Answer:
purity and pressure affects boiling point
what is chemical reaction ?
Two students are identifying a sample of tap water.
Student A says that tap water is a mixture, while
Student B says that it is a compound. Which student
is correct? Justify your answer.
Tap water is a mixture not compound due to presence of many substance.
Tap water is an example of mixture not compound because in tap water, water is not available in pure form, it has many substances mix with water and those substances make no bond with water.
It has dissolved compounds like calcium carbonate, magnesium and fluoride. Different elements or compounds are physically combined rather than chemically linked together so we can conclude that student A is correct that tap water is a mixture.
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An atom has the following electron configuration.
1s22s22p63s23p64s2
How many valence electrons does this atom have?
Answer:
2
Explanation:
4s2 has 2 valence electrons
Valence shell is the shell which is the outermost shell, that is filled in the last, before valence shell is penultimate shell. Therefore 2 valence electron are there in the valence shell.
What is element?Element generally consist of atoms or we can say atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
From our question the electronic configuration of element is given as
1s²2s²2p⁶3s²3p⁶4s²
Valence electron is the one which is present in the outermost shell or orbit. So, form above electronic configuration we can say that 4 is the outermost shell and in this shell 2 electron is present. Therefore 2 electron are there in the valence shell as valence electron.
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1. Write a balanced chemical equation, including physical state symbols, for the combustion of methane in gaseous gaseous carbon dioxide.
Answer:
CH4(g)+2O2(g)→CO2(g)+2H2O(g)
Explanation:
For a complete combustion reaction of a hydrocarbon, oxygen is always one of the reactants, and the products are always carbon dioxide and water.
Methane (CH4) is used in laboratory burner. When 1 mole of methane burns at constant pressure, it produces 804 kJ of heat and does 3 kJ of work.Methane (CH4) is used in laboratory burner. When 1 mole of methane burns at constant pressure, it produces 804 kJ of heat and does 3 kJ of work.
The enthalpy ΔH of combustion is - 804 kJ. The change in internal energy ΔE of the reaction process is -801 kJ
The objective of this question is to determine the value of ΔH and ΔE of combustion is for 1 mole of methane.
If we look closely at the question, we will realize that at constant pressure, methane burns and produces heat of 804 kJ into the surroundings.
Since heat is released;
ΔH = -804 kJ
It also does a work of 3kJ, since work is done on the system
W = - 3kJ
According to the first law of thermodynamics;
ΔE = ΔH - W
ΔE = (-804 - (-3 )) kJ
ΔE = -801 kJ
Therefore, we can conclude that the in 1 mole of methane, the enthalpy ΔH of combustion is - 804 kJ. The change in internal energy ΔE of the reaction process is -801 kJ
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Calculate the pH when the following quantities of 0.100 M NaOH solution have been added to 50.0 mL of 0.100 M HCl solution
Answer:
see explanation
Explanation:
Given 0.100M NaOH + 50ml 0.100M HCl
If 50ml of 0.100M NaOH is added to 50ml 0.100M HCl => pH = 7
if less than 50ml of 0.100M NaOH => pH < 7
if more than 50ml of 0.100M NaOH => pH > 7.
Example:
50ml(0.100M NaOH) + 50ml(0.100MHCl) =>
0.500mole NaCl + 0.500mole H₂O
In this mix, both NaOH and HCl are converted to NaCl and H₂O and NaOH or HCl are no longer present giving a neutral solution. Since neither Na⁺ nor Cl⁻ undergo hydrolysis, the pH is dependent upon H₂O ⇄ H⁺ + OH⁻ and [H⁺] = [OH⁻] = 10⁻⁷M => pH = -log[H⁺] = -log(10⁻⁷) = -(-7) = 7
If less than 50ml of 0.100M NaOH is added, the mix will have an excess of HCl and the pH will be acidic; i.e., less than 7.
If more than 50ml of 0.100M NaOH is added, the mix will have an excess of NaOH and the pH will be alkaline (basic); i.e., greater than 7.
Fusion is a type of _____.
chemical reaction
nuclear reaction
physical reaction
Answer:nuclear reaction
Explanation: Nuclear fusion is a type of nuclear reaction where two light nuclei collide together to form a single, heavier nucleus. Fusion results in a release of energy because the mass of the new nucleus is less than the sum of the original masses.
Fusion is the process that powers the sun and the stars. It is the reaction in which two atoms of hydrogen combine together, or fuse, to form an atom of helium. In the process some of the mass of the hydrogen is converted into energy.
Explain why Florida does not have long winters?
a guy walks into a bar and sees a non-linear person. he says hey wt y=mx+b is this? he threw a sploddy gun grenade in the place. how many non-linear people did he hurt?
How does the structure of compounds determines the properties of the compounds?
All of these properties are due to the chemical structure of the compound. The chemical structure includes the bonding angle, the type of bonds, the size of the molecule, and the interactions between molecules. Slight changes in the chemical structure can drastically affect the properties of the compound.
Hitting a ball with a baseball bat is an example of a force
True or False
Air is a mixture of (mostly) oxygen (molecular mass 16) and nitrogen (molecular mass 14) gases. At room temperature, which molecules in this room have more kinetic energy (on average)
The molecules of the two gases will have the same kinetic energy at room temperature.
The average kinetic energy of gaseous molecules can be calculated using the formula:
Kinetic Energy = 3/2RT, where R = constant and T = temperature in Kelvin
This means that the kinetic energy of a gaseous molecule is dependent on the temperature of the molecule only.
In other words, the molecular mass of molecules of gases has no bearing on the kinetic energy of each molecule.
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QUESTION 27
20 points
Compare and contrast how the selection of police officers in 1840s New York differed from police officer selection under the European
model.
Explanation:
During the 1800s in England, relations police, which became composed of male volunteers, became organised to observe over the protection and protection in their relatives. As Britain's populace step by step expanded, so did the quantity of crimes tha…
During the 1800s in England, relations police, which became composed of male volunteers, became organised to observe the protection and protection of their relatives.
What is protection?Protection is any measure taken to guard a thing against damage.
During the 1800s in England, relations police, which became composed of male volunteers, became organised to observe the protection and protection in their relatives.
As Britain's populace step by step expanded, so did the number of crimes that had been committed. This intended that regulation and order additionally needed to improve.
The New York City Police Department (NYPD) originates withinside the Government of New York City and tries to manipulate growing crime in early to mid-nineteenth century New York City.
This expanded crime became because of an expanding populace, brought about usually through negative Irish immigrants starting withinside the 1820s.
Whereas, as societies have become greater heterogeneous and complex, the function of the police is turning greater demanding. To fulfil this function, law enforcement officials want numerous broadly acknowledged competencies and private qualities, however much less is thought approximately how they're valued through police recruits.
Thus, we've tested the perspectives of police recruits in six European nations on 3 skills or traits of regarded significance for police work: knowledge, leadership, and the cap potential to shape precise family members with residents.
We have additionally explored versions in perspectives of recruits in distinct businesses and modifications of their perspectives for the duration of their schooling. For those purposes, we used survey facts accumulated withinside the RECPOL project.
Since the facts had been accumulated from distinct populations and at distinct times, the evaluation is primarily based totally on dimension invariance methodology, and one of the objectives became to spotlight the significance of rigorous appraisal of the pleasant and comparison of comparable survey facts the use of such methods.
The consequences display each variation and similarities in perspectives of recruits withinside the surveyed nations and modifications for the duration of schooling.
Police lifestyle seems to be an extensive factor, as greater objects withinside the carried out device can be validly utilized in comparisons of recruits in businesses with comparable policy traditions.
The consequences additionally confirmed exciting contrasts, e.g. new recruits in Sweden rated precise family members with residents greater surprisingly than recruits in businesses with a greater army history, however, this sample was modified for the duration of schooling, probably because of the effects of the recruitment process, schooling and lifestyle in the businesses.
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What is the molarity of Ca(NO3)2 in a solution resulting from mixing 150.0 mL of 0.200 M HNO3 with 150.0 mL of 0.0100 M Ca(OH)2
The molarity of the Ca(NO3)2 solution would be 0.005 M
First, let us look at the balanced equation of the reaction:
[tex]2HNO_3+Ca(OH)_2 ---> Ca(NO_3)_2+2H_2O[/tex]
The mole ratio of HNO3 to Ca(OH)2 is 2:1.
Mole of HNO3 = molarity x volume
= 0.2 x 150/1000
= 0.03 mole
Mole of Ca(OH)2 = 0.01 x 150/1000
= 0.0015
Thus, there is no limiting or excess reactant.
Also from the equation, mole ratio of Ca(OH)2 to Ca(NO3)2 is 1:1. Hence, the mole of Ca(NO3)2 would also be 0.0015 mole.
The total volume of the resulting solution would be: 150 +150 = 300 mL
Thus, the molarity of the resulting Ca(NO3)2 would be:
Molarity = mole/volume
= 0.0015/0.3
= 0.005 M
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I am not feeling well
I hope you feel better soon! :)
How large
would be needed to hold
a Container
of water
Answer:
Since water has a density of 1 gram per cubic centimeter, then the container would need to be 800 cubic centimeters. if this container were a perfect cube, then the length of the side of the container would be equal to the cube-root of 800, which is approximately 9.28 cm to a side, or 3.65 inches to aside.
What is the molality of sodium chloride in solution that is 13.0% by mass sodium chloride and that
the solution has a density of 1.10 g/mL?
Answer:
2.4 M
Explanation:
1. Suppose you have 100 mL solution:
Use density to find grams of solution:
100 mL solution x (1.10 g / 1 mL) = 110 g solution
2. FInd the amount of sodium chloride pure:
110 g solution x(13 g NaCl / 100 g solution) = 14.3 g NaCl
3. Change grams to mol:
14.3 g NaCl x ( 1 mol NaCl/ 58.44 g NaCl) = 0.24 mol NaCl
4. Molarity:
M = mol NaCl / L solution
M = 0.24 mol NaCl / 0.1 L = 2.4 M
Wyndirbu lie the following best describes the role played by
hydraulic fluid a hydraulic machine?
А
A source of fuel
B
A medium for the transfer of force
С
A coolant
D
A cleaning agent
Help pls
The role played by hydraulic fluid in a hydraulic machine is as a medium for
the transfer of force.
Hydraulic fluid is used primarily in a hydraulic machine for the transfer of
force from one point to another. This makes the system able to perform the
required functions.
Hydraulic fluid also has other functions such as being a coolant and as a
cleaning agent(removal of contaminants) which aren't its major function.
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The
is the wind system responsible for the movement of weather from west to east across most of the continental United States
A
polar easterlies
B
prevailing westerlies
C
trade winds
Answer:
Westerlies are prevailing winds that blow from the west at midlatitudes. They are fed by polar easterlies and winds from the high-pressure horse latitudes, which sandwich them on either side.Nov 15, C answer
a
A molecule that experiences London dispersion forces is
likely to have a • boiling point than a molecule
experiencing a dipole-dipole interaction.
pls
Answer:
it should be the second one since London dispersion causes interaction between molecules.
hope I helped.
Generally non ionic species with no polarity forms the London -dispersion bonds. London dispersion is weaker than the dipole-dipole interaction and hence it have less boiling point.
What is boiling point?Boiling point of a substance is the temperature at which the substance changes from liquid state to gaseous state or vapor where, the two states are in equilibrium.
Boiling of a substance depends on the molecular weight, bond type,temperature, pressure as well as purity of the substance.
London dispersion force is formed between two non-polar atoms. These atoms when come closer they attains a temporary polar nature and gets bonded.
Dipole-dipole bond is formed between two atoms of permanent dipole moment and they are polar compounds. Thus dipole-dipole interaction is stronger than London dispersion interaction. A strong bond needs more energy to boil.
Hence, molecules with Dipole-Dipole bond is having higher boiling point.
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What equipment is generally used to make lyophilized medications suitable for administering to the patient? a) Test tubes or sterile ampules b) Petri dishes and sterile droppers c) Sterile syringes or graduated cylinders d) Measuring cups and clean, warm water
Answer:
B) Sterile droppers and petri dishes
If a barometer were built using water (d=1.0 g/cm3) instead of mercury (d=13.6 g/cm3), would the column of water be higher than, lower than, or the same as the column of mercury at 1.00 atm? If the level is different, by what factor? Explain.
Explanation:
A more dense liquid stays lower while a less dense liquid stays higher. since water is 13.6 times less dense than mercury, the column for a barometer using water would have to be 13.6 times taller.
How many molecules are present in 4.61x10-2 mol of O2
Answer:
6.02 × 1023
The molar mass from the periodic table is 32.00 g O2 = 1 mol O2, and by definition, 1 mol O2 = 6.02 × 1023 molecules O2.
Which one of these is not an important structural feature found by the number of
electron rich regions
Hybridization
Bond Angles
Electronegativity
Electron Geometry
Answer:
Electronnegativity
Explanation:
There are three important structural features: Hybridization, Bond angels, and Electron Geometry.
The not so important structural feature found by the number of electron rich regions is electronegativity. Hence option c is correct.
What are structural feature?Structural feature is defined as the modeled as a directed acyclic graph (DAG), with the variable names as pathways and the variable values as nodes. The study of the construction of biological molecules is known as structural biology. Scientists study molecules in three dimensions using a range of imaging techniques to examine how they are put together, how they work, and how they interact.
Electronegativity is defined as the propensity for atoms involved in covalent bonds to draw the bonding electrons. The negatively charged electrons are drawn to the positively charged protons in the nucleus. The electronegativity or attraction will rise with the number of protons in the nucleus. Therefore, in a row of the periodic table, electronegativity rises from left to right.
Thus, the not so important structural feature found by the number of electron rich regions is electronegativity. Hence option c is correct.
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Help with this please
Answer:
12
Explanation:
There are 4 sulfur atoms in SO4
4×3=12
This means that it turns into 3×(SO4)
=3SO4
what is the best way to learn and understand high school chemstry?
Answer:
Firstly, try to Go through your chapter and pay attention to main keywords.
secondly try to watch 'Uube' videos related to specific topic instead of chapter and pay attention to it closely and watch it with a keen interest.
Discuss topics that you find harder with your friends or peer group members, Because you learn faster when you study with the people of your age.
Answer:
i think the best way to learn chemistry is study over things that involve it
Explanation:
A carrot originally has a mass of 0.39g and after being left in a salt solution overnight it gained 0.3g. Calculate the percentage mass increase of the carrot.
Answer:
77%
Explanation:
The formula for finding percent change is change/original.
So, you have to do 0.3/0.39
You have to divide this to get 0.769 which can be rounded 0.77
0.77 as a percentage is 77%
So, the percentage mass increase of the carrot is 77%
Calculate the mass of butane needed to produce 57.3 g of carbon dioxide.
Answer:
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A student experimentally determines the gas law constant, R, by reacting a small piece of magnesium with excess hydrochloric acid and then collecting the hydrogen gas over water in a eudiometer. Based on experimentally collected data, the student calculates R to equal 0.0832
Due to errors in volume and moles measurement by the student, the true value of the molar gas constant is less than the obtained value.
The Percent error is 1.39%
What is percent error?Percent error is defined as the ratio of error and true value of a measurement expressed as a percentage.
Percent error = (error/true value) × 100%Error = |true value - measured value|
The error in the students measurement = |0.08206 - 0.0832|
Error = 0.00114
Percent error = (0.00114/0.08206) × 100%
Percent error = 1.39%
The formula to determine the molar gas constant R is given below:
[tex]R = \frac{PV}{nT}[/tex]
Since the student value is higher than the true value, the possible sources of error include:
The student student does not equilibrate the water levels within the eudiometer and the beaker at the end of the reaction resulting in increased volumeThe student does not clean the zinc with sand paper, thus the number of moles of hydrogen gas produced is less than the actual value.Therefore, the true value of the molar gas constant is less than the obtained value.
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Someone plz help me asap
Answer: it would be the stem and the roots of the plant
Explanation: