You are given a sample of several compounds to separate by paper chromatography. You draw a pencil line exactly 1.00 cm from the bottom of the paper, and place a spot of sample on it. You dry the sample, then develop it in a solvent. When the chromatogram is taken out of the solvent, the paper is wet up to 9.17 cm from the bottom of the sheet. The compound you are interested in shows up as a spot 7.57 cm from the bottom of the paper. Calculate the following:
a. How far did the compound move?
b. In the same time, how far did the solvent move?
c. What is the Rf factor for the compound?
Answer:
a. 6.57 cm
b. 8.17 cm
c. 0.80
Explanation:
a. The compound moved from where it was first placed, to a spot 7.57 cm from the bottom of the paper, in other words:
7.57 cm - 1.00 cm = 6.57 cmb. A similar method is made for the solvent:
9.17 cm - 1.00 cm = 8.17 cmc. The Rf of the factor is equal to the distance that the compound moved divided by the distance the solvent moved:
6.57 cm / 8.17 cm = 0.80What type of reaction is _CaCO3 and H2
Decomposition: A substance breaks down to smaller species.
Rank the effective nuclear charge Z* experienced by a valence electron in each of these atoms:
atom Z* experienced by a valence electron.
An atom of carbon.
An atom of fluorine.
An atom of beryllium.
An atom of boron.
Answer:
The atoms are ranked in decreasing order as follows:
Fluorine ---4
Carbon ----3
Boron ------2
Beryllium --1
Explanation:
Effective nuclear charge (Zeff) is defined as the difference between the actual nuclear charge (the atomic number, Z) and the shielding constant (S).
It is calculated by finding the atomic number and electronic configuration, attributing a shielding value to each electron, adding all the shielding values and using the formula:
Z eff = Z - S
Effective nuclear charges:
An atom of carbon: 3.25
An atom of fluorine: 5.20
An atom of beryllium: 1.95
An atom of boron: 2.60
the law of conservation of mass
Answer: The Law of Conservation of Mass dates from Antoine Lavoisier's 1789 discovery that mass is neither created nor destroyed in chemical reactions. In other words, the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction.
Explanation:
Determine what happens in this reaction.S + Cl2 →SCl2
Sulfur act as a reducing agent and chlorine acts as an oxidizing agent.
Oxidation: The loss of electronsReduction: The gain of electronsOxidation number:The charge is based on the number of electrons assigned to an atom as compared to the neutral atom
Given reaction:-
[tex]S+Cl_2 \rightarrow SCl_2[/tex]
The oxidation state of sulfur in the left side is 0, but in right side is +2. So, sulfur is oxidized. The oxidation number of Cl in the reactant side is 0 and n the product side is -1. So, Cl acts as oxidizing agent.
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All of the following are characteristics of matter except
A.matter can disappear and reappear
B.matter has mass
C.matter occupies space
D.all things are composed of matter
Which has more calories: table sugar or aspartame?
Hello there!
Aspartame has 4 kilocalories of energy per gram and table sugar has 3.9 kilocalories. They are pretty much same but aspartame is 200 times sweeter than sucrose so probably would be aspartame that has more calories.
The substance krypton has the following properties: normal melting point:
normal melting point: 115.9 K
normal boiling point: 119.8 K
triple point; 0.72 atm, 115.8 K
critical point: 54.3 atm, 209.4 K
A sample of krypton is initially at a pressure of 59.8 atm and a temperature of 107.7 K. The pressure on the sample is reduced to 0.720 atm at a constant temperature of 107.7 K. Which of the following are true?
a. The final state of the substance is a solid.
b. One or more phase changes will occur.
c. The final state of the substance is a liquid.
d. The sample is initially a gas.
e. The solid initially present will vaporize.
Answer:
Part 1
triple point; 0.72 atm, 115.8 K
Part 2
Option D, The sample is initially a gas.
Explanation:
Part 1
The triple point of krypton is 0.72 atm
and the melting point of Krypton is -157.4 °C or 115.8 K
Hence, option C is correct
Part 2
Option D
At 59.8 atm, Krypton is a gas. It changes its state from gas to liquid and solid when the temperature is extremely low. Here the temperature is same , hence only option D is correct
A student holds their pen 20 centimeters above the desk. If the pen has a mass of 3
grams, how much potential energy does the pen have? (gravity is 9.8 m/s2)
SHOW YOUR WORK.
The potential energy : PE = 5.88 x 10⁻³ J
Further explanationGiven
height = h = 20 cm = 0.2 m
mass = 3 grams = 3 x 10⁻³ kg
Required
The potential energy
Solution
The energy produced from its position is called potential energy (PE)
which can be formulated as:
PE = m. g. h
Input the value :
PE = 3 x 10⁻³ x 9.8 x 0.2
PE = 5.88 x 10⁻³ J
Two colorless chemicals combine inside a glow
stick. When the chemicals combine, they produce
brightly colored light. The glow stick's temperature
does not change.
emission of heat
emission of light
color change
formation of gas
Answer:
Option B & Option C
Explanation:
correct on edge! :D
When chemicals combine chemical change takes place which is accompanied by emission of heat and light.
What is a chemical change?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
Learn more about chemical change,here:
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What is the percent composition of Mg in the compound Mg3(PO4)2?
A 21.92%
B 23.57%
C 32.32%
D 27.74%
Answer:
D 27.74%
Explanation:
Percent composition of Magnesium (Mg) in Magnesium Phosphate compound ie Mg3(PO4)2 = 27.74%
Answer:
The answer is D
Explanation:
I took the test
Racecar driver Keimesha was in a race and accelerated from rest to 39 m/s by the time she reached the finish line. Keimesha’s car moved in a straight line and traveled from the starting line to the finish line in 6.0 seconds. What was the acceleration of the dragster?
Answer:
the acceleration of the racecar is 6.5 m/s²
Explanation:
Given;
initial velocity of the racecar, u = 0
final velocity of the racecar, v = 39 m/s
time of motion, t = 6.0 s
The acceleration of the racecar is calculated as;
[tex]a = \frac{v-u}{t} \\\\a = \frac{39-0}{6} \\\\a = \frac{39}{6} \\\\a = 6.5 \ m/s^2[/tex]
Therefore, the acceleration of the racecar is 6.5 m/s²
A crane lifts a 5,800-N block from the ground to 20 m above the ground in 80 seconds. How much Power
did the crane use?
Answer:
1450 W
Explanation:
5800n x 20m =1450w
80s
b) All atoms contain
charged electrons.
Answer:
b) All atoms contain
charged electrons.
Explanation:
If 3.53 g of CuNO, is dissolved in water to make a 0.330 M solution, what is the volume of the solution in milliliters?
Answer:
84.8 mL
Explanation:
From the question given above, the following data were obtained:
Mass of CuNO₃ = 3.53 g
Molarity of CuNO₃ = 0.330 M
Volume of solution =?
Next, we shall determine the number of mole in 3.53 g of CuNO₃. This can be obtained as follow:
Mass of CuNO₃ = 3.53 g
Molar mass of CuNO₃ = 63.5 + 14 + (16×3)
= 63.5 + 14 + 48
= 125.5 g/mol
Mole of CuNO₃ =?
Mole = mass / Molar mass
Mole of CuNO₃ = 3.53 / 125.5
Mole of CuNO₃ = 0.028 moles
Next, we shall determine the volume of the solution. This can be obtained as follow:
Molarity of CuNO₃ = 0.330 M
Mole of CuNO₃ = 0.028 moles
Volume of solution =?
Molarity = mole /Volume
0.330 = 0.028 / Volume
Cross multiply
0.330 × Volume = 0.028
Divide both side by 0.330
Volume = 0.028 / 0.330
Volume = 0.0848 L
Finally, we shall convert 0.0848 L to millilitres (mL). This can be obtained as follow:
1 L = 1000 mL
Therefore,
0.0848 L = 0.0848 L × 1000 mL / 1 L
0.0848 L = 84.8 mL
Therefore, the volume of the solution is 84.8 mL.
Which of the following is formed when an acid reacts with a base? (1 point)
Alkaline
Hydrogen ion
Hydroxide ion
Salt
Answer:
Probably Alkaline
Explanation:
Not sure at all.
A speed boat, at full throttle, can go 65.0 miles in 1.5 hours. What is the average speed of the boat?
The average speed = 43.33 miles per hours(mph)
Further explanationGiven
distance = 65 miles
time = 1.5 hours
Required
The average speed
Solution
The average speed : distance traveled divided by time taken or total distance divided by total elapsed time
Can be formulated :
avg speed = distance : time
avg speed = d : t
Input the value :
avg speed = 65 miles : 1,5 hours
avg speed = 43.33 miles per hours(mph)
la densidad de un aceite liviano para vehiculo es 0.87g/cm3 calcules su volumen especifico y peso especifico
Answer:
Pe = 8700 N/m³
Vesp = 1,15 cm³/g
Explanation:
Ya que conocemos el valor de la densidad de este aceite, es muy sencillo calcular tanto volumen como peso específico.
En el caso de volumen específico, esta se refiere al cociente del volumen de un líquido con su masa respectiva. En otras palabras, es el inverso de la densidad, por tanto usamos la siguiente expresión para el volumen específico:
Vesp = 1/d
Vesp = 1 / 0,87
Vesp = 1,15 cm³/gPara el caso del peso específico, se calcula como el cociente de la masa del líquido y su volumen que ocupa. Sin embargo no conocemos ninguno de esos dos datos, por lo que para calcular el peso específico solo basta multiplicar este valor por la aceleración de gravedad, que vamos a asumir para este problema que es 10 m/s². Y ademas cambiaremos las unidades de densidad de g/cm³ a kg/m³. Esto es porque las unidades de peso específico son N/m³ y los newton (N) son kg m/s².
d = 0,87 g/cm³ * (1 kg/1000g) * (100 cm/1m)³ = 870 kg/m³
Pe = 870 kg/m³ * 10 m/s²
Pe = 8700 N/m³ESpero te sirva.
1. How many grams are there in 1.5 x 10^25 molecules of CO2?
Answer: 1.1 kg
Explanation:
Mw CO2 is 44g —> 6.02214076*10^23 molecules
1.5*10^25 molecules —> 1.1 kg
Practice: Balance each of the chemical equations below. (Some equations may already be in balance.) In the space to the right, classify the reaction as a synthesis, decomposition, single replacement, or double replacement reaction. A. AgNO3 + KCl ???? AgCl + KNO3 B. H2O + SO3 ???? H2SO4 C. KI + Cl2 ???? KCl + I2 D. NaHCO3 ???? Na2CO3 + H2O + CO2 E. Zn + HCl ???? ZnCl2 + H2 F. BaCl2 + Na2SO4 ???? BaSO4 + NaCl G. C3H8 + O2 ???? CO2 + H2O H. Al + CuCl2 ???? AlCl3 + Cu
Explanation:
A. AgNO3 + KCl --> AgCl + KNO3
Reaction is already balanced.
Type = Double Replacement
B. H2O + SO3 --> H2SO4
Reaction is already balanced.
Type = Synthesis
C. KI + Cl2 --> KCl + I2
Balanced Equation = 2KI + Cl2 --> 2KCl + I2
Type = Single Replacement
D. NaHCO3 --> Na2CO3 + H2O + CO2
Balanced Equation = 2NaHCO3 --> Na2CO3 + H2O + CO2
Type = Decomposition
E. Zn + HCl --> ZnCl2 + H2
Balanced Equation = Zn + 2HCl --> ZnCl2 + H2
Type = Single Replacement
F. BaCl2 + Na2SO4 --> BaSO4 + NaCl
Balanced Equation = BaCl2 + Na2SO4 → 2NaCl + BaSO4
Type = Double Replacement
G. C3H8 + O2 --> CO2 + H2O
Balanced Equation = C3H8 + 5O2 → 3CO2 + 4H2O
Type = Single Replacement
H. Al + CuCl2 --> AlCl3 + Cu
Balanced Equation = 2Al + 3CuCl2 → 2AlCl3 + 3Cu
Type = Single Replacement
Which statement is true about the speed of light? (2 points) Light travels relatively slowly. Distance in space is measured using the speed of light. Time in space is measured using the speed of light. The speed of light is unknown.
Distance in space is measured using the speed of light.
Answer:
Distance in space is measured using the speed of light.
Explanation:
I took the test
A student obtained 1.57 g of product in a chemical reaction in the lab although she expected to produce 2.04 g of product. What was the percent yield of the experiment?
A. 23.1%
B. 43.4%
C. 56.5%
D. 77.0%
Answer:
D. 77.0%
Explanation:
% yield = actual yield/theoretical yield x 100%
% yield = 1.57 g / 2.04 g x 100%
% yield = 76.96 (round up)
List the 4 cell structures from largest to smallest
Answer: The smallest structure is the double helix while the largest is the chromosome.
2. G2 phase is the third stage in cellular division wherein the cell prepares itself for the M phase.
3. Interphase comprises of 3 phases, namely, G1 phase, G2 phase, and S phase.
4. Metaphase is known to take less amount of time to complete.
Explanation:
1. The double helix of the DNA or deoxyribonucleic acid, nucleosome, coil, supercoil, and the chromosomes are all linked to the DNA and they vary in their sizes. The nucleosome is known to be the basic unit of the eukaryotic chromosome that is composed of DNA coiled around the histones. The supercoils and coils indicate to the structures which are derived from the folding as well as wrapping of the structure of the DNA. The chromosome refers to the thread-like structure which is made up of nucleic acid and is observed in the nucleus of the living organisms.
2. Cell cycle refers to the cellular division of the cell; it is the series of events which occurs within a cell that results in duplication of the DNA or deoxyribonucleic acid as well as division of the cytoplasm and other organelles in order to generate two daughter cells. This cycle comprises of 4 phases, namely, G1, S, G2, and M phase.
The cell enters the G1 phase wherein the cell synthesizes the proteins as well as mRNA or messenger ribonucleic acid in preparation for the next upcoming phases which lead to mitosis. Next stage is the S phase wherein the synthesis of DNA takes place.
G2 phase is the next phase wherein the cell prepares itself by allowing it to grow as well as generate new proteins needed for the next phase called M phase. Mitosis is the final stage wherein the two identical daughter cells are made from one parent cell.
3. The cell cycle is broadly segregated into 3 phases, namely, interphase, M phase, and cytokinesis. Interphase is the longest stage of the cellular cycle and it comprises of 3 phases, G1 phase, S, and G2 phase. There is a G0 phase or quiescent phase. During the G1 phase, the cell prepares itself for the next phases of cell cycle, S phase involves synthesis of DNA, and G2 is the production of new proteins needed for the M phase.
4. During the mitotic phase, the parental cell segregates and produces 2 identical daughter cells. This phase is further segregated into prophase followed by metaphase, anaphase, and finally telophase. During metaphase, the chromosomes align themselves onto the equatorial or metaphase plate and the centrosomes prepare to segregate the sister chromatids. This phase takes only about 4% of the time needed to finish the entire cell cycle.
Explanation:
What are the components of the system that influence its motion? *
Answer:
Motion control systems are any system that control one or more of the following of a machine: its position, velocity, force, and/or pressure. They generally consist of the follow components: Motion controller: the central part that operates the system (I.e. the brain)
What is the correct name for Hg(NO3)2?
Mercury (I) nitrate
Mercury (II) nitrate
Mercury nitroxide
Mercury dinitride
Answer: Hg(NO3)2 = Mercury (II) nitrate
The other answer is wrong. Mercury (I) nitrate is Hg2(NO3)2.
Why was d-day and the battle of France so important to American and the allies
Answer:
The Importance of D-Day
The D-Day invasion is significant in history for the role it played in World War II. It marked the turn of the tide for the control maintained by Nazi Germany; less than a year after the invasion, the Allies formally accepted Nazi Germany's surrender.
f) How many neutrons are there in the nucleus of arsenic?
1. Neodymium
2. Selenium
3. Strontium
Explanation:
How many neutrons are there in the nucleus of arsenic?42 neutrons
The nucleus consists of 33 protons (red) and 42 neutrons (blue).
Calculate the kinetic energy of an electron ejected from a piece of sodium (Φ = 4.41x10–19 J) that is illuminated with 265 nm light.
in Joules
Answer:
Explanation:
Energy of falling radiation having wavelength of 265 nm
= h c / λ where h is plank's constant , c is velocity of light and λ is wavelength of radiation . Putting the values
Energy of light photon = 6.6 x 10⁻³⁴ x 3 x 10⁸ / 265 x 10⁻⁹
= .0747 x 10⁻¹⁷
= 7.47 x 10⁻¹⁹ J .
Work function of sodium is 4.41 x 10⁻¹⁹
So kinetic energy of ejected electron = energy of falling photon - work function
= 7.47 x 10⁻¹⁹ - 4.41 x 10⁻¹⁹
= 3.06 x 10⁻¹⁹ eV .
Glycerol (C3H8O3), also called glycerine, is widely used in the food and pharmaceutical industries. Glycerol is polar and dissolves readily in water and polar organic solvents like ethanol. Calculate the mole fraction of the solvent in a solution that contains 2.51 g glycerol dissolved in 21.10 mL ethanol (CH3CH2OH; density
Answer: The mole fraction of the solvent in a solution that contains 2.51 g glycerol dissolved in 21.10 mL ethanol is 0.93
Explanation:
Given : Volume of ethanol (solvent) = 21.10 ml
density of ethanol (solvent)= 0.789 g/ml
Mass of ethanol (solvent) = [tex]0.789g/ml\times 21.10ml=16.6g[/tex]
Mass of glycerol (solute) = 2.51 g
Mole fraction of a component is the ratio of moles of that component to the total moles present.
moles of ethanol =[tex]\frac{\text {given mass}}{\text {molar mass}}=\frac{16.6g}{46g/mol}=0.36mol[/tex]
moles of glycerol =[tex]\frac{\text {given mass}}{\text {molar mass}}=\frac{2.51g}{92g/mol}=0.027mol[/tex]
mole fraction of ethanol (solvent) = [tex]\frac{\text {moles of ethanol}}{\text {moles of ethanol + moles of glycerol}}=\frac{0.36}{0.36+0.027}=0.93[/tex]
The mole fraction of the solvent in a solution that contains 2.51 g glycerol dissolved in 21.10 mL ethanol is 0.93
Help, due tonight (2/19/2021) at 11:59pm!
Answer:
283549.68 J
Explanation:
From the question given above, the following data were obtained:
Mass (M) = 2.7 Kg
Initial Temperature (T₁) = 5.4 °C
Final temperature (T₂) = 30.5 °C
Specific heat capacity (C) = 4184 J/KgºC
Heat (Q) =?
The amount of heat energy needed can be obtained as follow:
Q = MC(T₂ – T₁)
Q = 2.7 × 4184 × (30.5 – 5.4)
Q = 11296.8 × 25.1
Q = 283549.68 J
Thus, the heat energy needed is 283549.68 J