Answer:
There are 8 valence electrons
Explanation:
An element's atomic number refers to - (TEKS 8.5A)
Answer:
An element's atomic number refers to the number of protons found in the nucleus of each atom of the element.
Answer:
ur mom
Explanation:
ur mom lol
I need help fast pls someone
Answer:
I would say A. I'm no expert, but it can't be C obviously, and I think wind would hit all of it, wearing off the top as well like the great pyramids. B would be my next choice, but A i think would be best.
Calculate the pH of a solution formed by mixing 550.0 mL of 0.30 M HClO with 275.0 mL of 0.20 M CsClO. The Ka for HClO is 2.9 × 10-8.
Answer:
pH = 7.08
Explanation:
We can solve this problem using Henderson-Hasselbach's equation:
pH = pKa + log[tex]\frac{[ClO^-]}{[HClO]}[/tex]With the given concentrations and volumes, we can calculate the new values for [ClO⁻] and [HClO] when the solutions are mixed:
Total volume = 550.0 mL + 275.0 mL = 825.0 mL[HClO] = 550 mL * 0.30 M / 825 mL = 0.20 M[ClO⁻] = 275 mL * 0.20 M / 825 mL = 0.07 MNow we calculate pKa:
pKa = -log(Ka) = 7.54Finally we calculate the pH:
pH = 7.54 + log[tex]\frac{0.07}{0.2}[/tex] = 7.08Show your reasoning in describing what would be the effect on the calculated equilibrium constant for each of the following mistakes.
1. Your buret was not rinsed with NaNCS solution before use and still contained traces of distilled water.
2. The spectrophotometer was set well-past infinite absorbance upon calibration with the sample holder empty.
Answer:
The readings of equilibrium constant is incorrect.
Explanation:
There is a mistake in the value of equilibrium constant if the burette contains traces of distilled water because the water will be present in the solution from which equilibrium constant is calculated. The spectrophotometer did not give the correct reading because its calibration is incorrect. If we want to gain correct readings from the spectrophotometer, we must have to calibrate the instrument correctly.
Incorrect value of equilibrium constant is obtained.
What is equilibrium constant?Equilibrium constant of any reaction tells about the relative ration of the concentration of products to the reactants.
Value of equilibrium constant can be calculated in the aqueous medium where concentration of water also present. If we don't rinse the burette with the reaction solution then the already present traces of water affect the concentration of water during the calculation of equilibrium constant.
As the absorbance of any solution is also directly proportional to the concentration, so if the spectrometer is not calibrated accurately then incorrect value of absorbance also affects the value of equilibrium constant.
Hence, we get incorrect value of equilibrium constant for each of the given mistakes.
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l need introduction about vitamin please
Answer:
A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C
If energy cannot be created or destroyed, what happens to the kinetic and potential energy?
Answer:
According to the law of conservation of energy, energy cannot be created or destroyed, although it can be changed from one form to another. KE + PE = constant. ... As the car coasts down the hill, it moves faster and so it's kinetic energy increases and it's potential energy decreases. hope this helps
Explanation:
Answer:
They cannot be destroyed or created however,
Explanation:
it can only be transformed or transferred from one form to another.
Select the correct term(s) to complete each sentence. a) The ____ is assigned a relative intensity of 100. base peak molecular ion peak b) The ____ is the most intense peak in the mass spectrum. molecular ion peak base peak c) The ____ represents the original molecule that has only lost an electron. molecular ion peak base peak d) ____ could be/represent a smaller, charged fragment of the original molecule. The base peak The molecular ion A radical cation e) ____ is/represents a positively charged species. The base peak The parent ion The molecular ion A radical cation
Answer:
a) Base Peak
b) Base Peak
c) Molecular Ion
d) Base Peak and Radical Cation
e) The Parent Ion, Molecular Ion, the Radical Cation and the Base Peak
Explanation:
a) The Base Peak is assigned a relative intensity of 100.
b) The Base Peak is the most intense peak in the mass spectrum.
c) The Molecular Ion Peak represents the original molecule that has only lost an electron.
d) Base Peak and Radical Cation could be/represent a smaller, charged fragment of the original molecule.
e) The Parent Ion, the Molecular Ion, the Radical Cation/ the Base Peak is/represents a positively charged species.
