Answer:
A change is called irreversible if it cannot be changed back again. For example you cannot change a cake back into its ingredients again. Irreversible changes are permanent.
Explanation:
Hope this helps!! :))
Copper sulfate is made of one copper (Cu) atom, one sulfur (S) atom, and four oxygen (O) atoms. Write the chemical formula correctly.
28) Which of the following is true about the modern model of the atom?
A) Electrons orbit the nucleus in shells at fixed distances
B) Protons, neutrons, and electrons are located in the nucleus.
C)Atoms are hard, indivisible spheres.
D)A positive nucleus is surrounded by negative electrons.
Answer:
A) Electrons orbit the nucleus in shells at fixed distances
Answer:
the answer is A
Explanation:
An alkyl groyp has a formula of CxH6, determine the value of x
Answer:
i didnt understand
Explanation:
Answer:
x = 2 (C₂H₆)
Explanation:
The general formula for alkanes is CₓH₂ₓ₊₂
2x + 2 = 6
Simply solve for n:
2x = 4
x = 2
briefly describe the action of hardwater with soap
Answer:
The correct answer is - hard water reacts to form the calcium or magnesium salt of the organic acid of the soap.
Explanation:
Soaps are made up of fatty acids or oils by treating with strong alkali and are salts of sodium and potassium. Hard water, on the other hand, has a high concentration of minerals in comparison to soft water. When hard water and soap are mixed together the salts of the minerals like Ca2+ and Mg2+ ions present in hard water react with fatty acids of the soap.
The sodium salts are changed to the salts of calcium and magnesium which are precipitated to an insoluble substance. The insoluble salts of the calcium or magnesium dirt stick on the clothes thus cleaning ability of soap is reduced.
g Suppose you are titrating an acid of unknown concentration with a standardized base. At the beginning of the titration, you read the base titrant volume as 1.84 mL. After running the titration and reaching the endpoint, you read the base titrant volume as 27.30 mL. What volume, in mL, of base was required for the titration?
Answer:
25.46 mL
Explanation:
In a titration we use the volume and concentration of a solution to determine the previously unknown concentration of other solution. Let's consider the titration of an acid of unknown concentration with a standardized base (a base whose concentration we know). The generic neutralization reaction is:
HA + BOH ⇒ BA + H₂O
The base is in the buret and we will add it to the acid until the equivalence point is reached. The volume of base used is equal to the difference between the final reading of the buret and the initial reading of the buret.
V = 27.30 mL - 1.84 mL = 25.46 mL
In carrying out an analysis of a mixture, what do you expect to see when the TLC plate has been allowed to remain in the developing chamber too long, so that the solvent front has reached the top of the plate
Answer:
See explanation
Explanation:
In TLC, the plate is spotted at a point above the solvent front and the solvent moves up the plate by capillary action leading to the separation of the various components of the mixture spotted on the plate.
However, if the TLC plate is allowed to remain in the developing chamber for too long such that the solvent front reaches the top of the plate, the components of the mixture will recombine at the top of the plate and cancel out any separation which may have occurred on the plate.
The value of ΔH° for the reaction below is -6535 kJ. ________ kJ of heat are released in the combustion of 16.0 g of C6H6 (l)?
2C6H6 (l) + 15O2 (g) → 12CO2 (g) + 6H2O (l)
Answer:
the value of H° is below -6535 kj. +6H2O
Explanation:
6H2O answer solved
For the given reaction, 2 moles of C₆H₆ the heat energy released is - 6535 KJ. Then, for 16 g of the compound or 0.205 moles needs 669.83 KJ of heat released in combustion.
What is combustion ?Combustion is a chemical reaction that occurs between a fuel and an oxidizing agent, typically oxygen, resulting in the release of heat, light, and various combustion products, such as carbon dioxide and water vapor.
The process of combustion involves a rapid and exothermic (heat-releasing) oxidation reaction that produces a flame, which is visible in many cases.
Here, 2 moles of the hydrocarbon releases - 6535 KJ of energy.
molar mass of C₆H₆ = 78 g/mol
then no.of moles in 16 g = 16 /78 = 0.205 moles.
then energy released by 0.205 moles = 0.205 moles × 6535 KJ /2 moles = 669.83 kJ
Therefore, the heat energy released by 16 g of the compound in combustion is 669.83 kJ.
Find more on combustion :
https://brainly.com/question/13153771
#SPJ2
True or false? All producers are at the top of the food web
Answer:
false all producers are at the top of food web
A certain liquid has a normal freezing point of and a freezing point depression constant . A solution is prepared by dissolving some glycine () in of . This solution freezes at . Calculate the mass of that was dissolved.
The question is incomplete, the complete question is:
A certain substance X has a normal freezing point of [tex]-6.4^oC[/tex] and a molal freezing point depression constant [tex]K_f= 3.96^oC.kg/mol[/tex]. A solution is prepared by dissolving some glycine in 950. g of X. This solution freezes at [tex]-13.6^oC[/tex]. Calculate the mass of urea that was dissolved. Round your answer to 2 significant digits.
Answer: 129.66 g of glycine will be dissolved.
Explanation:
Depression in the freezing point is the difference between the freezing point of the pure solvent and the freezing point of the solution.
The expression for the calculation of depression in freezing point is:
[tex]\text{Freezing point of pure solvent}-\text{freezing point of solution}=i\times K_f\times m[/tex]
OR
[tex]\text{Freezing point of pure solvent}-\text{freezing point of solution}=i\times K_f\times \frac{\text{Given mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Mass of solvent (g)}}[/tex] ....(1)
where,
i = Van't Hoff factor = 1 (for non-electrolytes)
Freezing point of pure solvent = [tex]-6.4^oC[/tex]
Freezing point of solution = [tex]-13.6^oC[/tex]
[tex]K_f[/tex] = freezing point depression constant = [tex]3.96^oC/m[/tex]
[tex]M_{solute}[/tex] = Molar mass of solute (glycine) = 75.07 g/mol
[tex]w_{solvent}[/tex] = Mass of solvent = 950 g
Plugging values in equation 1:
[tex]-6.4-(-13.6)=1\times 3.96\times \frac{\text{Given mass of glycine}\times 1000}{75.07\times 950}\\\\\text{Given mass of glycine}=\frac{7.2\times 75.07\times 950}{1\times 3.96\times 1000}\\\\\text{Given mass of glycine}=129.66g[/tex]
Hence, 129.66 g of glycine will be dissolved.
HELPPPPPPPPPPPPMEEEEEEEEEE
Answer:
25%
Explanation:
Cystic fibrosis is a recessive allele, meaning that the child must be aa to suffer the symptoms. Only 1/4 of the paired alleles is aa, so the probability of getting cystic fibrosis would be 25%.
anuvia, the trade name for sitagliptin, was introduced in 2006 for the treatment of type 2 diabetes. In what type of orbital does the lone pair on each N atom reside.
Answer: hello your question is poorly written below is the complete question
answer:
For N1 : sp³ orbital
For N2: p orbital
For N3 : p orbital
For N4 : sp² orbital
For N5 : sp² orbital
Explanation:
Determining the type of orbital in which the lone pair on each N atom will reside.
From the configuration attached below we can determine the type of orbital and they are ;
For N1 : sp³ orbital
For N2: p orbital
For N3 : p orbital
For N4 : sp² orbital
For N5 : sp² orbital
Gold is a precious metal that is chemically unreactive. It is used mainly in jewelry, dentistry, and electronic devices. A piece of gold ingot with a mass of 301 g has a volume of 15.6 cm3. Calculate the density of gold.
Answer:
Density = 19.3 g/cm³
Explanation:
In order to answer this question we need to keep in mind the following definition of density:
Density = Mass / VolumeAs both the mass and the volume are given by the problem, we can proceed to calculate the density of gold:
Density = 301 g / 15.6 cm³Density = 19.3 g/cm³electron affinity of lithium is -60 whereas of cesium is -45.this trend is due to... plz give me accurate answer
Copper metal has a specific heat of 0.385 J/g.C. calculate the amount of heat required to raise the temperature of 22.8g of copper metal from 20.0C to 875°C
Answer:
7505.19 J
Explanation:
We'll begin by calculating the change in the temperature of copper. This can be obtained as follow:
Initial temperature (T₁) = 20 °C
Final temperature (T₂) = 875 °C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = 875 – 20
ΔT = 855 °C
Finally, we shall determine the heat required. This can be obtained as follow:
Specific heat capacity (C) = 0.385 J/gºC
Change in temperature (ΔT) = 855 °C
Mass (M) = 22.8 g
Heat (Q) required =?
Q = MCΔT
Q = 22.8 × 0.385 × 855
Q = 7505.19 J
Thus, 7505.19 J of heat energy is required.
Electrode A has a standard reduction potential of -0.21 volts and electrode B has a standard reduction potential of -0.15 volts. What electrode is the anode?
will give brainiest to person with the best answer ♡
So, we know the reduction potentials of the electrodes :
Electrode A = -0.21 V
Electrode B = -0.15 V
We want our cell to be spontaneous - this means that the voltage has to be positive. In order to do so, we need to turn the more negative reduction half reaction to be an oxidation half reaction.
-0.21 is more negative than -0.15, so electrode A will be the oxidation half reaction.
Anode is where the oxidation half reaction takes place, so electrode A is the correct answer . A fun way to remember this is An(ode)Ox(idation) = AnOx and Red(uction)Cat(hode) = RedCat
The E° cell will be 0.21 -0.15 V = 0.6 V
A 1.0 g sample of propane, C3H8, was burned in calorimeter. The temperature rose from 28.5 0C to 32.0 0C and heat of combustion 10.5 kJ/g. Calculate the heat capacity of the calorimeter apparatus in kJ/0C
Answer:
A 1.0 g sample of propane, C3H8, was burned in the calorimeter.
The temperature rose from 28.5 0C to 32.0 0C and the heat of combustion 10.5 kJ/g.
Calculate the heat capacity of the calorimeter apparatus in kJ/0C
Explanation:
[tex]Heat of combustion = heat capacity of calorimeter * deltaT\\[/tex]
Given,
The heat of combustion = 10.5kJ/g.
[tex]deltaT = (32.0-28.5)^oC\\deltaT = 3.5^oC[/tex]
Substitute these values in the above formula to get the value of heat capacity of the calorimeter.
[tex]deltaT =heat capacity of calorimeter * (change in temperature)\\10.5kJ/g = heat capacity of calorimeter * (3.5^oC)\\\\=>heat capacity of calorimeter = \frac{10.5kJ/g}{3.5^oC} \\=>heat capacity of calorimeter = 3.0 kJ/g.^oC[/tex]
Answer:
The heat capacity of the calorimeter is [tex]3.0kJ/g.^oC.[/tex]
Calculate the amount of heat required to completely sublime 55.0 g of solid dry ice CO2 at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 kj mol
Answer:
40.4 kJ
Explanation:
Step 1: Given data
Mass of CO₂ (m): 55.0 gHeat of sublimation of CO₂ (ΔH°sub): 32.3 kJ/molStep 2: Calculate the moles corresponding to 55.0 g of CO₂
The molar mass of CO₂ is 44.01 g/mol.
n = 55.0 g × 1 mol/44.01 g = 1.25 mol
Step 3: Calculate the heat (Q) required to sublimate 1.25 moles of CO₂
We will use the following expression.
Q = n × ΔH°sub
Q = 1.25 mol × 32.3 kJ/mol = 40.4 kJ
4-A major textile dye manufacturer developed a new yellow dye. The dye has a percent composition of 75.95% X, 17.72% N, and 6.33% H by mass with a molar mass of about 240 g/mol. Determine the molecular formula of the dye.
Answer:
C₁₅N₃H₅
Explanation:
Let's assume we have 240 g of the dye (1 mol), in that case we'd have:
240 g * 75.95/100 = 182.28 g of C240 g * 17.72/100 = 42.53 g of N240 g * 6.33/100 = 15.19 g of HNow we convert the masses of each element into moles, using their respective molar masses:
182.28 g C ÷ 12 g/mol = 15.19 mol C ≅ 1542.53 g N ÷ 14 g/mol = 3.04 mol N ≅ 3 15.19 g C ÷ 1 g/mol = 15.19 mol H ≅ 15Thus the molecular formula is C₁₅N₃H₅.
If you had used toluene instead of methyl benzoate in this reaction, what nitration product(s) would have formed? Write a stepwise mechanism for the nitration reaction of toluene.
Answer:
See explanation
Explanation:
The electrophilic substitution of aromatic compounds occurs faster in substituted aromatic compounds due to the fact that the ring becomes more or less susceptible to electrophilic attack depending on the nature of the substituent in the ring.
Electron pushing substituents such as alkyl groups stabilize the positive charge developed during electrophilic substitution hence they activate the ring towards electrophilic substitution.
The methyl group is an ortho - para directing substituent hence the product obtained by nitration of toluene is o-nitrotoluene and p-nitrotoluene.
The stepwise mechanism for obtaining these products is shown in the image attached to this answer.
2. Energy cycles through ecosystems because it returns to the sun.
True or false
Please help I will give 50 points
Answer:
false
Explanation:
energy does not return to the sun, it returns to the plants or producers. if energy were to return to the sun, it would have to travel though space.
Identify each of the following as endothermic or exothermic.
a. Water in a pond evaporates.
b. Methane gas burns on a stove top.
c. Water freezes to form ice.
d. Energy flows from the system to the surroundings.
e. Energy flows from the surroundings to the system.
Answer:
Identify each of the following as endothermic or exothermic.
a. Water in a pond evaporates.
b. Methane gas burns on a stovetop.
c. Water freezes to form ice.
d. Energy flows from the system to the surroundings.
e. Energy flows from the surroundings to the system.
Explanation:
An exothermic reaction is the one in which heat energy is released.
An endothermic reaction is one in which heat energy is absorbed.
a. Water in a pond evaporates.
This process absorbs heat energy.
Hence, this is an example of an endothermic process.
b. Methane gas burns on a stovetop and release heat energy and hence this is an example of an exothermic reaction.
c. Water freezes to form ice.
In this process heat energy is released.So this is an example of exothermic reaction.
d. Energy flows from the system to the surroundings.
That means heat energy is released into the surroundings.
So, this is an example of exothermic process.
e. Energy flows from the surroundings to the system.
That means energy is absorbed by the system.
So, it is an endothermic process.
Doc. No.
QMS
Rev. Date
1. In the reaction
P
> M + N
a) The reactants are:
b) The products are:
Answer: In the reaction:
a) The reactants are: P
b) The products are: M and N
Explanation:
The given reaction equation is as follows.
[tex]P \rightarrow M + N[/tex]
Reactants are the species present on the left side on an arrow in a chemical reaction equation.
On the other hand, products are the species which are present on the right side of an arrow in a chemical reaction equation.
Hence, in the given reaction equation P is the reactant. Whereas M and N are the products.
Thus, we can conclude that in the reaction:
a) The reactants are: P
b) The products are: M and N
I NEED THIS NOW NO LINKS OR ILL REPORT
What is a substance that has multiple elements in one area but are not
chemically combined; such as air? *
atom
element
compound
mixture
The correct answer is mixture
PLEASE TELL ME THE AWNSERS ITS A DOC FILE SO OPEN IT I WILL GIVE BRAINLIEST PLS HURRY
1 gallon =3.785 L how many liters of gasoline will fill a 10.00 tank
Answer:
37.85 L
Explanation:
3.785 x 10.00 = 37.85 L
it would take 37.85 L to fill a 10.00 tank
(sorry if im wrong pls dont report)
(hope this helps can i plz have brainlist :D hehe)
What happens to an electroscope when a negatively charged rod is brought close to the metal sphere at the top?
Answer:
When the negatively-charged rod is brought close to the electroscope, positive charges are attracted to it and negative charges are repelled away from it. The electroscope has a net neutral charge and the rubber rod has a net negative charge. If they are brought into contact, they will both take a net negative charge.
Explanation:
I looked it up
A 200. gram sample of a salt solution contains 0.050 grams of NaCl. What is the concentration of the
solution in parts per million (ppm)?
Answer:
2.5 × 10² ppm
Explanation:
Step 1: Given data
Mass of NaCl: 0.050 gMass of the sample: 200. gStep 2: Convert 0.050 g to μg
We will use the conversion factor 1 g = 10⁶ μg.
0.050 g × 10⁶ μg/1 g = 5.0 × 10⁴ μg
Step 3: Calculate the concentration of NaCl in ppm
The concentration of NaCl in ppm is equal to the micrograms of NaCl per gram of the sample.
5.0 × 10⁴ μg NaCl/200. g = 2.5 × 10² ppm
Answer:250 ppm
Explanation:
Determine the number of significant digits in each number and list the specific significant digits. 1. 306,000 2. 0.0073 3. 39.9999 4. 25.00 5. 40,000,021 6. 45,250.0 7. 0.00011 8. 420.030700
Answer:
1. 306,000: three significant figures because the last three zeros are not preceded by a decimal point.
2. 0.0073: two significant figures because the the leftmost zeros are not significant.
3. 39.9999: six significant figures because all these numbers are nonzero digits.
4. 25.00: four significant figures because right-handed zeros, after a decimal point, are significant.
5. 40,000,021: eight significant figures because intermediate zeros are significant.
6. 45,250.0: six significant figures because al the zeros are to the right of the nonzero digits.
7. 0.00011: two significant figures as well as #2.
8. 420.030700: nine significant figures because all the zeros are to the right of the first nonzero digits and after the decimal point.
Explanation:
Hello there!
In this case, by considering the given numbers, we can proceed as follows, by keeping in mind the rules for assigning significant figures:
1. 306,000: three significant figures because the last three zeros are not preceded by a decimal point.
2. 0.0073: two significant figures because the the leftmost zeros are not significant.
3. 39.9999: six significant figures because all these numbers are nonzero digits.
4. 25.00: four significant figures because right-handed zeros, after a decimal point, are significant.
5. 40,000,021: eight significant figures because intermediate zeros are significant.
6. 45,250.0: six significant figures because al the zeros are to the right of the nonzero digits.
7. 0.00011: two significant figures as well as #2.
8. 420.030700: nine significant figures because all the zeros are to the right of the first nonzero digits and after the decimal point.
Regards!
Aluminum metal reacts with oxygen gas in a combination reaction that forms a product that coat the metal preventing it from further oxidation. Which of the following is the correct balanced equation for the reaction?
a. Al(s) + 302(g) → 2903(s).
b. 2Al(s) + O2(g) → 2A10(s).
c. AI(s) + O2(g) → AIO (s).
d. 4Al(s) + 3O2(g) →2Al2O3.
e. 3Al(s) + O2 → Al3O2.
Answer:
d. 4 Al(s) + 3 O₂(g) → 2 Al₂O₃(s)
Explanation:
Aluminum metal reacts with oxygen gas in a combination reaction that forms a product that coats the metal preventing it from further oxidation: aluminum oxide. Aluminum is a cation with charge 3+ (Al³⁻) and oxide is an anion with charge 2- (O²⁻). Thus, the neutral compound aluminum oxide has the chemical formula Al₂O₃. The unbalanced chemical equation is:
Al(s) + O₂(g) → Al₂O₃(s)
We can balance using the trial and error method. First, we will balance O atoms by multiplying Al₂O₃ by 2 and O₂ by 3.
Al(s) + 3 O₂(g) → 2 Al₂O₃(s)
Finally, we get the balanced equation by multiplying Al by 4.
4 Al(s) + 3 O₂(g) → 2 Al₂O₃(s)
Zinc sulfate is a 2-ion electrolyte,
dissociating 40% in a
certain concentration. Calculate its
dissociation (i) factor.
On the basis of 40% dissociation, 100
particles of zinc sulfate
will yield:
40zinc ions
40 sulfate ions
60undissociated particles
Jo 11:03
Answer: The value of i is 1.4 and 40% dissociation of 100 particles of zinc sulfate will yield 60 undissociated particles.
Explanation:
The equation used to calculate the Vant' Hoff factor in dissociation follows:
[tex]\alpha =\frac{i-1}{n-1}[/tex]
where,
[tex]\alpha [/tex] = degree of dissociation = 40% = 0.40
i = Vant' Hoff factor
n = number of ions dissociated = 2
Putting values in above equation, we get:
[tex]0.40=\frac{i-1}{2-1}\\\\0.40=i-1\\\\i=1.4[/tex]
The equation used to calculate the degee of dissociation follows:
[tex]\alpha =\frac{\text{Number of particles dissociated}}{\text{Total number of particles taken}}[/tex]
Total number of particles taken = 100
Degree of dissociation = 40% = 0.40
Putting values in above equation, we get:
[tex]0.40=\frac{\text{Number of particles dissociated}}{100}\\\\\text{Number of particles dissociated}=(0.40\times 100)=40[/tex]
This means that 40 particles are dissociated and 60 particles remain undissociated in the solution.
Hence, 40% dissociation of 100 particles of zinc sulfate will yield 60 undissociated particles.
