Noble gases have 8 electrons in the outermost shells.
What are noble gases?They are the chemical elements that belong to group 8A of the periodic table.
They belong to group 8 because they have 8 electrons in their outermost shells. Their electron configuration is an octet. In other words, they do not need to donate or accept electrons to be stable.
Noble gases include helium, neon, argon, etc.
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Pls someone smart complete the matching
A scientist measures the standard enthalpy change for the following reaction to be -139.5 kj :
h2(g) + c2h4(g)c2h6(g)
based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of c2h4(g) is _____ kj/mol.
Answer:
A scientist measures the standard enthalpy change for the following reaction to be -139.5 kj :
h2(g) + c2h4(g)c2h6(g)
based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of c2h4(g) is _____ kj/mol
Explanation:
Hydrogen ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)
H2 (g)
0
0
130.7
Carbon ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)
C2H6 (g)
-84.7
-32.8
229.6
How many grams of carbon are contained in one mole of[tex]C_{3}H_{8}[/tex] ?
[tex]\quad \huge \quad \quad \boxed{ \tt \:Answer }[/tex]
[tex]\qquad \tt \rightarrow \:36 \:\: g [/tex]
____________________________________
[tex] \large \tt Explanation \: : [/tex]
The given compound has 3 carbon atoms, so in 1 mole of that compound, there will be 3 moles of carbon atoms.
Mass of each mole of carbon atoms = 12 g
For 3 mole carbon atoms, it will be 12 × 3 = 36 grams
Answered by : ❝ AǫᴜᴀWɪᴢ ❞
How are a mole and a dozen similar?
Mole and dozen are similar to each other because of the presence of number 12 in both measurements.
How are a mole and a dozen similar?The sample of 12 grams of carbon is equal to its one mole and we know that in one dozen, there are 12 numbers. Therefore, we considered mole similar to a dozen.
So we can conclude that Mole and dozen are similar to each other because of the presence of number 12 in both measurements.
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Which industrial methods of preparing alcohol are more economical? Explain.
The industrial methods of preparing alcohol that is more economical is fermentation.
What is fermentation?Fermentation is defined as the industrial method by which starch is converted to ethyl alcohol by using some specific enzymes and microorganisms known as yeast
It is an economical method because the raw material which is starch is readily available.
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Which of the following most accurately describes a regulatory molecule that must be transported to its place of action within the body?
hormone
polypeptide
enzyme
Answer:
the answer is hormone
Explanation:
because it is
In a process called photosynthesis, plants use carbon dioxide and water, along with energy from sunlight, to produce sugar and oxygen. photosynthesis is represented by the equation what must a plant need to produce 4 molecules of sugar? 6 molecules of co2 6 molecules of h2o 18 molecules of co2 24 molecules of h2o
24 molecules of H2O are needed by the plant to produce 4 molecules of sugar.
What is photosynthesis?The process by which plants convert carbon dioxide, water, and sunlight into oxygen and sugar-based energy is known as photosynthesis.
The photosynthesis equation is as follows:6CO2 + 6H2O + Sunlight → C6H12O6 + 6O2
The following three significant activities are involved in photosynthesis:
1. Chlorophyll absorbs light energy.
2. Water molecules are divided into hydrogen and oxygen and light energy is converted to chemical energy.
3. Carbon dioxide is converted to sugars.
Therefore, a plant needs four molecules of H2O and four molecules of CO2 to make one molecule of glucose or sugar, hence a plant needs 24 molecules of H2O and 24 molecules of CO2 to make four molecules of sugar.
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Answer:
D) 24 molecules of H2O
Explanation:
Just did the test on Edge 2023 and got it right. Have a nice day :)
For a particular chemical reaction, the enthalpy of the reactants is -400 kJ. The enthalpy of the products is -390 kJ. The entropy of the reactants is 0.2 kJ/K. The entropy of the products is 0.3 kJ/K. The temperature of the reaction is 25 degrees Celsius. What can you conclude about this reaction
Answer:
For a particular chemical reaction, the enthalpy of the reactants is -400 kJ. The enthalpy of the products is -390 kJ. The entropy of the reactants is 0.2 kJ/K. The entropy of the products is 0.3 kJ/K. The temperature of the reaction is 25oC. What can you conclude about this reaction?
It is exergonic
It is endergonic
it is a redox reaction
It is being catalyzed by an enzyme
Which of the following is NOT an example of combustion occurring?
A. A car engine
B. A rocket lifting off
C. Battery acid burning the floor
D. A bonfire
Answer:
C. Battery acid burning the floor
Explanation:
C. Battery acid burning the floor
in combustion fire is created
Battery acid burning the floor is NOT an example of combustion occurring.
The answer is option C.
What is combustion?Combustion is a chemical process or a reaction between the gas (Hydrocarbon) and Oxygen. while gasoline and oxygen react it releases warmth and light energy. heat and light energy then result in the flame. So, the system for Combustion reaction is Hydrobcarbon + Oxygen = warmness electricity.
Combustion in daily existence examples is: Burning of wooden or Coal for the family functions. Burning of Petrol or Diesel for using vehicles like vehicles. Combustion of herbal gas or LPG.
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Which shows a monosaccharide?
Monosaccharides are the group of carbohydrates that are the simplest form of sugar. Option A galactose is a monosaccharide sugar.
What are monosachharides?Monosaccharides are simple sugars and are the fundamental unit of carbohydrates.
The general structural formula for the monosaccharides is (CH₂O)ₙ
The structure of the monosaccharide sugar contains carbon, oxygen, and hydrogen molecules in their structure.
Galactose that is a simple sugar with six carbon atom rings Hence, option A is a correct option
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A, B, C, or D, thanks for the help
According to the label the true statement about the following substance is option c. It does not pose a health risk
What are lab labels ?
Specially designed labels with particularly specialised adhesive qualities are called "lab labels." In the pharmaceutical or medical industry, as well as in laboratories, they are used for labelling. For the labelling of tubes, test tubes, blood bags, and other types of vessels, special laboratory labels are created.
Labels on chemicals
The identify of the hazardous chemical(s) in the container (for example, chemical name) and the dangers present must both be listed on this label. This warning about hazards can be distributed in a variety of ways. Employers want to choose a solution that will function in each place.
The following label indicates that the chemical does not pose a health risk.
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Zac releases the air from a balloon. Which statement best describes what will happen to the air that was inside the
balloon?
O It will become more compacted.
O will remain the shape of the balloon but not the size.
O It will remain the size of the balloon but not the shape.
It will expand to fill the room.
Answer: It will expand to fill the room.
Explanation:
Gases will expand or compact to fill the available space.
Dalton law states that the partial pressure of a gas in a mixture of gases is _____ to the total pressure of the mixture.
Answer:
Dalton law states that the partial pressure of a gas in a mixture of gases is equal to the total pressure of the mixture.
lithium
potassium.
calcium
sodium
magnesium
aluminum.
zinc
iron
nickel
lead
hydrogen
copper
mercury
silver
gold
An unknown metal displaces aluminum (Al) from solution but does not displace sodium (Na). Using the activity series, determine the unknown
metal.
OA. Calcium (ca)
OB. zinc (Zn)
OC. manganese (Mn)
OD. magnesium (Mg)
increasing activity
calcium (Ca)
Answer:
The unknown metal could be calcium or magnesium.
Explanation:
Displacement of a metal from its chemical reaction is shown by the reaction known as single displacement reaction. The reactivity of metal is determined by the reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the reactivity series.
Metal B is more reactive than metal A.
The metal which easily displaced aluminium will lie above in the series but that same element cannot displace sodium, so it will lie below in the series.
Hence, from the series, we conclude that the unknown metal could be calcium or magnesium.
There are two common oxides of copper; one is 80% copper and the other is 89% copper by weight. Calculate the formula and name each compound.
80% copper (Cu)
Cu: 80 : 63.546 = 1.259
O: 20 : 16 = 1.25
Cu:O = 1 : 1
the formula: CuO
89% copper (Cu)
Cu: 89 : 63.546 = 1.4
O: 11 : 16 = 0.6875
Cu:O = 2:1
the formula: Cu₂O
The average temperature of healthy person is 98.6°F. What is it in
Celsius scale?
Answer:
37 Degrees Celsius
Explanation:
Energy associated with the flow of electrons is?
Answer:
Electric current
Definition:
The time rate of flow of electric charge, in the direction that a positive moving charge would take and having magnitude equal to the quantity of charge per unit time: measured in amperes.
Electricity is the flow of electrons. Where do these electrons come from? How are they put into circulation and what happens to them?Everything begins inside in the battery. The battery's zinc metal undergoes oxidation; here is where the flow of electrons into the conductors begins. Electrical field attraction will lead the wire's existing electrons to move towards the battery's positive terminal, and the loose electrons caused by the zinc metal will begin to fill the wire's empty spaces. process continues until the zinc metal's oxidation ceases. At rechargeable batteries, the oxidation-reduction process is also reversed by charging the battery, allowing the stored electrons in the positive terminal to flow back to the zinc metal's negative terminal.
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Describe the properties of noble gases. based on their electronic arrangement, explain whether they can exist alone in nature.
Noble gases exist as monatomic gases, which means that their molecules consist of a single atom.
What are noble gases?A "Noble gas" can be defined as a gas which does not undergo chemical reactions. Examples of Noble gases are helium, Neon, Argon, Krypton, Xenon, and Radon.
Properties of noble gases:
Noble gases are the least reactive of all elements because they have eight valence electrons, which fill their outer energy level. That's why noble gases rarely react with other elements and form compounds.
Atoms of noble gases do not bond with other gases. Only helium exists as atoms of Helium, not as diatomic molecules. Helium does not form compounds with atoms of other elements.
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Saturated fatty acids and unsaturated fatty acids differ in.
Answer:
the number off double bonds in a fatty acid chain
The cutoff frequency for a certain element is 1.22 x 1015 Hz. What is its work function in eV?
Hint: 1 eV 1.60 x 10-19 J
=[?] eV
someone please teach me how to solve this its gonna make me cry
The work function of the metal is obtained as 5.1 eV
What is the cutoff frequency?The cutoff frequency is the frequency below which photo electric effect can not occur as electrons are not removed from the metal surface.
Now;
fo = 1.22 x 10^15 Hz
Wo = hfo
Wo = 6.6 * 10^-34 * 1.22 x 10^15
Wo = 8.1 * 10^-19 J
If 1 eV = 1.60 x 10-19 J
x eV = 8.1 * 10^-19 J
x = 8.1 * 10^-19/ 1.60 x 10-19
x = 5.1 eV
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a serving of a particular fruit dessert contains 20.0 g of sugar. if all the sugar is sucrose, c12h22o11, how many molecules of sugar are present in this serving?
Taking into account the definition of Avogadro's number and molar mass, 3.49334×10²² molecules of sucrose are present.
Definition of molar massThe molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.
Avogadro's NumberAvogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.
Molecules of sugar in this caseIn first place, the molar mass of sucrose is 342 g/mole. So, you can apply the following rule of three: If by definition of molar mass 342 grams of the compound are contained in 1 mole, 20 grams of the compound are contained in how many moles?
[tex]amount of moles=\frac{20 gramsx1 mole}{342 grams}[/tex]
amount of moles= 0.058 moles
Now, considering the Avogadro's number, you can apply the following rule of three: If 1 mole of the compound contains 6.023×10²³ molecules, 0.058 moles contains how many molecules?
amount of moleculas= (6.023×10²³ molecules × 0.058 moles)÷ 1 mole
amount of molecules= 3.49334×10²² molecules
Finally, 3.49334×10²² molecules of sucrose are present.
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A student needs to standardize a base solution by titration with an acid solution of known concentration. She finds the volume of the acid solution needed to reach the endpoint for a sample of the base solution. Arrange the steps in the order that will allow her to determine the concentration of the base solution.
The steps usually involves adding the known solution (the titrant) to a known quantity of the unknown solution (the analyte) until the reaction is complete which can be understood in detail as below with the help of through out process of titration.
What is Titration ?A titration is a technique used to work out the concentration of an unknown solution based on its chemical reaction with a solution of known concentration.
Steps in order to determine the concenteration of base solution ;
(Acid-Base Titration)
Choose the titrant.Choose the titrate.Select the normality of the titrate.Choose the volume of the liquid to be pipetted out.Select the indicator.Start titration.End point is noted at the colour change of the solution.From the final reading the normality of titrant can be calculated by the equation:N₁V₁=N₂V₂
After finding the normality, the amount of given substance in the whole of the given solution can be calculated by the equation:Mass = Equivalent weight x Normality \ Volume {1000}
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Use the References to access important values if needed for this question. The Pauli Exclusion Principle tells us that no two electrons in an atom can have the same four quantum numbers. For each of the orbitals below list a set of possible quantum numbers. Give only one value for each Orbital ... n ... ... l ... ... ml ... ... ms ... 1s fill in the blank 4 There are a total of values possible for ml 3s
The quantum numbers are used to describe the position of an electron in atom.
What are quantum numbers?The quantum numbers are used to describe the position of an electron in atom. I have attached a picture that shows the complete question.
For the 1s orbital;
n =1
l = 0
ml = 0
ms = ±1/2
For the 2s orbital;
n = 2
l = 1
ml = -1, 0, 1
ms = ±1/2
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Which feature of a balanced chemical equation demonstrates the law of
conservation of mass?
A. It shows the products of a chemical reaction to the right of the
reaction arrow.
OB. It shows the reactants of a chemical reaction to the left of the
reaction arrow.
C. It has the same types of atoms on both sides of the reaction
arrow.
O
D. It has coefficients to show how much of each substance a
chemical reaction uses.
Answer:
C. It has the same types of atoms on both sides of the reaction arrow.
What is a chemical equation?A chemical equation is a symbolic representation of a chemical reaction; Reactants are represented on the left and the products on the right.
The law of conservation of mass states that in a closed system, mass is neither created nor destroyed during a chemical or physical reaction. The law of conservation of mass is applied whenever you balance a chemical equation. It is also applicable to stoichiometry. A balanced equation demonstrates the conservation of mass by having the same number of each type of atom on both sides of the arrow.
Consider the balanced equation for the combustion of methane.
[tex]CH_4 + 20_2 \implies CO_2 + 2H_2O[/tex]
All balanced chemical equations must have the same number of each type of atom on both sides of the arrow.
In this equation, we have 1 C atom, 4 H atoms, and 4 O atoms on each side of the arrow.
The number of atoms does not change, so the total mass of all the atoms is the same before and after the reaction. Mass is conserved.
The same atoms of the same element that are present in the reactants are also present in the products, according to the rule of conservation of matter.
This leads us to believe that the response to the question is true because: It has the same atom kinds on both sides of the reaction arrow (Option C)
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From 200 mg of CO₂, 1021 molecules are removed. How many molecules of CO₂ are left?
Answer:
CO_(2)` molecules removed `= 10^(21)` <br> No. of `CO_(2)` molecules left `= 2.74 xx 10^(21) - 10^(21) = 1.74 xx10^(21)` <br>
Explanation:
A volumetric pipette has one marked line that indicates a specific volume. Considering polar substances dip downward in a glass volumetric pippette creating a concave meniscus, what is the correct way to read a volumetric pipette to have the most accurate measurement?.
The best way to make an accurate measurement of the height of a polar liquid is to take the reading from the lowest point of the meniscus.
What is the meniscus of a liquid?The meniscus of a liquid is a curved that occurs at the top of a liquid placed in a container as a result of the attractive forces between the molecules of a the liquid.
Polar substances such as water have a concave meniscus as they dip downwards.
Therefore, the best way to make an accurate measurement of the height of a polar liquid is to take the reading from the lowest point of the meniscus.
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How many grams of aluminum
chloride, AlCl3, form when 0.25 mol
Al react?
2AI+ 3Cl₂ → 2AICI 3
[?] g AICI 3
From the equation, we know that for every 2 moles of aluminum consumed, 2 moles of aluminum chloride are produced.
This means that if 0.25 moles of Al react, then 0.25 moles of aluminum chloride are produced.
The atomic mass of Al is 26.9815385 g/mol.The atomic mass of Cl is 35.45 g/mol.So, the formula mass of aluminum chloride is:
26.9815385+3(35.45)=133.3315385 g/mol.Thus, 0.25 moles have a mass of:
(133.3315385)(0.25), which is about 33 g (to 2 sf)Brainliest to first decent answer
What is the chemical formula for the molecule represented by the model?
CHO
C4H9O2
C4H8O
C3H8O2
The correct formula of the molecule is C4H9O2.
What is a model?The model of a compound is a representation of the molecule. It gives us an idea of what the molecule looks like as well as its molecular formula.
Looking at the structure of the compound as shown in the model in the question, the correct formula of the molecule is C4H9O2.
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Answer:C4H9O2.
Explanation:
What is the change in
temperature when water goes
from 65.0 °C to 25.0 °C?
AT = [?] °C
Answer:
-40.0 °C
Explanation:
Change in temperature can be written as [tex]\displaystyle{\Delta T = T_2-T_1}[/tex]. The variables are defined below here:
[tex]\displaystyle{\Delta T}[/tex] means change in temperature.
[tex]\displaystyle{T_2}[/tex] means the final temperature value.
[tex]\displaystyle{T_1}[/tex] means the initial temperature value.
From the question, we know the temperature changes from 65.0 °C to 25.0 °C. Therefore, our initial temperature is 65.0 °C and final temperature is 25.0 °C.
Hence:
[tex]\displaystyle{\Delta T=25.0-65.0}\\\\\displaystyle{\Delta T = -40.0}[/tex]
Therefore, the change in temperature is -40.0 °C.
An element has two naturally-occurring isotopes. The mass numbers of these isotopes are 115.00 u and 117.00 u, with natural abundances of 25% and 75%, respectively. Calculate its average atomic mass. Report your answer to 2 decimal places.
[tex](115.00)(0.25)+(117.00)(0.75)=\boxed{116.50 \text{ u}}[/tex]