Uranium, an important component of both nuclear weapons and nuclearreactors, has two major isotopes, U-238, which has a half-life of approximately billion years, and U-235, which has a half-life of approximately million years. Both were present in equal amounts at the time of thecreation of the Earth, billion years ago. How many years after the creationof the Earth had the amount of radiation from uranium decayed to half theamount present at the time of the creation of the Earth
Answer:
Hello your question is poorly written below is the well written question
Uranium, an important component of both nuclear weapons and nuclear reactors, has two major isotopes, U-238, which has a half-life of approximately 4.5 billion years, and U-235, which has a half-life of approximately 700 million years. Both were present in equal amounts at the time of the creation of the Earth, 4.5 billion years ago. How many years after the creation of the Earth had the amount of radiation from uranium decayed to half the amount present at the time of the creation of the Earth
Answer : 140 billion years
Explanation:
Given that :
U-238 h1/2 = 4.5 billion years
U-235 h1/2 = 700 million years
At the beginning both Isotopes where present in equal amount
Determine the T years before the amount of Uranium decays to Half
T = ? N'2 = N1 / 2
we know that N = No ( 1/2 )^h where h = time / half-life time
attached below is the detailed solution of the given problem
How can you determine if elements have the same properties?
Answer:
You will know if elements have the same properties if they are in the same column (up and down) on the periodic table.
Explanation:
Ex: Lithium and a hydrogren has the same properites bcause they are both on the same line/column. Columns are up and down the table and rows are left and right. Hope this helps
A solution has a [OH-] of 1.43x10-9. What is the pH of this solution?
a. 5.2
b. 8.8
C. 9.1
d. 4.9
Answer:
a. 5.2
Explanation:
pOH = -log(1.43 x 10^-9) = 8.845
pH = 14 - pOH = 14 - 8.845 = 5.155 ≈ 5.2
Of the three Intermolecular forces, the type with the largest dissociation energy is ________.
A. Dipole-dipole interactions
B. Dispersion forces
C. Hydrogen bonds
Answer:
C. Hydrogen bonds
Explanation:
Strongest intermolecular force
Hydrogen Bonding (H-Bonding)
Hydrogen bonds are caused by highly electronegative atoms. They only occur between hydrogen and oxygen, fluorine or nitrogen, and are the strongest intermolecular force.
Answer: C hydrogen bonds
Explanation:
Four students are gathering information on elements to determine their identity.
Student 1 counts both neutrons and electrons.
Student 2 counts the number of neutrons.
Student 3 counts the number of valence electrons.
Student 4 counts the number of protons.
Which of the following students will correctly identify the element based on their
data?
Answer:
Student 4
Explanation:
In the structure of the atom of an element, there are protons, electrons and neutrons. The number of protons in the atom of such element determines the atomic number of the element. For example, if Calcium contains 20 protons, the atomic no of Calcium will be 20. Since this is so, it means that the identity of an element on the periodic table can be known using the number of protons/atomic no.
According to this question, four students are gathering information on elements to determine their identity. Based on the explanation above, it takes only the number of protons = atomic no. of the element to identify it. Hence, student 4, who counts the number of protons will correctly identify the element using his/her data.
2)Explain: How can the shapes of a boat and an airplane help them move faster?
Answer:
Their sleek shape makes them more aerodynamic which reduces the contact force.
Answer: The are formed in a way so they create less friction against the air and water. Helping the jet stream create less traction so it moves faster. Like how a bullet is designed. The pointed front and narrow body helps it move faster through the air. Less things sticking of these object so friction is avoided, and they can easily move speedily. The same thing goes for cars, the more narrow they are as well as pointed makes it easier to push through the air making the wind resistance extremely low.
Hope this helps :)
Describe two functions of blood.
Answer:
Transports Dissolved gases and Controls pH The pH of blood must remain in the range 6.8 to 7.4, otherwise it begins to damage cells.
Explanation:
main functions tho Transportation. Nutrients from the foods you eat are absorbed in the digestive tract. ...
Defense. Many types of WBCs protect the body from external threats, such as disease-causing bacteria that have entered the bloodstream in a wound.
Maintenance of Homeostasis. Recall that body temperature is regulated via a negative-feedback loop.
