Answer:
The full form of TLC is Thin layer chromatography which is used in separating non volatile mixtures.
Explanation:
In the context, the Rf values could not be read properly or determined properly and accurately if the solvent front flows to the top of the plate. If the solvent reaches the plate's top, then the Rf values reading will be different from the TLC plate where the solvent did not reach the plate's top.
If the solvent front reaches the top, then it is not possible to accurately determine draw the line and to determine how far the spot went. And thus it would be difficult to solve the ratio as the plate would keep advancing or developing and also the compound spot keeps rising. As a result, spots reaches higher or rises than the normal rise but the solvent front does not change, it remains same. Thus, the Rf value would be completely off.
What angle is needed to spread 4 bonds as far apart as possible?
Answer:
109°
Explanation:
According to Valence Shell Electron Pair Repulsion Theory, electron pairs on the valence shell of the central atom of a molecule must be positioned as far apart in space as possible to minimize repulsion between valence shell electron pairs.
The shape of a molecule depends on the number and type of electron pairs on the valence shell of its central atom. Lone pairs generally cause more repulsion than bond pairs of electrons.
The ideal bond angle for a molecule with four bonds is 109° which corresponds to a tetrahedral geometry. This enables the four bonds to spread as far apart in space as possible.
Akito is warming a test tube over a Bunsen burner. He heats it too much and the glass breaks.
Which best describes what Akito should do first?
Ο Ο Ο Ο
O get paper towels
O change lab stations
turn off the burner
remove his contacts
Answer:
c
Explanation:
What was Albert Einstein's contribution to our understanding of the
photoelectric effect?
A. He described the relationship between energy and mass.
B. He described photons as little packets of electrons.
C. He described electricity as moving electrons.
D. He described light as little packets called photons.
Answer: The Answer Is D, He described light as little packets called photons.
Explanation:
The contribution of Albert Einstein to our understanding of the photoelectric effect is he described light as little packets called photons. The correct option is D.
Who is Albert Einstein?The theory of relativity, which Albert Einstein developed and is rightfully famous for, transformed our understanding of space, time, gravity, and the cosmos.
Along with his work on relativity, the physicist established the scientific principles behind items like paper towels, lasers, and other everyday items.
Since Einstein first suggested using the use of light quanta to clarify the photoelectric impact, quantum theory accurately portrays the photoelectric impact. The quantum theory of radiation gives this concept a formal formulation.
Therefore, the correct option is D. He described light as little packets called photons.
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what is the balanced chemical equation when solid calcium oxide and carbon dioxide gas are formed by the decomposition of solid calcium carbonate (CaCO3)
how do you convert wavelength to frequency?
Answer:
Image result for how do you convert wavelength to frequency?
How do you calculate energy from wavelength?
Convert your wavelength into meters.
Divide the speed of light, ~300,000,000 m/s, by the wavelength in m. This gives you the wave's frequency.
Multiply the frequency by Planck's constant, 6.626 x 10-34. The result is the waves energy in joules (J).
Explanation:
Discuss and Implement the Price Adjustment Strategies in the current market. Apply each strategy with 3 examples along with the picture. This question is related to Marketing.
Answer:
There are many different price adjustment strategies which can be implemented in the current market.
Explanation:
Psychological pricing:
Psychological pricing is a strategy in which the price of a product is displayed with mostly one cent difference so the whole number shown is less by $1 and this difference can get higher if the price of the product is more.
Example 1: The price for a toy in a toy shop is $4.99, if rounded this will be $5 but the whole number visible is $4.
Example 2: The price of a laptop is $193, this again is nearly $200 but the price is reduced by $7 in order to influence their customers into buying the product.
Example 3: The price of a car is $35,995, this again is about $36,000 but the buyer may be influenced by this technique and result in purchasing the product with such price.
Geographical Pricing:
Geographical pricing is a strategy where different prices are charged in different outlets, this strategy is made keeping in mind the purchasing power of the locality, if the local people can pay higher price for a product then the price is high there but same product may have a lower price in an area where people can not pay high price.
Example 1: Price of a T-shirt is $15 in a posh area while the price of the same T-shirt is $5 in an area with poor locality.
Example 2: Price of a hair brush is $10 in a poor area while the same brush is available in a posh area at a rate of $35.
Example 3: Price for a food item is $6 in a restaurant in posh area while the same burger is available for $3 in a restaurant in a poor area.
Which four practices are examples of how humans use science?
A. Making decisions that help humans survive
OB. Developing technologies that help humans thrive
C. Developing explanations based on facts
D. Imagining entertaining stories that explain observations
O E. Gathering facts that explain natural events
Answer:
A. Making decisions that help humans survive
B. Developing technologies that help humans thrive
C. Developing explanations based on facts
E. Gathering facts that explain natural events
Explanation:
The above are examples of the practices of how humans use science.
Science has been of tremendous help to humans in making decisions that make humans survive and develop technologies that help humans thrive. It has helped to gather and develop explanations that are based on facts. It has helped to explain natural events.
In which field(s) is knowledge about how science works important?
A. Medicine
B. All of these are correct
C. Law
D. Politics
E. Agriculture
Answer:B
Explanation:
Which of the following experimental methods cannot be used to measure the rate of a reaction? Group of answer choices measurement of the absorbance of a colored reactant with time measurement of the change in the partial pressure of a gas-phase product over time measurement of the equilibrium concentration of an acidic product via titration with a strong base measurement of the absorbance of a colored product with time measurement of the change in the partial pressure of a gas-phase reactant over time
Answer:
measurement of the equilibrium concentration of an acidic product via titration with a strong base
Explanation:
The rate at which a reaction proceeds refers to how quickly the reaction is occuring. In other words, it is how quickly the reactants are changing to the products. According to the question, the rate of a reaction can be measured experimentally using the reactants' or products' properties e.g volume, pressure etc.
Since reactions must involve reactants and products, the manner in which either the reactants or products changes over time can be measured. For example; measurement of the absorbance of a colored reactant or product with time, measurement of the change in the partial pressure of a gas-phase reactant or product over time can be used.
However, a measurement of the equilibrium concentration of an acidic product via titration with a strong base will not tell us how fast the reaction is going because it is in an EQUILIBRIUM state i.e. reaction is occuring at an equal rate
For a trip to the Moon, a rocket must lift off from
Earth's surface. Suppose it takes 5 minutes for the
rocket to reach a velocity of 6,000 m/s upward from
a starting velocity of 0 m/s. What is the rocket's
acceleration?
Answer:
20 m/s^2
Explanation:
given,
final velocity (v) = 6000m/s
initial velocity (u) = 0m/s
time taken (t) = 5 minutes
= 5×60second
= 300second
acceleration(a) = ?
we know that,
a = (v-u)/t
= (6000-0)/300
= 20 m/s^2
What particle(s) of an atom would NOT found in the nucleus?
Electrons
proton
neutron
neutrons and electrons
Answer:
Electrons, they circle the nucleus.
Helium is more reactive than magnesium.
TRUE
FALSE
Answer: FALSE
Explanation: Magnesium is more reactive.
Hope this helps!
Answer:
False
Explanation:
Magnesium is more reactive.
If the density of a diamond is 3.5g/cm3, what would be the mass of a diamond whose volume is 0.5 cm3?
Answer:
1.75 g
Explanation:
as density ×volume =mass
3.5×0.5=mass
mass=1.75 g
plz mark as brainliest if it helps
The mass of the diamond which has a density of 3.5g/cm3 is [tex]1.75kg[/tex]
Density is given as:[tex]3.5g/cm3[/tex]having a volume of [tex]0.5 cm^3[/tex]But we know that Density can be regarded as the the ratio of mass to that of volume of that particular object.let us represent this mathematically as;[tex]Density=[/tex] [tex]\frac{ mass }{ volume }[/tex]we can make Mass the subject of the formula to find the mass[tex]Mass= ( Density * volume)[/tex]Then let us substitute the give value, then we will have[tex]= ( 3.5*0.5)[/tex][tex]= 1.75kg[/tex]
Therefore, the mass is[tex]1.75kg[/tex]
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Consider this equilibrium reaction at 400 K. Br2(g)+Cl2(g)↽−−⇀2BrCl(g)Kc=7.0 If the composition of the reaction mixture at 400 K is [BrCl]=0.00415 M, [Br2]=0.00366 M, and [Cl2]=0.000672 M, what is the reaction quotient, ???? ? ????= How is the reaction quotient related to the equilibrium constant, Kc, for this reaction?
Answer:
Q = 7.0
Q = kc. The reaction is in equilibrium
Explanation:
Based on the reaction:
Br₂ + Cl₂ ⇄ 2BrCl
Equilibrium constant of the reaction, kc, is the ratio of equilibrium concentrations products over reactants powered to its reaction coefficient:
Kc = [BrCl]² / [Br₂] [Cl₂] = 7.0
Now, reaction quotient, Q, is write as the same Kc but the concentrations are actual concentrations:
Q = [BrCl]² / [Br₂] [Cl₂]
Replacing:
Q = [0.00415M]² / [0.00366M] [0.000672M]
Q = 7.0
Now, as Q = Kc = 7.0, the reaction mixture is in equilibrium
Why are atoms usually portrayed as spheres when most orbitals are not spherically shaped?
a. The shape of an atom depends on the shape of its nucleus, not on the shape of its orbitals.
b. The shape of an atom depends on the shape of the outer orbital which always spherical
c. The shape of an atom is obtained by superimposing all of its orbitals.
d. The shape of an atom is not important so it is easier to treat atoms as spheres.
