Is instant coffee compound solution or heterogeneous mixture?
Give two reasons why the flame test is sometimes invalid
Answer: 1.A false positive and 2.A false negative.
Explanation:
A false positive the classic example is the contamination of almost any sample with sodium ions which gives an intense yellow line even when the sodium is present as only impurity.
A false negative here sodium ions is the culprit that masks other emissions unless the emissions are resolved spectroscopically rather than simply visually.
Why does it make sense that if an atom loses electrons, it is left with a positive charge?
Ions can be made by single element or covalently bonded group of elements. On removing an electron from an atom, atoms occupy positive charge.
What is Ions?Any species that contain charge whether it is positive charge or negative charge is called ions. The example of polyatomic ions are sulfate, phosphate, nitrate etc.
Cation is the species that loose electron and attain positive charge while anion is a species which gain electron and attains negative charge. Electrons are negatively charged. If we remove negative particles, the leftover atom is positive. when anion and cation combine in fixed ration the the overall charge of the molecule is zero that is molecule is neutral.
Therefore, on removing an electron from an atom, atoms occupy positive charge.
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The n = 1 shell contains ________ p orbitals. all the other shells contain ________ p orbitals.
Answer:
Zero; Three
Explanation:
The quantum numbers are the set of four described unique values that describes each electron in the orbitals of the atom. The four quantum numbers are the principal, azimuthal, magnetic, and spin.
The principal quantum number (n) gives the energy levels of the electrons. The value of n is always n ≥ 1.
The azimuthal quantum number, also known as the orbital quantum number, describes the shape of the subshell. The values of this quantum number ranges from 0 ≤ ℓ ≤ n − 1.
For n = 1,
The value of: ℓ = n-1 = 1-1 = 0
∵ ℓ = 0 ⇒ s-orbital
Therefore, in n=1 shell, there is only one value of ℓ. So, there is only one s-orbital and zero p-orbital.
For n > 1,
The value of: l = n-1 > 0
Therefore, for n > 1 shell, there are more than one values of ℓ. So, n > 1 shells contains a set of three p-orbitals each.
If you change peanuts into peanut butter is it a chemical or a physical change
What is number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction?
Which observation indicates that the kinetic-molecular theory has limited use for describing a certain gas?
D. Increasing collisions of gas molecules will increase energy between them.
If an atom has an equal number of electrons and protons, it would be considered ________
Which group of elements have some properties of metals and some properties of nonmetals?
A(n) __________ molecular orbital is lower in energy than the atomic orbital of which it is composed.
A [tex]\boxed{{\text{bonding}}}[/tex] molecular orbital is lower in energy than the atomic orbital of which it is composed.
Further Explanation:
Atomic Orbital:
The wave nature of electrons present in any atom is expressed by a mathematical function, known as atomic orbital. This wave function is used for determining the probability to find electrons in specific region around atomic nucleus.
Molecular orbitals:
These orbitals are formed by permitted interactions between atomic orbitals. Such orbitals are formed only if symmetries of bonded atomic orbitals match with each other. The number of atomic orbitals results in formation of same number of molecular orbitals.So if n atomic orbitals combine with each other,n molecular orbitals will result.
Following molecular orbitals are formed by interaction between atomic orbitals:
1. Bonding molecular orbitals
These orbitals are formed by constructive interference of waves of different atomic orbitals. Such orbitals are used to depict attractions between atomic orbitals. When electrons are placed in bonding molecular orbitals, this leads to bond strengthening and stabilization of resulting molecule. Hence such orbitals have lower energy, even less than that of combining atomic orbitals.
2. Antibonding molecular orbitals
These orbitals are formed by destructive interference of waves of different atomic orbitals. When electrons are placed in antibonding molecular orbitals, these experience greater repulsion, thereby resulting in repulsion between the combining nuclei.Suchelectrons tend to destabilize it so the energy of the anti-bonding molecular orbitals is higher.
3. Nonbonding molecular orbitals
The energy of such orbitals remains unaffectedif electrons are added or removedfrom them. These orbitals are considered equivalent to lone pairsrepresented in Lewis structures. The only difference is nonbonding molecular orbitals are used up in molecular orbital theory.
Therefore bonding molecular orbitals have lower energy than combining atomic orbitals.
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Answer details:
Grade: High School
Subject: Chemistry
Chapter: Chemical bonding and molecular structure
Keywords: atomic orbitals, molecular orbitals, Lewis structures, lone pairs, bonding, antibonding, nonbonding, molecular orbitals, constructive interference, destructive interference, electrons, energy.
Write a balanced equation for the reaction of aluminum with water (aluminum hydroxide is the other product).
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.
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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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?