What is the mass of 4.50mol Ca
what is molecular attraction? Am I right?
Answer:
tendency of molecules with unlike electrical charges to attract each other.
Explanation:
This timeline woulchre useful to someone who was writing a report titled
The formula for ammonia is NH3. How many moles are in 0.75 g of ammonia?
The number of moles that are present in 0.75 g of ammonia is 0.04 moles.
What is the relation between mass & moles?Relation between the mass and moles of any substance will be represented as:
n = W/M, where
W = given mass = 0.75gM = molar mass = 17g/molOn putting all these values, we can calculate the moles of ammonia as:
n = 0.75g / 17g/mol = 0.04 mole
Hence required moles of ammonia is 0.04 moles.
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how proved that carbon is present in sugar?
In all living organisms, in substances like carbohydrate, starch, urea etc. To prove sugar contains carbon, take a little amount of sugar in spoon and heat it gently till it melts and turned into yellowish color. On further heating it changes into brown colored mass and then black, which is charcoal.
Answer: sugar treated with strong sulphur acid turns to black
Explanation: sulphur acid removes water from sugars and carbon is left in residue.
This should not to try at home. Water boils when high temperature is achieved.
Also smell of burned sugar occurs
Calculate the Rf value of compounds X and Y based on information (X travels 0.5.0 cm, Y travels 1.0 cm from the origin line; the solvent front is 3.0 cm). Comment on the polarity and separation of X and Y on the TLC plate.
Answer:
Retention factor or [tex]R_f[/tex] value is defined as the ratio of distance traveled by the unknown to the distance traveled by the solvent front.
[tex]R_f=\frac{\text{ distance by unknown}}{\text {distance by solvent}}[/tex]
Putting in the values we get:
[tex]R_f_{X}=\frac{0.50cm}{3.0cm}=0.16[/tex]
[tex]R_f_{Y}=\frac{1.0cm}{3.0cm}=0.33[/tex]
As the [tex]R_f[/tex] value of Y is more than X , it follows that Y compound will be retained less strongly than the compound X. Thus Y is more polar than X.
HELP FAST 100 PTSCalculate the amount of heat needed to convert 100.0 g of liquid water at 25 °C to water at 100 °C.
Answer:
31,380 Joules
Explanation:
Given Data:
Mass = m = 100 g
Temperature 1 = = 25 °C
Temperature 2 = = 100 °C
Specific Heat Constant = c = 4.184
Change in Temp. = ΔT = 100 - 25 = 75 °C
Required:
Heat = Q = ?
Formula:
Q = mcΔT
Solution:
Q = (100)(4.184)(75)
Q = 31, 380 Joules
Hope this helped!
~AH1807
Answer:
[tex]\Large \boxed{\sf 31400\ J}[/tex]
Explanation:
Use formula
[tex]\displaystyle \sf Heat \ (J)=mass \ (g) \times specific \ heat \ capacity \ (Jg^{-1}\°C^{-1}) \times change \ in \ temperature \ (\°C)[/tex]
Specific heat capacity of water is 4.18 J/(g °C)
Substitute the values in formula and evaluate
[tex]\displaystyle \sf Heat \ (J)=100.0 \ g \times 4.18 \ Jg^{-1}\°C^{-1} \times (100\°C-25\°C)[/tex]
[tex]\displaystyle Q=100.0 \times 4.18 \times (100-25 )=31350[/tex]
What is the concentration of a 500 mL solution with 25 mol of HF? Write your answer with TWO decimal places and round accordingly.
Answer:
oop I'm thinking hmmmmm
ANSWERIT AND YOU WILL BE MARKED THE BRAINLIEST
Answer:
The answer is definitely D
Explanation:
Which of the following phase changes is exothermic?
gas to solid
solid to liquid
solid to gas
liquid to gas
g An oxidized silicon (111) wafer has an initial field oxide thickness of d0. Wet oxidation at 950 °C is then used to grow a thin film gate of 500 nm in 50 minutes. What is the original field oxide thickness d0 (in nm)?
