Answer 1 mole = 6.02 × 1023 atoms
0.25 moles × (6.02 × 1023) = 1.5 × 1023 atoms Carbon
for the first one
A 45.0 mL solution of 0.0450 M hydroxylamine is extracted with 125 mL of solvent. The distribution constant for the reaction is 5.00 and the pKa of the protonated form of hydroxylamine is 5.960. Calculate the concentration of hydroxylamine remaining in the aqueous phase at pH=4.50 and pH=6.50 .
Answer:
pH = 4.5, concentration = 0.045 M.
pH = 6.5, concentration = 0.175 M.
Explanation:
The ka for the can be calculated by using the formula below;
Ka = 10^-pka = 10^-5.960 = 1.1 × 10^-6
The concentration of hydrogen ion at pH = 4.50 can be calculated as given below;
{H^+ } = 10^-4.50 = 3.2 × 10^-5 M.
(NB=> 10 in this regards means the inverse of log).
The next step is to determine the distribution coefficient which can be calculated by using the formula below;
distribution coefficient = (partition coefficient) × ka / ka + ( concentration of Hydrogen ion,H^+).
distribution coefficient =( 5 × 1.1 × 10^-6 ) / 1.1 × 10^-6 + 3.2 × 10^-5 M. = 5.5 × 10^-6/ 3.2 = 0.00000171875
The fraction remaining from the compound = 45.0 mL / 45.0 mL + (0.00000171875 × 125).
= 0.999995.
Thus, the concentration at pH = 4.5 = 0.999995 × 0.0450 M = 0.045 M
(B). pH=6.50, thus the concentration of Hydrogen ion = 10^-6.5 = 3.2 × 10^-7 M.
distribution coefficient = (partition coefficient) × ka / ka + ( concentration of Hydrogen ion,H^+).
distribution coefficient = (5 × 1.1 × 10^-6)/ 1.1 × 10^-6 + 3.2 × 10^-7 M).
distribution coefficient = 5.5 × 10^-6/ 1.42 × 10^-6 = 3.9.
Therefore, the concentration = 3.9 × 0.0450 M = 0.175 M.
What can be done to remove a magnetic force around an electromagnet
made of a coiled copper wire wrapped around an iron bar and connected to a
power source?
O A. Uncoil the wire.
B. Remove the iron bar.
C. There is always a small magnetic force around the wire.
D. Stop the current.
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A weather balloon with a volume of 3.40774 L
is released from Earth’s surface at sea level.
What volume will the balloon occupy at an
altitude of 20.0 km, where the air pressure is
10 kPa?
Answer in units of L.
Answer: The volume occupied at an altitude of 20.0 km is 34.5289 L
Explanation:
Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.
[tex]P\propto \frac{1}{V}[/tex] (At constant temperature and number of moles)
where,
[tex]P_1[/tex] = initial pressure of gas = 101.325 kPa ( sea level)
[tex]P_2[/tex] = final pressure of gas = 10 kPa
[tex]V_1[/tex] = initial volume of gas = 3.40774 L
[tex]V_2[/tex] = final volume of gas = ?
Now put all the given values in the above equation, we get the final pressure of gas.
[tex]101.325\times 3.40774=10\times V_2[/tex]
[tex]V_2=34.5289L[/tex]
Therefore, the volume occupied at an altitude of 20.0 km is 34.5289 L
Examine the following electron configuration:
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p1
11) How many total electrons are there?
12) Which element is this?
13) How many electrons are in the fourth energy level of this element?
14) What is the valence electron configuration of this element?
15) How many electrons are in the outermost energy level?
Answer:
The answer to 12 is Indium... you should be able to figure out the rest from there with help from the internet since i've given you the element
Explanation:
I would usually do it but I got a ton of hw
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Answer:
Just count all the different elements like what elemets are in there and you have to identify the number of elemenst
Explanation:
for example H20 and a chemical for example thats two so you identofy which elelments are in there doesnt matter if thered multiple of it all its asking is what id the number of elemts there meaning like one or 2 mayne six different elements
Iodine 131, cesium 137, and strontium 90 are all considered isotopes. What are isotopes?
Answer:
Isotopes are variants of an element, where the number of neutrons is different but its number of protons stay the same.
Explanation:
If the number of protons had changed then it would just be a different element.
Electron number changing simply adds charge to the atom, and doesn't change it or anything.
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Answer:
Isotopes are one of two or more forms of the same chemical element.
Explanation:
Different isotopes of an element have the same number of protons in the nucleus, giving them the same atomic number,but a different number of neutrons giving each element isotope of a different atomic weight.
Exactly 56 grams of iron is mixed with 156 grams of oxygen. The elements are heated and they react. What best describes which remains after the reaction is complete?
Answer:
Explanation:
The chemical expression for the reaction between iron and oxygen is:
4Fe(s) + 3O₂ (g) [tex]\to[/tex] 2Fe₂O₃ (s)
The number of moles of Fe = mass of Fe/ molecular mass of Fe
The number of moles of Fe = 56 g/ 55.845 g/mol
The number of moles of Fe = 1.002 moles of Fe
The number of moles of oxygen = mass of oxygen/ molecular mass of oxygen
The number of moles of oxygen = 156 g /32 g/mol
The number of moles of oxygen = 4.875 moles of oxygen
Assume that Fe is the limiting reactant, the number of Fe₂O₃ can be calculated as:
moles of Fe₂O₃ = 1.002 mole of Fe × 2 moles of Fe₂O₃/ 4 moles of Fe
moles of Fe₂O₃ = 0.501 mole of Fe₂O₃
Assume that O₂ is the limiting factor, the number of Fe₂O₃ is:
moles of Fe₂O₃ = 4.875 moles of O₂ × 2 moles of Fe₂O₃/ 3 moles of O₂
moles of Fe₂O₃ = 3.25 mole of Fe₂O₃
Thus, after the reaction is complete, Fe and O₂ contain different moles of Fe₂O₃. Only Fe gets consumed in the reaction and it is the limiting factor.
A rigid container filled with a gas is placed in ice (ex. nalgene bottle). What will happen to the pressure of the gas? What do you think will happen to the volume?(Graph)
Explanation:
The pressure will decrease but the volume remains constant
Explain your thoughts on whether or not using solely IR is a good method to make positive IDs of chemicals.
Answer:
No, IR should not soely be used to identify molecules
Explanation:
IR is a method that identifies the functional groups in a molecule by deducing the frequency of stretching and vibration of bonds. Each peculiar type of bond has a frequency for the vibration of each bond represented on the IR spectrum.
However, one method is never enough to identify a compound. A combination of methods must always be used to clear up ambiguities arising from overlapping IR frequencies. Also, interpretation of the nuanced peaks of the fingerprint region in IR spectra is quite challenging and only gives a fair idea of the functional groups present in the compound.
Therefore other methods such as NMR, UV-VISIBLE etc should also be involved in the identification of compounds.
A system includes:
а
objects that are interacting.
B the surrounding air.
C the surface or medium on which the objects rest.
D all of the above.
When the absolute value of the difference in electronegativity of two adjacent atom in a compound is 1, they are most likely bonded by:____________.
a. nonpolar covalent bond
b. a polar covalent bond
c. ionic bonding
Answer:
A polar covalent bond
Explanation:
When the absolute value of the difference in electronegativity of two bonded atoms is between 0.4 and 1.8 they tend to form polar covalent bonds.
Rank the following from least to greatest electron affinity: Carbon (C), Nitrogen (N), Oxygen (O).
Group of answer choices
O < N < C
C < N < O
N < C < O
C < O < N
Answer:
C < N < O.
Explanation:
Hello!
In this case, since the electron affinity is a periodic property of elements indicating how likely is for the element to gain one electron, which is also related to the electronegativity, we can notice that fluorine is the most electronegative element or also, the element with the highest electron affinity whereas francium is the least electronegative element.
Therefore, we can infer that the electron affinity or electronegativity, increases from left to right and from bottom to top in the periodic table, it means that among carbon, nitrogen and oxygen, the element with the greatest electron affinity is oxygen, then nitrogen and finally carbon with the least one, thus answer is C < N < O.
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Copper coins turn green when exposed to water. What happens to this chemical reaction if the coins are heated?
1.The coins will turn green slower because chemical reactions slow down with higher temperatures
2.The coins will turn green faster because chemical reactions speed up with higher temperatures
3.The coins will turn green at the same rate as before because temperature has no affect on the speed of chemical reactions
4.The coins will not turn green, algae cannot survive in hot temperatures
Answer:
The coins will turn green faster because chemical reaction speed up with higher temperatures
Copper coins turn green when exposed to water because the coins will turn green faster because reaction speeds up with higher temperatures.
What is the rate of the chemical reaction?The rate of a chemical reaction can be defined as the speed at which the products are formed from the reactants. The rate of a reaction gives information about the time frame under which a reaction can be finished.
The rate of reaction can be described as the speed of a chemical reaction at which reactants are transformed into products. Some chemical reactions are generally instantaneous, while some reactions take time to reach the final equilibrium. Pressure increases the concentration of gaseous reactants resulting in an increase in the rate of reaction.
The rate of reaction will increase with an increase in the temperature of the reaction as the reactant molecules get more kinetic energy and increase the number of collisions.
Therefore, copper coins will turn green faster because reactions speed up with higher temperatures.
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What is the mass number of an atom that has 19 protons, 19 electrons, and 20 neutrons?
Answer:
[tex]\boxed {\boxed {\sf 39}}[/tex]
Explanation:
The mass number of an atom can be found by adding the number of protons and neutrons.
[tex]mass \ number =protons + neutrons[/tex]
There are 19 protons and 20 neutrons.
[tex]protons=19 \\neutrons=20[/tex]
[tex]mass \ number= 19+20[/tex]
[tex]mass \ number =39[/tex]
The mass number of this atom is 39
The properties of compund are different from the properties of their constituenr
Answer: Atoms of carbon and hydrogen
Explanation:
What is the primary means through which the Sun warms Earth?
a
b
Fluctuation of subatomic particles.
Fluctuation of gravitational fields.
C Transfer of energy through conduction.
D Transfer of energy by electromagnetic waves.
Answer:
D
Explanation:
Radiation - radiation is transfer of energy by electromagnetic waves
The sun warms the earth through the transfer of energy by electromagnetic waves. Therefore, option (D) is correct.
What are electromagnetic radiations?Electromagnetic radiation contains waves of the electromagnetic field, which propagate through space and carry radiant energy. It includes microwaves, radio waves, infrared, (visible) light, UV, X-rays, and gamma rays.
Electromagnetic radiation posses of electromagnetic waves, which oscillate with the electric and magnetic fields. Electromagnetic waves are created due to periodic changes in the electric field or magnetic field.
Depending on the periodic change that happens and the power produced, different wavelengths of the electromagnetic spectrum are produced. The effects of electromagnetic radiation on chemical compounds and biological organisms depend on the power of the radiation and its frequency.
In order of increasing frequency and decreasing wavelength, these waves are arranged in the electromagnetic spectrum. The transfer of electromagnetic waves from the Sun to the earth, the energy of these waves warms the earth.
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which charcoal Is used as gas mark absorbent
Answer:
where is the answers at
Explanation:
What evidence would a scientist use to determine the age of rock in a layer?
Answer: They can find fossils and use a technology called radiocarbon to find the age of the fossil and then do an approximate about the age of the rock.
Explanation:
What are phytoplankton and what percentage of oxygen do they produce? (ASAP)
Answer:
They are plants also known as plankton and they produce about 80-85% of the world's oxygen.
Explanation:
How many moles of water are produced if 5.43 mol PbO2 are consumed?
10.86 moles of water are produced
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
Pb + PbO₂ + 2H₂SO₄ ⇒ 2PbSO₄ + 2H₂O ( a car battery reaction)
From the equation :
mol ratio PbO₂ : H₂O = 1 : 2⇒ 1 mol PbO₂ produces 2 mol H₂O
so for 5.43 mol PbO₂ consumed, mol H₂O :
[tex]\tt 2\times 5.43=10.86~moles[/tex]
Answer:
10.9
Explanation:
edge 2020
A particular solution of hydrochloric acid is 3.0 M. How many moles of hydrochloric acid are present in 22.7 mL of this solution?
Answer:
0.0681 HCl moles
Explanation:
First we convert 22.7 mL to liters:
22.7 mL * [tex]\frac{1L}{1000mL}[/tex] = 0.0227 LThen we use the definition of molarity:
molarity = moles / litersmoles = molarity * litersmoles = 3.0 M * 0.0227 Lmoles = 0.0681 molesSo there are 0.0681 hydrochloric acid moles in 22.7 mL of a 3.0 M HCl solution.
what does the word "local" mean
Answer:
belonging or relating to a particular area or neighborhood, typically exclusively so
Explanation:
What is the effect of convection in the mantle on earths land formations?
Answer:
As tectonic plates slowly move away from each other, heat from the mantle's convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.
. The earth’s diameter is 1.276 x 107 meters. How many yards is this?
Answer:
1.396 x [tex]10^{7}[/tex] yards
Explanation:
The Earth has a spherical shape, thus its diameter is a straight line that passes through its center; dividing into two equal halves.
Given that the diameter of the earth is 1.276 x [tex]10^{7}[/tex] meters.
But,
1 meter = 1.09361 yards
So that,
1.276 x [tex]10^{7}[/tex] meters = x
⇒ x = 1.276 x [tex]10^{7}[/tex] x 1.09361
= 1.39545 x [tex]10^{7}[/tex] yards
The diameter of the earth is 1.396 x [tex]10^{7}[/tex] yards.
Which of the following best defines climate)_( Short-term atmospheric conditions of a region Ob The weather pattern of an area over two weeks or less Average weather conditions of a region over the long term Od A pattern of weather that never changes
Answer:
Average weather conditions of a region over the long term
Explanation:
Climate is the long-term average of weather, typically averaged over a period of 30 years. More rigorously, it denotes the mean and variability of meteorological variables over a time spanning from months to millions of years.
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which separation method would be most successful in separating the components of a homogeneous mixture
screening
evaporation
centrifugation
magnetic separation
Answer:
Evaporation is a technique used to separate out homogeneous mixtures where there is one or more dissolved salts.
Explanation:
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What is the total pressure of mixture in which H2 and CO exerted 31mmHg and 510mmHg respectively
Answer:
Ans: 541 mmHg
Explanation:
given:
H2 = 31mmHg
CO= 510mmHg
get the sum
31+510=541
What two atoms are held together by a covalent bond in NaHCO3
Answer: covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. Covalent bonds form only between atoms of nonmetals. The two atoms that are held together in a covalent bond may be atoms of the same element or different elements.
Explanation:
Select the atomic models that belong to the same element.
Answer:
top right and bottom left
Explanation:
just took test plato/edmentum
Using the VSEPR model, the molecular geometry of the central atom in ClO3- is:_____.a. bent. b. linear. c. trigonal pyramidal. d. trigonal planar. e. tetrahedral.
Answer:
D
Explanation:
it is trigonal planar, because central atom does not have the lone pairs, equal repulsion
The molecular geometry of the central atom in ClO3- will be triangular pyramidal.
What is VSPER model?The geometry of molecular structures can be predicted using the chemical model known as the valence shell electron pair repulsion hypothesis based on the number of electron pairs surrounding the core atoms of the molecules.
Since ClO3- has a steric number of 4 (one unpaired pair as well as three bonded pairs), can infer that its molecular shape is triangular pyramidal. Its electrical form is tetrahedral, as shown by the Lewis structure above.
Therefore, the correct answer will be option (c).
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