ways of expressing a solution
Answer:
There are several ways of expressing the concentration of a solution.
Explanation:
Concentration is the proportion of a substance in a mixture. There are several ways of expressing them, each with their own usefulness. What's incredibly useful is with a little math and conversion factors, these can all be interconverted.
Molarity (M) - amount (mol) of solute / volume (L) of solutionPros: Very common in labs, makes conversions easy. Cons: Effected by temperature (liquid expands with heat so unit volume of hot solution has less solute than cold solution) and mixing (volumes are not always additive (for instance, 50 mL of water and 50 mL of ethanol is not exactly 100 mL of mixture due to solvent-solvent interactions).Molality (m) - amount (mol) of solute / mass (kg) of solventPros: Preferred when temperature and density could change; molal is based on masses, not volume so molality does not change with temperature. Masses, unlike volumes sometimes, are always additive.Cons: When dealing with moles in reactions conversions are harder.Parts by mass a.k.a mass % (% w/w) - mass of solute / mass of solutionPros: Good indication of how pure a substance is; and good for very small concentrations such as toxin or pollutant levels in a biological or environmental setting, respectively.Cons: Not the most useful for reaction stoichiometry.Parts by volume a.k.a volume % (%v/v) - volume of solute / volume of solutionPros: Very good and common for measuring main ingredients in things, such as alcohol in hand sanitizer, hydrogen peroxide in those brown bottles you see, and how much alcohol in wine bottles.Cons: Again, not the easiest to use for reaction stoichiometry.Mole fraction (X) - amount (mol) of solute/ amount (mol) of solute + amount (mol) of solvent Pros: N/ACons: N/AMass per volume percentage - mass of solute / volume of solutionPros: Common for measuring main ingredients in medicine, such as how much of it is in an aqueous solution (example: benzocaine)Cons: Difficult to use with stoichiometry.Parts per million and parts per billion (ppm or ppb) - mass of substance / mass of sample * 10^6 or 10^9Pros: Excellent for expressing concentrations of very trace components such as a toxin or pollutant in blood, for example. Cons: Not very useful for large quantities of things.Note: to find the percent of some of these, such as for mass percent or volume percent, multiply the result by 100.
Additionally, with some practice you can answer a question such as, "The label on a 0.750-L bottle of Italian chianti says "11.5% alcohol by volume." How many liters of alcohol does the wine contain?". etc...
I really hope this helps! Take care.
[2071]State and explain Kohlrusch's law.
(2071]Why does the specific conductance decreases and equivalent conductance increase
with dilution of a solution of electrolyte?
ito unit How does it Vary with dilution?
1101
List the following compounds in order of increasing reactivity in an SN2 reaction.
A. 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane
B. 1-Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 2-Bromo-3-methylbutane
C. 1-Bromobutane, 1-Bromo-2,2-dimethylpropane, 1-Bromo-2-methylbutane, 1-Bromo-3-methylbutane
Answer:
A- 1-Bromopentane
>2-Bromopentane> 2-Bromo-2-methylbutane
B- 1-Bromo-3-methylbutane>2-Bromo-3-methylbutane> 2-Bromo-2-methylbutane
C- 1-Bromobutane > 1-Bromo-3-methylbutane>1-Bromo-2-methylbutane>1-Bromo-2,2-dimethylpropane
Explanation:
We must bear in mind that the ease of SN2 reaction is methyl > primary> secondary> tertiary.
As a result of this all primary alky halides react faster towards SN2 than secondary and tertiary alkyl halides.
Also, compounds that may form more stable carbocations by 1,2- alkyl shifts are less likely to participate in SN2 reaction
Calculate the molar mass of NH4NO3.
molar mass of NH4NO3 =
g/mol
Answer:
67g/mol
Explanation:
The given compound is:
NH₄NO₃ :
Problem here is to find the molar mass of the compound.
Now;
The molar mass is the sum of the atomic masses of the elements in the compound.
Atomic mass of N = 14g
Atomic mass of H = 1g
Atomic mass of O = 16g
So;
Molar mass = 14 + 4(1) + 1 + 3(16) = 67g/mol
Answer:
the answer is 80.0 grams per mole
Explanation:
An increase in aurora activity on Earth could be related to what activity on the Sun?
O A decrease in prominence
B decrease in solar Fares
Oc decrease in speed of solar wind
D increase in speed of solar wind
E increase in sun spots
Answer:
D.
Explanation:
INCREASE OF SOLAR WINDS When the sun is more active
Each graph below represents a different type of electromagnetic wave. Which graph most likely illustrates radio waves?
Answer: the answer is c
Explanation:
I just did the test
Each graph below represents a different type of electromagnetic wave. Then graph C most likely illustrates radio waves.
What is electromagnetic wave ?The electromagnetic field's waves, which travel through space and convey electromagnetic radiant energy, are what make up electromagnetic radiation. It consists of X-rays, gamma rays, microwaves, infrared, light, and radio waves. These waves are all a component of the electromagnetic spectrum.
There are seven different kinds of them are X-rays, gamma rays, visible light, infrared light, radio waves, and microwaves. They may be compared to seven distinct types of light.
Lower frequency electromagnetic radiation than microwaves is referred to be a radio wave. Radio waves have wavelengths that range from tens of thousands of meters to 30 centimeters. These are equivalent to frequencies between 3 Hz and 1 GHz (109 Hz).
Thus, option C is correct.
To learn more about electromagnetic wave follow the link;
https://brainly.com/question/3101711
#SPJ2
17. Find the average atomic mass unit of silicon given the following isotopes and
abundances: Silicon-28, Silicon-29, Silicon-30 with masses of 27.977, 28.976,
29.974, respectively. The percent abundance of the silicon isotopes is 92.2%, 4.7%
and 3.1%, respectively. Periodic table and it’s trends
The average atomic mass unit of Silicon : 28.0774
Further explanationGiven
Isotopes of Si(Silicon-28, Silicon-29, Silicon-30)
Required
The average atomic mass
Solution
Isotopes are elements that have the same Atomic Number (Proton)
Atomic mass is the average atomic mass of all its isotopes
Avg. atomic mass = %mass.isotopes 1 + %mass.isotopes 2...etc
Input the values :
Avg atomic mass = (0.922 x 27.977) + (0.047 x 28.976) + (0.031 x 29.974)
Avg atomic mass = 28.0774
What type of weather typically results from a low pressure system?
I need help!!!!
Answer:
Storms and hurricanes can be formed with low pressure. It always results into unsettled weather.
Explanation:
Hope this helps!
Which element is more reactive in water?
-Na
-Mg
Answer:
sodium
Explanation:
sodium is the second most reactive. Magnesium being the least reactive
Answer:
cesium
Elements with the Highest Reactivity
Francium is radioactive, with no stable isotopes. The most chemically reactive metal with a stable isotope is cesium. Cesium reacts explosively with water
Explanation:
Select the correct balanced equation for the combustion of methane.
CH4 + 02 -> CO 2 + H2O
Answer:
A: CH4 + 2O2 -> CO2 + 2H2O
Explanation:
CH4 + O2 -> CO2 + H2OCount how many elements they are in all molecules for the reactants and for the products.
For the reactants:C = 1 element
H = 4 elements
O = 2 elements
For the products:C = 1 element
O = 2 elements
H = 2 elements
O = 1 element
2 oxygen atoms + 1 oxygen atoms = 3 oxygen atoms total on the products side.
To balance this equation, we need to add 2 more elements of hydrogen and 2 more elements of oxygen. Therefore, we add a 2 to the coefficient of O2 for the reactants side and add a 2 to the coefficient of H2O for the products side.
Now let us try it.
CH4 + 2O2 -> CO2 + 2H2OCount how many elements they are in all molecules for the reactants and products.
For the reactants:C = 1 element
H = 4 elements
O = 4 elements
For the products:C = 1 element
O = 2 elements
H = 4 elements
O = 2 elements
2 oxygen atoms + 2 oxygen atoms = 4 oxygen atoms total on the products.
All of the elements are balanced.
So the final answer is A: CH4 + 2O2 -> CO2 + 2H2OHope it helped!
which toxic gas is released in incomplete combustion?
Answer:
Incomplete combustion produces carbon monoxide (CO), a toxic gas.
Explanation:
Combustion is the rapid chemical reaction of oxygen in the air or direct oxygen, which is defined as oxidizer, with the different elements that make up the fuel (mainly carbon (C) and hydrogen (H)). These chemical reactions release energy producing local increases in temperature, which causes a flow of heat to the outside.
In other words, on the one hand you have the fuel, which is the substance that oxidizes and that you can find in a solid, liquid or gaseous state and which is made up mostly of carbon and hydrogen.
The oxidizer, for its part, is the substance that oxidizes the fuel, and it is generally the oxygen found in the air.
Certain amounts of oxidizer and fuel must come into contact for combustion to occur.
Incomplete combustion occurs when part of the fuel does not fully react. Incomplete combustion produces carbon monoxide (CO), a toxic gas.
6
The volume of a gas increased from 2 to 6 L while the temperature was held constant. The
pressure of the gas:
increased by a factor of 3
decreased by a factor of 3
increased by a factor of 4
decreased by a factor of 4
Answer:
If the volume of a gas increased from 2 to 6 L while the temperature was held constant, the pressure of the gas decreased by a factor of 3.
Explanation:
Boyle's law that says "The volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure." This means that if the pressure increases, the volume decreases, while if the pressure decreases, the volume increases.
Boyle's law is expressed mathematically as:
Pressure * Volume = constant
or
P * V = k
To obtain the proportionality factor k you must make the quotient:
[tex]k=\frac{V2}{V1} =\frac{6 L}{2 L}[/tex]
k= 3
This means that if the volume of a gas increased from 2 to 6 L while the temperature was held constant, the pressure of the gas decreased by a factor of 3.
Explain how you could use displacement reactions to distinguish between
iron and zinc. You may use any solutions
you
choose.
Answer:
A double displacement reaction is a type of reaction in which two reactants exchange ions to form two new compounds. Double displacement reactions typically result in the formation of a product that is a precipitate.
Explanation:
zinc is more reactive than iron because it displace iron from its solution
I need help. Please help with the best of your ability.
Answer:
Photosynthesis transforms light energy into chemical energy by making sugars. Cellular respiration releases the chemical energy from food by breaking down sugars.
Explanation:
I'm actually learning this in school right now
Hope this helps!
~PurpleMist
How many units are in 1.54 moles?
Answer:
Every mole contains 6.022 x 10^23 atoms regardless of what type of moelcules it is (Gold, Silver). So the anwer is 1.54 times 6.022 x 10^2
Leopard seals are animals adapted to survive in the freezing conditions of Antarctica. Individual leopard seals vary in their different traits.
Which of the following variations would give a leopard seal the greatest chance of surviving in its harsh environment?
A. More spots on its coat. B. Thicker layer of blubber
C. More elongated head
D. Wider, flatter teeth
Answer:
B. Thicker layer of blubber
Explanation:
For the leopard seals to survives this harsh environment, it must have a thicker layer of blubber
Blubber is a thick layer of fat. It is called the adipose tissues and found in most marine organisms.
This layer helps in insulating the body against heat loss. By so doing, the animal is able to conserve internal heat. They have low thermal conductivity and do not easily lose heat or gain heat as such.Answer:
B
Explanation:
How does Bromine make it's escape.
Answer:
So, when bromine comes near the ethylene pi bond, it attacks the electron and grabs it, but the second bromine steals it away and departs as Br-. After all, bromine is more electronegative than carbon; the first bromine is just a link in the chain of events that allows the second bromine to escape with an electron.
Suppose that for a hypothetical reaction: A2(g) + 3B2(g) 2AB3(g) It is determined that at a certain temperature the equilibrium concentrations are [A2] = 0.0055, [B2] = 0.763 and [AB3] = 7.6×10-4. Calculate the numerical value of K for the reaction.
Answer:
The numerical value of K for the reaction is 2.36*10⁻⁴
Explanation:
A chemical equilibrium is a reaction that is never completed, since it occurs simultaneously in both directions (the reactants form products, and in turn, these form reactants again). In other words, it is a dynamic balance. When the concentrations of each of the substances involved (reactants or products) stabilize, that is, they are spent at the same rate as they are formed, chemical equilibrium is reached.
The equilibrium constant (Kc) is expressed as the ratio between the molar concentrations of reactants and products. Its value in a chemical reaction depends on the temperature, so this must always be specified.
Being:
aA + bB ⇄ cC + dD
then the constant Kc is:
[tex]Kc=\frac{[C]^{c} *[D]^{d} }{[A]^{a} *[B]^{b} }[/tex]
In the case of the reaction:
A₂(g) + 3 B₂(g) ⇒ 2 AB₃(g)
The constant Kc is:
[tex]Kc=\frac{[AB_{3} ]^{2} }{[A_{2} ] *[B_{2} ]^{3} }[/tex]
Being:
[AB₃]=7.6*10⁻⁴[A₂]= 0.0055[B₂]= 0.763and replacing, you get:
[tex]Kc=\frac{(7.6*10^{-4} )^{2} }{0.0055 *(0.763)^{3} }[/tex]
Kc=2.36*10⁻⁴
The numerical value of K for the reaction is 2.36*10⁻⁴
A chemist prepares a solution of silver (I) perchlorate (AgCIO4) by measuring out 134.g of silver (I) perchlorate into a 50.ml volumetric flask and filling the flask to the mark with water. calculate the concentration in mol/L of the silver (I) perchlorate soluation
Answer:
13 M
Explanation:
Molar mass of AgCIO4 = 207 g/mol
Number of moles of AgCIO4= 134/207= 0.65 moles
Number of moles= concentration × volume
Concentration = number of moles/volume
Concentration = 0.65 × 1000/50 = 13 M
What property is not a characteristic of metals? Brittle Shiny Ductile Malleable
Answer:
brittle is not a characteristic of metals
Answer:
Brittle
Explanation:
Brittle substances break easily and this is property of non metals.
Compound is a dull white smooth solid which does not conduct electricity.
a. True
b. False
Answer:
a. True.
Explanation:
Hello!
In this case, since dullness and smoothness are characteristic of materials that are not able to conduct the electricity, as they do not provide an appropriate pathway for the electrons to move around because of their amorphous structure, we realize the answer is a. True.
On the contrary, a lustrous and robust solid, is actually able to conduct electricity because it provides the pathway for the electron movements and therefore to conduct electricity.
Best regards!
What type of air mass is usually associated with hurricanes?
Answer:
Hurricanes conditions occur when warm, moist air evaporates from the surface of the ocean and rises quickly. This warm air meets cool air in the higher elevations that causes condensation of the warm air vapor. The condensation turns into storm clouds that make up hurricanes.
Tim and Jose are moving furniture. Tim pushes a 150 kg sofa with 300N
force. As a result, Sofa’s acceleration was __________ according to Newton’s
Second Law of motion. (F = ma)
Answer:
a = 2m/s²
Explanation:
Given data:
Mass of sofa = 150 Kg
Force applied = 300 N
Acceleration = ?
Solution:
Formula:
F = ma
F = force
m = mass
a = acceleration
by putting values,
300 N = 150 Kg × a
a = 300 N /150 Kg
a = 300 Kg m/s² / 150 Kg ( N = Kgm/s²)
a = 2m/s²
What do u notice about the molecules before and after the chemical reaction
Explanation:
In a chemical reaction, the atoms and molecules produced by the reaction are called products.
In a chemical reaction, only the atoms present in the reactants can end up in the products. No new atoms are created, and no atoms are destroyed.
In a chemical reaction, reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.
Which statement best describes the polarity of SF 4 CI 2?
Always polar , always non polar or depending on the arrangement of outer atoms ?
Answer:
use common sense!........
4NaOH + 4HCI - NaCl + H20
Answer:
NaOH + HCl —> NaCl + H₂O
Explanation:
From the question given above, we obtained the following equation:
4NaOH + 4HCl —> NaCl + H₂O
The equation can be balance as follow:
4NaOH + 4HCl —> NaCl + H₂O
There are 4 atoms of Na on the left side and 1 atom on the right side. It can be balance by putting 4 in front of NaCl as shown below:
4NaOH + 4HCl —> 4NaCl + H₂O
There are a total of 8 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 4 in front of H₂O as shown below:
4NaOH + 4HCl —> 4NaCl + 4H₂O
Next, divide through by 4 to express the equation with the lowest coefficients.
NaOH + HCl —> NaCl + H₂O
Now the equation is balanced.
NOTE: Smallest coefficients are always used to represent a balanced equation.
When fat comes in contact with sodium hydroxide, it produces soap and glycerin. Determine whether this is a physical change or a chemical change. Explain your
Answer:
It is a chemical change
Explanation:
The combination of sodium hydroxide and fat yields soap and glycerine.
We have to remember that one of the characteristics of a chemical change is that new substance(es) is/are formed. We have to look out for this when considering any process.
We can see here that new substances were formed (soap and glycerine). Based on this, we can assert that a chemical change has taken place.
John Dalton determined that the concept of atoms could be used to describe matter.
Which of the following is FALSE regarding John Dalton's four points about atomic theory.
A. Atoms are very small indivisible, indestructible particles.
B. Chemical compounds form when two or more kinds of atoms combine.
C. All matter is made up of atoms.
D. All molecules are identical in mass and other properties.
Answer:
D
Explanation:
I don't exactly remember his four points, but the D. is just not true anyway. For example, a molecule of water (H20) does that have the same properties or mass as Nitrogen dioxide or sulfer dioxide or something else
Answer:
The answer is D
Explanation:
As it is true that molecules are identical in mass.
Which of the following is one stage of the cell cycle?
A. Cytokinesis
B. Multiplication
C. Photosynthesis
D. Respiration
Answer: A
Explanation: cytokinesis is in the M phase.... Mitosis is followed by cytokinesis (cell separation)
Answer:
A. Cytokinesis
Explanation:
B. doesn't make sense it's for math
C. Is for plants not cells
D. is the action of breathing
So, A is the most likely answer.
Hope I helped!
Bowling with a volleyball instead of a bowling ball. Will this make it easier or harder to knock over pins?
Answer:
Definitely harder, since volleyballs are nowhere near as heavy as bowling balls, it’ll be harder too since there wont be much force to knock over pins