Answer:
Explanation:
Liquid to solid phase transitions are known as "freezing.". Solid to liquid phase transitions are known as "melting.". Solid to gas phase transitions are known as "sublimation.". In most cases, solids turn into gases only after an intermediate liquid state.
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
Which of the following is an organic moleclue ?
Answer:
water
Explanation:
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:
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
Which molecule has weakest bond?
Answer:
ionic bonds are the weakest bonds
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
2.0 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
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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state two applications of simple distillation of separating mixture
Answer:
Purify drinking water of unwanted
chemicals andminerals such as salt.Hope this helps! :D
Which of the following are elements in this equation: 2H2O2 (aq) → 2H2O (l) + O2 (g)?
Check all that apply:
A. O
B. g
C. Aq
D. H
Place these elements in order of increasing ionization energy and JUSTIFY A REASON FOR THIS TREND. C Ge Pb Si Sn
Answer: The given elements are arranged in order of increasing ionization energy as Pb < Sn < Ge < Si < C.
Explanation:
The amount of energy required to remove a loosely bound electron from an isolated neutral gaseous atom is called ionization energy.
Larger is the size of an atom more easily it will lose its valence electrons. Hence, less will its ionization energy.
Whereas smaller is the size of an atom more energy will be required to pull out the electron. Hence, more will be its ionization energy.
This means that on moving down a group ionization energy decreases and on moving along a period from left to right the ionization energy decreases.
The given elements are C, Ge, Pb, Si, and Sn. All these elements belong to group 14 of the periodic table.
Therefore, these elements are arranged in order of increasing ionization energy as follows.
Pb < Sn < Ge < Si < C
Thus, we can conclude that given elements are arranged in order of increasing ionization energy as Pb < Sn < Ge < Si < C.
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:
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.
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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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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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:
What is the significance of Plato’s problem of “saving the appearances” to the scientific mindset of the philosophers and Differentiate geocentric from heliocentric model of the universe.
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:
1. Molecules are held together by:
a, ionic bonds
b. covalent bonds
c. both a and b
A: ionic bond, you know why becasue it is
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.
maize is called monocot plant,why ? dive any two reasons
opss sorry this is science subject not chemistry
Answer:
because it has one cotyledon and it has parallel venation also maize is grain..
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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Explain the term pycnocline
Answer:
It is a Cline or layer where density gradient is greatest within a body of water
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.
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
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:
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:
1:Which example is not a physical change?
2: Which of the following is not a clue that a chemical reaction is taking place?
I need to know the answer asap
a) ¿De qué trata el cuento que leíste?
No hablo espanol could you put it in English?
What is the name of the process scientists use to give different names to different organisms?
astronomy
economy
identification
taxonom
Answer:
D). Taxonomy.
Explanation:
'Taxonomy' is described as the process or the science of finding, describing, classifying, and naming different organisms. It is characterized as the technique of classification of animals, micro-organisms, plants, etc. into different categories or hierarchies. It has primarily been divided into eight distinct types like kingdom, species, order, family, etc.
Astronomy is associated with the study of the physical universe while the economy is defined as the study of efficient utilization of resources and identification is the process of recognizing an object. Thus, option D is the correct answer.