Calculate the mass percentage of oxygen in dry air
Answer:
0.23 = 23% O by mass
Explanation:
Hi! Let's solve this!
We have the percentage data of each component in the air and its masses.
Nitrogen 0.78084 28.013
Oxygen 0.20948 31.998
Argon 0.00934 39.948
Carbon dioxide 0.000375 44.0099
Neon 0.00001818 20.183
Helium 0.00000524 4.003
Methane 0.000002 16.043
Krypton 0.00000114 83.80
Hydrogen 0.0000005 2.0159
Nitrous oxide 0.0000005 44.0128
Now we have to calculate a molar fraction.
(0.20948 * 31.998) = (0.78084 * 28.013)
+ (0.20948 * 31.998) + (0.00934 * 39.948) + (0.000375 * 44.0099) + (0.00001818 * 20.183) + (0.00000524 * 4.003) + (0.000002 * 16.043) + (0.00000114 * 83.80) + (0.0000005 * 2.0159) + ( 0.0000005 * 44.0128) = 0.23 = 23% O by mass
Which element has the same number of valence electrons as phosphorus? which element has the same number of valence electrons as phosphorus? bi in te rb?
The statement of element has the same number of valence electrons as phosphorus is "Bi."
What are valence electrons?The electrons present in an atom's outermost energy level, are known as valence electrons. The number of valence electrons in neutral atoms is equal to the main group number of the atom. Valence electrons have a higher energy than inner orbit electrons and therefore involved in the majority of chemical reactions. They help us figure out an element's chemical properties, such as its valency and how it forms bonds with other elements.
An atom with a closed valence electron shell is usually chemically inert. In the outermost energy orbitals, Group 5A elements have five valence electrons (ns2np3). Bismuth (Bi) is positioned in group 5, and hence does have the same number of valence electrons as phosphorus (P), which is 5, since they both belong to the nitrogen family. Rubidium, on the other hand, is an s-block element with one valence electron.
Hence the correct answer is Bi.
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Identify the molecule with the strongest intermolecular force
HF
HCl
Hl
HBr
What precipitate forms when silver nitrate and potassium chromate solutions are mixed?
A precipitate is an insoluble product formed, when two solutions are mixed, this reaction is called precipitation reaction.
The balanced equation for this reaction is:
2 AgNO3 + K2CrO4 (aq)------->Ag2CrO4 (s) + 2 KNO3
so when silver nitrate and potassium chromate solutions are mixed, precipitates of silver nitrate are formed.
Explanation:
When we obtain insoluble solid from a liquid solution, then this insoluble solid is known as precipitate.
When silver nitrate and potassium chromate solutions are mixed together then there is formation of silver chromate and potassium nitrate.
The reaction is as follows.
[tex]2AgNO_{3}(aq) + K_{2}CrO_{4}(aq) \rightarrow Ag_{2}CrO_{4}(s) + 2KNO_{3}(aq)[/tex]
This insoluble solid [tex]Ag_{2}CrO_{4}[/tex] is the precipitate and it has a red-brown color.
What is emitted when the radioactive nucleus of 131 53i decays to form the stable isotope of xenon 131 54xe?
Final answer:
In the decay of iodine-131 to xenon-131, a beta particle and gamma rays are emitted as the nucleus transitions from an unstable to a stable state.
Explanation:
When the radioactive nucleus of iodine-131 (131I_53) decays, it emits a beta particle (an electron, β) and transforms into an unstable form of xenon-131 (131Xe_54m), which is then followed by a gamma decay. The gamma decay involves the emission of gamma rays as the nucleus transitions from its excited state (131Xe_54m) to its ground state, resulting in a stable isotope of xenon-131 (131Xe_54). This process can be written as follows:
131I_53 → 131Xe_54m + β-This type of decay is common in nuclear reactions and is one method of radioactive decay wherein unstable nuclei transition to a more stable form.
Which is the balanced chemical equation for the reaction of nitrogen (n2) with oxygen (o2) to form no?
Final answer:
The balanced chemical equation for the reaction between molecular nitrogen (N₂) and oxygen (O₂) to form nitrogen monoxide (NO) is N₂(g) + O₂(g) → 2 NO(g). It ensures there is an equal number of nitrogen and oxygen atoms on both sides of the equation.
Explanation:
The balanced chemical equation for the reaction of molecular nitrogen (N₂) with oxygen (O₂) to form nitrogen monoxide (NO) is:
N₂(g) + O₂(g) → 2 NO(g)
Each molecule of nitrogen monoxide consists of one nitrogen atom and one oxygen atom. To balance the chemical equation, we must have equal numbers of each type of atom on either side of the arrow. Since we start with two nitrogen atoms on the left, we need two nitrogen atoms on the right, which means we'll need two NO molecules. The same logic applies to oxygen, therefore we need only one O₂ molecule to balance the two oxygen atoms needed to produce the two NO molecules. Thus, the equation is balanced with one N₂, one O₂, and two NO molecules.
How many more atomic orbitals does a d sublevel hold than a p sublevel
The d sublevel holds two more atomic orbitals than the p sublevel, with the p subshell having three orbitals and the d subshell having five orbitals.
Explanation:The question is about the number of atomic orbitals in different sublevels of an atom, specifically comparing d and p sublevels. In any atom, the sublevels, denoted by s, p, d, and f, have a specific number of orbitals where an electron can most probably be. The p subshell contains three orbitals, while the d subshell contains five orbitals. Therefore, the d sublevel holds two more atomic orbitals than the p sublevel.
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The Lewis dot structure for nitrogen shows the symbol, N, surrounded by a total of _____ dots.
In the Lewis dot structure for nitrogen (N), the symbol is surrounded by five dots, representing its five valence electrons. Three of these are unpaired and available for bonding.
Explanation:In the Lewis dot structure, the symbol for the element is surrounded by dots representing its valence electrons. Nitrogen (N) has five valence electrons. Therefore, in the Lewis dot structure for nitrogen, the symbol N, is surrounded by five dots.
There are three unpaired electrons and one electron pair in terms of bonding. The three unpaired electrons are available to form bonds with other atoms (most often seen in compounds like ammonia - NH3), while the pair of electrons remains as a lone pair on nitrogen in its compounds.
The Lewis dot symbol for nitrogen is a convenient way to visualize the valence electrons and helps predict the number of bonds formed by the element in its compounds.
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Do the positive ions tend to be metals or nonmetals?
Answer: The correct answer is metals.
Explanation:
Ions are formed when an atom gains or looses electrons.
When an atom looses electrons, it tends to form positive ions known as cations.
When an atom gains electrons, it tends to form negative ions known as anions.
Metals are the elements which looses electrons to form positive ions. For Example: Sodium will loose 1 electron to form [tex]Na^+[/tex] ions.
Non-metals are the elements which gains electrons to form negative ions. For Example: Chlorine will gain 1 electron to form [tex]Cl^-[/tex] ion.
Hence, the correct answer is metals.
What mass of carbon dioxide (co2) can be produced from 15.6 g of c6h14 and excess oxygen?
Answer: The mass of carbon dioxide produced is 46.7 grams.
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] .....(1)
Given mass of hexane = 15.6
Molar mass of hexane = 88.2 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of hexane}=\frac{15.6g}{88.2g/mol}=0.177mol[/tex]
The chemical equation for the combustion of hexane follows:
[tex]2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O[/tex]
As, oxygen gas is present in excess, it is considered as an excess reagent.
Thus, hexane is considered as a limiting reagent because it limits the formation of product
By Stoichiometry of the reaction:
2 moles of hexane produces 12 moles of carbon dioxide
So, 0.177 moles of hexane will produce = [tex]\frac{12}{2}\times 0.177=1.062mol[/tex] of carbon dioxide
Now, calculating the mass of carbon dioxide by using equation 1:
Molar mass of carbon dioxide = 44 g/mol
Moles of carbon dioxide = 1.062 moles
Putting values in equation 1, we get:
[tex]1.062mol=\frac{\text{Mass of carbon dioxide}}{44g/mol}\\\\\text{Mass of carbon dioxide}=(1.062mol\times 44g/mol)=46.7g[/tex]
Hence, the mass of carbon dioxide produced is 46.7 grams.
When liquid phosphorus trichloride is added to water, it reacts to form aqueous phosphorous acid, h3po3(aq), and aqueous hydrochloric acid?
Answer: check explanation
Explanation:
Complete question: When liquid phosphorus trichloride is added to water, it reacts to form aqueous phosphorous acid, h3po3(aq), and aqueous hydrochloric acid. express your answer as a balanced chemical equation. Identify all the phases in your answer?
SOLITION:
The solution to the question we have here is to balance the chemical reaction. But before we do that, let us take some notes on one of the REACTANTS, Phosphorus trichloride. Phosphorus trichloride is also known as trichlorophosphine. Phosphorus trichloride is a yellow fuming liquid that has a pungent smell. The smell of Phosphorus trichloride is very similar to that of Hydrogen chloride.
Phosphorus trichloride has a molecular weight of 137.33 g/mol.
Phosphorus trichloride can react with water to form HP0(OH)2 with HCl or H3PO3 and HCl.
The balanced equations of Reaction are given below;
(1). PCl3 (l)+ 3H2O (l) --------> H3PO3 (aq) + 3HCl (aq).
(2). PCl3 (l) + 3H2O (l) ------> HPO(0H)2 (aq) + 3HCl (aq).
For the question, the reaction to use is the equation (1).
Phosphorus trichloride,PCl3 is in liquid phase, water,H2O is in liquid phase two( both reactants are in liquid phase).
H3PO4 are both in aqeous phase.
Final answer:
Liquid phosphorus trichloride reacts with water to form aqueous phosphorous acid and aqueous hydrochloric acid through hydrolysis, showcasing its application in producing phosphorous acid.
Explanation:
When liquid phosphorus trichloride (PCl3) is added to water, it reacts to form aqueous phosphorous acid, H3PO3(aq), and aqueous hydrochloric acid. This reaction is an example of hydrolysis, a chemical process by which a compound reacts with water, leading to the decomposition of the original compound and the formation of new compounds. In this particular reaction, the phosphorus trichloride undergoes hydrolysis to yield phosphorous acid and hydrochloric acid, as represented by the chemical equation PCl3(l) + 3H2O(l) → H3PO3(aq) + 3HCl(g). Phosphorous trichloride is thus a valuable precursor for generating phosphorous acid, a compound that finds application in various chemical syntheses and industries.
Select true or false: substitute natural gas can be synthesized by passing carbon monoxide and hydrogen over ni or co at 400°c.
Final answer:
The statement is true; substitute natural gas can be synthesized by passing carbon monoxide and hydrogen over a nickel or cobalt catalyst at 400°C, as part of the process of producing syngas, which can be further converted into other hydrocarbons.
Explanation:
The statement that substitute natural gas can be synthesized by passing carbon monoxide (CO) and hydrogen (H₂) over Ni (nickel) or Co (cobalt) at 400°C is true. This process is part of producing syngas (synthesis gas), which primarily consists of CO and H₂. When these gases are passed over a Ni or Co catalyst at the temperature mentioned, it can lead to the production of a mixture suitable for further conversion into substitute natural gas or other hydrocarbons.
The efficiency of this process and the resulting H₂/CO ratio is influenced by the catalytic material and operation conditions. It is important to note that syngas, obtained by reacting methane with steam over a Ni catalyst at high temperatures (700 - 1100 °C), can then be used as a precursor to produce a wide range of fuels when combined in the correct ratios over a suitable catalyst.
Which type of solid consists of atoms or molecules held together by dipole-dipole forces, london disperson forces, and/or hydrogen bonds? ionic molecular metallic covalent-network metallic and covalent-network?
A mass of gas has a volume of 4 m3, a temperature of 290 K, and an absolute pressure of 475 kPa. When the gas is allowed to expand to 6.5 m3, its new temperature is 277 K. What's the absolute pressure of the gas after expansion?
A. 104.1 kPa
B. 293.9 kPa
C. 279.2 kPa
D. 178.5 kPa
To solve this we assume that the gas is an ideal gas. Then, we can use the ideal gas equation which is expressed as PV = nRT. At number of moles the value of PV/T is equal to some constant. At another set of condition of temperature, the constant is still the same. Calculations are as follows:
P1V1/T1 = P2V2/T2
P2 = P1 (V1) (T2) / (T1) (V2)
P2 = 475 kPa (4 m^3) (277 K) / (290 K) (6.5 m^3)
P2 = 279.20 kPa
Therefore, the changes in the temperature and the volume lead to a change in the pressure of the system which is from 475 kPa to 279.20 kPa. So, there is a decrease in the pressure.
What is a gaseous state of a liquid or solid at room temperature?
Polymerization is most directly responsible in determining which structure of a protein?
A.quaternary
B.secondary
C.tertiary
D.primary
Answer:Primary
Explanation:
Which answer provides the correct name for name the following hydrocarbon?
Moving left to right: A hydrocarbon chain made of a methyl group (CH subscript three) single bond carbon triple bond carbon single bond CH bonded to a methyl group (CH subscript three) and a chain including a methelyne group (CH subscript two) single bond methyl group (CH subscript three) .
4-ethyl-2-pentyne
4-methyl-2-hexyne
2-heptyne
4-methy-hexane
Answer : The correct option is, 4-methyl-2-hexyne
Explanation :
The rules for naming of alkyne are :
First select the longest possible carbon chain. The longest possible carbon chain should include the carbons of triple bonds. The naming of alkyne by adding the suffix -yne. The numbering is done in such a way that first carbon of triple bond gets the lowest number. The carbon atoms of the triple bond get the preference over the other substituents present in the parent chain. If two or more similar alkyl groups are present in a compound, the words di-, tri-, tetra- and so on are used to specify the number of times of the alkyl groups in the chain.According to the given information, the name of the hydrocarbon is, 4-methyl-2-hexyne.
The structure of given compound is shown below.
The hydrocarbon described in the question, a chain with methyl groups (CH3) at either end and a carbon-carbon triple bond in the middle, is named as 4-methyl-2-hexyne.
The structure you've provided corresponds to the hydrocarbon named as
4-methyl-2-hexyne
. This hydrocarbon has two methyl groups (CH
3
) at the ends of the main carbon chain, and in the middle, it includes a carbon-carbon triple bond as suggested by '-yne' ending. The placement of the methyl group is at the 4th position as the counting starts from the end of the chain closer to the triple bond.
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If eight atoms of iron react completely with six molecules of oxygen, how many units of iron oxide will be formed?
The process by which hydrogen and oxygen combine to form water can be classified as a what
The process by which hydrogen and oxygen combine to form water can be classified as Combination reaction.
What is Combination Reaction ?A combination reaction is a reaction where two or more elements or compounds combine to form a single compound.
Such reactions are represented by equations of the following form :
X + Y → XY.
The combination of two or more elements to form one compound is called a combination reaction.
Therefore, The process by which hydrogen and oxygen combine to form water can be classified as Combination reaction.
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How many moles of o are in 15.0 mol fe(no3)3?
Answer : The number of moles of oxygen atoms are 135 moles.
Explanation : Given,
Moles of [tex]Fe(NO_3)_3[/tex] = 15.0 mole
The given chemical formula is, [tex]Fe(NO_3)_3[/tex]
By the mole concept:
In [tex]Fe(NO_3)_3[/tex], there are 1 mole of iron (Fe) atom, 3 moles of nitrogen (N) atoms and 9 moles of oxygen (O) atoms.
As, 1 mole of [tex]Fe(NO_3)_3[/tex] contains 9 moles of oxygen atoms
So, 15.0 moles of [tex]Fe(NO_3)_3[/tex] contains [tex]15.0\times 9=135[/tex] moles of oxygen atoms.
Hence, the number of moles of oxygen atoms are 135 moles.
Why is mendeleevâs periodic table considered a viable scientific model?
A certain compound is made up of two chlorine atoms, one carbon atom, and one oxygen atom. what is the chemical formula of this compound? express your answer as a chemical formula.
Answer: The chemical formula for the compound is [tex]COCl_2[/tex]
Explanation:
A chemical compound which is formed by the combination of carbon, oxygen and chlorine atoms.
We are given:
Number of carbon atoms in the compound = 1
Number of oxygen atoms in the compound = 1
Number of chlorine atoms in the compound = 2
The chemical formula for the compound will be [tex]COCl_2[/tex]. The chemical name for the given compound is phosgene.
Hence, the compound is [tex]COCl_2[/tex]
If you reacted 93.7 grams of iron with excess copper sulfate solution, what mass of copper would you expect to make? You may need to balance the equation first. Fe + CuSO4 -> Cu +FeSO4 A. 89.18 grams
B. 106.25 grams
C. 1.67 grams
D. 104.5 grams
Label each as an endothermic or exothermic reaction or process. a. liquid freezing b. solid melting c. liquid turning into gas d. gas cooling and condensing on the side of a glass e. 2 chemicals mixed together in a beaker and now the beaker feels warm to the touch
Liquid freezing is an endothermic reaction and all other statements are exothermic,exothermic,endothermic,exothermic reactions respectively.
What are endothermic reactions?An endothermic reaction is defined as a chemical reaction which is a thermodynamic process accompanied by an increase in enthalpy of the system.In this process, a system absorbs energy from the surroundings which is mainly thermal energy.
Thus an endothermic reaction leads to an increase in the temperature of the system with a decrease in the temperature of the surroundings.Endothermic reactions usually involve the formation of bonds which requires input of energy.In endothermic reactions, entropy of the surrounding decreases.
Many endothermic processes involve the physical changes rather the chemical changes.In an endothermic reaction ,the potential energy of products is greater than that of reactants.
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Final answer:
An exothermic process releases heat, while an endothermic process absorbs heat. Liquid freezing, gas cooling and condensing, and a warm beaker after mixing chemicals are exothermic. Solid melting and liquid turning into gas are endothermic.
Explanation:
We can label each process as either endothermic or exothermic based on whether the process absorbs or releases heat, respectively. Here is the labeling for each of the given processes:
a. liquid freezing - This is an exothermic process because heat is released to the surroundings as the liquid turns into a solid.b. solid melting - Melting is an endothermic process because heat is absorbed from the surroundings to change the solid into a liquid.c. liquid turning into gas - This transition is endothermic as heat is absorbed to change the liquid into a gas (evaporation or boiling).d. gas cooling and condensing - The process of a gas turning into a liquid (condensation) is exothermic, releasing heat to the surroundings.e. 2 chemicals mixed together and the beaker feels warm - When mixing leads to an increase in temperature, it indicates an exothermic reaction because heat is being released to the surroundings.The transition of substances between different phases and the chemical reactions that release or absorb heat are classified as either exothermic or endothermic.
Which one of the following is NOT a cause of acid precipitation?
a. sulfur dioxide from burning coal
b. nitrogen oxides from car exhaust
c. destruction of the ozone layer
Answer:
c. destruction of the ozone layer
Explanation:
The destruction of the Ozonoe Layer is causing for example that the world starts to heat, and global warming is a direct consequence of the destruction of the ozone layer, but the acid precipitation is cause by certain gases that are emitted by human activity like industries, that get trapped in the drops of rain fall and make acidic rain.
Which of the models shown below best represents the modern understanding of the structure of the atom?
The wave-mechanical model of the atom was proposed by Erwin Schrodinger that combined the works of Bohr and de Broglie. The electron was a three dimensional wave circling the nucleus in a whole number of wavelengths allowing the waveform to repeat itself as a stable standing wave (it can absorb energy form a nearby source which is oscillating at a proper frequency) representing the energy levels of Bohr model. He also said that Broglie’s model was correct about the matter waves and the electrons are located in the atomic space according to standing wave frequencies.
It's the 3rd option sis
List 2 of the important properties of gases.
which is an anion ca2+ ag+ o2- k+
Answer:
O2- is an anion
Explanation:
An atom or molecule is said to be neutral when it has a zero net charge. In contrast, if the system has a net charge it is termed as an ion.
A cation is an atom or a molecular system with a net positive charge whereas an anion carries a net negative charge.
In the given examples:
Ca2+ : net positive, cation
Ag+: net positive, cation
O2-: net negative, anion
K+: net positive, cation
A generic salt, ab2, has a molar mass of 169 g/mol and a solubility of 1.10 g/l at 25 °c. what is the ksp of this salt at 25 °c?
Which answer best explains the relationship between size and mass of the sun?
Answer:
Average in size 100% Im not sure about mass, I think it's small correct me if not.
Explanation:
just had this