In this experiment you are directed to add a limited amount of naoh (aq) and then an excess amount. a similar strategy will be used with the addition of nh3(aq). why?
Adding a limited amount of NaOH and then an excess amount is because initially, a metal hydroxide may form which gets soluble when more base will be added and then form a metal complex.
What is qualitative analysis?Qualitative Analysis can be described as the determination of non-numerical information about a chemical species, a reaction, etc. Qualitative analysis is often easier, faster, and cheaper to perform.
In qualitative analysis, we commonly add the base in drops, and then in addition will be done in excess. When the base is added in drops, then metal hydroxide is formed and this metal hydroxide is often insoluble.
After the formation of metal hydroxide, the base can be added in excess so that the metal hydroxide which was formed first will dissolve in the excess base by forming a metal complex.
For example,
[tex]CuCl_2(aq) + 2NaOH(aq) \longrightarrow Cu(OH)_2(s) + 2NaCl(aq)\\Cu(OH)_2(s) + 2OH^-(aq) \longrightarrow[Cu(OH)4]^{2+}(aq)[/tex]
This same strategy can be used with the addition of ammonia NH₃(aq).
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Adding limited and then an excess amount of NaOH and NH₃(aq) helps in selective titration and neutralization reactions when dealing with mixtures. It ensures accurate stoichiometry and the formation of desired products while maintaining appropriate conditions such as pH.
In the described experiment, adding a limited and then an excess amount of NaOH as well as NH₃ is a strategy used to perform selective titrations in the presence of multiple reactive species. The use of NaOH in limited amounts allows for the neutralization of specific components, such as acids in a mixture, while minimizing interference from other components. For NH₃, since it is a weak base and would react to form ammonium ions (NH₄⁺ ), adding NaOH in excess ensures that any conjugate acid forms of amines present are converted back to the free base, making it easier to extract due to its non-polar nature.
When dealing with a mixture containing NH₄⁺ ions, their titration with NaOH can be problematic due to a poorly-defined end point. This is because NH₄⁺ is a weak acid with a very low acid dissociation constant (Ka), resulting in an end point that is difficult to detect accurately. By adding NaOH in varying amounts, chemists are able to control the reactions and attain the correct stoichiometry needed for analytical purposes or product formation.
Moreover, buffers such as the HC₂H₃O₂/NaC₂H₃O₂ buffer help to maintain pH levels when strong bases are added, preventing significant pH changes by converting the OH⁻ ions into water instead of simply increasing the basicity of the solution.
Is instant coffee compound solution or heterogeneous mixture?
Aqueous lithium sulfate was mixed with aqueous strontium chlorate, and a crystallized strontium sulfate product was formed. consider the other product and its phase, and then write the balanced molecular equation for this precipitation reaction
Lithium sulfate is Li2SO4
Strontium chlorate is Sr(ClO3)2
Strontium sulfate is SrSO4
So the complete balanced chemical reaction for this is:
Li2SO4 (aq) + Sr(ClO3)2 (aq) --> SrSO4 (s) + 2 LiClO3 (aq)
This is a type of double replacement reaction since there is an exchange of ions.
In a precipitation reaction between aqueous lithium sulfate and strontium chlorate, strontium sulfate precipitates while lithium chlorate remains aqueous. The balanced molecular equation for this reaction is: Li2SO4 (aq) + Sr(ClO3)2 (aq) → SrSO4 (s) + 2 LiClO3 (aq).
Explanation:When aqueous lithium sulfate (Li2SO4) is mixed with aqueous strontium chlorate (Sr(ClO3)2), one product that forms is strontium sulfate (SrSO4), which crystalizes due to its insolubility in water. The other product is lithium chlorate (LiClO3), which remains aqueous due to its high solubility.
The balanced molecular equation representing this precipitation is: Li2SO4 (aq) + Sr(ClO3)2 (aq) → SrSO4 (s) + 2 LiClO3 (aq).
This equation reflects the conversion of the reactants, lithium sulfate and strontium chlorate, into the products, strontium sulfate (a precipitate) and lithium chlorate.
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What is the concentration of a solution prepared by dissolving 100g of sorbitol in 1000 ml of water?
first you divide them together and get an answer of 10 then you times it by 5 and your answer is 50 ml
A tub of water is placed in a small room. If heat is removed from the room, which of the following will most likely occur if enough heat is removed?
Question 3 options:
A.The water will freeze.
B.The water will evaporate.
C.The water will become a gas.
D.The water will change from gas to solid
Calculate the number of moles of oxygen atoms in 35.2 grams of oxygen.
Atomic Weight of Oxygen is 16 g/mol
Use the equation n=m/MM
You know m (mass) and MM (molar mass), sub in into the equation.
Ans: 2.2 mol
What does the velocity of a wave describe
Answer:if you increase the frequency, the wave length will be shortened
Explanation:
An _____ is a hydrocarbon in which one or more hydrogen atoms is replaced by a -COH group.
A. aldehyde
B. alcohol
C. ester
D. amino acid
Answer : The correct option is, (A) Aldehyde
Explanation :
Alcohol group : It is the class of organic compound in which the hydroxy (-OH) group is attached to a hydrocarbon is known as alcohols.
The general representation of alcohol are, [tex]R-OH[/tex].
For example : [tex]CH_3-CH_2-OH[/tex] is obtained when one hydrogen atom is replaced by [tex]-OH[/tex] group.
Amino acid : Amino acid are the acid that contains two functional groups which are carboxylic group, [tex]-COOH[/tex] and ammine group, [tex]-NH_2[/tex].
The bond present between the two amino acid is a peptide bond. The peptide bond is formed between the nitrogen of one amino acid and carbon of another amino acid.
Ester group : It is the class of organic compound in which the [tex]-COO[/tex] group is attached to a hydrocarbon is known as ester.
The general formula of ester are, [tex]R-COO-R^'[/tex]. It is directly attached to the two alkyl group of carbon.
Aldehyde group : It is the class of organic compound in which the (-CHO) group is attached to a hydrocarbon is known as aldehyde.
The general representation of aldehyde are, [tex]R-CHO[/tex].
For example : [tex]CH_3-CH_2-CHO[/tex] is obtained when one hydrogen atom is replaced by [tex]-CHO[/tex] group.
Hence, the correct option is, (A) Aldehyde
Which ion will form a basic solution when dissolved in water? hso4-?
Final answer:
The hydrogen sulfate ion (HSO4-) will form a slightly basic solution when dissolved in water because it reacts to produce hydroxide ions (OH-) which increases the pH above 7.
Explanation:
The hydrogen sulfate ion (HSO4-) is the conjugate base of sulfuric acid (H2SO4) and the conjugate acid of sulfate (SO42-). When HSO4- is dissolved in water, it can react with water to form hydrogen sulfate (H2SO4) and hydroxide ions (OH-), which causes the solution to be basic. This is due to the fact that it slightly ionizes to produce OH- ions. Based on the reactions and comparative strengths of acids and bases, HSO4- being a conjugate base of a strong acid is a very weak base and will therefore form a solution that is slightly basic, provided that the resulting concentration of OH- ions is greater than that of H3O+ ions in the water.
Compare and contrast the bonds in these two compounds: MgCl2 and C2H6. Include similarities and differences. Be sure to discuss both compounds in your answer.
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Xenon (xe) of mass 5.08 g reacts with fluorine to form 9.49 g of a xenon fluoride compound. what is the empirical formula of this compound?
Final answer:
To find the empirical formula of a xenon fluoride compound, first calculate the mass of fluorine that reacted, then determine the mol amounts of both xenon and fluorine, and finally, simplify their ratio. The calculations reveal that the empirical formula of the compound is XeF₆.
Explanation:
To determine the empirical formula of the xenon fluoride compound formed when xenon (Xe) reacts with fluorine, we first need to figure out the mass of fluorine that reacted with xenon. Given that the original mass of xenon is 5.08 g and the final mass of the xenon fluoride compound is 9.49 g, the mass of fluorine that reacted can be calculated as 9.49 g - 5.08 g = 4.41 g.
Next, we calculate the molar amounts of xenon and fluorine in the compound. The molar mass of xenon (Xe) is approximately 131.29 g/mol, and the molar mass of fluorine (F) is approximately 19.00 g/mol. Therefore, the molar amount of xenon is 5.08 g / 131.29 g/mol = 0.0387 mol, and the molar amount of fluorine is 4.41 g / 19.00 g/mol = 0.232 mol.
Then, to find the empirical formula, we divide the molar amounts of both elements by the smallest value to simplify the ratio. This gives us a molar ratio of Xe:F approximated to 1:6, leading to the empirical formula of XeF₆.
Methane is a colorless, odorless gas. It oxidizes in air and has a boiling point of -161° C. Which property of methane is a chemical property? A. odor B. color C. boiling point D. oxidizes in air
The property of methane which is a chemical property is its ability to oxidize in air.
What are the chemical properties?These properties are defined as those properties which become evident during or after a chemical reaction after the identity of the substance is changed during chemical reaction.
These properties cannot be determined externally just by viewing the substance ,these change immensely after a substance undergoes a chemical change.These are used for identification of unknown substances and for building up chemical classifications.
The major chemical properties are flammability,toxicity,reactivity,acidity and heat of combustion.For a chemical property to be apparent , it is necessary that the structure of the substance is altered.
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A(n) __________ is a substance in which atoms of two or more elements are combined in a fixed proportion.
A compound is a pure substance formed by chemically bonding two or more different elements in a fixed ratio. It can only be broken down into simpler substances through chemical processes.
An compound is a substance in which atoms of two or more elements are combined in a fixed proportion. A compound is a pure substance composed of atoms of two or more different chemical elements bonded in some fixed ratio, forming molecules of that substance. These atoms are held together by chemical bonds and the compound has properties different from the individual elements that compose it. Compounds can be separated into simpler substances and elements only through chemical methods, not by physical means such as filtering or distillation.
Jimmy does a cannonball into the swimming pool. After surfacing and floating for a few seconds, he observes something interesting. He notices that if he takes deep breaths his body seems to float more. Also he notices that he sinks into the water after he releases his breath. Explain why this is happening to Jimmy.
Explain the conductivity results observed for sodium chloride in the solid state and in aqueous solution
NaCl when in solid state does not conduct electricity while it does in aqueous solution.
Explanation:
NaCl (or what we call common salt) first needs to be either melted or dissolved in a solution for it to conduct electricity. The reason for this is that electrons in a solid state does not have enough freedom to move to either the Cathode (-ve) or to the Anode (+ve). So in a liquid state the electrons are now free enough to move.
The ionic nature of sodium chloride (NaCl) influences its ability to conduct electricity. It is non-conductive in solid form as the ions are fixed and aren't able to move. However, in an aqueous solution or when molten, the ions dissociate and can freely move, enabling the conduction of electricity.
Explanation:Sodium chloride, or NaCl, displays different conductivity results in its solid state versus aqueous solution due to its ionic nature. When NaCl is in its solid state, it does not conduct electricity because the ions are fixed in place and cannot flow. It is said that electricity is the flow of charged particles, and in the case of a solid such as solid NaCl, these charged particles, i.e. ions, are unable to flow due to the rigid ionic lattice structure.
However, the situation changes when sodium chloride is in an aqueous solution or when it is molten. Sodium chloride, when dissolved in water, dissociates into ions, producing free flowing Na+ and Cl- ions. These ions are electrolytes and are capable of conducting an electrical current in solution. Similar thing happens when it becomes molten due to high heat, sodium chloride melts at around 801 °C, freeing the ions and allowing them to conduct electricity.
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If an atom has an equal number of electrons and protons, it would be considered ________
What types of orbital overlap occur in cumulene? check all that apply. check all that apply. p/p overlap sp/sp2 overlap s/sp overlap sp/sp overlap s/s overlap sp2/sp2 overlap s/sp2 overlap?
What substance is present in a solution consisting solely of electrolytes?
Dalton theorized that atoms are indivisible and that all atoms of an element are identical. Scientists now know that
A. Dalton’s theories are completely correct.
B. atoms of an element can have different numbers of protons.
C. atoms are all divisible.
D. all atoms of an element are not identical but they all have the same mass.
Scientists know that atoms of elements are all divisible.
What is atomic structure ?Atomic structure refers to the structure of atom which consists of a nucleus in the center with protons and neutrons being present inside the nucleus .Protons are positively charged sub atomic particles while the neutrons are sub atomic particles which are electrically neutral.
Outside the nucleus , in circular orbits there are electrons revolving around the nucleus with negative charge on each electron .The history of atomic structure dates back to the time of Democritus who proposed that matter is made up of atoms.
The study of atom gives a great insight about the wide range of chemical reactions , chemical bonds and their physical properties.To explain the atomic structure , various atomic models were proposed like Dalton's atomic theory ,Thomson's atomic model and Rutherford's atomic model and Bohr's atomic model.
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What is the mass of the light bulb and paperclips together?
Which scenario would cause a covalent bond to form?
Which of the following is the number of protons plus the number of neutrons?
Atomic charge
Mass number
Atomic number
Atomic isotope number
The number of protons plus the number of neutrons is the mass number.
The ionic charge depends on the number of electrons.
The atomic number is the number of protons.
Atoms can have different isotopic masses, but there is no such thing as atomic isotope number.
What is unique about the orbitals around the nucleus of an atom?
The thing that makes the orbitals surrounding an atom's nucleus special is that the energy level changes as the electrons occupy space farther away from the nucleus. The s, p, d, and f orbitals are distinct because the nucleus is dropped as their energy rise and their bonds weaken.
Generally speaking, an atom's electrons have a lot of special characteristics, such as how they orbit the nucleus.
The electrons that it contains
Additionally, the energy level that changes when electrons occupy space farther from the nucleus
The s, p, d, and f orbitals are distinct because the nucleus is dropped as their energy rise and their bonds weaken.
If you change peanuts into peanut butter is it a chemical or a physical change
When elemental sodium is added to water, the sodium atoms ionize spontaneously. uncharged na becomes na+. this means that the na atoms have been _____________?
Final answer:
Sodium atoms are oxidized when they lose an electron and change into sodium cations upon contact with water. This forms positively charged Na+ ions that are surrounded by water molecules in a process known as dissociation.
Explanation:
When elemental sodium is added to water, the sodium atoms ionize spontaneously. This transformation from an uncharged Na to Na+ means that the Na atoms have been oxidized. An oxidation process involves the loss of electrons, changing the sodium atom into a sodium cation.
A sodium atom (Na) has equal numbers of protons and electrons, making it uncharged. Once an electron is lost, the sodium cation (Na+) has one more proton than electrons, thus acquiring an overall positive charge.
Dissociation in water occurs when atoms or groups of atoms break off from molecules and form ions. For example, when table salt (NaCl) is added to water, it dissociates into Na+ and Cl− ions.
During this process, spheres of hydration form around the ions, with water molecules orienting themselves around the positive sodium ion and negative chloride ion due to their polar natures.
Describe how formal charges are used to choose between possible molecular structures
Write a balanced equation for the reaction of aluminum with water (aluminum hydroxide is the other product).
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The following graph shows the relationship between predator and prey populations. If the time is measured in months, how long does the predator rise in population follow the prey rise in population?
a. About six months
b. About two months
c. About one month
d. About eight months
Janice is given a mixture of alcohol and water. The teacher tells her that she can use temperature to separate these compounds. What property is being demonstrated by this experiment.
A) conduction
B) density
C) solubility
D) boiling
Answer: D) boiling
Explanation:
In order to separate a mixture of alcohol and water the mixture can be heated until the alcohol boils. The boiling point of alcohol is lower than water. The alcohol will boil off leaving the water.
Final answer:
The experiment utilizes the physical property of boiling points to separate a mixture of alcohol and water through distillation, demonstrating how substances with different volatilities can be separated without altering their chemical properties. The correct answer is D) boiling.
Explanation:
The experiment demonstrates the physical property of boiling points by utilizing temperature to separate a mixture of alcohol and water. This is because alcohol and water have different boiling points, which allows them to be separated through a process known as distillation. Distillation relies on the fact that the substance with the lower boiling point (in this case, alcohol) will vaporize first, and then it can be condensed back into a liquid and collected separately from water. This method is a physical process that does not alter the chemical properties of the substances involved.
Therefore, the correct answer to the question is D) boiling. This property is crucial for separating mixtures into their component substances by taking advantage of their different volatilities, a measure of how easily a substance converts to gas at a given temperature.
Hannah does an experiment. She has two colorless chemicals that she mixes together in a beaker. Which of the following indicates that a chemical change occurs when she mixes the two chemicals together? I. The chemicals change color from colorless to purple. II. A yellow gas forms. III. A brown solid forms in the bottom of the beaker. IV. The temperature of the chemicals rises 15°C. A. II and III only B. I, II, III, and IV C. I and III only D. I, II, and III only
Answer:
B. I, II, III, and IV
Explanation:
A chemical change occurs when the original substances (the reactants) are changed into a new substance or substances (the products). A chemical change can be indicated by a color change, gas formation, solid formation, or a temperature change. I, II, III, and IV all indicate that a chemical change has occurred when Hannah mixes the two chemicals
A chemical change occurs when she mixes the two chemicals together. The chemicals change color from colorless to purple, a brown solid forms in the bottom of the beaker and a yellow gas forms
What is chemical change ?Chemical synthesis, or, alternatively, chemical breakdown into two or more separate molecules, occurs when one material reacts with another to create a new substance.
These processes are referred to as chemical reactions, and they are often irreversible, barring additional chemical reactions. When one chemical material changes into one or more others, as when iron rusts, this is referred to as a chemical transformation.
Chemical reactions produce changes in the way that atoms and molecules are ordered, which leads to the formation of new substances with new characteristics.
Thus, option B is correct.
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