Answer:
Establish and Use a Secure Connection
Use SSH Keys Authentication
Secure File Transfer Protocol
Secure Sockets Layer Certificates
Use Private Networks and VPNs
Explanation:
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.
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.
what is a physical quantity
The number of calories listed on a food label always refers to the number in the entire package
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
An isotope of cesium (cesium-137) has a half-life of 30 years. If 1.0 g of cesium-137 disintegrates over a period of 90 years, how many g of cesium-137 would remain?
Answer:
3 half-lives 7. An isotope of Cesium (Cesium-137) has a half life of 30 years. If 1.0 mg of cesium-137 disintegrates over a period of 90 years, how many mg of cesium-137 would remain? of sodium-25 is 60 seconds? : 3 minutes t=601 = 3 half-lives 5.0mg ~ 2.5 mg + 1.25mg →) 625 mg.
Explanation:
Hope this helps
where:
[tex]N_{0}[/tex] = Initial quantity of the sample = 1.0g
t = time in years of disintegration = 90 years
[tex]t\frac{1}{2}[/tex] = Half life of cesium isotope = 30 years
N(t) = Quantity of substance after disintegration = ?
Solving for N(t)N(t) = [tex]1 ( \frac{1}{2})^ \frac{90}{30}[/tex]
N(t) = [tex]1 (\frac{1}{2})^{3}[/tex]
N(t) = 0.125 grams
Therefore, the quantity of cesium-137 that would remain after disintegrating over a period of 90 years is 0.125 grams.
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[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
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:
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.
Based on the number of valence electrons indicated by its location in the periodic table ,which elements behavior would you predict to be closest to that of potassium (k)
Answer:
Na sodium or Rb rubidium
Explanation:
Because Na is present in first group all members of group 1 have 1 electron in valence shell and show similar properties.
How many molecules are in 20,484 grams of H2O?
Answer:
3.4027x10^-22
Explanation:
How many molecules are equal to 89.23g of calcium oxide
Answer:
1.593 moles
Explanation:
Therefore, 1.593 moles are equal to 89.23 g of calcium oxide.
Answer:
9.64 × 10²³ molecules
Explanation:
Given data:
Mass of calcium oxide = 89.23 g
Number of molecules = ?
Solution:
First of all we will calculate the number of moles of calcium oxide.
Number of moles = mass/molar mass
Number of moles = 89.23 g/ 56.1 g/mol
Number of moles = 1.6 mol
Number of molecules;
1 mole contain 6.022 × 10²³ molecules
1.6 mol × 6.022 × 10²³ molecules / 1mol
9.64 × 10²³ molecules
The number 6.022 × 10²³ is called Avogadro number.
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!
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
Ramelteon is a hypnotic agent used in the treatment of insomnia: Considering the labeled drawing above, which of the highlighted atoms has a delocalized lone pair? Select all that apply. 1 2 3 Identify the geometry of each atom (except for hydrogen atoms). All sp2-hybridized carbon atoms have geometry. All sp3-hybridized carbon atoms have geometry. The nitrogen atom has geometry. The oxygen atom of the C=O bond has geometry, and the other oxygen atom has geometry.
Answer:
1 and 2
Trigonal planar
Tetrahedral
Trigonal Planar
Linear
Bent ( v- shape)
Explanation:
The highlighted atoms has a delocalized lone pair - 1 and 2
All sp2-hybridized carbon atoms have geometry- Trigonal planar
All sp3-hybridized carbon atoms have geometry - Tetrahedral
The nitrogen atom has geometry - Trigonal Planar
The oxygen atom of the C=O bond has geometry - Linear
and the other oxygen atom has geometry - Bent ( v- shape)
P.S - The correct question is -
Ramelteon has been an aromatic compound with 3 ring structure followed by the aliphatic chain.
The drug has antagonist structure to the melatonin and has been used to treat insomnia by acting as the melatonin representative.
Geometry in the structureThe labelled atom in the structure is oxygen of the pentane ring, nitrogen in the aliphatic chain, and carbonyl oxygen.
The delocalized lone pair has been observed in the compound which has been contributing to the resonating structure. The delocalized lone pair ion the given structure is oxygen of the pentane ring, and nitrogen in the aliphatic chain.
The geometry of the atom has been based on the hybridization and the lone pairs.
The geometry of [tex]\rm sp^2[/tex] hybridized carbon has been trigonal planar. The geometry of [tex]\rm sp^3[/tex] hybridized carbon atom has been tetrahedral. The nitrogen in the chain has trigonal planar geometry. The C=O oxygen has been comprising linear geometry, while the oxygen has bent v shape.