Answer:
The shape of an atom is not important so it is easier to treat atoms as spheres.
Explanation:
In considering the shape of an atom, we do not consider the shape of the orbitals individually.
Hence, we do not seek to determine the exact shape of the atom, rather we simply treat the atom as spheres. Even though most orbitals are not spherically shaped.
What is the purpose of keeping a running list of new vocabulary words?
A. To make it easier to decode the word when you see it again
B. To provide an easy-to-remember picture associated with the word
C. To make it easier to remember and use new words
D. To allow you to critically evaluate every new word you come
across
Shjajfbcjahaixhfjwnzhsbsjxjdbxbsjzjfbwnznsnwnnsndndnwnbwjshsbdbdndnndndndbxbxnsnsn
Answer:
C
Explanation:
As C would be the wisest choice as being able to remember and use more words than the average human not only opens up your vocabulary but also your chances of writing a better essay using said words.
Answer:
C
Explanation:
Makes it easier to remember and use new words
Describe the evidence for Mercury having a molten iron core
In the density of a liquid activity, the graph had an intercept. If you were to make a similar graph using metal blocks, would the graph have an intercept?
Answer:
NO
Explanation:
It would be difficult to plot a line of best fit on the scattered graph of the activities of metal blocks as the activities would almost be the same horizontally on the graph and an attempt to draw/determine an intercept will be almost impossible. The line of best fit is usually drawn to determine the relatedness/correlation of the variables.
Drawing intercept for the activities of the liquid is easier because a line of best fit can be easily placed between the clustered liquid activities on the scattered plot.
john has a solution with a pH of 12.21. what is the hydrogen ion concentration of this solution?
Answer:
In this way, ph is determined by hydrogen ion concentration . In the case of neutral solution [H+] =10-7 which we call a ph of 7. This means, for example, that a hydrogen-ion concentration of a solution with a ph of 4 is 10-4 mol/l, meaning it contains 0.0001 mole of hydrogen ion in a solution of 1 liter.
Write balanced molecular and net ionic equations for the following metathesis (double displacement) reactions, if they occur. If no reaction occurs, write NR on the product side. All reactants are aqueous. Phase subscripts must be included to indicate what products stay in solution (aq), and what products precipitate (s).
a. zinc acetate + sodium carbonate
b. barium nitrate + sodium sulfate
c. lead (II) nitrate + sodium sulfate
d. zinc acetate + sodium sulfate
e. barium nitrate+ potassium iodide
f. lead (I) nitrate+ potassium iodide
g. zinc acetate + potassium iodide
Answer:
attached below is the required solution
Explanation:
A) Zinc acetate + Sodium carbonate
B) barium nitrate + sodium sulfate
C ) lead ( II ) nitrate + sodium sulfate
D) Zinc acetate + sodium sulfate
E) barium nitrate + potassium iodide
F) Lead ( I ) nitrate + potassium iodide
G) Zinc acetate + potassium iodide
A net ionic equation shows the ions that underwent change in a reaction hence it excludes the spectator ions.
A metathesis reaction is one which the cations exchange anion partners in the products. A general example of a methathesis reaction is AX + BY ---> AY + BX.
The molecular and net ionic equation for the reactions are;
1) Zn(CH3COO)2(aq) + Na2CO3(aq) -----> ZnCO3(s) + 2CH3COONa(aq)
Net ionic equation; Zn^2+(aq) + CO3^2-(aq) ------> ZnCO3(s)
2) Ba(NO3)2(aq) + Na2SO4(aq) ------> BaSO4(s) + 2NaNO3(aq)
Net ionic equation; Ba^2+(aq) + SO4^2-(aq) ------> BaSO4(s)
3) Pb(NO3)2(aq) + Na2SO4(aq) ------> PbSO4(s) + 2NaNO3(aq)
Net ionic equation; Pb^2+(aq) + SO4^2-(aq) ------> PbSO4(s)
4) Zn(CH3COO)2(aq) + Na2SO4(aq) ------> ZnSO4(s) + 2CH3COONa(aq)
Net ionic equation: Zn^2+(aq) + SO4^2-(aq) ------> ZnSO4(s)
5) Ba(NO3)2(aq) + 2KI(aq) ------> 2KNO3(aq) + BaI2(aq)
There is no net ionic equation for this reaction.
6) Pb(NO3)2(aq) + 2KI(aq) -------> PbI2(s) + 2NaNO3(aq)
Net ionic equation: Pb^2+(aq) + 2I^-(aq) -----> PbI2(s)
7) Zn(CH3COO)2(aq) + 2KI(aq) -----> ZnI2(aq) + 2CH3COOK(aq)
There is no net ionic equation for this reaction
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What percentage of light hits Earth’s surface directly?
3 percent
5 percent
31 percent
47 percent
Answer: yall trust me on this one, i took one for the team. The answer is "C" or you can say 31 percent. boys get me 50 thanks.
Explanation:
The percentage of sunlight that hits the Earth's surface directly is 31 percent. The correct option is C.
What is sunlight?Sunlight is the electromagnetic radiation transferred by the sun.
The sun is 93 million away from the earth, so it takes eight and half minutes to reach the sunlight to the earth.
Only 30 to 34 percent of light reaches the earth, and the remaining lights are reflected back by clouds and the earth itself.
Thus, the correct option is C, 31 percent.
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Given that the specific heat of chromium is 0.455J/g∙K find the final temperature after 35.9J of energy is removed from 11.7g of chromium at 28.5°C.
Answer:
[tex]T_2=35.2\°C[/tex]
Explanation:
Hello,
In this case, since the heat is computed in terms of mass, specific heat and temperature as follows:
[tex]Q=mCp(T_2-T_1)[/tex]
In such a way, for the given heat, we obtain the following temperature:
[tex]T_2=T_1+\frac{Q}{mCp}\\ \\T_2=28.5\°C+\frac{35.9J}{11.7g*0.455\frac{J}{g\°C} }\\ \\T_2=35.2\°C[/tex]
Best regards.
is a light bulb chemical or physical change. State evidence why
Answer:
It is a chemical change.
Explanation:
When the electricity is off, the filament cools down to its original physical state. This physical process repeats every time the light is turned on and off. However, if the bulb is cracked and air is introduced, the oxygen in the air reacts with the tungsten filament which then undergoes a chemical change.
2. You are tasked with calculating the average weight of kindergartners in a class of
21 students. Their weights range from a low of 40.5 lbs to a high of 58.6 lbs.
How many significant figures should be in the average that you find?
an object has a mass of 14g and a volume 3.5 mL. what is the density of the object ?
Given :
Mass of object , M = 14 g .
Volume of object , V = 3.5 mL .
To Find :
The density of the object .
Solution :
Density of an object is given by :
[tex]Density=\dfrac{Mass}{Volume}\\\\\rho=\dfrac{M}{V}\\\\\rho=\dfrac{14}{3.5}\ g/mL\\\\\rho=4\ g/mL[/tex]
Therefore , the density is 4 g/mL .
Hence , this is the required solution .
which of the following is not true about water ? *
Water has a freezing point of 0℃
Water is chemically stable and makes a good energy source
Water has a density of 1 g/mL
water is polar
water has a boiling point of 100℃
Water is less dense as a solid
1
Select the correct answer.
Which statement about the relationship between laws, hypotheses, and theories is true?
A.
Laws that remain true over an extended period of time are considered theories.
B.
A theory that holds true for a long time is considered a law.
C.
If a law is not contradicted after a lot of testing, it may be considered a hypothesis.
D.
If a hypothesis is not contradicted after a lot of testing, it may be considered a law.
Answer:
the answer is D
Explanation:
Discuss the effect of changing the flow tube radius on flow rate.
Answer:
The flow rate of a tube is the volume of fluid flowing through the tube per unit time. The flowrate is proportional to the product of the velocity of the fluid through the tube, and the cross-sectional area of the tube.
That is
Q = AV
where
A is the area of the tube
V is the velocity of the tube
The cross-sectional area of the tube is proportional to the radius of the tube. From the above equation, we can deduce that if the velocity of the fluid flowing through the tube is held constant, the flowrate of the fluid through the tube will increase with an increase in the radius of the tube, and it will decrease with a decrease in the radius of the tube.
1- Science that deals with the identification and quantification of the components of material systems
A)Analytical Science
B)Biochemistry
C)Organic Chemistry
D) Inorganic Chemistry
Q1-(30 Marks) Choose the correct answer
Answer:
Analytical science
Explanation:
Is condensation phyiscal change
Answer:
condensation is the change of the physical state of matter from the gas phase to the liquid phase :)
Explanation:
Answer:
Yes.
Explanation:
Condensation is the change of physical state of matter from gas to liquid.