Answer:
(D) (CH3CH2)2NH
Explanation:
In order to decide which base is strongest we need to calculate its PKb
PKb = -log [Kb]
A large Kb value and small PKb value gives the strongest base
Compound Kb PKb
(A) C6H5NH2 - 4 x 10^-10 9.349
(B) NH3 1.76x 10^-5 4.754
(C) CH3NH2 4.4x 10^-4 3.357
(D) (CH3CH2)2NH 8.6x 10^-4 3.066
(E) C5H5N 1.7x10^-9 8.77
Clearly (CH3CH2)2NH is the strongest base.
Looking at the different chemical structures, which one(s) might be able to hold
cancer fighting drugs and could then travel through the body safely until they
released the drugs into the cancer cells?
a) Graphite and diamond because these well known substances have been used
for years to treat cancer
b) Graphite because it is found in pencils and is a good lubricant
c) Fullerene and carbon nanotubes because they have empty spaces inside the
molecules
d) Diamond because it is one of the hardest substances
Answer:
c) Fullerene and carbon nanotubes because they have empty spaces inside the molecules
Explanation:
Fullerene and carbon nanotubes would be the most desired in order to hold the cancer fighting drugs and to carry them through the body safely.
These molecules have empty spaces in them. The cavities makes it possible for storage. As they pass through the body, they can be held perfectly well to their target site of action.what type of chemical reactions is NaOH(ag)+HCI(ag)=NaCL(ag)+H2O
Answer:
i hope it helps
Explanation:
This reaction involve an acid (HCl) reacting with a base (NaOH), producing a salt (NaCl) and water. Therefore it's a neutralization reaction.
THIS IS A SCIENCE QUESTION
Which choice describes how temperature differences affect air?
A. Hot air rises, and cold air sinks.
B. Hot air sinks, and cold air rises.
C. Hot air is steady, and cold air moves fast.
D. Hot air moves fast, and cold air rises.
Answer:
A
Explanation:
Hot air is less dense therefore it rises. Cold air is more closely packed therefore it is more dense. Less dense things rise while more dense things sink.
Answer:
A
Explanation:
Think of it like an hot air balloon
Hot air makes it rise and cool air sinks it downwards
At STP, one mole of oxygen and one mole of neon contain equal numbers of
Answer:
D) particles but the oxygen has a greater mass.
Explanation:
Just took the test and got it right
At STP, one mole of oxygen and one mole of neon contain equal numbers of particles but oxygen has greater mass.
What is a mole?Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.
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A chemist determines that a sample of petrified wood has a carbon-14 decay rate of 6.00 counts per minute per gram. The decay rate of carbon-14 in fresh wood today is 13.6 counts per minute per gram, and the half life of carbon-14 is 5730 years. What is the age of the piece of wood in years?
Answer:
6,765 years
Explanation:
Calculation to determine the age of the piece of wood in years
First step is to calculate decimal fraction of Carbon-14 that was remaining
Decimal fraction of Carbon-14= 6.00 counts per minute per gram/ 13.6 counts per minute per gram
Decimal fraction of Carbon-14 remaining= 0.4411765
Second step is to calculate the numbers of half-lives that have elapsed
(1/2)^n= 0.4411765
Hence,
n log 0.5 = log 0.4411765
n = 1.18057
Last step is to calculate the length of time that has elapsed
Using this formula
Elapsed length of time=Half life of carbon-14 *n
Let plug in the formula
Elapsed length of time=5,730 years * 1.18057
Elapsed length of time= 6,765 years
Therefore the age of the piece of wood in years will be 6,765 years
Answer the following questions about the last lesson below. What did we figure out about chain reactions? What did we figure out about fission? Fission produce more energy than a typical fuel sources, chain reaction
Answer:
(Nothing)-But No answer
How many atoms are in 2.00 moles of titanium
Answer:
3.04 atoms
Explanation:
because of the switzer theory
2 plus 45 was near tyhe decimal value of h solve for 123v minus 45b
Answer:
47
Explanation:
What is MS-Word?MS Word Ki Hai hardware software Ki Hai
Answer:
Ms word is a type of application that is used to make your work more easier nd attractive.
Explanation:
For ex- you can draw a line,you can highlight your text,make your text bold and you can also increase and decrease the font size.
What impact can limiting factors have on a population?
(a) Higher birth rate
(b) Higher death rate
(c) Stable population
(d) Lower death rate
Answer:
The answer is B. Limiting factors can lower birth rates, increase death rates.
Which substance can be decomposed by a chemical change?
a. calcium
b. potassium
c. sodium
d. sodium chloride
Which of the following is a chemical change?
A. Boiling water using fire
B. Breathing in oxygen and breathing out carbon dioxide
C. Ripping a piece of paper in half
D. Melting gold to make jewelry
Find the enthalpy for a constant pressure calorimetry reaction where the reaction occurs in a 250ml aqueous solution. The temperature changes from 25.0c to 26.1 c
Assume that cool = 4.18j/gt
Answer:
[tex]\Delta H=1149.5J[/tex]
Explanation:
Hello!
In this case, since the calorimeter contains a solution for which the specific heat is 4.18 J/g°C, which is equal to that of the water, we can also notice that the density is 1.00 g/mL and therefore the present mass is 250 g. In such a way, we compute the enthalpy change as shown below:
[tex]\Delta H=mC\Delta T[/tex]
Thus, by plugging in the mass, specific heat and temperature change, we obtain:
[tex]\Delta H=250g*4.18\frac{J}{g\°C}(26.1\°C-25.0\°C)\\\\\Delta H=1149.5J[/tex]
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If you start with 1.5 moles of H2O, how many moles of H4SiO4 do you make?
Answer:
0.75moles of H₄SiO₄
Explanation:
Given parameters:
Number of moles of H₂O = 1.5moles
Unknown:
Number of moles of H₄SiO₄ = ?
Solution:
To solve this problem, we need to write the reaction equation first;
SiO₂ + 2H₂O → H₄SiO₄
From the balanced reaction equation:
2 moles of water will produce 1 mole of H₄SiO₄
So 1.5 moles of water will produce [tex]\frac{1.5}{2}[/tex] = 0.75moles of H₄SiO₄
A molecule is made up of two or more atoms bonded together. True or false
Answer:
True
Explanation:
a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance.
If the root word "derm” means "skin,” which of these words means "the study of skin diseases and treatment”? dermatologically dermatological dermatologist dermatology
Answer:
it would be dermatology
Explanation:
the first two dont make sense, and a dermatologist is the doctors themselves, so therefore dermatology is the study of it
A radical is a reactive intermediate with a single ___ electron, formed by ___ of a covalent bond. Allylic radicals are stabilized by_____, making them ___ stable than tertiary radicals. A compound that contains an especially weak bond that serves as a source of radicals is called a radical ____. Treatment of cyclohexene with N-bromosuccinimide in the presence of light leads to___ by ___ intermediates. The stability of a radical ____ as the number of alkyl groups bonded to the radical carbon increases. Although alkanes undergo radical substitution reactions with both Cl_2 and Br_2 chlorination is ___ than bromination. A compound that prevents radical reactions from occurring is called a radical ___ Treatment of cyclohexene with bromine in an organic solvent leads to ___ by ___ intermediates. Radical halogenation reactions occur ____ racemization at a stereogenic center.
Answer:
unpaired
homolysis
more
initiator
allylic substitution
radical
increases
faster
inhibitor
addition
ionic
with
Explanation:
The list of suitable words to be used to fill in the blank spaces in the sentences have been shown in the image attached.
A radical is any specie that contains an unpaired (odd) electron. Radicals are formed by homolysis of covalent bonds.
Due to the double bond involved in resonance, allylic radicals are more stable than tertiary radicals although stability of radical increases with the number of alkyl groups present. Initiators easily supply free radicals for radical reactions.
Addition reactions are faster with Cl2 than with Br2 because chlorine is more reactive than bromine. The addition of Br2 to cyclohexene occur via ionic mechanism and ionic intermediates.
Radical halogenation reactions occur with racemization at a stereogenic center.
Which TWO statements describe the ocean floor giving brainliest pls
Answer:
i think that it is. d and b, im not completely sure but ik d is included
Explanation:
Answer:
think b and a
Explanation:
Why does sodium have a lower melting point then magnesium
Answer:
Number of delocalized electrons
Explanation:
Magnesium has more delocalized electrons compared to sodium and this accounts for the higher melting point.
When magnesium atoms comes together to form a metallic bonds, they have more network of delocalized electrons. There is more pull for the localized electrons due to the nuclear charge on the nucleus. This strong intermolecular metallic bond increases the melting point of magnesium.Oxidation of 1-pentanol could produce 1-pentanal and 1-pentanoic acid
What physical and chemical properties should braces (used to straighten teeth possess in order to attain its desired goal to straighten the teeth) while not presenting a health hazard to the individual?
Answer: Braces are used by the people to correct the alignment and position of tooth or teeth in the jaw.
Explanation:
The teeth braces must have strong tensile strength and must create a constant pressure on the teeth so as to allow the straightening of the teeth.
The strong force of attraction between the molecules of the braces material that can be steel, nickel, molybdenum, copper, titanium. This makes the bracing material rigid on the teeth.
Methane (CH4) is the main component of marsh gas. Heating methane in the presence of sulfur produces carbon disulfide and hydrogen sulfide as the only products. (a) Write the balanced chemical equation for the reaction of methane and sulfur. (Use the lowest possible coefficients. Include states of matter under SATP conditions in your answer.)(b) Calculate the theoretical yield of carbon disulfide when g of methane is reacted with an equal mass of sulfur.
Answer:
71.25 g
Explanation:
Methane + Sulfur = Carbon Disulfide + Hydrogen Sulfide
The equation is given as;
CH4 + S --> CS2 + H2S
Upon balancing, we have;
CH4(g) + 4S(s) → CS2(l) + 2H2S(g)
Theoretical yield of carbon disulphide;
Equal masses of 120g
The limiting reactant is sulphur It determines how much of the product is formed.
From the equation;
4 mol of S produces 1 mol of CS2
upon converting to masses using; Mass = number of mol * Molar mass
4 mol of S = 4 * 32
1 mol of CS2 = 76g
128g of S produces 76g of C2, 120g would produce ?
128 = 76
120 = x
x = 120 * 76 / 128
x = 71.25g
(a). The balanced chemical reaction will be:
[tex]\rm CH_4\;(g)+\;4\;S\;(s)\rightarrow\;CS_2\;(l)+\;2\;H_2S\;(g)[/tex]
(b). 120 grams of sulfur will produce 71.25 grams of carbon disulfide.
The heating of methane in the presence of sulfur can be given by:
[tex]\rm CH_4\;+\;S\;\rightarrow\;CS_2\;+\;H_2S[/tex]
(a). The lowest possible coefficients have been used to balance the number of elements on both sides i.e. reactant and the product.
[tex]\rm CH_4\;+\;4\;S\;\rightarrow\;CS_2\;+\;2\;H_2S[/tex]
The state of the elements has also been mentioned in the chemical equation. The state of methane is gas, sulfur is solid, carbon disulfide is liquid and hydrogen disulfide is gas.
Thus the balanced chemical reaction will be:
[tex]\rm CH_4\;(g)+\;4\;S\;(s)\rightarrow\;CS_2\;(l)+\;2\;H_2S\;(g)[/tex]
(b). When 120 grams of sulfur reacts, the yield of carbon disulfide will be:
From the balanced equation, 4 moles of sulfur will give 1 mole of carbon disulfide.
4 moles of Sulfur = mole [tex]\times[/tex] molecular weight
4 moles of Sulfur = 4 [tex]\times[/tex] 32
4 moles of Sulfur = 128 grams.
1 mole of carbon disulfide = 76 grams.
So, 128 grams of sulfur produces, 76 grams of carbon disulfide.
Thus, 120 grams of sulfur will produce = [tex]\rm \dfrac{76}{128}\;\times\;120[/tex] grams Carbon disulfide
120 grams of sulfur will produce = 71.25 grams of Carbon disulfide.
Thus, 120 grams of sulfur will produce 71.25 grams of carbon disulfide.
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What is the pH at the equivalence point of the titration of 50.0 mL of 0.300 M NH3(aq) with 0.150 M HCl(aq)?
Answer:
pH = 5.19, at the equivalence point
Explanation:
This is titration of a weak base and a strong acid. pH in the equivalence point will be acid. To determine this pH, we know that in in the equivalence point:
mmoles base = mmoles of base
50 mL . 0.3M = 0.150 M . Volume of acid
Volume of acid = (50 . 0.3)/ 0.15 → 100 mL
Total volume of equivalence point is 50 mL + 150 mL = 200 mL
Neutralization reaction is:
NH₃ + HCl → NH₄Cl
NH₃ + H₃O⁺ ⇄ NH₄⁺ + H₂O
15 15
0 0 15
Ammonia's Kb = 1.8×10⁻⁵
In the equivalence point, we have only ammonium, beacuse all the amonia reacted to the protons. Let's make the equilibrium
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka
I: 15 - - -
Eq: 15-x x x
Ka = 1×10⁻¹⁴ / Kb → 5.55×10⁻¹⁰
[NH₄⁺] = 15 mmoles / 200 mL = 0.075 M
In the equilibrium, we can avoid the 15 - x, because Ka is soo small.
Expression for Ka is [ NH₃ ] . [H₃O⁺] / [NH₄⁺] = 5.55×10⁻¹⁰
[H₃O⁺] = √(5.55×10⁻¹⁰ . 0.075)
[H₃O⁺] = 6.45×10⁻⁶
- log [H₃O⁺] = pH → 5.19
how many atoms of oxygen are in a molecule of nitroglycerin
Answer:
i think there are 3 carbon and 5 hydrogen
Explanation:
There are 9 atoms of Oxygen in a molecule of nitroglycerin.
What is Nitroglycerin?Nitroglycerin is also called Trinitroglycerin, It is an oily, thick, colorless liquid.
A vasodilator, nitroglycerin is generally used to relieve anginal chest pain. Currently, the FDA has approved it for the acute prophylaxis of angina pectoris owing to coronary artery disease as well as the acute alleviation of an episode.
It is used in manufacturing explosives.
The molecular formula of Nitroglycerin is C₃H₅N₃O₉
The chemical formula is 1,2,3-trinitroxypropane.
A molecular formula shows the number of atoms present in the compound.
The number of atoms of Carbon present is 3.
The number of atoms of Hydrogen present is 5.
The number of atoms of Nitrogen present is 3.
The number of atoms of Oxygen present is 9.
So, the total number of atoms of Oxygen present is 9.
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Which of the period 2 homonuclear diatomic molecules are predicted to be paramagnetic?
Need help!! (10 Points)
which liquid is the most viscous and why?
the increase in atomic radius as you go down the periodic table is caused by?
Answer: The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase.
Which characteristic applies to all mixtures?
Answer:
A mixture is the blending of two or more dissimilar substances. A major characteristic of mixtures is that the materials do not chemically combine. Mixtures can be divided into those that are evenly distributed (homogeneous) and those that aren't (heterogeneous).
Explanation:
Answer:
A mixture is the blending of two or more dissimilar substances. A major characteristic of mixtures is that the materials do not chemically combine. Mixtures can be divided into those that are evenly distributed (homogeneous) and those that aren't (heterogeneous
How many unshared electrons are found in the lewis dot structure of Carbon Dioxide or CO2?
There are 4 lone pairs of electrons present in the carbon dioxide molecule
PLEASE MARK ME AS BRAINLIEST
Answer:
Explanation:
Carbon dioxide, CO2
Each oxygen contributes 2 electrons - 1 for each bond. That means there are a total of 8 electrons around the carbon, in 4 pairs. Because there are 4 bonds, these are all bond pairs.
How red blood cells different to animal cells
Answer:
By contrast, the red blood cells of mammals lack nuclei and other internal structures found in most animal cells. This simplification allows mammal red blood cells to carry more gas-transporting proteins and to squeeze through smaller blood vessels.
Explanation:
