Answer:
pKa = 9
Explanation:
In this case, we have to remember the meaning of "p". When we use "p" in any calculation we have to apply the minus ten based logarithm, so:
[tex]p~=~-Log[/tex]
For example, when we use the "pH" value. We have to apply the minus ten based logarithm of the concentration of the hydronium ion:
[tex]pH~=~-Log[H^+][/tex]
So, if we have wanted to calculate the pKa value. We have to apply the minus ten based logarithm of the Ka value, so:
[tex]pKa~=~-Log~Ka[/tex]
Now we can plug the value into the equation:
[tex]pKa~=~-Log~1x10^-^9[/tex]
[tex]pKa~=~9[/tex]
The pKa value is 9.
I hope it helps!
An object has a density of 16.3 g/mL and a volume of 0.46 L. Calculate the
mass of the object in pounds.
Answer:
The answer is
16.50 IbsExplanation:
To find the mass of a substance given the density and volume we use the formula
mass = Density × volumeFrom the question
Density = 16.3 g/mL
volume = 0.46 L
We must first convert the volume from L to mL
If 1 L = 1000 mL
Then 0.46 L = 0.46 × 1000 = 460 mL
Substitute the values into the above formula and solve
That's
mass = 16.3 × 460 = 7498 g
To convert the mass from g to lbs we use the conversion
1g = 0.0022 Ibs
If 1 g = 0.0022 Ibs
Then 7498 g = 7498 × 0.0022
We have the final answer as
16.50 IbsHope this helps you
The first periodic table was organized according to atomic mass, but the current periodic table is arranged according to atomic number. why is the atomic number now the basis for the periodic table?
Answer:
It helps identify trends and group elements with similar properties.
Explanation:
Arranging the elements according to the atomic mass wouldn't help us have groups and periods with predictable properties that we can have when arranging it according to atomic number. Don't forget that isotopes have different masses.
Answer:
Not only on the basis of atomic number its acctually on the basis of their electronic configuration, chemicals properties and physical properties.
Which property of matter during a chemical change but does not change during a physical change
Answer:
The difference between physical change and chemical change is that chemical reaction is composition there is a change in the composition substances in question. In a physical change, there is a difference in the appearence, smell, or simple display of a sample matter
Explanation:
Fatty acids and glycerol are the subunits of the energy storage molecules called
Answer:
true fats; triglycerides
Explanation:
How is the le chatelier's principle used to ensure the reaction will go to completion?
Answer:
This done such that when a reaction is in equilibrium and disturb by and external force which would prevent its completion its adjust so as to offset that external force and still go on to completion
Write the chemical formula for this molecule
Answer:
C2H4O
Explanation:
The chemical molecular formula is C2H4O.
Also note*: Acetaldehyde is the chemical name for this structural formula.
The atomic number can tell us how many neutrons are in an atom. Question 4 options: True False
Answer:
true i think
Explanation:
There are billions of stars in the known universe. None of them seem to be as bright as the Sun. Which statement gives the best reason why the Sun appears to be the brightest star? A. All-stars have the same apparent brightness, but the Sun has more absolute brightness. B. The Sun is the biggest of all the stars and therefore has the greatest absolute brightness. C. The Sun is the hottest of all the stars and therefore has the greatest absolute brightness. D. The Sun is the closest star to Earth and so it seems brighter than distant stars that have much greater absolute brightness.
Answer:
The answer is D. The Sun is the closest star to Earth and so it seems brighter than distant stars that have much greater absolute brightness.
Explanation: Stars like red super giants like beetleguise are way brighter and bigger than the sun, but the sun is closest to the earth. It is only in its main sequence stage but seems bright because of its short distance from the sun( 93 million miles).
There are billions of stars in the known universe, none of them seem to be as bright as the Sun beacuse the Sun is the closest star to Earth.
What are stars?Stars are those astronomical bodies which are formed by the mixture of gases mainly of hydrogens and heliums, which are held by its own gravity.
In the universe or in the sky many stars are present which are luminous in appearance but among all of them only sun looks like more brighter, because the distance between the earth and the sun is not that much high as in between the other stars. That's why sun looks more brighter rather than other stars.
So, the Sun is the closest star to Earth and so it seems brighter than distant stars that have much greater absolute brightness.
To know more about sun, visit the below link:
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What rules can you use to tell how many protons, neutrons and electrons make up an atom or ion?