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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.
Select the correct balanced equation for the double displacement reaction of calcium carbonate and hydrochloric
acid (Rolaids and stomach acid)
CaCO3 + HCL -> CaCl2 + H2CO3
Answer:
B: CaCO3 + 2HCl -> CaCl2 + H2CO3
Explanation:
CaCO3 + HCl -> CaCl2 + H2CO3Count how many elements they are in all molecules for the reactants and for the products.
For the reactants:Ca = 1 element
C = 1 element
O = 3 elements
H = 1 element
Cl = 1 element
For the products:Ca = 1 element
Cl = 2 elements
H = 2 elements
C = 1 element
O = 3 elements
To balance this equation, we need to add 1 more element of Chlorine and Hydrogen. Therefore, we add a 2 to the coefficient of HCl for the reactants side.
Now let us try it.
CaCO3 + 2HCl -> CaCl2 + H2CO3Count how many elements they are in all molecules for the reactants and products.
For the reactants:Ca = 1 element
C = 1 element
O = 3 elements
H = 2 element
Cl = 2 element
For the products:Ca = 1 element
Cl = 2 elements
H = 2 elements
C = 1 element
O = 3 elements
All of the elements are balanced.
So the final answer is B: CaCO3 + 2HCl -> CaCl2 + H2CO3Hope it helped!
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
A 25.00 mL sample of an H2SO4 solution of unknown concentration is titrated with a 0.1322 M KOH solution. A volume of 41.22 mL of KOH is required to reach the equivalence point. What is the concentration of the unknown H2SO4 solution? Express your answer in molarity to four significant figures.
Answer:
[tex]0.1090\ \text{M}[/tex]
Explanation:
Volume of [tex]KOH[/tex] = 41.22 mL
Molarity of [tex]KOH[/tex] = 0.1322 M
Number of moles of [tex]KOH[/tex]
[tex]n=\text{Molarity}\times \text{Volume of }KOH\\\Rightarrow n=0.1322\times 41.22\times 10^{-3}\\\Rightarrow n=0.005449284\ \text{mol}[/tex]
2 moles of [tex]KOH[/tex] reacts with 1 mole of [tex]H_2SO_4[/tex]
So,
[tex]0.005449284\ \text{mol}[/tex] of [tex]KOH[/tex] reacts with M mole of [tex]H_2SO_4[/tex]
[tex]M=\dfrac{0.005449284}{2}=0.002724642\ \text{mol}[/tex]
Volume of [tex]H_2SO_4=25\times 10^{-3}\ \text{L}[/tex]
Concentration of [tex]H_2SO_4[/tex] is
[tex]M=\dfrac{0.002724642}{25\times 10^{-3}}\\\Rightarrow M=0.10898568\approx 0.1090\ \text{M}[/tex]
The concentration of the unknown [tex]H_2SO_4[/tex] solution is [tex]0.1090\ \text{M}[/tex].
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.
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
1)
If I have 45 liters of helium in a balloon at 25°C and increase the
temperature of the balloon to 55° C, what will the new volume of the
balloon be?
Answer:
52.8 Liters
Explanation:
Gay-Lussacs law states that P1/T1 = P2/T2
if:
P1 = 45T1 (in Kelvins) = 25 + 273.1 =298.1P2= ?T2 = 55 + 273.1 = 328.1then:
45/298.1 = P2/328.1
P2 = 52.8
The new volume of the balloon is 52.8 Liters this can be calculated by using gas laws.
Charles law:Charles law states the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature. It is given by
V₁/T₁ = V₂/T₂
What information do we have?
V₁ = 45 L
T₁ = 25 + 273.1 =298.1 K
T₂ = 55 + 273.1 = 328.1 K
To find:
V₂= ?
On substituting the values:
45/298.1 = V₂/328.1
V₂ = 52.8 L
Thus, the volume of the balloon is 52.8 liters.
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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:
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
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.
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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
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
what is the simplified chemical équation for Vinegar diluted in water?
[tex]\purple{\tt{\huge{Answer}}}[/tex]
CH3COOH is an accepted and common form of writing the structure of acetic acid (commonly known as vinegar when diluted in water).
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!
How much heat do you need to raise the temperature of 100 g of aluminum from 30°C to 150°C?
Answer:
Heat energy can be calculated by using the specific heat of a substance multiplying it to the mass of the sample and the
change in temperature. It is expressed as:
Energy = mCAT
Energy = 100 (0.90) (150 - 30)
Energy = 10800 J