If 3.000g of k2co3 were used in this experiment (instead of khco3),
a. what is the balanced equation for the equation? k2co3 + 2hcl = 2kcl + co2 + h2o
b. how many milliliters of 6.0 m hcl would be needed ________ml hcl
c. how many grams of kcl would be formed in the reaction? ________ g kcl
A. The balanced chemical equation is correct:
k2co3 + 2hcl --> 2kcl + co2 + h2o
B. First let us calculate the moles of K2CO3.
moles K2CO3 = 3 g / (138.205 g/mol) = 0.0217 mol
From the equation, we need 2 moles of HCl per 1 mole of K2CO3, hence:
moles HCl needed = 0.0217 mol * 2 = 0.0434 mol
So the volume required is:
volume HCl = 0.0434 mol / 6 M = 7.24 x 10^-3 L = 7.24 mL
C. The number of moles of HCl and KCl is equal hence:
moles KCl = 0.0434 mol
The molar mass of KCl is 74.5513 g/mol, so the mass is:
mass KCl = 0.0434 mol * 74.5513 g/mol = 3.24 grams
In a reaction of K2CO3 with HCL the balanced chemical equation is K2CO3 + 2HCL = 2KCL + CO2 + H2O. For 3g of K2CO3, approximately 7.2 mL of 6M HCL would be required and the reaction would yield approximately 3.2g of KCL.
Explanation:The topic that is being asked here revolves around chemical equations, stoichiometry and calculations pertaining to a chemical reaction. In the question, you have the chemical reaction K2CO3 + 2HCL = 2KCL + CO2 + H2O where K2CO3 is reacting with Hydrochloric acid (HCl) to form Potassium chloride (KCl), Carbon dioxide (CO2), and Water (H2O).
b) The molar mass of K2CO3 is approximately 138.205g/mol. Since you have 3g, that is approximately 0.0217 mol of K2CO3. Since 2 mol of HCl react with 1 mol of K2CO3, you would require 0.043 mol of HCL which in mL for 6M HCl would be approximately 7.2 mL HCl.
c) Given the reaction, 2 mol of KCL are generated per mol of K2CO3. So with 0.0217 mol of K2Co3, you will produce close to 0.043 mol of KCl. The molar mass of KCl is about 74.55g/mol, so the mass produced would be about 3.2g of KCL.
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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.
A (an) _____ is an easier path for electron flow that can cause shocks or an electric fire.
Final answer:
A short circuit is a low-resistance path between the terminals of a voltage source that can lead to electrical fires and shocks, especially when worn insulation allows conductors to touch.
Explanation:
A short circuit, also known as a "short," is an easier path for electron flow that can cause shocks or an electric fire. It is an undesired low-resistance path that develops between the terminals of a voltage source.
When the insulation on wires gets worn out, such as in a toaster, the wires may come into contact and a short circuit can occur. The electrical power formula P = V²/r indicates that the electrical power (P) dissipated increases rapidly when resistance (r) is low, which creates significant thermal energy resulting in the cord melting or burning. This scenario not only poses a thermal hazard by potentially starting a fire but also a shock hazard if a person comes into contact with the energized wires or the appliance itself.
What is the mass of the light bulb and paperclips together?
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
Describe how formal charges are used to choose between possible molecular structures
What electrically neutral atom will have an electron configuration of 1 s 22 s 22 p 4? Use a periodic table.
Question 5 options:
nitrogen (N)
oxygen (O)
carbon (C)
fluorine (F)
Answer:
oxygen (O)
Explanation:
Oxygen is electrically neutral atom will have an electron configuration of 1 s 22 s 22 p 4. Therefore, option B is correct.
What is electronic configuration ?The distribution of electrons in an element's atomic orbitals is described by the element's electron configuration. Atomic electron configurations adhere to a standard nomenclature in which all atomic subshells that contain electrons are arranged in a sequence with the number of electrons they each hold expressed in superscript.
One orbital can house a maximum of two electrons, and there are four different types of orbitals (s, p, d, and f). More electrons can be held in the p, d, and f orbitals since they contain various sublevels. According to its location on the periodic table, each element's electron configuration is distinct.
The arrangement of electrons within an atom's orbitals is known as its electronic configuration. Each neutral atom contains an equal number of electrons, which is a fixed number.
Thus, option B is correct.
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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.
Fats that are liquid at room temperature can be made more solid by the process of ________.
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.
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.
Jupiter has a gravity of 2.9, what would your weight be on Jupiter if you weighed 84 lbs on Earth?
Which particle(s) determine(s) the identification of an atom?
Which type of change occurs when electrons form a bond between two atoms?
a. atomic change
b. chemical change
c. physical change
d. phase change?
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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