Answer:
A ; 20g of water has the least number of molecules
Explanation:
Here, we want to know which of the options represent the least number of molecules;
To calculate this, we are going to first calculate the number of moles using the formula below;
Number of moles = mass/molar mass
Then from the number of moles, we can calculate the number of molecules by multiplying the number of moles by 6.02 * 10^23 molecules
Let’s proceed;
a. That will be 20/18.02 = 1.1099 moles
1.1099 * 6.02 * 10^23 = 6.68 * 10^23 molecules
b. That will be 77/16.06 = 4.8 moles
4.8 * 6.02 * 10^23 = 2.89 * 10*24 molecules
c. That will be 68/42.09 = 1.62 moles
1.62 * 6.02 * 10^23 = 9.73 * 10^23 molecules
d. That will be 100/44.02 = 2.27 moles
2.27 * 6.02 * 10^23 = 1.37 * 10^24 molecules
e. That will be = 84/20.01 = 4.2 moles
4.2 * 6.02 * 10^23 = 2.53 * 10^24 molecules
From all the values obtained, the lowest is 20g of water
What has 2 protons and 2 neutrons in the center of the atom
Answer:
HELIUM
Explanation:
HELIUM HAS 2 PROTON I
what is the balanced chemical equation when solid calcium oxide and carbon dioxide gas are formed by the decomposition of solid calcium carbonate (CaCO3)
An aluminum cylinder has a radius of 3.2 cm and a length of 8.6 cm. What is the mass of the aluminum cylinder if aluminum has a density of 2.7 g/cm3?
please help :)
Answer:
750g of Aluminum
Assuming 8.6 cm lenth is the height of the cylinder. The volume of a cylinder is: V = [tex]\pi[/tex]*r^2*h
V = 3.14cm x 10.24cm x 3.6cm
V = 280cm^3
Now density = mass/volume
2.7g/cm^3 = mass/280cm^3
2.7g/cm^3 x 280cm^3 = mass/280cm^3 x 280cm^3
= 750g of Aluminum
The element X has three naturally occurring isotopes. The isotopic masses (amu) and % abundances of the isotopes are given in the table below. Calculate the average atomic mass of the element in amu. PLEASE HELP ASAP
Answer:
162.349
Explanation:
(.3060 * 159.37) + (.1579 * 162.79) + (.5361 * 163.92) = 162.349
A certain substance X has a normal freezing point of −3.1°C and a molal freezing point depression constant =Kf·6.23°C·kgmol−1. Calculate the freezing point of a solution made of 12.3g of urea NH22CO dissolved in 300.g of X. Be sure your answer has the correct number of significant digits.
Answer:
Freezing T° of solution = - 7.35 °C
Explanation:
This is about the freezing point depression, a colligative property which depends on solute.
The formula is: Freezing T° pure solvent - Freezing T° solution = m . Kf . i
Freezing T° of pure solvent is -3.1°C
At this case, i = 1. As an organic compound the urea does not ionize.
We determine the molality (mol/kg of solvent)
We convert mass to moles:
12.3 g . 1mol / 60.06 g = 0.205 moles
0.205 mol / 0.3 kg = 0.682 mol/kg
We replace data in the formula:
-3.1°C - Freezing T° of solution = 0.682 mol/kg . 6.23 kg°C/mol . 1
Freezing T° of solution = 0.682 mol/kg . 6.23 kg°C/mol . 1 + 3.1°C
Freezing T° of solution = - 7.35 °C
what would happen to the solvent if a reaction was refluxed without a condenser
Answer:
Solvent will be lost as gas and not return into the vessel via condensation.
Explanation:
Reflux is a technique used in chemistry to boil a particular solvent and convert the gas formed back into liquid by condensation. This technique allows a solvent to be heated at a regulated temperature but for a prolonged period of time than it would normally take place.
The reflux procedure makes use of a reflux CONDENSER, which is an apparatus that allows vapour from the heating/boiling to flow back into the reaction vessel. The CONDENSER functions to prevent the loss of the SOLVENT as vapour by providing a cooling effect on the vapour.
Therefore, if a reaction was refluxed without a condenser, THE SOLVENT WILL BE LOST AS VAPOUR
Which is most reactive toward electrophilic aromatic substitution?
Complete Question
Which is most reactive toward electrophilic aromatic substitution?
A Phenol
B Anisole
C Nitro-benzene
D Benzene
Answer:
The correct option is A
Explanation:
Generally the rate at which electrophilic aromatic substitution reaction occur is dependent on the nucleophilicity(nucleophile strength ) of Benzene ring.Now a functional group which increase the electron density in the benzene ring when attached to it increases its nucleophilicity and this in-turn will increase the rate at which electrophilic aromatic substitution reaction occur
Now Phenol is a compound that is made up of OH functional group and then the benzene ring
Anisole is a compound that is made up of [tex]OCH_3[/tex] functional group and then the benzene ring
Nitro-benzene is a compound that is made up of [tex]NO_2[/tex] functional group and then the benzene ring
Now since OH is the highest In series of activating group compared to the activation groups we are considering (i.e [tex]OCH_3[/tex] and [tex]NO_2[/tex] )
Then Phenol is the answer
What is the term for a solution that is holding more dissolved solute than it should be able to at a particular temperature?
Explanation:
Sometimes, a solution contains more dissolved solute than is normally possible. This type of solution is said to be supersaturated. A saturated solution can become supersaturated if more solute is added while the temperature is raised.
hope it will help u ✌️
How can pH go high over time
Factors that raise pH in a swimming pool. 1. Natural pH Rise: Carbon Dioxide Loss. The chemistry of pH sounds a lot more complicated than it is. In short, the less CO 2 in solution, the ... 2. Sanitizers and their pH Impact. 3. pH and alkalinity adjustment chemicals.
The density of ice is 0.917 g/cm3. What volume of ice does 52.75 g occupy?
Answer:
The answer is
57.52 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
mass of ice = 52.75 g
density = 0.917 g/cm³
The volume of the ice is
[tex]volume = \frac{52.75}{0.917} \\ = 57.52453653[/tex]
We have the final answer as
57.52 mLHope this helps you
The two forces acting on a boat or some other floating object are________
and gravity.
Answer:
buoyancy. ...
Explanation:
........
Answer:
buoyancy
Explanation:
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i am timed please help
Answer:
mixture
Explanation:
there was leftover components meaning there was something mixed into the liquid
what is zirconium electron configuration
kr,5s2,4d2
Explanation:
as itis in the 2nd transition series
Not divisible
O atom
O compound
O mixture
O solution
Answer:
mixture or atom
Explanation:
I HOPE IT WILL HELP YOU
Explanation:
and ,answer is mixture.
what is the strength of alloys and what is the solubility of alloys please answer this simple question within 12 hours will mark brainliest for sure
Answer:Features very high tensile strength and toughness. Titanium alloys are light in weight, have superior corrosion resistance properties and can withstand extreme temperatures. ... Titanium alloys are heat-treated to increase their strength in terms of fracture toughness, fatigue strength and high temperature strength.35 grams is the sollubility.
Explanation:
Discuss the effect of changing the flow tube radius on flow rate.
Answer:
The flow rate of a tube is the volume of fluid flowing through the tube per unit time. The flowrate is proportional to the product of the velocity of the fluid through the tube, and the cross-sectional area of the tube.
That is
Q = AV
where
A is the area of the tube
V is the velocity of the tube
The cross-sectional area of the tube is proportional to the radius of the tube. From the above equation, we can deduce that if the velocity of the fluid flowing through the tube is held constant, the flowrate of the fluid through the tube will increase with an increase in the radius of the tube, and it will decrease with a decrease in the radius of the tube.
What is another name for Group 6A? O A. Group A6 O B. Group 6B O C. Group 16 D. Group 6
Answer: group 16
Explanation: apex
Brian's aunt has cats. When Brian recently visited her, he started sneezing badly and believes that it was because
he is allergic to cats.
What would be the next step for Brian to form a hypothesis?
O by avoiding going to his aunt's house
by wearing a nose mask near cats
by visiting other households with cats
O by visiting his aunt's house again with the cats outside
Answer:
By visiting other households with cats.
Explanation:
This will give Brian a variety of other houses and determine if it is truly cats or just alleries from other items. This is the most direct way to get Brian the answer he is looking for.
Answer:
c
Explanation:
i just did it
Which of the following are false about Prokaryotic Transcription termination?
A. It can occur in a factor dependent fashion.
B. It can occur in a factor independent fashion.
C. It may involve Rho protein.
D. none of the above.
Answer: none of the above
Explanation:
In Prokaryotic Transcription termination, it should be noted that the RNA polymerase transcribes through a terminator sequence, which in turn results in the polymerase to be separated from the DNA and thereby leads to its release of the transcrip.
Prokaryotic Transcription termination can occur in a factor dependent fashion, can occur in a factor independent fashion and may involve Rho protein.
Therefore, none of the options is false.
You have an atom with a mass number of 100 with 85 neutrons. What is this
element?
Answer:
phosphorus i believe
Explanation:
in order to find the atomic number you minus the mass number from number of neutrons then just look it up in a periodic table
The mass number of the atom is 100 and number of neutrons is 85. Then, number of protons is 15. Then, element with 15 protons and 15 electrons is phosphorous.
What is mass number ?An atom is composed of subatomic particles electrons, protons and neutrons. Protons and neutrons are located inside the nucleus. The mass number of an atom is sum of number of protons and neutrons.
The number of electrons in an atom in its neutral state is called its atomic number. In a neutral atom, the number of electrons and proton are the same.
Give the mass number = 100
no.of neutrons = 85
no.of protons = 100 -85 =15
no.of electron = 15
Thus, atomic number = 15.
The element with atomic number of 15 is phosphorous (P).
Find more on phosphorous :
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Which of the following is true concerning y? A) wdescribes the probability of finding an electron in space. B) ya describes the exact path of electron motion in an orbital. C) w? describes the electronic structure of the atom according to the Bohr model. D) w describes the exact volume of an atom. E) w2 describes the size of an atom.
Answer:
wdescribes the probability of finding an electron in space.
Explanation:
The quantum mechanical model of the atom assigns wave properties to the electron. This is in accordance with Heisenberg's uncertainty principle.
The probability of finding the electron in a given volume element is given as the square of the wave function while the wave function itself does not really have a physically significant meaning.
However, the wave function is a mathematical function that contains a detailed information about the behavior of an electron.
If you were running an experiment to determine the temperature at which beans sprouted (germinated) the fastest, what would be the outcome (dependent variable)?
Answer:
Temperature on beans sprouted
Explanation:
The variable amount is the amount that changes continuously. We calculate the sprout of the bean at which temperature it is sprouting rapid, in that case, the temperature acts as a variable amount.Materials
80 mL Carbonated Water
80 mL Acetic Acid
(2) Chalk Pieces (CaCO3)
Permanent Marker
*80 mL Tap Water
*Timer (watch, cell phone, internet, etc.)
Note: You must provide the materials listed in *red.
Labware
(3) 250 mL Beakers
Digital Scale
EXERCISE 1: SPELEOLOGY (UNDERSTANDING CAVE FORMATION)
In this exercise, you will observe what happens to chalk in different solutions and compare your observations to what occurs in nature.
1. Do the results of the exercise support your hypothesis? Explain your reasoning.
2. Compare and contrast the reaction of the chalk pieces in each solution.
3. Is this exercise an analog for physical or chemical weathering? Explain your reasoning.
4. Using your observations of the chalk in different solutions, explain how a limestone cave forms.
Answer:
Limestone caves are formed when acid rain occurs.
Explanation:
When chalk pieces which is made of calcium carbonate react with acetic acid, it produces carbon dioxide, calcium acetate, and water. When calcium carbonate react with Carbonated Water produces calcium bicarbonate. Limestone cave forms when the dissolution of limestone occur when rainwater which is acidic due to the addition of carbondioxide in the air react with limestone. This dissolution removes the lime from the rock and caves are formed.
The chalk has been made up of calcium carbonate. The reaction of calcium carbonate with different solutions results in the formation of varying products.
The reaction of chalk with acetic acid results in the formation of Calcium acetate, with the production of carbon dioxide and water.
The reaction of chalk with carbonated water results in the formation of calcium bicarbonate.
The limestone caves has been formed by the dissociation of limestone with reaction of acid, forming carbon dioxide.
The formation has takes place in the acidic solution, and carbon-dioxide thus the resultant can be due to the acid rain.
For more information about the limestone cave, refer to the link:
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Enzymes which are usually increase the rate of a reaction by________.
Which action changes the identity of substance referenced
Answer:
When iron turns to rust, the chemical identity of the iron changes. When you break ice, the ice is still ice
11.In 13C NMR spectroscopy, the signal due to this type of carbon occurs furthest downfield.A)–CºNB)C)D)E)–CºC–
Answer:
C=O
Explanation:
The nuclear magnetic resonance (NMR) spectroscopy is a method that employs the technique to observe the local magnetic fields are atoms. This analytical technique exploits sufficient differences in the frequency of nuclear magnetic resonance in protons and atoms within organic compounds that depend on their neighboring atoms.
Amongst all the given options, the carbonyl is the right option because the carbon is doubly bonded to the oxygen and the hybridization of this double bond is sp² hybridized, as a result, the electron density at the carbon possess a lower amount in order to have more magnetic field.
The increasing order of these chemical shifts are as follows:
C - X < [tex]\mathbf{C -O }[/tex]≅[tex]\mathbf{ \mathrm{-C\equiv C-}}}[/tex] < -C≡N < C=O
The elements carbon, hydrogen, oxygen, and nitrogen make up which percentage of the human body?
Answer:
96% Hope it helps
Explanation:
Roughly 96% of the mass of the human body is made up of just four elements: oxygen, carbon, hydrogen and nitrogen, with a lot of that in the form of water. The remaining 4% is a sparse sampling of the periodic table of elements.
Determine the equilibrium expression for the following reaction:
2NaHCO3(s)⇋Na2CO3(s)+H2O(g)+CO2(g)
Answer:
K = [Na2CO3] [H2O] [CO2] / [NaHCO3]²
Explanation:
2NaHCO3(s)⇋Na2CO3 (s) + H2O(g) + CO2(g)
To write an expression for equilibrium constant, K, for the above reaction, it is important that we have an idea of what equilibrium constant is all about and how we can determine it.
Equilibrium constant for a reaction is simply defined as the ratio of the concentration of the product raised to their coefficient to the concentration of the reactant raised to their coefficient.
Thus the expression for the equilibrium constant for the above equation can be written as follow:
K = [Na2CO3] [H2O] [CO2] / [NaHCO3]²
what is Corona virus And explain breifly in
Answer:
it is a viral disease . it is infected by one person to other .
Because a gas has no definite volume or shape, in what way does it take up space? (2 points)
Group of answer choices
By taking the volume of a solid
By taking the volume of a liquid
By taking the shape of its container
By taking the volume of its container
Answer:
By taking the volume of the container.
Answer:
By taking the volume of the container
Explanation:
it does not have any specific volume or shape, so the way it volume is the volume of container.
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