4,032
BT electron
nSO2= 3nFe/
What does Etching , Stratches and sample size impact hardness results of metals
Answer:
Etching is used to reveal the microstructure of the metal through selective chemical attack. It also removes the thin, highly deformed layer introduced during grinding and polishing. ... The specimen is etched using a reagent.
Explanation:
hope it was helpful.....
CAN SOMEONE PLEASE HELP ME I WILL MARK YOU AS BRAINLIEST
Explanation:
[tex]2H_2O_2 \rightarrow 2H_2O + O_2[/tex]
First convert the amount of water into moles:
360 g H2O × [tex]\left(\dfrac{1\:\text{mol}H_2O}{18.015\:\text{g}H_2O}\right)[/tex]
[tex] = 20. \:\text{mol}H_2O[/tex]
Now let's calculate the number of moles of O2 gas produced.
20 mol H2O × [tex]\left(\dfrac{1\:\text{mol}O_2}{2\:\text{mol}H_2O}\right)=10\:\text{mol}O_2[/tex]
The volume of gas at 10°C and 5 atm can be found using the ideal gas law:
[tex]PV=nRT[/tex]
[tex]V= \dfrac{nRT}{P}[/tex]
[tex]= \dfrac{(10)(0.082)(283)}{(5)}=46.4\:L[/tex]
which of group of organism has the least biomass?which has the least energy
Answer:
The answer is consumers
Answer:
Consumers are the group of organisms that has the least biomass and energy.
Give the balanced equation for the neutralisation of the excess NaOH with HCI.
1 NaCl + 1 HCl ➡️ 1 NaCl + Water (H2O) .
Write briefly on carbohydrates
Answer:
carbohydrates are simple sugars which can be broken down to form 3 sugars.
which are , (maltose) (fructose) & (glucose)
Which of the following colors has the highest energy? O A. Red O B. Green O C. Blue O D. Yellow
Answer:
C. BlueExplanation:
This is because, Blue color highest frequency of energy after Violet and Indigo.
A 100.0-g sample of water at 27.0oC is poured into a 71.0-g sample of water at 89.0oC. What will be the final temperature of the water? (Specific heat capacity of water = 4.184 J/goC.)
Answer: The final temperature will be [tex]52.74^oC[/tex]
Explanation:
Calculating the heat released or absorbed for the process:
[tex]q=m\times C\times (T_2-T_1)[/tex]
In a system, the total amount of heat released is equal to the total amount of heat absorbed.
[tex]q_1=-q_2[/tex]
OR
[tex]m_1\times C\times (T_f-T_1)=-m_2\times C\times (T_f-T_2)[/tex] ......(1)
where,
C = heat capacity of water = [tex]4.184J/g^oC[/tex]
[tex]m_1[/tex] = mass of water of sample 1 = 100.0 g
[tex]m_2[/tex] = mass of water of sample 2 = 71.0 g
[tex]T_f[/tex] = final temperature of the system = ?
[tex]T_1[/tex] = initial temperature of water of sample 1 = [tex]27^oC[/tex]
[tex]T_2[/tex] = initial temperature of the water of sample 2 = [tex]89.0^oC[/tex]
Putting values in equation 1, we get:
[tex]100.0\times 4.184\times (T_f-27)=-71.0\times 4.184\times (T_f-89)\\\\171T_f=9019\\\\T_f=\frac{9019}{171}=52.74^oC[/tex]
Hence, the final temperature will be [tex]52.74^oC[/tex]
complete and balanced the following equations by predicting the products of each reaction pair.
NA + LiCI -> _ + _
Explanation:
this is a single Replacement Reaction, so Na and Cl will form a bond.
