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.
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
[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
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.
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.
Is sodium hydroxide an alkali or an insoluble base
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
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.
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
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 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.
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:
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
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!
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.
Trey was asked to build a working model of a landform for a science project. He chose to build a model of a volcano.
Trey formed a base out of clay and then painted the model so it resembled a cinder cone volcano.
Finally, Trey mixed baking soda, vinegar, and red food coloring in the base, so it mimicked lava flowing out of the volcano. Once
he was finished with his project, Trey's teacher asked how useful his model was.
What factor best determines the usefulness of the model?
A. how closely the model's color matches the real world
how closely the model's behavior matches the real world
C. how closely the model's size matches the real world
how closely the model's composition matches the real world
B.
D.
Answer:
The answer is "how closely the model's behavior matches the real world "
Explanation:
Your options were glitched out, so it only showed A and C, and B and D were blank so lol
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
the man is being warmed by?
radiation
convention
conduction
Answer:
Comvection
Explanation:
The movement causes the density to rise and therefore transfer more heat
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:
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
A(n)_________contains only one type of atom, whereas a(n)_________ is composed of two or more different elements bonded together. A(n)___________ also contains more than one substance, but these can be separated by physical means, whereas the components of a compound cannot.
Answer:
1. Element
2. Compound
3. Mixture
Explanation:
Elements and compounds are both pure substances. ELEMENTS are substances that contain only one type of atom. For example, Cl2 contains only chlorine atoms. COMPOUNDS, on the other hand, contain atoms of two or more elements that are chemically joined together. For example, CaCl2 contains atoms of calcium and chlorine.
MIXTURES are another kind of substances that contains more than one substances, however, unlike compounds, they are not chemically joined. Mixtures can easily be separated by physical means.
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.
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!
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!........
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
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.
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.
In table below, there are descriptions of an experiment on samples of three different chemical compounds. Decide whether the compound is ionic or molecular, if you can. If there is not enough information to decide, choose can't decide in the third column.
Compound Description Ionic or molecular?
can't decide
1 Compound 1 is a hard grayish-white solid. A small 250. mg
sample of it is put into a quartz tube and heated strongly.
It starts to melt at 1055. °C.
2 Compound 2 is a hard grayish-white solid. When tapped
gently with a small hammer, a sample fractures into
fragments and a whitish powder. The powder is soluble in
water, and when 15 g are dissolved in 100 mL of water,
the solution conducts electricity well.
3 Compound 3 is a soft waxy white solid that can be easily
shaped and molded by hand. When the flame of an ordinary
laboratory burner is held about 10 cm away from the solid,
it rapidly and extensively melts into a clear liquid.
Answer:
Compound 1- ionic solid
Compound 2- can't really decide
Compound 3- molecular solid
Explanation:
An ionic solid has a very high melting point. It is hard but not brittle. It's solution or melt but not it's solid conducts electricity. Compound 1 is an ionic solid.
We can't really decide on compound 2 since it is brittle yet it's solution conducts electricity.
Lastly, compound 3 is a molecular solid since it has a low melting point.
Answer:
Compound 1- ionic solid
Compound 2- can't really decide
Compound 3- molecular solid
Explanation:
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