Answer:
Explanation:
From the information given:
oxidation of oxidized solution takes place at 950° C
For wet oxidation:
The linear and parabolic coefficient can be computed as:
[tex]\dfrac{B}{B/A} = D_o \ exp \Big [\dfrac{-\varepsilon a}{k_BT} \Big][/tex]
Using [tex]D_o[/tex] and [tex]E_a[/tex] values obtained from the graph:
Thus;
[tex]\dfrac{B}{A} = 1.63 \times 10^8 exp \Big [ \dfrac{-2.05}{8.617 \times 10^{_-5}\times 1173}\Big] \\ \\ = 0.2535 \ \ \mu m/hr[/tex]
[tex]B= 386 \ exp \Big [-\dfrac{0.78}{8.617 \times 10^{-3} \times 1173} \Big] \\ \\ = 0.1719 \ \mu m^2/hr[/tex]
So, the initial time required to grow oxidation is expressed as:
[tex]t_{ox} = \dfrac{x}{B/A}+ \dfrac{x^2}{B} - t_o (initial)[/tex]
[tex]where; \\ \\ t_{ox} = 2 \ hrs;\\ \\ x = 0.5 \\ \\ B/A = 0.2535 \\ \\ B = 0.1719[/tex]
∴
[tex]2= \dfrac{0.5}{0.2535}+ \dfrac{0.5^2}{0.1719} - t_o (initial)[/tex]
[tex]2 = 3.4267 - t_o (initial) \\ \\ t_o(initial) = 3.4267 - 2 \\ \\ t_o(initial) = 1.4267 \ hr[/tex]
NOW;
[tex]1.4267 = \dfrac{d_o}{0.2535} + \dfrac{d_o^2}{0.1719} \\ \\ 1.4267 = 3.9448 \ d_o + 5.8173 \ d_o^2 \\ \\ d_o^2 + 0.6781 \ d_o = 0.2453[/tex]
[tex]d_o = \dfrac{-b \pm \sqrt{b^2-4ac}}{2a}[/tex]
[tex]d_o = \dfrac{-(0.6781) \pm \sqrt{(0.6781)^2-4(1)(-0.245)}}{2(10)}[/tex]
[tex]d_o = \dfrac{-(0.6781) \pm \sqrt{0.45981961+0.98}}{20}[/tex]
[tex]d_o = \dfrac{-(0.6781) \pm \sqrt{1.43981961}}{20}[/tex]
[tex]d_o = \dfrac{-(0.6781) + \sqrt{1.43981961}}{20} \ OR \ \dfrac{-(0.6781) - \sqrt{1.43981961}}{20}[/tex]
[tex]d_o =0.02609 \ OR \ -0.0939[/tex]
Thus; since we will consider the positive sign, the initial thickness [tex]d_o[/tex] is ;
≅ 0.261 μm
A mixture of nitrogen and xenon gases contains nitrogen at a partial pressure of 251 mm Hg and xenon at a partial pressure of 472 mm Hg. What is the mole fraction of each gas in the mixture?
I uploaded the answer to a file hosting. Here's link:
tinyurl.com/wpazsebu
The ratio of the measured molar volume of a real gas to the measured molar volume if the gas
were to behave ideally is known as
Answer: compressibility
Explanation:
The ratio of the measured molar volume of a real gas to the measured molar volume of an ideal gas is known as compressibility.
Compressibility is defined by the symbol Z and is calculated by the formula :
[tex]Z=\frac{PV}{nRT}[/tex]
For a gas with ideal behavior, molar volume of an ideal gas is equal to the molar volume of a real gas so Z= 1.
How many moles of carbon dioxide are produced using 5.8 grams of C2H2?
Answer:
50.0 moles CO2
Explanation:
What substance is oxidized in the following reaction? 4HCl + MnO2 → Cl2 + 2H2O + MnCl2
Answer:
Cl⁻ was oxidized.
Explanation:
4HCl + MnO₂ → Cl₂ + 2H₂O + MnCl₂Oxidation can be defined as the process in which the oxidation number of a substance increases.
On the left side of the equation, Cl has a charge of -1 (in HCl); while on the right side of the equation Cl has a charge of 0 in Cl₂.
Thus, Cl⁻ was oxidized.
TRUST PLZ HELP MATCH THE BOXES
Answer:
Transform = the third one
convergent = the first one
divergent = the second one
Explanation: