what percentage of air is oxygen?

Explanation:

Answer:

A.

Explanation:

Lithium's electron configuration is 1s^2 and 2s^1 , therefore the orbital diagram would have 2 in 1s box and 1 in 2s box.

Lithium's electron configuration is 1s^2 and 2s^1 , therefore the orbital diagram would have 2 in 1s box and 1 in 2s box. Thus, option A is correct.

An atom in the neutral state has the same number of protons and electrons. Since protons carry the positive charge and electrons carry negative charge of equal magnitude as that of protons, so, in neutral state the overall charge on the atom is zero.

Atomic number of Lithium is 3. Under neutral state it has 3 protons and 3 electrons. So, its overall electric charge is 0.

If an atom of Lithium loses one of its outermost electron, it is left with 2 electrons and 3 protons. Since, number of protons is 1 more than the number of electrons, the electrical charge on Lithium atom would be positive and the magnitude of charge will be equal to the number of electrons lost, which is 1 in this case.

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Answer: 5.5 atm

Explanation:

Answer: See below

Explanation:

Sodium (Na) - 1 electron on outer shell so would need to lose 1 electron for a full outer shell - making it a 1+ ion

Surfur (S) - 6 electrons on outer shell so would need to gain 2 electrons for a full outer shell - making it a 2- ion

Strontium (Sr) - 2 electrons on outer shell so would need to lose 2 electrons for a full outer shell - making it a 2+ ion

The percentage by mass of hydrogen can be calculated from the problem as 2.016

To calculate the mass percent of an atom in a compound, you first need to determine the molar mass of the compound and the molar mass of the atom of interest.

Determine the molar mass of the compound by adding up the atomic masses of all the atoms in the compound.

Determine the number of moles of the atom of interest in one mole of the compound. This is done by dividing the atomic mass of the atom by the molar mass of the compound.

We know that the relative molecular mas of the compound is; 300 g/mol

Then;

Percent by mass of hydrogen is; 6/300 * 100/1

= 2.016%

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Answer:

3.8%

Explanation:

Ca × 1 = 50

C ×4 = 48

H × 6 = 6

O × 4 = 64

158

6÷158×100% = 3.8%

Answer:

53.69 mg/m³

Explanation:

To calculate the concentration of ethyl acetate in milligrams per cubic meter, we need to know the total volume of the room and the amount of ethyl acetate that evaporated in grams.

The total volume of the room is:

V = l x w x h

V = 9.00 m x 6.00 m x 3.00 m

V = 162.00 cubic meters

To convert the amount of ethyl acetate evaporated from grams to milligrams, we multiply by 1000:

amount of ethyl acetate = 8.701 g = 8,701 mg

Now we can calculate the concentration of ethyl acetate in milligrams per cubic meter:

concentration = amount of ethyl acetate / volume of room

concentration = 8,701 mg / 162.00 cubic meters

concentration = 53.69 mg/m³

Therefore, the concentration of ethyl acetate in the unventilated room is 53.69 mg/m³.

The basic units of the human body are called cells, and they carry out specialized tasks to keep the body alive. Cells in a city might be compared to people who perform particular duties and contribute to the general efficiency of the city.

Organizational hierarchy is built up from lower levels. Consequently, molecules combine to create molecules, molecules create cells, cells create tissues, tissues create organs, organs create organ systems, and organ systems create beings. The body's next level of organisation. A tissue is made up of related cells with a common purpose. Human tissues can be divided into four categories: epithelial, muscular, nerve, and connective.

The major levels of organisation in the body, from the most basic to the most complex, are atoms, molecules, organelles, cells, tissues, organs, organ systems, and the human body.

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Answer: calm water.

Explanation:

Based οn the wοrds prοvided, a pοssible title fοr this sectiοn οf Sheila's nοtes cοuld be Mass.

In chemistry, prοperties οf matter refer tο the characteristics οr attributes that can be used tο describe and identify a substance. These prοperties can be divided intο twο categοries: physical prοperties and chemical prοperties.

Physical attributes are thοse that can be examined οr measured withοut changing the substance's makeup. Mass, vοlume, density, cοlοr, melting pοint, bοiling temperature, and sοlubility are examples οf physical qualities.

Chemical prοperties, οn the οther hand, describe hοw a substance interacts with οther substances tο prοduce new substances.

Understanding the prοperties οf matter is impοrtant in chemistry because it allοws scientists tο identify and classify different substances based οn their unique characteristics. This knοwledge can alsο be used tο predict hοw substances will behave under different cοnditiοns and tο design new materials with specific prοperties fοr variοus applicatiοns.

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Complete question:

Sheila spilled tea on her notes and is now unable to read some words.

What is the correct title for this section of Sheila’s notes?

