Answer:
A: melting point and the other one is i think element
is the center of an atom is called the nucleus?
Answer:
The center of the atom contains the nucleus so yes
Explanation:
During the formation of water from hydrogen atoms and one oxygen
Answer:
B
Explanation:
hydrogen only has one electron/molecule in it's only shell so it can get together and make a bond
Explain how the immune system responds to pathegons
Answer:
The immune system responds to antigens by producing cells that directly attack the pathogen, or by producing special proteins called antibodies. Antibodies attach to an antigen and attract cells that will engulf and destroy the pathogen. The main cells of the immune system are lymphocytes known as B cells and T cells.
For the following reaction at equilibrium SO3(g) + NO(g) = SO2(g) + NO2(g)It is found that [SO2] = 0.70 M and [NO] = 1.20 M. Calculate the equilibrium constant for the readction knowing that the initial concentration were [SO3] = 2.55 M and [NO] = 1.90 M.
Answer:
[tex]K=0.14[/tex]
Explanation:
Hello!
In this case, for the undergoing chemical reaction, we can write the equilibrium expression via:
[tex]K=\frac{[SO_2][NO_2]}{[SO_3][NO]}[/tex]
Whereas the equilibrium concentration of both SO3 and NO are 2.55 M and 1.90 M respectively, it means that the extent of reaction [tex]x[/tex] is:
[tex]x=1.90M-1.20M=0.7M[/tex]
Because the equilibrium expression in terms of the reaction extent is:
[tex]K=\frac{x*x}{([SO_3]_0-x)([NO]_0-x)}[/tex]
It means that the concentration of SO3, NO, SO2 and NO2 at equilibrium are:
[tex][SO_3]=2.55M-0.70M=1.85M[/tex]
[tex][NO]=1.20M[/tex]
[tex][SO_2]=0.70M[/tex]
[tex][NO_2]=0.70M[/tex]
Thus, the equilibrium constant for such reaction is:
[tex]K=\frac{0.70*0.70}{1.85*1.90}\\\\K=0.14[/tex]
Best regards!
find examples for each polysaccharides type.
Answer:
Glycogen: It is made up of a large chain of molecules. ...
Cellulose: The cell wall of the plants is made up of cellulose. ...
Starch: It is formed by the condensation of amylose and amylopectin. ...
Insulin: It is made up of a number of fructofuranose molecules linked together in chains.
Explanation:
Which of the following are fair conductors and are always solid at room temperature?
1.Metals
2.Nonmetals
3.Metalloids
4.Ions
Answer:
Metalloids and ions
Explanation:
Mercury is not solid at room temperature. (Metals)
Many nonmetals aren't good at conducting electricity. Oxygen for example. (Nonmetals)
Metalloids are always solid at room temp and are fair conductors. (Metalloids)
Ions are same as metalloids. (Ions)
PLS GIVE BRAINLIEST
What is the hybridization state on the central N atom in the azide ion, N3−?
An element has 4 protons, 5 neutrons, and 4 electrons. Choose the correct answer. *
Answer:
4
Explanation:
[tex]\int\limits^a_b {x} \, dwetjernjtnx[/tex]
Molarity to percent by mass. Convert 1.672 mol/L MgCl2(aq) solution to percent by mass of MgCl2 in the solution. The solution density at this concentration is 1.137 g/mL. Answer to 4 significant figures with appropriate units.
Answer:
[tex]\%m/m=14\%[/tex]
Explanation:
Hello!
In this case, since the molarity of magnesium chloride (molar mass = 95.211 g/mol) is 1.672 mol/L and we know the density of the solution, we can first compute the concentration in g/L as shown below:
[tex][MgCl_2]=1.672\frac{molMgCl_2}{L}*\frac{95.211gMgCl_2}{1molMgCl_2}=159.2\frac{gMgCl_2}{L}[/tex]
Next, since the density of the solution is 1.137 g/mL, we can compute the concentration in g/g as shown below:
[tex][MgCl_2]=159.2\frac{gMgCl_2}{L}*\frac{1L}{1000mL}*\frac{1mL}{1.137g}=0.14[/tex]
Which is also the by-mass fraction and in percent it turns out:
[tex]\%m/m=0.14*100\%\\\\\%m/m=14\%[/tex]
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If you travel 7.5 km and walk for 1.5 h, what is your average speed?
Show your work?
What is the change in internal energy (ΔΕ) of a system when 5 kJ of work is done on the system while it releases 13 kJ of energy to the surroundings?
The change in internal energy (ΔΕ) of a system : -8 kJ
Further explanationThe laws of thermodynamics 1 state that: energy can be changed but cannot be destroyed or created
The equation is:
[tex]\tt \Delta U=Q+W[/tex]
Energy owned by the system is expressed as internal energy (U)
This internal energy can change if it absorbs heat Q (U> 0), or releases heat (U <0). Or the internal energy can change if the system does work or accepts work (W)
The sign rules for heat and work are set as follows:
• The system receives heat, Q +
• The system releases heat, Q -
• The system does work, W -
• the system accepts work, W +
5 kJ of work is done on the system : W = +5 kJ
releases 13 kJ of energy to the surroundings : Q = -13 kJ
[tex]\tt \Delta E=-13+5=-8~kJ[/tex]
Which of the following is a chemical change? A. soil drying as water evaporates B. a rock eroding as the wind removes particles from it C. a solution of salt water being diluted as water is added to it D. silver tarnishing as the silver metal reacts with sulfur
Answer:
Its D
Explanation:
I took the quiz
Answer:
D
Explanation:
IT IS REACTING
An object has a mass of 3.50 grams and a density of 5.61 g/mL. What is the volume of this object? *
Answer:
0.62 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question we have
[tex]volume = \frac{3.50}{5.61} \\ = 0.6238859...[/tex]
We have the final answer as
0.62 mLHope this helps you
How would I find the answer?
Answer:
Kr
Explanation:
The noble gas that is isoelectronic with Br⁻ is krypton.
This is because krypton is the closest noble gas to Br on the periodic table.
Electronic configuration of Bromine is;
2, 8, 18, 7
Br⁻ becomes; 2, 8, 18, 8
Krypton is; 2, 8, 18, 8
In which direction will the following equilibrium shift when solid sodium fluoride is added to an aqueous solution of acetic acid? CH3COOH â CH3COOâ + H+ A. The equilibrium shifts to the right, to form more products. B. The equilibrium shifts to the left, to form more reactants. C. There is no change; the system is still at equilibrium.
Answer:
A. The equilibrium shifts to the right, to form more products.
Explanation:
When sodium fluoride, NaF, is added to an aqueous solution, some HF is produced:
NaF + H₂O ⇄ OH⁻ + Na⁺ + HF.
That is, some H⁺ reacts decreasing its concentration.
Now, the equilibrium of the acetic acid is:
CH3COOH ⇄ CH3COO⁻ + H⁺
As the concentration of H⁺ decreases:
A. The equilibrium shifts to the right, to form more products.
In order to restore the initial equilibrium.
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]
PLease help me I am giving a lot of points for this please help me
Answer:
Under balanced its motion under motion its s = d/t under s - d/t is time d = distance s= speed
Explanation:
What creates a weather front?
A weather front is a transition zone between two different air masses at the Earth's surface. Each air mass has unique temperature and humidity characteristics. Often there is turbulence at a front, which is the borderline where two different air masses come together. The turbulence can cause clouds and storms.
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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In ethane, C2H6, ethene (ethylene), C2H4, and ethine (acetylene), C2H2, there are direct carbon-carbon bonds. Which one is the shortest?
a. The carbon-carbon bond in ethane's the longest!)
b. The carbon-carbon bond in ethene is the longest
c. The carbon-carbon bond in ethyne is the longest.
d. All of the carbon-carbon bonds have the same length.
Answer:
a. The carbon-carbon bond in ethane's the longest!)
Explanation:
Ethane is a chemical compound that is organic in nature. Its chemical formula is [tex]$C_2H_6$[/tex]. It has two carbon atoms and six of hydrogen atoms that is connected to the carbon atoms.
Ethane is odorless and colorless at the standard temperature and standard pressure.
The carbon to carbon atoms in ethane is connected by a single bond.
The length of single carbon-carbon bond is greater than carbon-carbon double bond and triple bond.
Thus, carbon-carbon bond length in ethane is the longest.
i really need help with the rest of this assignment. theres 10 pages of multiple choice questions, i can mark brainliest and pay money if you help me :)
Answer:
Hey! I'll help you.
Explanation:
I got your back.
Whats the answer 50 points and brainliest if its right
Answer:
D
Explanation:
why did Aristotle disagree with Democritus
Answer: He theorized that all material bodies are made up of indivisibly small “atoms.” Aristotle famously rejected atomism in On Generation and Corruption. Aristotle refused to believe that the whole of reality is reducible to a system of atoms.
Explanation:
Aristotle disagreed with Democritus primarily on the nature of matter and the concept of atomism.
Democritus proposed the theory of atomism, suggesting that all matter is composed of indivisible and indestructible particles called atoms. He believed that atoms combine and interact to form different substances.
On the other hand, Aristotle rejected the notion of atomism and instead proposed a different theory of matter. According to Aristotle, matter is continuous and infinitely divisible. He believed that substances are composed of four primary elements - earth, air, fire, and water - which have different inherent properties and undergo transformations through the combination and separation of these elements.
Aristotle's disagreement with Democritus stemmed from their differing views on the fundamental nature of matter. While Democritus emphasized the discrete and fundamental nature of atoms, Aristotle emphasized the continuous and composite nature of matter. Their contrasting viewpoints reflected a broader philosophical divide between atomism and holism in ancient Greek philosophy.
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A buffer is prepared by mixing 204.0 mL of 0.452 M HCl and 0.500 L of 0.400 M sodium acetate (NaC2H3O2):
Calculate the pH of the buffer.
How many grams of KOH must be added to 0.500 L of the buffer to change the pH by 0.15 units?
Answer:
pH = 4.89
0.6171g of KOH must be added
Explanation:
Sodium acetate reacts with HCl producing acetic acid as follows:
NaC2H3O2 + HCl → HC2H3O2 + NaCl
That means the moles added of HCl are moles of acetic acid produced and moles of acetate are initial moles - moles of HCl
Moles HCl = Moles acetic acid:
0.204L * (0.452mol / L) = 0.0822 moles acetic acid.
Initial moles sodium acetate:
0.500L * (0.400mol / L) = 0.200 moles
Moles sodium acetate:
0.200 moles - 0.0822 moles = 0.1172 moles sodium acetate
The pH of this buffer (Mixture of a weak acid and its conjugate base) is obtained using H-H equation:
pH = pKa + log [A-] / [HA]
Where pH is pH of the buffer,
pKa is pKa of the buffer (4.74 for acetic acid)
[A-] Moles of sodium acetate -Conjugate base-
And HA moles of acetic acid -Weak acid-
pH = 4.74 + log [0.1172 moles] [0.0822 moles]
pH = 4.89In 0.500L the moles of the buffer are:
0.500L * (0.200moles / 0.704L) = 0.142 moles of buffer
For a pH of 0.15 units more (4.89 + 0.15 = 5.04):
5.04 = 4.74 + log [Acetate] / [Acetic acid]
0.3 = log [Acetate] / [Acetic acid]
1.9953 = [Acetate] / [Acetic acid] (1)
And as:
0.142 = [Acetate] + [Acetic acid] (2)
Replacing (2) in (1):
1.9953 = 0.142 - [Acetic acid] / [Acetic acid]
1.9953 [Acetic acid] = 0.142 - [Acetic acid]
2.9953 [Acetic acid] = 0.142 moles
[Acetic acid] = 0.0474 moles of acetic acid must remain after the addition of KOH.
In the beginning, moles of acetic acid are:
0.0822 moles * (0.500L / 0.704L) = 0.0584 moles.
That means moles added of KOH (Equal to moles of acetic acid that react) are:
0.0584 moles - 0.0474 moles = 0.0110 moles of KOH
In grams (Molar mass KOH = 56.1g/mol):
0.0110 moles KOH * (56.1g/mol) =
0.6171g of KOH must be added6.0 L of a gas exert a pressure of 2.5 atm. When the pressure is increased 2 points
to 10.0 atm, what is the new volume of the gas?
O 1.0L
O 1.5L
O 1.7L
O 25L
A buffer solution of volume 0.500 L contains 1.68 g NH3and 4.05 g (NH4)2SO4.
Required:
a. What is the pH of this solution?
b. If 0.88 g of NaOH is added to the solution, what will be the pH?
Answer:
wait
Explanation:
a. The pH of this solution is 9.45.
b. If 0.88 g of NaOH is added to the solution, the pH will be 9.74.
What is pH means?a way to gauge how basic or acidic a material or solution is. On a scale of 0 to 14, pH is measured. A pH of 7 indicates neutrality on this scale, which implies it is neither acidic nor basic. More basic substances have a pH value more than 7, whereas more acidic substances have a pH value less than 7.
first of all we should calculate the molarity of the compounds
no. of moles of NH₃ = weight / molecular weight = 1.68 / (14+3) = 0.099
no. of moles of (NH₄)2SO4 = 4.05 / {2×(14+4) + 32 + 64} = 0.031
no. of moles of NH4+ = 2×0.031 = 0.062
[NH₃] = no. of moles / volume(L) = 0.099/ 0.5 = 0.198
[(NH₄⁺] = 0.031/0.5 = 0.124
1) now we know that
pH + pOH = pkw
pOH = pkw - pH = 14 - pH ---- -1
also
pOH = pkb + log ( [salt]/[base])
from 1
14 - pH = pkb + log ( [salt]/[base])
putting values
14- pH = -log(1.8e-5) + log(0.124/0.198)
14 - pH = 4.54
pH = 9.45
2) if 0.88g NaOH is added then as we know that NaOH is a base then it will reduce the buffer capacity
as there would be OH- ions initially present
hence the buffer action will move backward
i.e
pOH = pkb + log {(salt-x) / (base+x)}
where x= molarity of NaOH
no of moles of NaOH = 0.88 / (23+16+1) = 0.022
molarity of NaOH = 0.022/0.5 = 0.044
then 14 - pH = -log(1.8e-5) + log{ (0.124-0.044) / (0.198+0.044) }
14 - pH = 4.26
pH = 9.74
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Calculate the percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl on the assumption that their force constants are the same. The mass of 23Na is 22.9898mu.
Answer:
1.089%
Explanation:
From;
ν =1/2πc(k/meff)^1/2
Where;
ν = wave number
meff = reduced mass or effective mass
k = force constant
c= speed of light
Let
ν =1/2πc (k/meff)^1/2 vibrational wave number for 23Na35 Cl
ν' =1/2πc(k'/m'eff)^1/2 vibrational wave number for 23Na37 Cl
The between the two is obtained from;
ν' - ν /ν = (k'/m'eff)^1/2 - (k/meff)^1/2 / (k/meff)^1/2
Therefore;
ν' - ν /ν = [meff/m'eff]^1/2 - 1
Substituting values, we have;
ν' - ν /ν = [(22.9898 * 34.9688/22.9898 + 34.9688) * (22.9898 + 36.9651/22.9898 * 36.9651)]^1/2 -1
ν' - ν /ν = -0.01089
percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl;
ν' - ν /ν * 100
|(-0.01089)| × 100 = 1.089%
Answer:
1.089%
Explanation:
From;
ν =1/2πc(k/meff)^1/2
Where;
ν = wave number
meff = reduced mass or effective mass
k = force constant
c= speed of light
Let
ν =1/2πc (k/meff)^1/2 vibrational wave number for 23Na35 Cl
ν' =1/2πc(k'/m'eff)^1/2 vibrational wave number for 23Na37 Cl
The between the two is obtained from;
ν' - ν /ν = (k'/m'eff)^1/2 - (k/meff)^1/2 / (k/meff)^1/2
Therefore;
ν' - ν /ν = [meff/m'eff]^1/2 - 1
Substituting values, we have;
ν' - ν /ν = [(22.9898 * 34.9688/22.9898 + 34.9688) * (22.9898 + 36.9651/22.9898 * 36.9651)]^1/2 -1
ν' - ν /ν = -0.01089
percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl;
ν' - ν /ν * 100
|(-0.01089)| × 100 = 1.089%
A 32.65 g metal is placed in a flask. Liquid toluene is added to the flask so that the total volume of the metal and liquid toluene together is 50.00 mL. The metal and toluene together weigh 58.58 g. The density of toluene at the temperature of the experiment is 0.8640 g/mL. What is the density of the metal?
An organic thiol compound is 38.66% C, 9.73% H, and 51.61% S by mass. What is the empirical formula of this compound?
Answer:
Empirical formula is C₂H₆S
Explanation:
Given data:
Percentage of hydrogen = 9.73%
Percentage of carbon = 38.66%
Percentage of sulfur = 51.61%
Empirical formula = ?
Solution:
Number of gram atoms of H = 9.73 / 1.01 = 9.6
Number of gram atoms of S = 51.61 / 32 = 1.6
Number of gram atoms of C = 38.66 / 12 = 3.2
Atomic ratio:
C : H : S
3.2/1.6 : 9.6/1.6 : 1.6/1.6
2 : 6 : 1
C : H : S = 2 : 6 : 1
Empirical formula is C₂H₆S.
A microwave operates at 7.42 mm wavelength. How much energy is produced in Joules from 359 photons?
answer numerically using scientific notation with e and significant figures.
Answer:
[tex]E=9.62\times 10^{-21}\ J[/tex]
Explanation:
Given that,
The wavelength of a microwave is 7.42 mm or 0.00742 m
No. of photons, n = 359
We need to find the energy produced by this no of photons. It can be given by the formula as follows :
[tex]E=\dfrac{nhc}{\lambda}\\\\E=\dfrac{359\times 6.63\times 10^{-34}\times 3\times 10^8}{0.00742}\\\\=9.62\times 10^{-21}\ J[/tex]
or
[tex]E=9.62e^{-21}\ J[/tex]
So, the required energy is [tex]9.62\times 10^{-21}\ J[/tex].
Answer:
⬆️That guy deserves brainliest
Explanation: