Complete Question
You are given a solution containing a pair of enantiomers (A and B). Careful measurements show that the solution contains 98% A and 2% B. What is the enantiomeric excess?
Answer:
The value is [tex]k = 96 %[/tex]
Explanation:
From the question we are told that
The percentage of enantiomer A is A = 98%
The percentage of enantiomer B is B = 2%
Generally the enantiomeric excess is mathematically represented as
[tex]k = \frac{A -B}{A+B} * 100[/tex]
=> [tex]k = \frac{98 -2}{98+2} * 100[/tex]
=> [tex]k = 96 %[/tex]
Why is the atomic theory a theory and not a law?
10 Points)
A theory is the best possible explanation based on all existing evidence.
A theory is a pattern in nature.
O A theory does not change.
O A theory is more important than a law.
Answer: A) A theory is the best possible explanation based on all existing evidence
A law in physics and chemistry is a description of what is going on. For instance, newton's law of motion helps us find out an objects acceleration if we know its mass and the force applied. The theory of gravity on the other hand is the best guess we make as to why objects with mass are attracted to one another.
Theories change over time if new evidence is found that contradicts the old theory. Saying "a theory is more important than a law" is subjective, and I would argue that both are equally important in their own way.
The atomic theory a theory is the best possible explanation based on all existing evidence. The correct option is A.
What is a theory?The word theory renowned as to an untested hunch or one can say a guess with not having a supporting evidence.
A theory, has nearly the opposite implications for scientists. A theory is a well-supported explanation of an innate phenomenon that can encompass laws, hypotheses, along with facts.
Theories are developed to elaborate, predict, as well as comprehend phenomena, also to challenge and extend existing understanding within the constraints of critical boundary assumptions.
A theory does not become a scientific law as new or better evidence accumulates.
The theories are explanations, as well as laws are patterns located in large amounts of data that are frequently expressed as an equation. A theory will always be a theory in all aspect, and a law will always be a law.
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A cube of aluminum measures 3 cm on each side and weighs 81 g. What is its density? (HINT: find the volume of the block first)
D=
M=
V=
Answer:
27
Explanation: volume-3 times 6=18 /mass- 81 times 6= 486.... 486 divided by 18 = 27.... a cube has 6 sides.
The density of a substance is simply defined as the mass of the subtance per unit volume of the substance.
[tex]Density = \frac{Mass }{Volume }[/tex]
To obtain the density of the aluminum, we'll begin by calculating the volume of the aluminum. This can be obtained as follow:
From the question given above, each side of the aluminum cube measures 3 cm. Thus,
Length (L) = 3 cm
Width (W) = 3 cm
Height (H) = 3 cm
Volume = Length × Width × Height
Volume = 3 × 3 × 3
Volume = 27 cm³Therefore, the volume of the aluminum is 27 cm³
Finally, we shall determine the density of the aluminum. This can be obtained as follow:
Mass = 81 g
Volume = 27 cm³
Density =?[tex]Density = \frac{Mass }{Volume }\\\\Density = \frac{81}{27}[/tex]
Density = 3 g/cm³Therefore, the density of the aluminum is 3 g/cm³
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In which of the following atoms are valence electrons in the lowest average potential energy states?
Cl
Br
F
I
Answer:
C) F
Explanation:
Valence electrons are the electrons present in the outermost shell of an atom and have the highest energy level of an atom whereas electrons at ground state or lower orbitals have less potential energy.
This is so because orbitals nearby nucleus are strongly bonded with the atomic nucleus and have less energy than an outermost shell.
So, the potential energy states of an atom depend on the number of orbitals. In the given options fluorine with atomic number 9 has less number of orbitals that is 2 orbitals and valence electrons will be present in second orbitals, so fluorine will have the lowest average potential energy states.
Hence, the correct option is "C) F".
1. Assume this experiment (after the extractions are complete) left you with 4 pure products (aspirin, acetaminophen and caffeine, and the binder). Your lab mate distracted you after you had labeled the binder and now you can’t remember which of the remaining 3 products is which. What would be a simple test that you can perform in the laboratory to distinguish between the 3 remaining solids isolated from your experiments?
Answer:
Explanation:
Out of aspirin, acetaminophen and caffeine, aspirin is an acid because it is acetyl saliciylic acid . Hence it can be tested with litmus paper .
acetaminophen contains phenolic functional group , hence it is a weak acid . It can be tested with any test with which phenol test are done, like with neutral solution of ferric chloride .
caffeine is weak basic substance . It can also be tested with the help of testing a basic substance .
On the basis of your understanding of the general solubility guidelines, predict which of the following substances are likely to be soluble in water.
a. zinc chloride
b. cobalt(III) sulfide
c. lead(II) nitrate
d. chromium(II) hydroxide
e. lead(II) sulfate
f. magnesium carbonate
g. sodium iodide
h. ammonium carbonate
Answer:
ZnCl2
sodium iodide
ammonium carbonate
Pb(NO3)2
Explanation:
Substances that dissolve in water can be accurately determined using the solubility rules.
According to the solubility rules, all nitrates are soluble. This implies that lead II nitrate is also soluble in water.
Similarly, all chlorides are soluble in water hence ZnCl2 is soluble in water.
Sulphates are soluble except those of Pb, Ba, Ca and Mg.
Also, NaI is highly soluble in water.
Lastly, all carbonate salts are insoluble except those of sodium, potassium and ammonium. Hence ammonium carbonate is soluble in water.
The first energy level which has p orbitals to fill is ___
1
2
3
4
Answer:
2
Explanation:
The Aufbau sequence of increasing energy levels is 1s,2s,2p,3s,3p,4s,3d and so on....
Hope this helps! :D
1. In general, what is meant by the term chemical bond? Name and
describe the 3 principle types of chemical bonds.
Answer: The simplest and most common type is a single bond in which two atoms share two electrons. Other types include the double bond, the triple bond, one- and three-electron bonds, the three-center two-electron bond and three-center four-electron bond. ... Bonds within most organic compounds are described as covalent.
Explanation:
it is the main factor of contact metamophism.
Answer:
The size of a contact aureole depends on a number of factors that control the rate at which heat can move out of the pluton and into the surrounding country rock. Among these factors are: The size and temperature of the intrusion. This will control how much heat is available to heat the surrounding country rocks
Explanation:
Hope this helps u
crown me as brainliest
Which are replenished MORE quickly than they are used?
A. energy resources
B. material resources
C. renewable resources.
D. nonrenewable resources
Answer:
C renewable
Explanation:
because renewable energy repleneshes itself, therefore the quickest
Renewable resources are replenished MORE quickly than they are used (option C).
Renewable resources can be defined as a type of resource that cannot be depleted, thereby supplying a constant source of such resources.A source of renewable energy can be used to obtain unlimited amounts of energy without damaging the environment.Renewable sources of energy include solar energy, wind energy, hydrothermal energy, etc.In conclusion, renewable resources are replenished MORE quickly than they are used (option C).
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A balloon contains 1.1 L of gas at a pressure of 0.80 atm. How will the volume
change if the pressure is increased to 2.0 atm?
Answer:
Final volume = 0.44 L
Explanation:
Given data:
Initial volume of balloon = 1.1 L
Initial pressure = 0.80 atm
Final volume = ?
Final pressure = 2.0 atm
Solution:
The given problem will be solved through the Boly's law,
"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"
Mathematical expression:
P₁V₁ = P₂V₂
P₁ = Initial pressure
V₁ = initial volume
P₂ = final pressure
V₂ = final volume
Now we will put the values in formula,
P₁V₁ = P₂V₂
0.80 atm × 1.1 L = 2.0 atm × V₂
V₂ = 0.88 atm. L/ 2.0 atm
V₂ = 0.44 L
Prior to science lab, Maria had been drinking a can of soda. When she walked into the lab she set it down on the hot plate at her station. She heard a liquid beginning to boil, and realized that the previous students had forgotten to turn off the hotplate and the boiling noise was from the remaining soda in the can. Without thinking, she picked up the can with her bare hands, and put it upside down into the sink which was half full of liquid. Immediately the can crushed as though it was going to be recycled. What do you think is happening to the soda and air in the can? Support you claim in Question 4, by explaining why you think it is happening. Formulate your hypothesis for the problem. Critique Maria’s laboratory safety procedures.
Answer:
See explanation
Explanation:
When the temperature was increased, the pressure of the gas in the can was increased.
When Maria removed the can and placed it in cold liquid, the decrease in temperature led to a corresponding decrease in pressure of the gas inside the can hence the can was crushed.
Hypothesis: The pressure of the gas in the can is directly proportional to temperature.
Maria was careless about the experiment. She ought to have first checked whether the hot plate was off before placing the soda can. Secondly,she should not have immediately plunged the soda can into liquid because it will shrink due to decrease in pressure. She should not also have removed the soda can with bare hands to avoid getting burns and blisters.
The ion with the smallest diameter is ________. The ion with the smallest diameter is ________. Be2 Sr2 Ca2 Ba2 Mg2
Answer:
Be2^+
Explanation:
Ionic diameter increases down the group. This implies that Be2^+ will have the smallest diameter.
This extremely small diameter makes Be2^+ to differ considerably from other ions of group 2 elements.
For instance, the compounds of beryllium are mostly covalent in nature.
what happens when a solution of an acid is mixed with a solution of a base in a test tube?
Answer:
Explanation:
When acid is mixed with a solution of base it results in a neutralization reaction. Neutralization is an exothermic reaction which results in the formation of salt.
OMG plz help me out with this!!
What are 3 differences between animal cells and plant cells?
What do the cell wall and chloroplasts do for the plant cell?
What are 2 things that animal cells and plant cells have in common?
Thank you!
Which statement explains why NaBr is classified as a compound?
1.
Na and Br are chemically combined in a fixed proportion.
2.
Na and Br are both nonmetals.
3
NaBr is a solid
298 Kand standard pressure.
4.
NaBr dissolves in H20 at 298 K.
Submit
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Answer:1
Explanation:i know cuz I got it right
NaBr is classified as a compound because sodium and bromine are chemically combined in a fixed proportion.
Explanation:
Element is defined as the simplest form of a substance that cannot be divided further by any physical means.For example oxygen ([tex]O_2[/tex]), coal (carbon) etc.A compound is defined as the form of a substance in which two or more different elements are chemically combined together in a fixed proportion.For example sodium chloride (NaCl), nitric acid ([tex]HNO_3[/tex])A compound can be further divided into a simple substance.So, from this, we can conclude that NaBr is classified as a compound because sodium and bromine are chemically combined in a fixed proportion.
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What is the concentration (g/L) of an albumin solution made by mixing 0.20 mL of 6.0 g/L solution with 2.72 mL BCG reagent? Assume volumes are additive.
Answer:
0.41g/L
Explanation:
To find the concentration of the albumin in the mixture we need to find the mass in grams and the volume in liters of the solution:
Mass of albumin:
0.20x10⁻³L * (6.0g / L) = 1.2x10⁻³g of albumin
Volume of the solution:
0.20mL + 2.72mL = 2.92mL = 2.92x10⁻³L
Thus, concentration of albumin is:
1.2x10⁻³g of albumin / 2.92x10⁻³L =
0.41g/LThe atomic notation for a particular atom of boron is ' B. The
atomic number is while the mass number is
Answer:
5;11
Explanation:
What concentration of NO−3NO3− results when 897 mL897 mL of 0.497 M NaNO30.497 M NaNO3 is mixed with 813 mL813 mL of 0.341 M Ca(NO3)2?
Answer:
Explanation:
NaNO₃ = Na⁺ + NO₃⁻¹
.497 M .497 M
moles of NO₃⁻¹ = .897 x .497 = .4458 moles
Ca( NO₃)₂ = Ca + 2 NO₃⁻¹
.341 M 2 x .341 M = .682 M
moles of NO₃⁻¹ = .813 x .682 = .5544 moles
Total moles = .4458 moles + .5544 moles
= 1.0002 moles
volume of solution = 897 + 813 = 1710 mL
= 1.710 L
concentration of nitrate ion = 1.0002 / 1.710 M
= .585 M
4. What reagent would you predict to be in excess for reacting 7.50 mL of a 0.10M BaCl2 solution with 7.50 mL of 0.10M KIO3 solution
Answer : [tex]BaCl_2[/tex] reagent predict to be in excess.
Explanation : Given,
Concentration of [tex]BaCl_2[/tex] = 0.10 M
Volume of [tex]BaCl_2[/tex] = 7.50 mL = 0.0075 L (1 L = 1000 mL)
Concentration of [tex]KIO_3[/tex] = 0.10 M
Volume of [tex]KIO_3[/tex] = 7.50 mL = 0.0075 L
First we have to calculate the moles of [tex]BaCl_2[/tex] and [tex]KIO_3[/tex].
[tex]\text{Moles of }BaCl_2=\text{Concentration of }BaCl_2\times \text{Volume of }BaCl_2[/tex]
[tex]\text{Moles of }BaCl_2=0.10M\times 0.0075L=0.00075mol[/tex]
and,
[tex]\text{Moles of }KIO_3=\text{Concentration of }KIO_3\times \text{Volume of }KIO_3[/tex]
[tex]\text{Moles of }KIO_3=0.10M\times 0.0075L=0.00075mol[/tex]
Now we have to calculate the excess and limiting reagent.
The balanced equilibrium reaction will be:
[tex]BaCl_2+2KIO_3\rightleftharpoons Ba(IO_3)_2+2KCl [/tex]
From the balanced reaction we conclude that
As, 2 mole of [tex]KIO_3[/tex] react with 1 mole of [tex]BaCl_2[/tex]
So, 0.00075 moles of [tex]KIO_3[/tex] react with [tex]\frac{0.00075}{2}=0.000375[/tex] moles of [tex]BaCl_2[/tex]
From this we conclude that, [tex]BaCl_2[/tex] is an excess reagent because the given moles are greater than the required moles and [tex]KIO_3[/tex] is a limiting reagent and it limits the formation of product.
Hence, [tex]BaCl_2[/tex] reagent predict to be in excess.
Which phase change results in an increase in entropy?
1.
12(9) - 12(s)
2.
CH2(g) - CH40
3.
Br2(1) - Br2(g)
4.
H20(1) - H20(s)
The phase change that results in an increase in entropy is the change; Br2(1) - Br2(g)
What is entropy?The term entropy refers to the degree of disorderliness in a system. We have to note that gases have a higher entropy than liquids and liquids have a higher entropy than the solids.
As such, the phase change that results in an increase in entropy is the change; Br2(1) - Br2(g)
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What is the mass number of an element?
A. Mass number is the number of protons in the nucleus.
B. Mass number is the mass of the protons in the nucleus.
C. Mass number is the mass of the most abundant isotope.
D. Mass number is the atomic mass of a particular isotope.
The mass number of an element is the sum of the protons and neutrons present in the nucleus of the atoms of the element.
What is mass number?The mass number of an element is the number obtained when the number of protons and neutrons in the nucleus of an atom of the element are summed together.
The sum of protons and neutrons in the nucleus of an atom is collectively known as the nucleon. Thus, the mass number of an atom can also be referred to as the nucleon of the atom.
This can be mathematically expressed as:
Mass number = number of protons + number of neutrons.
Atoms generally contain protons, neutrons, and electrons. The protons are positively charged and are located in the nucleus, the neutrons are also located in the neucleus but have no charges. The electrons, on the other hand, are located outside the nucleus in regions referred to as orbitals.
The sum of the protons and neutrons determine the mass of an atom because the contribution of electrons to the mass of atoms is negligible.
Thus, the mass number of an element is the sum of proton and neutron numbers present in the nucleus of the atoms of the element.
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Need help with 6 plsss
Answer:
I think is is D cause none of the other ones seen right
Answer:
The answer is D. The 2s subshell can hold more electrons
Scientific notation
3.7 x 10^6
The answer should be 37,000,000
Atoms of two different elements must have different
electrical charges.
numbers of neutrons.
atomic numbers.
energy levels.
GIVE EXPLANATION!!!!
Answer:
c atomic numbers
Explanation:
hope this helps
Answer:
atomic numbers
Explanation:
In order for two atoms to be different, they have to have a different number of protons. Protons are represented by the atomic number. Thus, atoms of two DIFFERENT elements must have different atomic numbers.
I took the test and got 100%
Hope this helps!
Determine the pH of a 0.461 M C6H5CO2H M solution if the Ka of C6H5CO2H is 6.5 x 10-5. Determine the pH of a 0.461 M C6H5CO2H M solution if the Ka of C6H5CO2H is 6.5 x 10-5. 11.74 9.48 5.48 4.52 2.26
Answer:
the answer
Explanation:
the answer
The pH of the solution can be calculated using the Ka value and molarity of the acid. pH of the acid is obtained as 2.26.
What is pH?pH of a solution is the measure of acidity or basicity. Mathematically it is the negative logarithm of H+ ion concentration in the solution.
pH = - log [H+]
The constant Ka is called ionization constant of an acid. Acetic acid ionizes into equimolar concentrations of H+ and CH₃COO- ions. The Ka can be written as:
[tex]\rm K_{a} = \frac{[CH_{3}COO^{-}][H+]}{[CH_{3}COOH]}[/tex]
Where, [CH₃COO-] = [H+] Thus the expression becomes changed and from the values of Ka and molarity of the acid, H+ ion concentration can be calculated.
6.5 × 10⁻⁵ = [H+]² / [0.461 M]
[H+] = 0.0054.
Now, the pH can be calculated as follows:
pH = - log [0.0054]
= 2.26.
Therefore, the pH of the acidic solution is 2.26.
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Determine the percent ionization of a 0.225 M solution of benzoic acid. Express your answer using two significant figures.
Answer:
1.68% is ionized
Explanation:
The Ka of benzoic acid, C₇H₆O₂, is 6.46x10⁻⁵, the equilibrium in water of this acid is:
C₇H₆O₂(aq) + H₂O(l) ⇄ C₇H₅O₂⁻(aq) + H₃O⁺(aq)
Ka = 6.46x10⁻⁵ = [C₇H₅O₂⁻] [H₃O⁺] / [C₇H₆O₂]
Where [] are concentrations in equilibrium
In equilibrium, some 0.225M of the acid will react producing both C₇H₅O₂⁻ and H₃O⁺, the equilibrium concentrations are:
[C₇H₆O₂] = 0.225-X
[C₇H₅O₂⁻] = X
[H₃O⁺] = X
Replacing:
6.46x10⁻⁵ = [X] [X] / [0.225-X]
1.4535x10⁻⁵ - 6.46x10⁻⁵X = X²
1.4535x10⁻⁵ - 6.46x10⁻⁵X - X² = 0
Solving for X:
X = -0.0038. False solution, there is no negative concentrations.
X = 0.00378M. Right solution.
That means percent ionization (100 times Amount of benzoic acid ionized over the initial concentration of the acid) is:
0.00378M / 0.225M * 100 =
1.68% is ionizedMagnesium oxide is 60.3% magnesium by mass. What is the mass fraction of magnesium in magnesium oxide?
a. 0.603
b. 0.397
c. 39.7
d. 60.3
e. None of these
Answer:
A. 0.603
Explanation:
Mass fraction of an element in a substance = mass of that element / total mass of the substance.
Mass of magnesium = 24.3g/mol
Mass of oxygen = 16g/mol
Total mass of MgO = 24.3+16 = 40.3g/mol
Hence, the mass fraction of magnesium in Magnesium oxide =
24.3/40.3
= 0.6029
= 0.603
Another way is to divide the percentage by mass of magnesium by 100 i.e. 60.3% = 60.3/100
= 0.603
Into which two smaller groups are plants divided.
(a)vascular and nonvascular
(b)seed and seedless
(c)monocots and dicots
(d)seeds and spores
giving 17 points please help
explain how sound and vibration are related ?
Answer:
because they can create noise
Explanation:
sounds is through music or songs but vibration is just quick vibrate music, not quite sure , it's just my instinct, lol
Assuming that a cheese sandwich consists of 2 slices of bread and 3 slices of cheese, determine the number of whole cheese sandwiches that can be prepared from 44 slices of bread and 63 slices of cheese.
Answer:
21 is the max but with the bread ypu could make 22 if you had 3 more cheese
