Answer:
Student 4
Explanation:
In the structure of the atom of an element, there are protons, electrons and neutrons. The number of protons in the atom of such element determines the atomic number of the element. For example, if Calcium contains 20 protons, the atomic no of Calcium will be 20. Since this is so, it means that the identity of an element on the periodic table can be known using the number of protons/atomic no.
According to this question, four students are gathering information on elements to determine their identity. Based on the explanation above, it takes only the number of protons = atomic no. of the element to identify it. Hence, student 4, who counts the number of protons will correctly identify the element using his/her data.
Which set of coefficients would be needed to balance the chemical equation below?
Answer:
2Zn2+3O2 ----> 2ZnO+2SO2
Explanation:
A separatory funnel contains the two immiscible liquids water and toluene. Use the given densities to determine which layer is on top and which is on the bottom in the binary mixture.
Solvent Density (g/mL)
toluene 0.87
water 0.998
Drag and drop each label into the box to indicate the position of the liquid in the mixture.
Top layer
Bottom layer
Answer:
Top layer TolueneBottom layer WaterExplanation:
When two non-miscible liquids are put together, the one with the higher density will be on the bottom, while the one with the lower density will be on top.
Meaning that in this problem's case toluene would be on the top layer and water in the bottom layer.
Consider the following equilibrium
N204(9) - 2NO2(9) Keq = 5.85 x 10-3
Which statement about this system is true?
If the equilibrium concentration of NO2 is 1.78 x 10-2 M, the equilibrium concentration of N2O4 is
The equilibrium concentration of N₂O₄, given that the concentration of NO₂ is 1.78×10⁻² is 5.42×10⁻²
Data obtained from the question N₂O₄ <=> 2NO₂Equilibrium constant (Keq) = 5.85×10⁻³ Equilibrium concentration of NO₂ = 1.78×10⁻²Equilibrium concentration of N₂O₄ =?How to determine the equilibrium concentration of N₂O₄Keq = [Product] / [Reactant]
Keq = [NO₂]² / [N₂O₄]
5.85×10⁻³ = [1.78×10⁻²]² / [N₂O₄]
Cross multiply
5.85×10⁻³ × [N₂O₄] = [1.78×10⁻²]²
Divide both sides by 5.85×10⁻³
[N₂O₄] = [1.78×10⁻²]² / 5.85×10⁻³
[N₂O₄] = 5.42×10⁻²
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Answer:
First answer is "The equilibrium lies to the left", and the second one is 5.42 x 10^-2 M.
Explanation:
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Any groups present on a benzene ring can impact the success and regioselectivity of an electrophilic aromatic substitution. Determine which group from the list best fits each activation and directing description.
Strongly deactivating meta- director __________
Moderately deactivating meta- director ________
Strongly activating ortho-/para- director _________
Weakly deactivating ortho-/para- director _________
Weakly activating ortho-/para- director ________
Answer:
Explanation:
In electrophilic aromatic substitution, the substituent(s) that favors electrophilic attack is said to be ortho or para to the substituent. Meta directors are deactivators. Altogether, these directors have an integral role to play in the success and regioselectivity of electrophilic aromatic substitution reactions.
From the information given: The;
Strongly deactivating meta- director ⇒ NO₂ (nitro group)
Moderately deactivating meta- director ⇒ CN (cyano group)
Strongly activating ortho-/para- director ⇒ OH (hydroxy; group)
Weakly deactivating ortho-/para- director ⇒ -X (halide group)
Weakly activating ortho-/para- director ⇒ - Ph (phenyl group)
Ortho and para substituents favors the electrophilic substitution reaction and meta substituents are deactivators.
What is regioselectivity ?Regioselectivity of any reaction tells about the preferred side over another side of the reaction to success.
Ortho or para substituents on the benzene ring will increase the chances of electrophilic aromatic substitution by increase the s electrons on the ring. While the meta directors are deactivators, they have an integral role to play in the success and regioselectivity of electrophilic aromatic substitution reactions.
