thels
temperature is on the x-axis.
B. The temperature is on the y-axis and the
phase is on the x-axis.
C. The time is on the y-axis and the temperature
is on the x-axis.
D. The temperature is on the y-axis and the time
is on the x-axis.
Answer: d
Explanation:
On edg
Which of the following is chemical property?
Question is in the picture help ASAP please
Answer:
C
Explanation:
Look at the picture below. Name the isotope.
Answer:
carbon-13
Explanation:
Dinitrogen tetraoxide, a colorless gas, exists in equilibrium with nitrogen dioxide, a reddish brown gas. One way to represent this equilibrium is:
The question is incomplete, the complete question is shown in the image attached
Answer:
F
T
Explanation:
From the equilibrium equation;
N2O4(g) ⇄NO2(g)
We must have to remember that;
1) At equilibrium, the concentration of the species on both sides of the reaction equation may not necessarily be the same but must be held at a constant value because the rate of forward reaction equals the rate of reverse reaction.
2) The rate of forward reaction must equal the rate of reverse reaction.
If the rate of forward reaction is k1 and the rate of reverse reaction is k2. Then it follows that at equilibrium k1 = k2.
Is iron man made or natural
Answer:
Iron is natural. Paper is man-made
Explanation:
Answer:
iron
Explanation:
If you wanted to change the polarity of hydrogen bromide (HBr) by substituting the bromine with a different atom. Which atom would increase the polarity of the molecule?
Answer:
This question is incomplete as it lacks options, the options are:
A. chlorine (CI)
B. iodine (1)
C. sulfur (S)
D. hydrogen (H)
The answer is A. Chlorine
Explanation:
Polarity of a substance in chemistry is a function of electric charges in the atoms of the molecules involved. Polarity, however, can be increased or decreased in molecules depending on the charges of the atoms that form them.
Since polarity increases when an atom in the molecule has a high ability to pull electrons toward itself i.e. electronegativity, one atom that can be substituted for Bromine in the hydrogen bromide (HBr) molecule in order to increase its polarity is CHLORINE. This is because Chlorine (Cl) is more electronegative than Bromine atom, hence, will pull more electrons from hydrogen to make the HCl molecule more polar than HBr.
To increase the polarity of HBr, the bromine atom can be replaced with a hydrogen atom.
A polar molecule is one in which a dipole moment exists. There is a positive end and a negative end in a polar molecule. Conventionally, the direction of the dipole is from the positive end of the molecule towards the negative end of the molecule.
If we want to increase the polarity of the molecule then we must substitute the bromine atom with a more electronegative atom. In this case, chlorine is the best option.
Missing parts;
If you wanted to change the polarity of hydrogen bromide (HBr) by substituting the bromine by a different atom. Which atom would increase the polarity of the molecule?
A. chlorine (CI)
B. iodine (1)
C. sulfur (S)
D. hydrogen (H)
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Assume that the top of your head has a surface area of 25 cm x 25 cm. How many newtons of force push on your head at sea level? If you estimate this area to be 100 in2, what is the force in pounds?
Answer:
(a) 6332.812 N (b) 1469.59 pounds.
Explanation:
Given that,
The surface area of the top of yu head is 25 cm x 25 cm
Area = 625 cm² = 0.0625 m²
Atmospheric pressure on it is 101325 Pa.
(a) Pressure acting on an object is given by force acting per unit area. It can be written as :
[tex]P=\dfrac{F}{A}\\\\F=PA\\\\F=101325\ Pa\times 0.0625\ m^2\\\\F=6332.812\ N[/tex]
6332.812 N of force is acting on your head at sea level.
(b) If area, A = 100 in²
We know that,
1 atm = 14.6959 pounds/in²
[tex]P=\dfrac{F}{A}\\\\F=PA\\\\F=14.6959 \ \text{Pounds}/in^2\times 100\ in^2\\\\F=1469.59\ \text{pounds}[/tex]
So, the force is 1469.59 pounds.
A. The force required to push your head at sea level is 6332.8125 N
B. The force in pound is 1469.59 lb
A. Determination of the force required at sea level.
Pressure (P) = 101325 Nm²
Area (A) = 25 cm × 25 cm = 0.25 m × 0.25 m = 0.0625 m²
Force (F) =?P = F / A
Cross multiply
F = PA
F = 101325 × 0.0625
F = 6332.8125 NTherefore, the force required to push your head at sea level is 6332.8125 N
B. Determination of the force in pounds
Area (A) = 100 in²
Pressure (P) = 14.6959 pound / in²
Force (F) =?F = PA
F = 14.6959 × 100
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An atom of an element has two electrons in the first energy level and five electrons in the second energy level. Write the electron configuration and name the element. How many unpaired electrons does an atom of this element have?
Answer:
electronic configuration: 1s^2,2s^2,2p^3
name: nitrogen
unpaired electron: 3
Explanation:
The atom with 2 electrons and 5 electrons in the first and second energy level is NITROGEN. The element has 3 unpaired electron.
The electronic configuration of the atom is 1s² 2s² 2p³Since the atom has 7 Electrons, the element which has 7 electrons is NITROGEN. The 2p orbital has 3 unpaired electrons in it's second energy level.Therefore, the 2p orbital has 3 unpaired electrons in it's outermost shell.
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How do hurricanes form? How do hurricanes form?
a Hurricanes form when winds circulate about a column of cool air.
b Hurricanes form when two warm fronts meet over the ocean
c Hurricanes form when warm air over the equator mixes with cold air from the poles
d Hurricanes form as a result of rising warm air and circulating winds
Answer:
D. Hurricanes form as a result of rising warm air and circulating winds
Explanation:
How many moles of O2 are required to react completely with 5.00 moles of C4H10?
A) 10.0
B) 20.0
C) 26.5
D) 32.5
Answer:
32.5
Explanation:
2C⁴H¹⁰ needs 13 O²
5 C⁴H¹⁰ needs (13/2 × 5) O² = 32.5 O²
The answer is D, 32.5
(I took the test)
If you start with 34.0 grams of silver (I) nitrate, how many grams of solid silver would be
produced?
Answer:
6.36 g AgCl
Hope this helps!
How does one determine a percent composition from an empirical
formula?
A. Divide the atomic mass of the element by its subscript and
multiply by 100%
O B. Divide the mass of the compound by the atomic mass of
the element and multiply by 100%
O C. Divide the subscript of the element by the mass of the
element and multiply by 100%
O D. Divide the total mass of each element by the mass of the
compound and multiply by 100%
The way one determines a percent composition from an empirical formula is to divide the total mass of each element by the mass of the compound and multiply by 100%.
What is empirical formula?Empirical formula is a notation that indicates the ratios of the various elements present in a compound, without regard to the actual numbers.
The empirical formula of a compound is the simplest ratio that can exist between the constituent elements of a compound.
However, the percent composition of a compound can be determined by dividing the total mass of each element by the mass of the compound and multiply by 100%.
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