Course Home P Acceptable units x + courseld=16709491&OpenVellumHMAC=f5c9929f4e4da0b5529475e262c91d79=10001 1 Review art A alculate the heat change in calories for condensation of 11.0 g of steam at 100°C. xpress your answer as a positive value using three significant figures and inc 2 MIKIN M HA Value CS
Answer:
The heat change in calories for condensation of 11.0 g of steam at 100°C is 5930 calories
Explanation:
Latent heat of condensation is the heat released when one mole of steam or water vapor condenses to form liquid droplets. The heat of condensation of water at 100° C is about 2,260 kJ/kg, which is equal to 40.68 kJ/mol. Since condensation of steam and vaporization of water occur at the same temperature and require the same amount of energy to occur, the heat of condensation is exactly equal to the heat vaporization, but has the opposite sign. In the vaporization, heat energy is absorbed by the substance, whereas in condensation heat energy is released by the substance.
The specific latent heat of vaporization of steam at 100° C = 40.68 kJ/mol
Number of moles of moles of water in 11.0 g of steam = mass/ molar mass
Molar mass of water = 18.0 g/mol
Number of moles of steam = 11.0 g / 18.0 g/mol = 0.61 moles
Heat released = 40.68 K/mol × 0.61 moles = 24.815 kJ
Converting to kcal by dividing 24.815 kJ by 4.184 = 5.93 kcal or 5930 calories
Therefore, the heat change in calories for condensation of 11.0 g of steam at 100°C is 5930 calories
Select the keyword or phrase that will best complete each sentence about the three general rules of for drawing Lewis structures.a. main group b. hafnium c. valence d. hydrogen e. core f. transition metal1. Draw only__the electrons. 2. Give every___element (except hydrogen) an octet of electrons. 3. Give each____two electrons.
Answer:
1. Draw only the valence electrons.
2. Give every element main group element (except hydrogen) an octet of electrons.
3. Give each hydrogen two electrons.
Explanation:
Lewis structures are used to describe the arrangement or configurations of the valence electrons of molecules and polyatomic ions involved in electronic bonding. A Lewis structure consists of the symbols of the elements in the molecule surrounded by dots with each dot representing each of the elements valence electrons. Also, the electrons shared between two elements are shown by dots between the two elements and these electrons are known as shared electron pairs. The valence electrons on atom that is not involved in bonding is known as lone pairs.
The three general rules for drawing Lewis structures are:
1. Draw only the valence electrons. Only the valence electrons of the atoms of elements are shown since they are the only electrons involved in chemical bonding.
2. Give every element main group element (except hydrogen) an octet of electrons. The complete eight valence electrons of the noble gases is associated with their stability. Thus, the main group elements show a tendency to form enough bonds to obtain eight valence electronsmin order to achieve stability. This is known as the octet rule. However, since the maximum number of valence electrons for elements in the first period of the period table is two, the noble gas helium has completely-filled valence shell containing two electrons known as a duplet. Hydrogen belongs to the first period and is therefore an exception tomthe octet rule.
3. Give each hydrogen two electrons. Hydrogen attains a duplet structure in accordance with the structure of helium
Anew fictitious element was discovered. It is a metal named jolmium, J,and it has three valence electrons. If it combineswith iodine it forms jolmium iodide. Answer the following questions.a.Is this compound ionic or covalent
a. Is this compound ionic or covalent?
b. What is the formula of Jolmium iodide?
c. What is the charge on the metal J in this compound?
d. Explain how you know that is the charge?
Answer:
A new fictitious element was discovered.
It is a metal named jolmium, J, and it has three valence electrons.
If it combines with iodine it forms jolmium iodide. Answer the following questions.
a.Is this compound ionic or covalent
b. What is the formula of Jolmium iodide?
c. What is the charge on the metal J in this compound?
d. Explain how you know that is the charge?
Explanation:
It is given the element jolmium J is a metal with three valence electrons.
Since metals are highly electropositive, they lose electrons easily and form cations (Ions with a positive charge).
[tex]J^{3+}[/tex] ion will be formed.
b) The formula of jolmium iodide is shown below:
[tex]J^{+3} I^{-1}\\The formula becomes:\\JI_{3}[/tex]
a) The compound is ionic in nature.
Since the compound formed between a metal atom and a nonmetal atom will take place by transfer of electrons.
Hence, it is ionic in nature.
c) The charge on the metal J in this compound is +3.
d) Given J has three valence electrons.
That means it can lose three electrons to form a bond.
So, its valency is three.
Which of the following ions is formed when an acid is dissolved in a solution? (5 points) H+
O−
OH−
SO42+
Answer:
Hence, option B is correct. 1 and 2
Explanation:
NH 4 Cl is a weak base-strong acid salt.
NaCN is a salt of a strong base (NaOH) and weak acid (HCN).In water,
1. NH 4 Cl produces acidic solution
2. KHSO 4 produces acidic solution
because the neutral salt of strong base KOH and strong acid H 2 SO 4 is K 2 SO 4
3. NaCN produces basic solution
4. KNO
3 produces neutral solution
I think this is right but I hope its help ,ur welcome ♥️♥️
Answer:
H+
Explanation:
I took the test :)
You have been observing an insect that defends itself from enemies by secreting a caustic liquid. Analysis of the liquid shows it to have a total concentration of formate plus formic acid (Ka =1.8 x 10^-4) of 1.45 M; the concentration of formate ion is 0.015 M. What is the pH of the secretion?
Answer:
pH = 1.76
Explanation:
The mixture of formate and formic acid produce a buffer. The pH of the buffer is obtained using H-H equation as follows:
pH = pKa + log [A-] / [HA]
Where pH is the pH of the buffer:
pKa = -log Ka = 3.74
[A-] is molar concentration of conjugate base (Formate) = 0.015M
[HA] is molar concentration of weak acid (Formic acid) = 1.45M - 0.015M = 1.435M
Replacing:
pH = 3.74 + log [0.015M] / [1.435M]
pH = 1.76What is the IUPAC name of the following compound?
OH
s
Answer:
2-isopropyl-4-methylphenol.
Explanation:
Hey there!
In this case, according to the given information, it turns out possible for us to assign the appropriate IUPAC name of the given compound, by considering that the phenol stands for the parent chain and we have isopropyl methyl radicals which the former is called first due to the alphabet consideration.
In such a way, the name would be 2-isopropyl-4-methylphenol.
Regards!
5-Analysis of a 12.04-g sample of a liquid compound composed of carbon, hydrogen, and nitrogen showed it to contain 7.34 g C, 1.85 g H, and 2.85 g N. What is the percent composition of this compound
Answer:
%C = 60.9%; %H = 15.4%; %N = 23.7%
Explanation:
Step 1: Given data
Mass of the sample (m): 12.04 gMass of Carbon (mC): 7.34 gMass of Hydrogen (mH): 1.85 gMass of Nitrogen (mN): 2.85 gStep 2: Calculate the percent composition of this compound
To calculate the percent by mass of any element (E), we will use the following expression.
%E = mE/m × 100%
%C = 7.34 g/12.04 g × 100% = 60.9%
%H = 1.85 g/12.04 g × 100% = 15.4%
%N = 2.85 g/12.04 g × 100% = 23.7%
A recipe calls for 1/4 cup of butter. One ounce (oz) of butter is equivalent to 2 tablespoons (T), and there are 8 oz of butter in 1 cup. Which of the following statements correctly interpret the information provided?
a. The information provided gives the conversion factor 8oz/2T.
b. The information provided gives the conversion factor 8oz/1 cup.
c. The recipe requires 64 T of butter.
d. The recipe requires 4T of butter.
Answer:
D
Explanation:
8oz=1cup
Xoz=1/4cup
cross multiply
Xoz=8×1/4=2
2oz=1/4cup
1oz=2T
2oz=x
cross multiply
×=2×2=4T
The cup of butter, number of tablespoons and ounces of butter are all in direct proportion with one another. The interpretation of the information provided is:
(b). The information provided gives the conversion factor 8oz/1 cup.
Given that:
[tex]1\ recipe = \frac{1}{4}\ cup[/tex]
[tex]1\ oz = 2T[/tex]
[tex]8\ oz = 1\ cup[/tex]
Multiply both sides of [tex]1\ oz = 2T[/tex] by 8
[tex]8 \times 1oz = 8 \times 2T[/tex]
[tex]8 oz = 16T[/tex]
Substitute 8oz for 1 cup in: [tex]1\ recipe = \frac{1}{4}\ cup[/tex]
[tex]1\ recipe = \frac{1}{4} \times 8oz[/tex]
Substitute [tex]8 oz = 16T[/tex]
[tex]1\ recipe = \frac{1}{4} \times 16T[/tex]
[tex]1\ recipe = 4T[/tex]
The interpretations are as follows:
[tex]1\ recipe = 4T[/tex] means that 1 recipe requires 4T of butter [tex]8\ oz = 1\ cup[/tex] means that the information provided gives a conversion of 8oz/1 cupHence, (b) is correct
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A certain alkyl halide is reacted with OH- to form an alcohol. The alkyl halide is optically active but the product(s) is/are optically inactive. Which of the following could be the reactant?a) 3-bromo-3-methylhexane.b) 1-chlorobutane.c) 2-bromo-2-methylbutane.d) 3-bromo-2,3,4-trimethypentane.
Answer:
a. 3-brumo - 3-methylhexane
Explanation:
Alkyl Halides can undergo substitution reactions. Nucleophiles are electron rich species and has negative charge while Electrophiles are electron deficient species which carry positive charge. Alkyl halide which have polar carbon atom are electrophiles.
Which of the following is an example of a nonrenewable resource?
a
cattle
b
uranium
c
cotton
d
trees
Answer:
b . uranium, It is not a renewable resource.
A sample of drinking water was tested for Pb2 and was found to have a Pb2 concentration of 17.50 ppb. A 9.00 mL sample of the drinking water was spiked with 1.00 mL of a 2.29 ppb Pb2 standard. Analysis of the spiked sample gave a concentration of 15.93 ppb Pb2 . Find the percent recovery of the spike.
Answer:
[tex]X=75\%[/tex]
Explanation:
From the question we are told that:
Concentration [tex]C_1=17.50ppb[/tex]
Volume [tex]v=9mL[/tex]
Spike Volume [tex]V_s=1.00mL[/tex]
spike Conc [tex]C_2=2.29 ppb[/tex]
Analysis Conc [tex]C_s=15.93 ppb[/tex]
Generally the equation for percent recovery is mathematically given by
[tex]X=\frac{C_s'-C_1'}{C_2'}[/tex]
Where
Concentration of spiked sample C_s'
[tex]C_s'=C_s*(v+v_s)[/tex]
[tex]C_s'=15.92*(9+1)[/tex]
[tex]C_2=159.2[/tex]
Concentration of unspiked sample C_1'
[tex]C_1'=17.50*9mL[/tex]
[tex]C_1'=157.5[/tex]
Concentration of spike sample C_2'
[tex]C_2=2.29*1[/tex]
[tex]C_2=2.29[/tex]
Therefore
[tex]X=\frac{159.2-157.5}{2.29}[/tex]
[tex]X=75\%[/tex]
According to the law of conservation of matter, what cannot change during a chemical reaction?.
Answer:The law of conservation of mass states that in a chemical reaction mass is neither created nor destroyed. ... The carbon atom changes from a solid structure to a gas but its mass does not change. Similarly, the law of conservation of energy states that the amount of energy is neither created nor destroyed.
Explanation:
Which of the following is true for a nuclear reaction? (5 points)
Select one:
a.Electrons are lost.
b.Electrons are gained.
c.The identity of element changes.
d.The identity of element remains same.
the identity of element remains same
Which of these increases the friction of someone walking on the floor?
Answer:
.This is because gravity pulls down harder on the heavier one, which increases its friction with the floor
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A certain shade of blue has a frequency of 7.16x10^14Hz. What is the energy of exactly one photon of this light? Planck’s constant h=6.626x10^-34 j•s.
Explanation:
the answer is in the image above
Which type of chemistry studies the chemical reactions that occur in the human body?
O biochemistry
O materials chemistry
O physical chemistry
O environmental chemistry
Answer:
Which type of chemistry studies the chemical reactions that occur in the human body? .
biochemistry
The correct answer is biochemistry.
What is Biochemistry?Biochemistry is the study of the chemical process that occur in living things.Why other Options are incorrect?Materials Chemistry is the section of Materials Science and Engineering that investigates the chemical nature of materials.Physical chemistry is the branch of chemistry that deals with physical structure of chemical compound. Environmental chemistry is the study of chemical process that deals with environment.
Learn more about Biochemistry here
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Toothpastes containing sodium hydrogen carbonate (sodium bicarbonate) and hydrogen peroxide are widely used. Write Lewis structures for the hydrogen carbonate ion and hydrogen peroxide molecule, with resonance forms where appropriate.
Answer:
See explanation and images attached
Explanation:
The first image shows the structure of hydrogen peroxide. It does not exist as resonance structures. The structure and properties of the molecule can wholly be explained on the basis of a single Lewis structure.
However, the structure of the bicarbonate ion in sodium bicarbonate can not be completely described by a single Lewis structure. Hence, two resonance structures are shown for the bicarbonate ion. In each case, Na^+ is the counter ion.
Diazomethane has the molecular formula CH2N2. Draw the preferred Lewis structure for diazomethane and assign formal charges to all atoms, if any.
Answer:
See explanation
Explanation:
We define the formal charge on an atom in a molecule as the charge it carries assuming that electrons in all chemical bonds of the molecule were shared equally between atoms irrespective of the electronegativity of each atom.
The formula for calculating the formal charge on an atom in a molecule is;
Formal Charge = [number of valence electrons on neutral atom] – [(number of lone electron pairs) + (½ number of bonding electrons)] ·
The formal charge on the two nitrogen atoms in diazomethane is obtained as follows;
Middle nitrogen atom = 5 – 8/2 – 0 = +1
Last nitrogen atom = 5 – 4/2 – 4 = –1
The Lewis structure of the molecule is shown in the image attached.
An ideal gas is made up of gas particles that...
(A) ...have volume.
(B) ... attract each other.
(C)...can be liquified.
(D) ... are in random motion.
Answer:
Its D Are in random motion
i hope it will help you if not soo sorry :)
What is the pH of a 1.0 x103 M KOH solution?
A. 11
B. 4.0
C. 10
D. 3.0
Answer:
Option A. 11
Explanation:
We'll begin by calculating the concentration of Hydroxide ion in the solution. This can be obtained as follow:
KOH (aq) —> K⁺(aq) + OH¯(aq)
From the balanced equation above,
1 mole of KOH produced 1 mole of OH¯.
Therefore, 1×10¯³ M KOH will also produce 1×10¯³ M OH¯.
Next, we shall determine the pOH of the solution. This can be obtained as follow:
Concentration of Hydroxide ion [OH¯] = 1×10¯³ M
pOH =?
pOH = –Log [OH¯]
pOH = –Log 1×10¯³
pOH = 3
Finally, we shall determine the pH of the solution. This can be obtained as follow:
pOH = 3
pH =?
pH + pOH = 14
pH + 3 = 14
Collect like terms
pH = 14 – 3
pH = 11
Therefore, the pH of the solution is 11
22)
)
Limestone can form as a result of
A)
metamorphosis of conglomerate rock
B)
cooling of molten rock under the oceans
C)
precipitation from evaporating water
D)
radioactive decay of dolostone
Answer:
tge answer is a
Explanation:
I'm smart like that
A student is adding DI water to a volumetric flask to make a 50% solution. Unfortunately, he was not paying attention and filled the flask past the calibration mark. Instead of starting over, the student decides to continue with the experiment. How will the student's results be affected by his mistakes
Answer:
His results will be skewed because there was more water than stock solution. Which would cause the percentage solution to be less than 50% therefore the density would be less than the actual value.
Explanation:
The solution will have percentage less than that of 50%. Therefore the density would be less than the actual value.
Suppose there should be 50 mL of the solution, and he added 60 mL. So 10 mL of the solution is added more.
Suppose the mass of the solute is m.
Originally, the density is = [tex]$\frac{m}{50}$[/tex] [tex]\left(\frac{\text{mass}}{\text{volume}}\right)[/tex]
Now after adding extra 10 mL , the density becomes [tex]$\frac{m}{60}$[/tex].
Therefore, [tex]$\frac{m}{50}>\frac{m}{60}$[/tex]
So the density decreases when we add more solution.
