Which of the following statements is correct concerning the class of reactions to be expected for benzene and cyclooctatetraene?
A) Both substances undergo addition reactions.
B) Both substances undergo substitution reactions.
C) Benzene undergoes addition; cyclooctatetraene undergoes substitution.
D) Benzene undergoes substitution; cyclooctatetraene undergoes addition.
Answer:
Both substances undergo substitution reactions.
Explanation:
Let us go back to the idea of aromaticity. Aromatic substances are said to possess (4n + 2) π electrons according to Huckel rule.
Aromatic substances are unusually stable and the aromatic ring can not be destroyed by addition reactions.
Since both benzene and cyclooctatetraene are both aromatic, they do not undergo addition reactions whereby the aromatic ring is destroyed. They both undergo substitution reaction in which the aromatic ring is maintained.
Radon-220 undergoes alpha decay with a half-life of 55.6 s.?
Assume there are 16,000 atoms present initially and calculate how many atoms will be present at 0 s, 55.6 s, 111.2 s, 166.8 s, 222.4 s, and 278.0 s (all multiples of the half-life). Express your answers as integers separated by commas.
Calculate how many atoms are present at 50 s, 100 s, and 200 s (not multiples of the half-life).
The half life of a radioactive isotope refers to the time taken for half of the number of original number of atoms present in the sample to decay.
The equation below gives the number of atoms present at time t
[tex]N=Noe^-kt[/tex]
N = Number of atoms present at time t
No = Number of atoms initially present
k = decay constant
t = time taken
Given that;
t1/2 = 0.693/k
where t1/2 = half life
k = 0.693/t1/2
k = 0.693/ 55.6 s
k = 0.0125 s-1
Substituting values;
N = 16,000 e^-0.0125(0)
N = 16,000 atoms
At 50 s
N = 16,000 e^-0.0125(50)
= 8564 atoms
At 100 s
N = 16,000 e^-0.0125(100)
= 4584 atoms
At 200 s
N = 16,000 e^-0.0125(200)
= 1313 atoms
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Help please due today
Edit : OPTION C is the answer
Option B is the best, Even though the cost is 30 Billion it essentially takes Lesser time to construct. For Plan A, They would have to construct the overground railway and then take a lot of time and effort to create wildlife corridors and then plant trees. Plan B takes much less time compared to plan A and might as well have a lesser impact on the environment!
If equal moles of boric acid (H3BO3) and NaOH fully react, what species would be in solution at the end of the reaction??
1) H3O+
2) OH-
3) H2BO3-
4) H3BO3
5) OH- and H3O+
The reaction between boric acid and sodium hydroxide is an example of a weak acid strong base reaction.
Boric acid is a weak acid while sodium hydroxide is a strong base.
Having that in mind, we know that a weak acid dissociates only to a small extent in solution while a strong base is almost 100% ionized in solution.
It the follows that a lot of OH- will be left behind after the reaction since only a little fraction of it reacts with the H^+ from boric acid.
Hence, if equal moles of boric acid (H3BO3) and NaOH fully react, OH- is left in the solution after reaction.
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What is an example of an extensive property
For a colligative property such as freezing point depression, :________
a) the charge on the particle affects the property.
b) only the molar mass of the particle matters, not the number of particles.
c) the size of the particle affects the property but not the charge.
d) the number of particles matter but not what they are.
Heating water makes most solids in it
soluble, and it makes gases
soluble.
Increasing the pressure on a gas above water makes the gas
soluble. Compounds with comparatively stronger ionic bonds are
soluble.
Answer:
1. more
2. less
3. more
4. less
Explanation:
What is the amount of heat required to change one mole of a substance from the solid to liquid state known as?
Select the correct answer below:
A) the enthalpy of fusion
B) the melting point
C) the entropy of disorder
D) none of the above
A) the enthalpy of fusion
Explanation:
the heat of vaporization, is the amount of energy needed to change a liquid to a gas at constant temperature and pressure. The energy required to melt a solid to a liquid is called the heat of fusion, and the heat of sublimation is the energy.
Answer:
A
Explanation:
Which of the following statements accurately describes how a catalyst acts in a chemical reaction?
I. Decreases the kinetic energy of the reaction
II. Is not consumed by the reaction
III. Increases the equilibrium constant
IV. Reduces the required activation energy
a) II, III, and IV only
b) I and III only
c) I and II only
d) II and IV only
Answer:
d) II and IV only.
Explanation:
A catalyst increases the kinetic energy of reactant molecules which increases the magnitude of collision. These then decreases the activation energy . A catalyst is not consumed by reaction because it is neither reactant nor a product, hence has no effect on equilibrium constant.
[tex].[/tex]
Answer:
A
Explanation:
it speed up a chemical reaction without being consumed by the reaction and increases the reaction rate by lowering the activation energy for a reaction but the average kinetic energy of the molecules remains the same well the required energy decreases
Convert 1.25 x 1024 atoms of carbon to moles of carbon.
Answer:
2.076
Explanation:
1 mole is 6.02 * 10^23
To convert from atoms (or molecules or compounds or ions etc.) to mols, you divide the number of atoms (or molecules or etc.) by 6.02 * 10^23
So it is (1.25 * 10^24)/(6.02 * 10^23)
=2.076
Answer:
[tex]\boxed {\boxed {\sf 2.08 \ mol \ C}}[/tex]
Explanation:
We are asked to convert a number of carbon atoms to moles.
We will use Avogadro's Number for this, which is 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. For this problem, the particles are atoms of carbon. There are 6.022 ×10²³ atoms of carbon in 1 mole of carbon.
We will also use dimensional analysis to solve this problem. To do this, we use ratios. Set up a ratio using the underlined information.
[tex]\frac {6.022 \times 10^{23} \ atoms \ C}{1 \ mol \ C}[/tex]
We are converting 1.25 ×10²⁴ atoms of carbon to moles, so we multiply the ratio by that value.
[tex]1.25 \times 10^{24} \ atoms \ C* \frac {6.022 \times 10^{23} \ atoms \ C}{1 \ mol \ C}[/tex]
Flip the ratio. It remains equivalent, but it allows us to cancel the units atoms of carbon.
[tex]1.25 \times 10^{24} \ atoms \ C* \frac{1 \ mol \ C} {6.022 \times 10^{23} \ atoms \ C}[/tex]
[tex]1.25 \times 10^{24} * \frac{1 \ mol \ C} {6.022 \times 10^{23} }[/tex]
[tex]\frac{1.25 \times 10^{24} } {6.022 \times 10^{23} } \ mol \ C[/tex]
[tex]2.075722351 \ mol \ C[/tex]
The original measurement of atoms has three significant figures, so our answer must have the same. For the number we calculated, that is the hundredths place. The 5 in the thousandths place tells us to round the 7 up to an 8.
[tex]2.08 \ mol \ C[/tex]
1.25 ×10²⁴ atoms of carbon is equal to approximately 2.08 moles of carbon.
Which of the following reasons is why spent fuel rods are stored in a pool of water?
Answers
A.
Water recovers useful energy from the continuing reaction.
B.
Water increases the speed of the chain reaction in the fuel rods.
C.
Water acts as a radiation shield to reduce the radiation levels.
D.
Water dissolves the nuclear waste in the rods so it is easier to handle.
Answer:
C. water acts as a radiation shield to reduce the radiation level
Critique this statement: Promotion of electrons is accompanied by a release of energy
Answer: Promotion of electrons is accompanied by a release of energy because of absorption of photon.
Explanation:
Promotion of electrons occurs when an electron accepts or absorbs a photon which leads to it's movement from a lower energy level orbital to a higher energy orbital.
According to Bohr, the electrons was restricted to certain energy levels and was thought to move along certain circular orbits around the nucleus. These energy levels were identified by means of principal quantum number, n. The wave mechanics model of atom does not restrict the electrons to a certain energy levels only. Instead it describes a region around the Nucleus called orbitals where there is a possibility of finding an electron with a certain amount of ENERGY.
The energy levels are composed of one or more orbitals and the distribution of electrons around the nucleus is determined by the number and kind of energy levels that are occupied.
Bohr made an assumption that an electron emits energy in the form of radiation when it moves from a higher to a lower permitted orbit, this produces a line in the atomic emission spectrum. Since the energies of the higher and lower orbits are fixed, the line will be of a particular energy and frequency.
Nombre de la siguiente estructura de compuesto orgánico
Answer:
Nombre de la siguiente estructura de compuesto orgánico
Explanation:
Evaluate the exponential expression (−2)6.
A general exponential expression is something like:
A^n
This means that we need to multiply the number A by itself n times.
Using that we will get (-2)^6 = 64
With that definition, we can rewrite:
(-2)^6 = (-2)*(-2)*(-2)*(-2)*(-2)*(-2)
So we just need to solve the above expression.
Also, remember the rule of signs:
(-)*(-) = (+)
We will get:
(-2)*(-2)*(-2)*(-2)*(-2)*(-2) = [(-2)*(-2)]*[(-2)*(-2)]*[(-2)*(-2)]
= 4*4*4 = 16*4 = 64
Then we got:
(-2)^6 = 64
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What did Millikan discover
Answer:
Robert Millikan was a physicist who discovered the elementary charge of an electron using the oil-drop experiment
Answer:
the mass of an electron using the Oil-Drop experiment.
Explanation:
The average temperature at the South Pole In January is - 35.4 °C.
Convert this temperature to degrees Fahrenheit. Round your answer to 3 significant digits.
°F
Answer:
-31.72°F
Explanation:
(-35.4°C × 9/5) + 32 = -31.72°F
The average temperature at the South Pole In January is - 35.4 °C. This temperature in Fahrenheit is -31.72 °F
To convert Celsius to Fahrenheit, you can use the formula:
°F = (°C × 9/5) + 32
Let's calculate the temperature at the South Pole in degrees Fahrenheit:
°F = (-35.4 × 9/5) + 32
°F = (-63.72) + 32
°F = -31.72
Rounding to three significant digits, the temperature at the South Pole in degrees Fahrenheit is approximately -31.7 °F. The negative sign indicates that the temperature is below the freezing point in both Celsius and Fahrenheit scales. The South Pole experiences freezing temperatures, as it is located near the Earth's southernmost point and experiences long periods of darkness during January.
Hence, the temperature in Fahrenheit is -31.7 °F.
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A reactant. Q. decomposes at a second order. The slope of the graph 1/[Q] (1/M) vs time (s) is -0.04556. If the initial
concentration of Q for the reaction is 0.50 M, what is the concentration in M. of Q after 10.0 minutes?
Answer:
0.034 M
Explanation:
1/[A] = kt + 1/[A]o
[A] = ?
k= 0.04556
t= 10.0 minutes or 600 seconds
[A]o = 0.50 M
1/[A] = (0.04556 × 600) + 1/0.50
[A] = 0.034 M
The following is what kind of reaction?
2 CH4 +4 02 → 2 CO2 + 4H2O
Answer:
It is a combustion reaction.
Calculate the heat change in calories for melting of 0.30 kg of water at 0*C. The
heat of fusion for water is 80 cal/g. The heat of vaporization of water is 540 cal/g.
The specific heat capacity of water is 1.00 cal/g*C.
Answer: 24 kcal
Explanation:
Given
Mass of water [tex]m=0.3\ kg[/tex]
Temperature of water [tex]T_1=0^{\circ}[/tex]
Heat of fusion [tex]L_f=80\ cal/g[/tex]
Heat of vaporization [tex]L_v=540\ cal/g[/tex]
Specific heat of water [tex]c=1\ cal/g.^{\circ}C[/tex]
Heat require to melt the ice is
[tex]\Rightarrow Q=mL_f\\\Rightarrow Q=0.3\times 1000\times 80\\\Rightarrow Q=24000\ cal\ or\ 24\ kcal[/tex]
Thus, 24 kcal of heat is required to melt 0.3 kg of ice.
What is the equilibrium expression for the reaction below?
Caco (s)
Cao(s) + CO (g)
A.
B.
[Cacoz]
[Cao]
[Caco.]
[Cao]+[CO,
[Cao][COL]
[Caco:]
C.
D. [co]
Answer:
D. [CO₂]
Explanation:
Let's consider the following equation at equilibrium.
CaCO₃(s) ⇄ CaO(s) + CO₂(g)
The equilibrium constant, Kc, is the ratio of the equilibrium concentrations of products over the equilibrium concentrations of reactants each raised to the power of their stoichiometric coefficients. It only includes gases and aqueous species.
Kc = [CO₂]
Which is an example of genetic engineering?
A.
humans’ ability to digest cow milk
B.
some bacteria’s resistance to antibiotics
C.
golden rice enriched with vitamin A
D.
lizards with longer legs for surviving floods
Answer:
C. Golden rice enriched with vitamin A
pls help name any of these compounds
Answer:
D. Propanol
Explanation:
C3H7OH the presence of alcohol functional group makes it propanol
Which is a statement of cell theory? All cells are made up of living molecules. All plants are made of cells. All animals are made of cells. All cells are produced from other cells.
Answer:
all cells are produced from other preexisting cells through cell division
A complex ion that forms in solution has a structure that:____.
a. can be determined simply by stoichiometry.
b. can be predicted on the basis of electrical charge.
c. can only be determined experimentally.
d. cannot be determined.
Answer:
can only be determined experimentally.
Explanation:
In the early days of inorganic chemistry, the structure of complex ions remained a mystery hence the name ''complex''.
These ions appear to have structures that defied accurate elucidation. However, by diligent laboratory investigation, Alfred Werner was able to accurately determine the structure of cobalt complexes. As a result of this, he is regarded as a pathfinder in coordination chemistry.
Hence, the structure of complex ions can only be determined experimentally.
Answer:
c. can only be determined experimentally
Explanation:
It is not possible to know for certain the structure of a complex ion on the basis of stoichiometry or by the electrical charges on the components. The structure of the resulting complex ion can only be known by experiment.
As discussed in class, the Fischer esterification reactants and products are at equilibrium. How was the equilibrium of the reaction that you performed shifted towards the products
Answer:
See explanation
Explanation:
The particular reactants in the Fischer esterification reaction were not stated.
Generally, a Fischer esterification is a reaction that proceeds as follows;
RCOOH + R'OH ⇄RCOOR' + H2O
This reaction occurs in the presence of an acid catalyst.
We can shift the equilibrium of this reaction towards the products side in two ways;
I) use of a large excess of either of the reactants
ii) removal of one of the products as it is formed.
Any of these methods shifts the equilibrium of the Fischer esterification reaction towards the products side.
1. Consider the following thermochemical reaction for kerosene:
2 C12H26(l) + 37 O2(g) 24 CO2(g) + 26 H2O(l) + 15,026 kJ
(a) When 21.3 g of CO2 are made, how much heat is released?
(b) If 500.00 kJ of heat are released by the reaction, how grams of C12H26 must have been consumed ?
(c) If this reaction were being used to generate heat, how many grams of C12H26 would have to be reacted to generate
enough heat to raise the temperature of 750g of liquid water from 10oC to 90oC?
2. Consider the reaction: NaNO3(s) + H2SO4(l) → NaHSO4(s) + HNO3(g) ΔH° = 21.2 kJ
How much heat must absorbed by the reaction system to convert 100g of NaNO3 into NaHSO4(s)?
3. What is the enthalpy change when 49.4 mL of 0.430 M sulfuric acid reacts with 23.3 mL of 0.309 M potassium
hydroxide?
3.
H2SO4(aq) + 2KOH(aq) → K2SO4(aq) + 2H2O(l) ΔH° = –111.6 kJ/mol
do you have the specific heat for part 2?
What is a chemical formula, and what does it tell you?
Explanation:
chemical formula tells you the specific elements included in the compound and the number of atoms of each. The letters in a chemical formula are the symbols for the specific elements. So for example, H means hydrogen.
Explanation:
A chemical formula is a way of presenting information about the chemical properties of atoms that contribute a particular chemical compound or molecule, using chemical elements.
8. Build a neutral lithium atom.
Now, what must you do to make the lithium atom's charge change to +1?
Hint: Lithium is atomic number 3.
Add 2 electrons
Remove 1 electron
Add 1 electron
Add 1 proton
Answer:
Remove 1 electron
Explanation:
In the atom of each element, there are three subatomic particles viz: proton, neutron and electron. The number of proton (positively charged) and electron (negatively charged) determines the charge of that element. The more the proton, the more positively charged an ion is and vice versa for electron.
According to this question, a neutral atom of lithium (Li) with atomic no. 3 is given i.e. a lithium atom with charge 0. To make the lithium atom's charge change to +1, ONE ELECTRON MUST BE REMOVED OR LOST.
Note that, the proton number (atomic number) of an element does not change, rather the electron number changes in relation to the no. of protons.
g Identify the process in which the entropy increases. Group of answer choices a decrease in the number of moles of a gas during a chemical reaction the phase transition from a gas to a liquid the phase transition from a solid to a gas freezing water
Answer:
phase transition from a solid to a gas
Explanation:
Entropy refers to the degree of disorderliness in a system. The more disorderly a system is, the greater the entropy of the system.
Decrease in the number of moles of a gas decreases the entropy of the system. Similarly, the entropy of solids is less than that of liquids. The entropy of liquids is less than that of gases.
Therefore, a change of phase from solid to gas represents an increase in entropy of the system.
(a) (i) What is the name of apparatus used to measure conductivity of water
Answer:
An electrical conductivity meter (EC meter) measures the electrical conductivity in a solution. It has multiple applications in research and engineering, with common usage in hydroponics, aquaculture, aquaponics, and freshwater systems to monitor the amount of nutrients, salts or impurities in the water.