Strongly deactivating meta director nitro group.
Moderately deactivating meta director cyano group.
Strongly activating ortho/para director hydroxy group.
Weakly deactivating ortho/para director halide group.
Weakly activating ortho/para director phenyl group.
Hence, from the above discussion it is clear that Ortho and para substituents favors the electrophilic substitution reaction and meta substituents are deactivators.
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According to the Brinsted -Lowry. what is an acid ? what is a base ?
Answer:
According to the Brønsted definition, an acid is a substance capable of donating a proton, and a base is a substance capable of accepting a proton. ... The species giving up the proton is HCl, an acid. The species accepting the proton is water, the base. The species Cl- is the conjugate base of HCl.
How many grams of nitrogen dioxide are required to produce 260 grams of nitrogen monoxide? 3NO2 + H20 → 2HNO3 + NO
Answer:
1196 g
Explanation:
N= 14 O= 16
every 3 moles of NO2 gives one mole of NO
So, 3[14 + (2×16)] = 138 grams of NO2
gives : 14+16 = 30 grams of NO
NO2 NO
138 30
? 260
Therefore, 260 × 138 ÷ 30 = 1196 g of NO2 are required
Calculate the wave number and
Frequency of violet radiation having
wavelength of 3500 Å
Answer: frequency is 8.57 ·10^14 Hz
Explanation: lambda = 3500 A = 0,000 000 350 m
Wave number is 1/ lambda = 2857142.857 1/m
Wave equation c = frequency · lambda and f = c / lambda
Frequency = 300 000 000 m/s / 0,000 000350 m
The wavelength number is [tex]2.85\times 10^{6}\ m^{-1}[/tex] and the frequency is [tex]8.57\times 10^{14}\ Hz[/tex].
Explanation:
Given that,
The wavelength of violet radiation,
[tex]\lambda=3500\ A\\\\=3500\times 10^{-10}\ m\\\\=3.5\times 10^{-7}\ m[/tex]
To find,
The wave number and frequency of violet radiation.
Solution,
Wavelength, [tex]\lambda=3.5\times 10^{-7}\ m[/tex]
Wave number is the reciprocal of the wavelength,
[tex]\overline{\lambda}=\dfrac{1}{\lambda}[/tex]
Put all the values,
[tex]\overline{\lambda}=\dfrac{1}{3.5\times 10^{-7}}\\\\\overline{\lambda}=2.85\times 10^{6}\ m^{-1}[/tex]
The relation between the wavelength, frequency and speed of wave is given by :
[tex]f=\dfrac{c}{\lambda}[/tex]
Where
c is the speed of light
Put all the values,
[tex]f=\dfrac{3\times 10^8}{3.5\times 10^{-7}}\\\\f=8.57\times 10^{14}\ Hz[/tex]
So, the wavelength number is [tex]2.85\times 10^{6}\ m^{-1}[/tex] and the frequency is [tex]8.57\times 10^{14}\ Hz[/tex].
Reference,
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A gas has an initial pressure of 2065 mmHg and temperature of 416 K. What is
the new pressure in atm if the temperature is cooled to 382 K?
Answer:
1896 mmHg
Explanation:
P1/T1 = P2/T2
P1 = 2065 mmHg
T1 = 416 K
P2 = ?
T2 = 382 K
Solve for P2 --> P2 = P1T2/T1
P2 = (2065 mmHg)(382 K) / (416 K) = 1896 mmHg
The correct value of m, n, x and y to obtain a balanced equation is?
m B2O3(s) + n HF(l) → x BF3(g) + y H2O(l)
a.
m=1, n=1, x=1 and y=1
b.
m=1, n=6, x=2 and y=3
c.
m=1, n=1.5, x=1 and y=1
d.
m=2, n=12, x=4 and y=6
Answer:
d
Explanation:
answer d makes the equation balance
Volume and moles are __________ related. This relationship can be calculated by using ___________ Law.
indirectly; Boyle’s
directly; Boyle’s
indirectly; Charles’
directly; Charles’
indirectly; Avogadro’s
directly; Avogadro’s
Answer:
The correct answer is - directly; Avogadro’s.
Explanation:
At the same temperature and pressure, gases of the same or equal volume have the same number of molecules. The relation between the moles of the gases and the volume of the gases are indirectly proportional to one another at the same temperature and pressure. This law is called Avogadro's law. In the case of an ideal gas of a particular mass has the volume and moles are directly proportional.
Thus, the correct answer is - directly; Avogadro’s.
Unit 4.2 quiz chemistry
Explain clearly in 2 ways each in which a soap and a detergent are similar and different.
Explanation:
the soap is the product made from a detergent
Wht is fluorine more chemically reactive than nitrogen
for many reasons fluorine is mor reactive than nitrogen
1: F is more electronegative atom than N
2: F just needs an electron and N needs 3 electrons to reach noble gases electron configuration
4: F2 bond is weaker than N2 bond
Your friend the archaeologist, who studies the ancient human past, has asked you to find a numerical date for some hominid artifacts found buried by ash from a volcanic eruption. To do this, you can use carbon-14 dating, which has a half-life of 5,730 years, or uranium-238, which has a half-life of 4.5 billion years. Based on their half-lives, which isotopic dating system will give your friend the most accurate numerical age
Answer:
I think it the carbon 14 which is a half life of 5730 because in 4.5billion years ago I don't think any human being existed on earth I'm not sure I hope that I helped you and good luck .
Carbon-14 dating will be used to find a numerical date for some hominid artifacts found buried by ash from a volcanic eruption.
What is carbon dating?
Radiocarbon dating also known as carbon dating or carbon-14 dating.
It is a method for establishing the age of an organic thing using the properties of radiocarbon, a radioactive carbon isotope.
Willard Libby created the approach in the late 1940s.
Thus, Carbon -14 dating will give your friend the most accurate numerical age.
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Please help I have no idea where to start
Answer:
Download Ptable, it will show all of the elements, and you can click on them, and it will show all the information you need about them!
Explanation:
I hope this helps!!!!!
How many moles of water will be produced from the reactions 3.25 moles of hydrochloric acid react with excess calcium hydroxide
Answer:
3.25 moles of H2O
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
2HCl + Ca(OH)2 —> CaCl2 +2H2O
Now, we can obtain the number of mole H2O produced from the reaction as follow:
From the balanced equation above,
2 moles of HCl reacted to produce 2 moles of H2O.
Therefore, 3.25 moles of HCl will also react to produce 3.25 moles of H2O.
Therefore, 3.25 moles of H2O were produced from the reaction.
What is the name of the variable that changes by itself in an experiment?
Answer:
the independent variable (sometimes known as the manipulated variable )
Explanation:
is the variable whose change isn't affected by any other variable in the experiment
calculate the ph of one solution containing 0.1 M formic acid and 0.1 M sodium formate before and after the addition of 1mL of 5 M Naoh. how much could the Ph change if the NaOh were added to 1 L of pure water
Answer:
Pka of formic acid (HCOOH)= 3.75
pH= PKa +log [ Sodium formate/ formic acid] = 3.75
NaOH reacts with HCOOH as HCOOH (aq) + NaOH(aq) --> NaCHO2 (aq) and H2O (l)
Moles of HCOOH= 0.1*1= 0.1 moles
Moles of NaOH= 5*1/1000= 0.005 moles
HCOOH is in excess and the excess is = 0.1 - 0.005 = 0.095
Moles of sodium formate = 0.005 + 0.1 = 0.105 moles of HCOOH= 0.095
volume after mixing = 1 + 5 /1 000=1.005
Concentrations : HCOOH= 0.095/1.005 sodium formate= 0.105/1.005
pH= 3.75+log (0.105/0.095)=3.85
When NaOH is added, molarity is , 1*5= 1000*M
M= 5/1000=0.005
The pH remains the same. Only the molarity of NaOH changes.
What is a hot spot? Must be in your own words ( please hurry)
Answer:
It depends. what hot spot are you looking for?
Answer:
A hot spot is an area on Earth over a mantle plume or an area under the rocky outer layer of Earth, called the crust, where magma is hotter than surrounding magma. The magma plume causes melting and thinning of the rocky crust and widespread volcanic activity.
Explanation:
Hope this is what you mean be hot spot!
I hope this helps you!
write the balanced chemical equation of the reaction between strong acid and weak base also mention the types of salt obtained in the reaction
Answer:
write the balanced chemical equation of the reaction between strong acid and weak base also mention the types of salt obtained in the reaction
Explanation:
HCl → H+(aq) + Cl−(aq) (100%)
Any acid that dissociates 100% into ions is called a strong acid. If it does not dissociate 100%, it is a weak acid. HC2H3O2 is an example of a weak acid:
HC2H3O2→ H+(aq) + C2H3O2−(aq) (~5%)
Because this reaction does not go 100% to completion, it is more appropriate to write it as an equilibrium:
HC2H3O2 ⇄ H+(aq) + C2H3O2−(aq)
As it turns out, there are very few strong acids, which are given in Table 12.2 “Strong Acids and Bases”. If an acid is not listed here, it is a weak acid. It may be 1% ionized or 99% ionized, but it is still classified as a weak acid.
Mass of watch glass + filter paper = 105.98 g
Mass of watch glass + filter paper + crystallized product = 109.03 g
Mass of uncrystallized product (show work) =
Mass of methyl benzoate = 3.08 g
Volume of nitric acid used = 2.0 mL
Theoretical yield based on each of the starting materials
(Please use two Dimensional Analysis (DA) equations, one for the maximum amount of product obtainable from the amount of methyl benzoate you used and the other from the concentrated nitric acid, then use the lesser of the two to determine the Limiting Reagent; you must determine the number of moles in 2.00 mL of concentrated nitric acid [concentration 69.0% (w/w), and density (1.42 g/mL)].
Required:
a. Identity of the Limiting reagent (LR) based on the above two DA equations = __________
b. Max amount of product obtainable from the LR = ___________
c. Mass of the product you obtained: ____________
Answer:
Explanation:
Mass of uncrystallized product = (Mass of watch glass + filter paper + crystallized product) - (Mass of watch glass + filter paper)
Mass of uncreystaliized product = 109.03 gm - 105.98 gm
Mass of uncrystaliized product = 3.05 gm
For methyl benzoate;
mass = 3.08 g
no of moles = 3.08 g/ 136.15 g/mol = 0.0226 mole
It is possible for the formation of 1 mole of nitro methyl benzoate from a mole of methyl benzoate.
moles of nitro methyl benzoate that can be formed from 0.0226 moles of methyl benzoate = 0.0226 moles
∴
mass of nitro methyl benzoate = 0.0226 mol × 181.15 gm /mol
mass of nitro methyl benzoate = 4.098 gm
For HNO_3 solution:
mass = 1.42 gm/ml × 2.0 ml
mass = 2.84 gm
Mass of HNO3 in 2.84 gm solution[tex](69\% w/w)= 2.84 gm * \dfrac{69}{100 }[/tex]
= 1.9596 gm
Moles of HNO3 = [tex]\dfrac{ 1.9596 \ gm }{ 63.01 gm /mol}[/tex]
= 0.0311 mole
1 mol of HNO_3 can be formed from 1 mole of nitro methyl benzoate
Thus; moles of nitro methyl benzoate that can be formed from 0.0311 mole of HNO_3 = 0.02256 mole
The mass for nitro methyl benzoate can now be determined as:
= 0.0311 mole × 181.5 gm/mole
= 5.634 gm
Since the mass formed from methyl benzoate is lesser, then methyl benzoate serves as the limiting reagent.
The mass obtainable from the LR = 4.098 gm
The empirical formula for compound is P2O5. The molar mass of the compound is 283.89g. What is the molecular formula?
Answer:
P4O10
Explanation:
(P2O5)n=283.89
62+80=283.89
142n=283.89
n=2
P2O10
The empirical and molecular formula are related by the formula, molecular formula=2×empirical formula ,meaning double the atoms present in empirical formula,hence molecular formula is P₄O₁₀.
What is empirical formula?Empirical formula of a compound is defined as the simplest whole number ratio of atoms which are present in a compound.It does not make any mention of the arrangement of atoms or the number of atoms. The empirical formula gives information about the ratio of number of atoms which are present in a compound.
Molecular formula is determined from the empirical formula by dividing the molar mass of a compound by the empirical formula mass. The resultant which should be a whole number or very close to the whole number , then the subscripts are multiplied by the whole number to get the molecular formula.
For the compound P₂O₅ the subscripts of phosphorous and oxygen are multiplied by 2 and hence the molecular formula P₄O₁₀.
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_______ prohibits and punishes certain conduct for the benefit of society.
Answer:
animal
Explanation:
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which memrane lines the abdomino pelvic cavity
Answer:
The peritoneum
Explanation:
The peritoneum is the serous membrane that surrounds several organs in the abdominopelvic cavity. The tunica vaginalis is the serous membrane, which surrounds the male gonad, the testis. The two layers of serous membranes are named parietal and visceral. Between the two layers is a thin fluid filled space.
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The answer for this
Balance Chemical Equations, will give brainiest.
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1) 2KCIO3=2kci+3o2
2)CH4 + 2O2 → CO2 + 2H2O
3) 2HCl + Ca(OH)2 → CaCl2 + 2H2O
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A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over the next few minutes?
Molecules in both the metal and the surrounding air will start moving at lower speeds.
Molecules in both the metal and the surrounding air will start moving at higher speeds.
The air molecules that are surrounding the metal will slow down, and the molecules in the metal will speed up.
The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.
Answer:
The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.
Explanation:
There will be a transfer of thermal energy (heat) from the hot metal plate to the surrounding air. This transfer of energy equates to a transfer of kinetic energy in the molecules. As the plate loses heat, the molecules in the plate will lose kinetic energy and slow down. As the surrounding air gains heat, the molecules will gain kinetic energy and speed up.
Answer: C
Explanation:
Predict the products and balance the equation
classify the reaction
Answer:
[tex]C_3H_8+5O_2\rightarrow 3CO_2+4H_2O[/tex]
Explanation:
Hello there!
In this case, when coming across combustion reactions whereby hydrocarbons as fuels are burnt in the presence of oxygen, the main products are said to be carbon dioxide and water in agreement to the breaking and rearrangement of bonds due to the collisions among molecules. Thus, for the reaction between propane and oxygen we have the following balanced reaction:
[tex]C_3H_8+5O_2\rightarrow 3CO_2+4H_2O[/tex]
Best regards!
HELP FAST 100 PTS Calculate the amount of heat needed to lower the temperature of 50.0g of ice from -40 °C to -100 °C.
Answer:
[tex]\Large \boxed{\sf -6000 \ J}[/tex]
Explanation:
Use formula
[tex]\displaystyle \sf Heat \ (J)=mass \ (kg) \times specific \ heat \ capacity \ (Jkg^{-1}\°C^{-1}) \times change \ in \ temperature \ (\°C)[/tex]
Specific heat capacity of ice is 2,000 J/(kg °C)
Substitute the values in formula and evaluate
[tex]\displaystyle \sf Heat \ (J)=0.05 \ kg \times 2000 \ Jkg^{-1}\°C^{-1} \times (-100\°C-(-40 \°C))[/tex]
[tex]Q=0.05 \times 2000 \times (-100-(-40)) =-6000[/tex]
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