Answer:
If it started with Plato or a little later, the job for Greek Astronomers employed as the platonic tradition was, correctly or incorrectly, to save appearances: obviously to describe, in a mixture of uniform circular motions, irregular motion observed by senses.
Explanation:
2.0 L of oxygen gas and 8.0 L of nitrogen gas at STP are mixed together. The gaseous mixture is compressed to occupy 2.0 L at 298 K. What is the pressure exerted by this mixture?
Answer:
5.5 atm
Explanation:
Step 1: Calculate the moles in 2.0 L of oxygen at STP
At STP, 1 mole of an ideal gas occupies 22.4 L.
2.0 L × 1 mol/22.4 L = 0.089 mol
Step 2: Calculate the moles in 8.0 L of nitrogen at STP
At STP, 1 mole of an ideal gas occupies 22.4 L.
8.0 L × 1 mol/22.4 L = 0.36 mol
Step 3: Calculate the total number of moles of the mixture
n = 0.089 mol + 0.36 mol = 0.45 mol
Step 4: Calculate the pressure exerted by the mixture
We will use the ideal gas equation.
P × V = n × R × T
P = n × R × T / V
P = 0.45 mol × (0.0821 atm.L/mol.K) × 298 K / 2.0 L = 5.5 atm
A student is performing an acid-base extraction on unknown compounds, and she extracts the organic layer with 5% HCl solution and separates off the aqueous layer. She then adds sodium hydroxide solution to the aqueous layer and observes a white precipitate. Which of the following functional group(s) is most likely in the precipitated compound?
a. ether
b. amine
c. carboxylic acid
d. ester
Answer:
amine
Explanation:
We have to bear in mind that amines are basic compounds. This idea will be very important in attempting to answer this question.
So, when she adds 5% HCl solution in order to extract the organic layer, the amine forms a hydrochloride salt which is contained in the aqueous layer.
The addition of a base such as NaOH leads to the formation of a white precipitate of the amine.
5. If 4 moles of nitrogen gas reacts with excess hydrogen gas, how many moles of NH3 will be produced?
Be sure to balance the equation first.
__N2 + __ H2 → __ NH3
a. 8 moles NH3
b. 4 moles NH3
C. 2 moles NH3
d. 12 moles NH3
The warming of our atmosphere is due to contain gases like carbon dioxide and water vapor called greenhouse gases that insulate (trap heat) Earth. What would happen to Earth without these greenhouse gases?
Answer:
the earth would be covered in ice and we would not be able to survive as there is not natural insulation
Each compound listed can be converted to hexanoic acid or sodium hexanoate. Identify the reagent or reagents that can perform this transformation.
a. hexanal
b. methyl hexanoate
c. I -bromopentane
d. 1 -hexanol
(or hexan- 1 -o1)
e. hexanenitrile
Answer:
a. Hexanal
Reagent: - Hot acidified potassium permanganate solution.
or : Ammoniacal silver nitrate solution
or : Fehling's solution.
or : Hot acidified potassium dichromate ( VI ) solution.
Some organic compounds can be oxidised to carboxylic acid using suitable oxidising agents. Alkanes can be converted to acid or acid salt by carboxylation reaction and alkyl halides can be converted using Grignard reagent and then hydrolysis.
What are carboxylic acids?Carboxylic acids are organic acids containing the functional group COOH. It can be prepared through oxidation of various of organic compounds.
Hexanal can be converted to hexanoic acid using carboxylation that is reaction with carbon dioxide.
Methyl hexanoate is an ester which can be converted to hexanoic acid by hydrolysis. Reaction with water introduces the H+ group into the ester group COOMe.
1 bromopentane can be converted into hexanoic acid using grignard reagent RMg followed by hydrolysis.
Alcohols can be easily oxidised to acids. Thus, 1-hexanol can be oxidised to hexanoic acid using oxidising agents such as potassium permanganate.
Nitriles can be oxidised to corresponding carboxylic acid using oxidising agents such as chromium chloride or grignard reagent.
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I need to know the answer asap
How much heat is given off when 16 g liquid methanol (CH3OH) at its freezing point
changes to solid methanol? (methanol AH+ = 3.16 kJ/mol)
A. 0.79 kJ
B. 0.18 kJ
C. 1.58 kJ
D. 0.36 kJ
Answer:
c. 1.58 KJ
Explanation:
I took the test:)
Answer:
1.58 KJ
Explanation:
Uranium-235 decays to form lead-207. The half-life of uranium-235 is 704,000,000 years. What is the approximate age of an igneous rock with a 1:1 ratio of uranium-235 atoms to lead-207 atoms?
Answer:
The approximate age of the igneous rock is [tex]7.042\times 10^{6}[/tex] years.
Explanation:
Chemically speaking, the Uranium-235 decays to form Lead-207 throughout time. All isotopes decay exponentially by means of the following model:
[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (1)
In addition, we can determine the time constant of the former isotope in terms of its half life, that is:
[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (2)
Where:
[tex]m_{o}[/tex] - Initial mass of Uranium-235, in atoms.
[tex]m(t)[/tex] - Current mass of Uranium-235, in atoms.
[tex]\tau[/tex] - TIme constant, in years.
[tex]t_{1/2}[/tex] - Half-life of Uranium-235, in years.
Please remind that a 1 : 1 ratio of Uranium-235 to Lead-207 atoms means that current mass of Uranium-235 is a half of its initial mass. If we know that [tex]m(t) = 0.5\cdot m_{o}[/tex] and [tex]t_{1/2} = 7.04\times 10^{8}\,yr[/tex], then the approximate age of the igneous rock is:
[tex]\tau = \frac{7.04\times 10^{8}\,yr}{\ln 2}[/tex]
[tex]\tau \approx 1.016\times 10^{9}\,yr[/tex]
[tex]t = -\tau \cdot \ln \left(\frac{m(t)}{m_{o}} \right)[/tex]
[tex]t = -(1.016\times 10^{9}\,yr)\cdot \ln \frac{1}{2}[/tex]
[tex]t \approx 7.042\times 10^{6}\,yr[/tex]
The approximate age of the igneous rock is [tex]7.042\times 10^{6}[/tex] years.
4. Iron (III) oxide, Fe2O3, is formed when iron, Fe, combines with oxygen in the air. How many grams of
Fe2O3 are formed when 12.5 g of Fe reacts completely with oxygen?
4Fe +302 → 2Fe203
a. 8.74 g Fe2O3
b. 17.9 g Fe2O3
C. 32.2 g Fe2O3
d. 71.5 g Fe2O3
Sodium (Na) has an ionic charge of +1. Sodium forms an ionic bond with Chlorine (Cl) to form table salt. What charge must the chlorine ion have?
PLS ANSWER LEGITIMATLEY! THANKS! WILL MARK BRAINLIEST!
Explanation:
sodium has a positive charge and chlorine has a negative charge a negative and a positive charge you automatically for an ionic bond therefore the chlorine has to have a negative one charge
How many moles of water are produced when 2 moles of NaHCO3 react with 2 moles of HCI?
Answer:
H₂O = 3.56 moles
MgCl₂ = 1.78 moles
Explanation:
A galvanic cell generates a cell potential of 0.32V when operated under standard conditions according to the reaction above. Which conditions are needed to construct a similar cell that generates the lowest cell potential?
The complete question is shown in the image attached to this answer.
Answer:
C
Explanation:
Let us quickly remember that the EMF of a cell under non standard conditions in given by the Nernst equation.
This equation states that;
E = E°cell - 0.592/n log Q
Where
E = EMF under non standard conditions
E°cell= standard EMF of the cell
n = number of electrons transferred
Q = reaction quotient
If the reaction quotient is greater than 1 then cell potential is less than the standard cell potential.
The cell that generates the lowest cell potential is the cell depicted in option C because Q has the greatest positive value(Q<1).
The cell potential is the redox potential that measures the acquired to lost electrons at the electrodes. The lowest cell potential is generated by cell C with 0.5 M.
What is EMF?EMF is the electromotive force that is the total of the electric potential difference produced at the half cells of the galvanic cell (electrochemical cell).
EMF of the cell is given as,
[tex]\rm E = \rm E^{\circ} - \dfrac{0.592}{n}\; log Q[/tex]
Here, E is the electromotive force, [tex]\rm E^{\circ}[/tex] is the standard EMF, n is the number of the transferred electrons, and Q is the reaction quotient.
When the reaction quotient (Q) is greater than 1 then, cell potential will be less than standard cell potential.
Therefore, cell C with 0.5 M and Q > 1 is a similar cell.
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state two applications of simple distillation of separating mixture
Answer:
Purify drinking water of unwanted
chemicals andminerals such as salt.Hope this helps! :D
Therefore, the independent variable was _____ and the dependent variable was _____
sugar concentration
pressure
solubility
temperature
Answer:
temperature and solubility
Explanation:
In the experiment where we are testing the solubility of sugar at different temperatures and pressure, the dependant variable is the solubility and the independent variables are the temperature, pressure and sugar concentration.
What is independent variables ?Independent variables in an experiment is the variables which does not depends on any other variables and on which we can have access or control.
Dependant variables are dependant on the independent variables and they change with respect to the change in independent variables. On dependant variables are those which we are studying and can have no direct control over it,
In the solubility measurement, solubility is the dependant variable and the we are measuring it under different conditions that are the independent variables such as temperature, pressure, sugar concentration etc.
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For the following example identify the following h2o
Answer:
Explanation:
Well you didn’t send a picture of the question but h2O is water so. If the questions answer has a option of water then pick that one
Chemistry explaining the vapour pressure
Answer:
Vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system.
Explanation:
Cyclohexane (C6H12) is found in gasoline. It is burned for fuel in a combustion reaction. The unbalanced combustion reaction for octane is shown below. C6H12 + O2 + CO2 + H2O + heat When the reaction is balanced, how many carbon dioxide molecules are produced for every cyclohexane molecule burned? O A1 O B. 9 O c. 6 O D. 3
Answer:
6
Explanation:
C[tex]_6[/tex]H[tex]_{12}[/tex] + O[tex]_2[/tex] → CO[tex]_2[/tex] +H[tex]_2[/tex]O + heat can be balanced as C[tex]_6[/tex]H[tex]_{12}[/tex] + 6O[tex]_2[/tex] → 6CO[tex]_2[/tex] +6 H[tex]_2[/tex]O + heat. Therefore, the correct option is option C.
What is combustion reaction?
Combustion is a chemical reaction that often involves the presence of oxygen and produces light and heat within the form of flames. Because of the physical characteristics of the chemical process and the fact that more energy is produced than can be released through the surrounding medium, the rate or speed with which the substances that react combine is high. As a result, the ambient temperature about the reactants is increased, accelerating the reaction even further.
A lit match is a common illustration of a combustion reaction. A flame is produced when a match strikes something because friction warms the head of the match to a temperature where the chemicals respond by creating additional heat than can be released into the atmosphere. C[tex]_6[/tex]H[tex]_{12}[/tex] + O[tex]_2[/tex] → CO[tex]_2[/tex] +H[tex]_2[/tex]O + heat can be balanced as C[tex]_6[/tex]H[tex]_{12}[/tex] + 6O[tex]_2[/tex] → 6CO[tex]_2[/tex] +6 H[tex]_2[/tex]O + heat
Therefore, the correct option is option C.
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what is the role of salinity in water density?
Answer:
Higher the salinity, more is the density.
Explanation:
The oceanic water is a large storehouse of heat and salinity. The salinity is higher at someplace while it's lower at some places is due to the presence of freshwater and cool water that is less dense. Areas of higher salinity are due to the high evaporation, less precipitation, and influx of rivers. The warm water floats at the top while the cold and cool water at the bottom.What is the scientific method?
O A. A book describing scientific experiments
B. A description of proper laboratory techniques
O C. A scientific approach to answering questions
D. A way of thinking about scientific problems
Answer:
C.A scientific approach to answering questions
Explanation:
What is the total energy (in Joules) required to raise the temperature
of 630 g of water from 20°C to 110°C?
What is the name of Earth's home galaxy?
The Milky Way
The Elliptical
The Spiral Way
The Irregular
100 points
Answer:
The Milky Way
Explanation:
Answer:
Your answer is the Milky WAy!
Brainliest?
Which of these metals reacts more vigorously with water?
1. Zinc
2. Magnesium
Answer:
magnesium
Explanation:
because zinc does not react with water because it too forms a protective layer of insoluble.
This is for my science class.
A donut falls from a table and has a kinetic energy of 2 joules when it hits the floor. How much kinetic energy would it have had if it was twice the mass?
Answer:
4 joules
Hope this helps if it does consider giving brainliest
Cya on the next one!
Explanation:
4 joules.
When it left the table it would have mgh potential energy that would have been converted to kinetic when it hit the floor. If the mass (m) was twice the energy would have been twice.
Which example of regeneration is also considered reproduction?
Explanation:
Regeneration is a type of asexual reproduction in which the organism is capable of regrowing certain body parts.
Answer: Regeneration is defined as organism's ability to regrow damaged or lost body parts. It is a type of asexual reproduction which is shown by many fully differentiated organisms. Organism such as Hydra uses regenerative cells for reproduction in the process of budding. The young Hydra gets its nourishment from the parent.
Explanation:
The force needed to overcome the attraction among molecules at the surface of a liquid is called?
Answer:
The type of force is known as cohesive force
2. What are the two types of pressure?
O Medium pressure/Extreme pressure
ebo...
Medium pressure/ Low pressure
O High pressure/Low pressure
Medium pressure/ High pressure
Answer:
O High pressure/Low pressure
Explanation:
A low pressure system has lower pressure at its center than the areas around it. Winds blow towards the low pressure, and the air rises in the atmosphere where they meet. ... A high pressure system has higher pressure at its center than the areas around it. Winds blow away from high pressure.
The two types of pressure commonly referred to are high pressure and low pressure. Therefore option 3 is correct.
High pressure/Low pressure: This option correctly identifies the two main types of pressure. High pressure refers to conditions where the pressure is greater than atmospheric pressure, such as in compressed gases or in high-pressure systems.
Low pressure refers to conditions where the pressure is less than atmospheric pressure, such as in a vacuum or in areas of low atmospheric pressure, like the center of a weather system.
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What is the mole fraction, , of solute and the molality, (or ), for an aqueous solution that is 12.0% NaOH by mass?
Answer:
Molefraction is the ratio of the number of moles of solute and total number of moles in solution. Moles = (given mass) / (molar mass) = 1000/18 = 55.5 moles. Therefore 1/(55.5+1) = 0.017. Molefraction of solute in 1 m aqueous solution is 0.017.
Explanation:
explain the importance of fingerprint record in criminal investigation.
Answer:
One of the most important uses for fingerprints is to help investigators link one crime scene to another involving the same person. Fingerprint identification also helps investigators to track a criminal's record, their previous arrests and convictions, to aid in sentencing, probation, parole and pardoning decisions.
Explanation:
Which type of molecule is shown below? I CH3 C=C H CH3 O A. Alkene O B. Cyclic alkane O C. Alkane O D. Alkyne
Answer:
Alkene
Explanation:
Took the test.
The correct answer is Option (A) Alkene.
What is Alkene?Alkenes are the hydrocarbon which contain double bond of carbon and carbon.The general formula of alkene are CnH2n.Alkenes are unsaturated hydrocarbons. Why other options are incorrect?The other options are incorrect because the structure given in the question is C4H8. The IUPAC name of the structure is is 1- butene .The structure describes the general formula of alkene CnH2n where we can say that n= 4Hence , Option (A) is correct and rest options are incorrect.Learn more about Alkenes below
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consider the unbalanced chemical equation hf + al -> alf3 + h2. when coefficients are added to balance the equation, which two substances have a coefficient of two?
a. hf
b. alf3
c. h2
d. al
Answer:
a
Explanation:
because you need to add 2 to to hf to make it equal to h2