Answer:
Explanation:
This question appears incomplete, however
The number of protons of an element/atom (atomic number) can be determined by checking for the position of the element on the periodic table. This is because elements are arranged according to there atomic number on the periodic table.
The number of electrons of any element (of a neutral atom) is equal to the number of protons of the same element.
The number of neutrons of an element/atom is determined by subtracting the atomic number of the element from it's mass number. Hence, mass number is the addition of the atomic number and the number of neutrons.
Ions are charged particles that have the same number of protons and neutrons as there parent atoms. Hence, they have different number of electrons when compared to there specific parent/neutral atom.
A negatively charged atom has more electrons than it's original atom. For example, fluoride ion (F⁻) has 10 electrons while fluorine atom has 9 electrons (meaning fluoride ion has one more electron than it's parent fluorine). The increase is dependent on the number "attached" to the charge. A positively charged atom has less electrons than it's original atom. For example, calcium ion (Ca²⁺) has 18 electrons while calcium atom has 20 electrons (meaning the calcium ion has 2 electrons less than it's parent calcium atom). As said earlier, the decrease here is also dependent on the number "attached" to the charge.
The rule used for the determination of the protons, electrons, and neutrons has been the equal number of protons and electrons, while the number of the neutrons has been the difference in the atomic mass and the protons.
The atom has been the smallest particle that has comprised of electrons, protons, and neutrons as the subatomic particle. The neutrons and protons in the atoms have consisted within the nucleus. The electrons in the atom are revolving around the nucleus.
The atoms have been consisted of an equal number of protons and electrons, while the number of neutrons has been the difference in the atomic mass and the protons.
The ions have been formed with the loss or gain of the electrons by the atom in the terms of valence electrons to complete its octet.
For more information about the electrons and protons, refer to the link:
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When of a certain molecular compound X are dissolved in of benzonitrile , the freezing point of the solution is measured to be . Calculate the molar mass of X. If you need any additional information on benzonitrile, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to significant digit.
Answer:
49.0g/mol is molar mass of X
Explanation:
551mg of X are dissolved in 100g of benzonitrile
Freezing point of solution: -13.4°C
The freezing point depression of a solution (Colligative property) follows the equation:
ΔT = Kf*m*i
Where ΔT is change in freezing point from the pure solvent (Benzonitrile: -12.8°C) to the solution (-13.4°C)
Kf is freezing point depression of benzonitrile: 5.34°C/m
m is molality of the solution (Moles X / kg of benzonitrile)
And i is Van't Hoff factor (1 for any solute in benzonitrile)
ΔT = -12.8°C - (-13.4°C) = 0.6°C
Solving for molality of the solution:
ΔT = Kf*m*i
0.6°C = 5.34°C/m*m*1
0.1124m = molality of the solution
Moles of X are:
0.1124mol/kg benzonitrile * 0.1kg benzonitrile = 0.01124 moles X
In 551mg = 0.551g:
Molar mass:
0.551g / 0.01124mol =
49.0g/mol is molar mass of X
A student mixed together 8 g of sugar, 5.20 g of salt
and 100.01 g of flour to make cookies. What is the TOTAL
mass (add them all together) of the mixture expressed with
the correct number of significant figures?
A) 100g
B) 113g
C) 113.21g
D) 113.2g
its C) 113.21g
u just add all the masses
An ibuprofen suspension for infants contains 100 mg/5.0 mL suspension. The recommended dose is 10 mg/kg body weight. How many mL of this suspension should be given to an infant weighing 18 lb?
Answer:
32,8mL
Explanation:
1lb=2.2kg
18lb= 8.2 kg
100mg/5mL=20mg/1mL
164mg=32.8mL
what was the physical property used by mendleev in creating his periodic table.
Answer:
melting point and boiling point
Which of the following options is correct?
All of the following are chemically modified carbohydrates except
a. galactosamine.
b. cellulose.
c. glucosamine.
d. chitin.
e. glucuronic acid.
Answer:
b. cellulose.
Explanation:
Cellulose is a polysaccharide consisting of a long chain of repeating glucose units (i.e., β-D-glucose units) that produce long unbranched chains. Cellulose can be considered as a natural polymer (i.e., a non-modified carbohydrate) because it is composed of repeated chains of β-D-glucose molecules stuck together. The cellulose polysaccharide is a principal component of plant cell walls.
which has the greatest percentage of oxygen? CO2, NO2,SO2 and MgO?
Answer:
CO₂
Explanation:
Please see attached picture for full solution.
* The masses of each atom can be found in the periodic table of elements
Draw the Lewis structure for COCl2, including lone pairs.What is the molecular shape of COCl2? The C - Cl bond in COCl2 is polar or nonpolar? What is the Cl - C - Cl bond angle? The molecule COCl2 is polar or nonpolar?
Answer:
See explanation
Explanation:
COCl2 Contains two polar C- Cl bonds due to the electro negativity difference between carbon and chlorine.
There are 24 valence electrons in COCl2, the ideal bond angle is 120° based on the valence shell electron pair repulsion theory since the molecule trigonal planar. However, the double bond present compresses the bond angle to about 111°.
The dipoles in COCl2 do not cancel out hence the molecule is polar
The Lewis structure for COCl₂, including lone pairs is attached to the image below.
Carbon (C) has 4 valence electrons, oxygen (O) has 6 valence electrons, and chlorine (Cl) has 7 valence electrons.
In this structure, the oxygen atom is double-bonded to the carbon atom, and there is a single bond between the carbon atom and each chlorine atom. The oxygen atom has 2 lone pairs of electrons.
The molecular shape of COCl₂ is linear. The carbon atom is bonded to two chlorine atoms, and there are no lone pairs on the carbon atom. Therefore, the electron domain geometry is linear.
To learn more about Lewis structure, follow the link:
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How many atoms are in 6.30 moles of selenium (Se)?
x 10
atoms
Answer:
3.79 e+24
Explanation:
1 mol = 6.022*10^24 atoms
6.30 * ×[tex]\frac{6.022*10^2^3atoms}{1mol}[/tex] = 3.79386*10^24
The answer must have 3 sig figs
Let’s take a look at sodium (Na) and chlorine (Cl). Draw what I am describing, and you will see it better. A sodium atom has how many protons? __________ A sodium atom has how many electrons? __________ How many electrons will go in the first shell? __________ How many in the second shell? __________ How many in the third? __________ Now draw this out on the diagram in Figure 2.1, and take a look at it, in particular the third (valence) shell. We know that Na requires eight electrons in its valence shell to become stable. But how many does it have? __________ So, to fill this shell, will it be easier for sodium to steal seven more electrons from another atom, or will it be easier for sodium to give up that one electron and get rid of that third shell? Sodium is simply going to give away that last electron. This means that it will lose an electron (negative charge) but will keep the same number of protons (positive charges). What will the sodium ion’s overall charge be now? _
what's another name for chemical change
Answer:
chemical action; chemical change; chemical process.
Explanation:
Answer: Chemical reaction
Which of these relationships is true of an uncharged atom?
A) The atomic mass is equal to the atomic number.
B) The number of electrons is equal to the number of neutrons.
C) The number of protons is equal to the number of electrons.
D) The atomic mass is equal to the number of electrons.
Answer:
The correct option is C) The number of protons is equal to the number of electrons.
Explanation:
Atoms are made up of particles called protons, neutrons, and electrons. Protons and neutrons are in the center of the atom and form the nucleus, while electrons surround the nucleus. Electrons have a negative charge. The charge of the protons is positive and finally, the neutrons have no charge.
If the atom has no charge, this means that the total charge of the atomic nucleus, which is positive due to the presence of the protons, is equal to the negative charge of the electrons, so that it cancels out.
So, the correct option is C) The number of protons is equal to the number of electrons.
Select the appropriate shape for the given volume formula
Answer: Cylinder , Sphere , Rectangular prism , Cone
i did an online work
A piece of metal with a mass of 611 g is placed into a graduated cylinder that contains 25.1 mL of water rising the water level 256.7 mL what is the density of the metal?
Answer:
The answer is
2.64 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass = 611 g
volume = final volume of water - initial volume of water
volume = 256.7 - 25.1 = 231.6 mL
The density of the metal is
[tex]density = \frac{611}{231.6} \\ = 2.638169257...[/tex]
We have the final answer as
2.64 g/mLHope this helps you
Can someone help me please I can’t get this hi
plants are unable to move to a new location in response to changes in their environment. Which organelle plays a role in maintaining homeostasis in a plant?
Answer:
Plants are unable to move to a new location in response to changes in their environment. Which of the following organelles plays a role in maintaining homeostasis in a plant? a. Cell Wall b. Chloroplast c. Vacuole d. Nucleus ____ 6. In the diagram below, Cell I and II represent typical cells. In both cells,
Explanation:
:P
Answer:
Vacuole
Explanation:
did it!
Which compound has the highest boiling point? HF, HI, HBr, HCl, or F2?
Answer:
HF
Explanation:
This concept can be understood from the knowledge of Intermolecular forces of attraction.
Intermolecular bonds are Van der Waals forces which are weak forces of attraction joining non-polar and polar molecules together. They exist in the form of London Dispersion Forces and Dipole-dipole attraction.
An example of Dipole-dipole attraction is the hydrogen bond which is a unique dipole-dipole attraction between polar molecules in which a hydrogen atom is directly joined to a highly electronegative atom such as fluorine, oxygen, or nitrogen).
Molecules that possess the characteristics of hydrogen bonding have a higher boiling point. In the given question, only HF undergo hydrogen bond due to the electronegative effect of the fluorine element.
F2 occurs as a weak London dispersion force and it occurs between non-polar molecules.
Chelsi has talked to her artist friends about how much money they earn each year from working in the arts. She
gathers these values from seven people: [$1,500; $6,700; $2,200; $8,100; $50,500; $12,000; $2,200).
What is the median of this data set?
$2,200
$6,700
$7,400
$11,900
Answer: 6,700
Explanation: took the test got it right :) (2020)
Answer:
B 6700
Explanation:
Which of the following statements is a true statement concerning a reaction that has reached a state of equilibrium?
a. A system has reached equilibrium when there are equal amounts of products and reactants present in the system.
b. A system has reached equilibrium when the rate constant for the forward reaction equals the rate constant of the reverse reaction.
c. A system has reached equilibrium when the reaction has stopped and no more products are formed.
d. A system has reached equilibrium when the concentrations of reactants and products remain constant.
Answer: A system has reached equilibrium when the concentrations of reactants and products remain constant.
Explanation:
The reactions which do not go on completion and in which the reactant forms product and the products goes back to the reactants simultaneously are known as equilibrium reactions.
The equilibrium is dynamic in nature and the reactions are continuous in nature. Rate of forward reaction is equal to the rate of backward reaction.
Equilibrium state is the state when reactants and products are present but the concentrations does not change with time, that is the concentration remains constant.
A graduated cylinder is filled with 3 mL of water. A toy car that
weighs 29 g is gently placed in the cylinder and the water level
rises to 19 mL. What is the density of the toy car? Round to the
thousandths place.
Answer:
Density = 1.813 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
From the question
mass of toy car = 29 g
Volume = New volume - original volume of water in cylinder
That's
volume = 19 - 3 = 16 mL
Substitute the values into the above formula and solve for the density
That's
[tex]Density = \frac{29}{16} \\ = 1.8125[/tex]
We have the final answer as
Density = 1.813 g/mL to the nearest thousandth
Hope this helps you
Answer:
1.813 g/mL
Explanation:
The density can be found with the following formula.
[tex]d= \frac{m}{v}[/tex]
where [tex]m[/tex] is the mass and [tex]v[/tex] is the volume.
We know the mass is 29 grams. We must find the volume.
The volume is equal to the volume of water that is displaced. Subtract the initial volume of water from the final volume.
⇒ final volume - initial volume of water
The initial volume of water is 3 mL and the final volume is 19 mL.
⇒ 19 mL - 3 mL
⇒ 16 mL
The volume of the toy car is 16 mL.
Now we know the mass and the volume.
[tex]m= 29g\\v=16mL[/tex]
Substitute the values into the formula.
[tex]d=\frac{m}{v}[/tex]
[tex]d=\frac{29g}{16mL}[/tex]
[tex]d=1.8125 g/mL[/tex]
Round to the nearest thousandth. The 5 in the ten thousandth place tells us to round the 2 to a 3.
[tex]d\approx1.813 g/mL[/tex]
The density of the toy car is about 1.813 grams per milliliter.
why is time plotted on the x axis and distance on the y axis?
Answer:
because time is independent and distance is dependent . time goes on if distance is not there but if distance is covered it is covered in certain time . that's why distance is taken on y axis while displacement on x axis
Convert 75 mL of water to gallons (show work)
Answer:
[tex]\huge\boxed{\sf 75\ mL = 0.02\ gallons}[/tex]
Explanation:
1 mL = 0.000264 gallons
Multiplying both sides by 75
75 mL = 0.000264 * 75 gallons
75 mL = 0.02 gallons