Answer: Solubility increases so more solute dissolves

Explanation:

The solubility is a measure of the concentration of the dissolved gas particles in the liquid and is a function of the gas pressure. As you increase the pressure of a gas, the collision frequency increases and thus the solubility goes up, as you decrease the pressure, the solubility goes down.

If the volume is increased to 1125 in El with a new pressure of 99.7 K PA, the new temperature will be around 808 K.

Once the piston's pressure has doubled, it goes downward until the gas's pressure and the piston pressure are equal. The gas has now lost half of its original volume. The volume of gas falls to one-fourth of its initial volume if the pressure on the piston is once more increased by a factor of two.

This issue can be resolved using the coupled gas law:

(P1V1) / T1 = (P2V2) / T2

Using the following conversions, we can first change the starting volume to litres and the original pressure to atmospheres (atm):

1 mL = 0.001 L

1 kPa = 0.00987 atm

V1 = 850 mL = 0.85 L

P1 = 11.4 kPa = 0.1126 atm

T1 = 467 K

The new volume and pressure can also be converted to litres and atmospheres:

V2 = 1125 mL = 1.125 L

P2 = 99.7 kPa = 0.984 atm

Now we can plug in the values and solve for T2:

(P1V1) / T1 = (P2V2) / T2

(0.1126 atm * 0.85 L) / 467 K = (0.984 atm * 1.125 L) / T2

T2 = (0.984 atm * 1.125 L * 467 K) / (0.1126 atm * 0.85 L)

T2 = 808 K

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Answer:

548 K

I hope this helps! Cheers ^^

As the concentration of a solution increases, the vapor pressure decreases.

Raoult's law states that the vapor pressure of a solution is proportional to the mole fraction of the solvent present in the solution.

When a solute is added to a solvent, it reduces the mole fraction of the solvent, and therefore the vapor pressure of the solution decreases. This is because the solute molecules occupy space on the surface of the solution, which reduces the number of solvent molecules that can escape into the gas phase, and thus reduces the vapor pressure of the solution.

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Complete question:

As the concentration of a solution increases, the vapor pressure _____

Answer:

oxygen molecule, water molecule, glucose molecule, amino acid molecule, carbon dioxide molecule, protein molecule, starch molecule.

Explanation:

Answer: Sucrose is a glycosyl glycoside formed by glucose and fructose units joined by an acetal oxygen bridge from hemiacetal of glucose to the hemiketal of the fructose.

Explanation:

When 58.15 g of PCl5 reacts with water, 20.36 g mass of HCl will be produced. Rounded to the hundredths place, the answer is 20.36 g HCl.

What is the mass?

To solve this problem, we need to use the balanced chemical equation and stoichiometry. The balanced chemical equation is:

PCl5 (s) + H2O (l) → POCl3 (l) + 2HCl (aq)

From the equation, we can see that 1 mole of PCl5 reacts with 1 mole of H2O to produce 1 mole of POCl3 and 2 moles of HCl. We can use this information to calculate the moles of HCl produced from the given mass of PCl5.

First, we need to convert the mass of PCl5 to moles:

58.15 g PCl5 x (1 mol PCl5/208.24 g PCl5) = 0.2793 mol PCl5

Next, we can use the mole ratio from the balanced equation to calculate the moles of HCl produced:

0.2793 mol PCl5 x (2 mol HCl/1 mol PCl5) = 0.5586 mol HCl

Finally, we can convert the moles of HCl to grams using its molar mass:

0.5586 mol HCl x (36.46 g HCl/1 mol HCl) = 20.36 g HCl

Therefore, when 58.15 g of PCl5 reacts with water, 20.36 g of HCl will be produced. Rounded to the hundredths place, the answer is 20.36 g HCl.

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Complete question is: When 58.15 g of phosphorus pentachloride reacts with water, 20.36 g mass of hydrogen chloride will be produced.

Answer:

The density of an object is constant.

Density is a derived unit of measure.

The density of an object determines whether it will sink or float.

80 g of 15% solution and 120 g of 20% solution are needed to prepare 200 g of 17% solution.

What is Mass Percentage?

Mass percentage is the percentage of the mass of the solute in a solution to the total mass of the solution. It is calculated by dividing the mass of the solute by the total mass of the solution and multiplying by 100%. The mass percentage is often used in chemistry to express the concentration of a solution.

Let x be the mass of the 15% solution needed and y be the mass of the 20% solution needed to prepare 200 g of 17% solution. Then we have the system of equations:

x + y = 200 (total mass of the solution)

0.15x + 0.20y = 0.17(200) (total amount of solute in the solution)

Solving for x and y, we get:

x = 80 g of 15% solution

y = 120 g of 20% solution

Therefore, 80 g of 15% solution and 120 g of 20% solution are needed to prepare 200 g of 17% solution.

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Answer:

At a temperature of 300K, a gas has a volume of 3.0 L. If we double the temperature to 600K, the volume will increase to 6.0 L. However, the pressure will remain the same at 1 atm. Therefore, the new volume is 6.0 L x 1 atm = 6.0 L

Answer: Brainlest Please!

Explanation:

To determine how many bars Alexander should pack, we first need to calculate the energy required for the uphill climb and the return trip. We can use the formula for gravitational potential energy to calculate this:

Energy required = m * g * h

where m is the mass of Alexander and his backpack, g is the acceleration due to gravity, and h is the height of the mountain.

First, we need to convert Alexander's weight from pounds to kilograms:

180 lb * (1 kg / 2.205 lb) = 81.65 kg

Assuming Alexander's backpack weighs 10 kg, his total mass is:

m = 81.65 kg + 10 kg = 91.65 kg

Next, we need to convert the height of the mountain from meters to joules:

5620 m * 91.65 kg * 9.81 m/s^2 = 5,029,669 J

Since Alexander assumes he will need as much energy for the return trip, the total energy required is:

2 * 5,029,669 J = 10,059,338 J

Now, we can calculate the number of bars required to provide this amount of energy.

Each bar weighs 100 g, and contains 10 g of fat, 40 g of protein, and 50 g of carbohydrates.

First, we need to calculate the total energy per bar:

10 g of fat * 9 Cal/g + 40 g of protein * 4 Cal/g + 50 g of carbohydrates * 4 Cal/g = 410 Cal

Next, we can calculate the number of bars required:

10,059,338 J * (1 Cal / 4.184 J) * (1 bar / 410 Cal) = 605 bars

Therefore, Alexander should pack approximately 605 nutrition bars for his trip up and down Mt. Krumpett.

Answer:

Explanation:

Limiting is HCl and excess is Ca(OH)2

excess is 296 grams Ca(OH)2

2 moles H2O will be formed

Answer:

option a

Velocity is plotted on the x-axis of a graph and speed is plotted on the y-axis.

(1) The larger ion is Cr³+

(2) The larger ion is Ca.

In the first pair, we are comparing the cations Cr²⁺ and Cr³⁺. Cations are positively charged ions that form when an atom loses one or more electrons. The charge on a cation tells you how many electrons it has lost. In this case, Cr²⁺ has lost 2 electrons, while Cr³⁺ has lost 3 electrons.

When comparing the sizes of ions, we need to consider the ionic radius. The ionic radius is the distance between the nucleus of an ion and its outermost electron shell.

As we move from left to right across the periodic table, the number of protons in the nucleus increases, which pulls the electrons closer to the nucleus and makes the atoms smaller. As we move down a column in the periodic table, the number of electron shells increases, which makes the atoms larger.

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answer: 3057.44 m^3

Explanation:

This is Charles Law which is V1/T1=V2/T2  and temp must be in kelvin

So v2=V1 x T2/T1

v2= 3100 X 359.15 / 364.15  = 3057.44 m^3

t1= 91 +273.15 = 364.15

t2=86+273.15 =359.15

It is a synthetic statin, an dihydroxy monocarboxylic acids, a pyrimidine, a sulfonamide, and a monofluorobenzene. It shares a functional connection with hept-6-enoic acid.

20 mg of rosuvastatin are contained in each film-coated tablet (as rosuvastatin calcium). Each 20 mg tablet also includes 0.025 milligrammes Sunset yellow FCF, 0.029 mg Allura red AC, and 91.755 mg lactose monohydrate.

Yet, because cholesterol has a steroid nucleus, it will behave differently. Aldehyde, ketone, ether, and amide groups don't exist in cholesterol. It only possesses one hydroxyl group, which, like carbohydrates, contains the functional group alcohol.

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Answer:

1. The balanced equation is 2KCIO3 → 2KCI + 3O2. According to the law of conservation of mass, the mass of the reactants must equal the mass of the products. Therefore, the mass of oxygen produced is:

Mass of oxygen = Mass of KCIO3 - Mass of KCI

Mass of oxygen = 500 g - 303 g

Mass of oxygen = 197 g

Therefore, 197 g of O2 are produced.

2. The balanced equation is N2 + 3H2 → 2NH3. We need to find out how much H2 is needed to react with 100 g of N2 to produce 121 g of NH3. First, we need to calculate the number of moles of N2 and NH3:

Moles of N2 = Mass of N2 / Molar mass of N2

Moles of N2 = 100 g / 28 g/mol

Moles of N2 = 3.57 mol

Moles of NH3 = Mass of NH3 / Molar mass of NH3

Moles of NH3 = 121 g / 17 g/mol

Moles of NH3 = 7.12 mol

According to the balanced equation, 1 mole of N2 reacts with 3 moles of H2 to produce 2 moles of NH3. Therefore, the number of moles of H2 needed is:

Moles of H2 = Moles of N2 x (3/1)

Moles of H2 = 3.57 mol x 3

Moles of H2 = 10.71 mol

Finally, we can calculate the mass of H2 needed:

Mass of H2 = Moles of H2 x Molar mass of H2

Mass of H2 = 10.71 mol x 2 g/mol

Mass of H2 = 21.42 g

Therefore, 21.42 g of H2 are needed.

3. The balanced equation is 4Fe + 3O2 → 2Fe2O3. We need to find out how much oxygen is needed to react with 350 g of Fe to produce 500 g of Fe2O3. First, we need to calculate the number of moles of Fe and Fe2O3:

Moles of Fe = Mass of Fe / Molar mass of Fe

Moles of Fe = 350 g / 55.85 g/mol

Moles of Fe = 6.26 mol

Moles of Fe2O3 = Mass of Fe2O3 / Molar mass of Fe2O3

Moles of Fe2O3 = 500 g / 159.69 g/mol

Moles of Fe2O3 = 3.13 mol

According to the balanced equation, 4 moles of Fe react with 3 moles of O2 to produce 2 moles of Fe2O3. Therefore, the number of moles of O2 needed is:

Moles of O2 = Moles of Fe x (3/4)

Moles of O2 = 6.26 mol x (3/4)

Moles of O2 = 4.69 mol

Finally, we can calculate the mass of O2 needed:

Mass of O2 = Moles of O2 x Molar mass of O2

Mass of O2 = 4.69 mol x 32 g/mol

Mass of O2 = 150.08 g

Therefore, 150.08 g of O2 are needed.

4. The balanced equation is CH2 + 2O2 → CO2 + 2H2O. We know that 16 g of CH2 reacts with 64 g of O2 to produce 44 g of CO2. We need to find out how much water is produced. First, we need to calculate the number of moles of CH2 and CO2:

Moles of CH2 = Mass of CH2 / Molar mass of CH2

Moles of CH2 = 16 g / 14 g/mol

Moles of CH2 = 1.14 mol

Moles of CO2 = Mass of CO2 / Molar mass of CO2

Moles of CO2 = 44 g / 44 g/mol

Moles of CO2 = 1 mol

According to the balanced equation, 1 mole of CH2 reacts with 2 moles of O2 to produce 2 moles of H2O. Therefore, the number of moles of H2O produced is:

Moles of H2O = Moles of CH2 x (2/1)

Moles of H2O = 1.14 mol x 2

Moles of H2O = 2.28 mol

Finally, we can calculate the mass of H2O produced:

Mass of H2O = Moles of H2O x Molar mass of H2O

Mass of H2O = 2.28 mol x 18 g/mol

Mass of H2O = 41.04 g

Therefore, 41.04 g of H2O are produced.

5. The balanced equation is CaCO3 → CaO + CO2. We need to find out how much CO2 is produced from the decomposition of 200 g of CaCO3 if 112 g of CaO are produced. First, we need to calculate the number of moles of CaCO3 and CaO:

Moles of CaCO3 = Mass of CaCO3 / Molar mass of CaCO3

Moles of CaCO3 = 200 g / 100.09 g/mol

Moles of CaCO3 = 1.999 mol

Moles of CaO = Mass of CaO / Molar mass of CaO

Moles of CaO = 112 g / 56.08 g/mol

Moles of CaO = 1.999 mol

According to the balanced equation, 1 mole of CaCO3 produces 1 mole of CaO and 1 mole of CO2. Therefore, the number of moles of CO2 produced is:

Moles of CO2 = Moles of CaCO3 x (1/1)

Moles of CO2 = 1.999 mol

Finally, we can calculate the mass of CO2 produced:

Mass of CO2 = Moles of CO2 x Molar mass of CO2

Mass of CO2 = 1.999 mol x 44 g/mol

Mass of CO2 = 87.96 g

Therefore, 87.96 g of CO2 are produced.

Substance that gives out ions when dissolved in water, which are able to conduct electricity describes an electrolyte.

Answer:

Ca²+O²

Explanation:

The Ca gives out 2 electrons and oxygen gains 2 elctrons

Answer: The percentage of fluorine as F- in a HF solution at pH 2.33 is 9.09%.

Answer: 204.63 K

Explanation:

Ideal gas law

Pv=nRT

T=PV/nR

T= 5.6 X 12/(4 x0.0821)= 204.63 K

R= ideal gas constant = 0.0821