What is the volume of 7.25 g of oxygen gas at STP?

Which of the following is a change in physical composition?it could be D. A brick being ground up into fine dust. as this is a change from one physical form to another                                                                                                                             Which of the following is a change in chemical composition?  would be A. A white precipitate forming as a result of the combination of two liquids. as this is a clear chemical change                                                                                What kind of bond would you expect between H, S and O?  i belive it would be D. Covalent                                                                                      

Which of the following is not one of the three processes of the hydrologic cycle?  this gose to B. Collection the water cycle has nothing to do with this so there for its not part of the cycle

Given : Density of Air is 1.19 gram per liter

[tex]\mathsf{\heartsuit\;\; Density\;of\;Air = \frac{Mass\;of\;Air}{Volume\;of\;Air}}[/tex]

Given : Mass of Sample of Air = 50 grams

[tex]\mathsf{\implies 1.19 = \frac{50}{Volume\;of\;Air}}[/tex]

[tex]\mathsf{\implies Volume\;of\;Air = \frac{50}{1.19}}[/tex]

[tex]\mathsf{\implies Volume\;of\;Air = 42\;Liter}[/tex]

Given : Dry Air is about 20.95% Oxygen by Volume

[tex]\mathsf{\implies Volume\;of\;Oxygen\;in\;42\;Liter\;of\;Air = 20.95\%\;of\;42\;Liter}[/tex]

[tex]\mathsf{\implies Volume\;of\;Oxygen\;in\;42\;Liter\;of\;Air = (\frac{20.95}{100})\times 42}[/tex]

[tex]\mathsf{\implies Volume\;of\;Oxygen\;in\;42\;Liter\;of\;Air = 0.2095 \times 42}[/tex]

[tex]\mathsf{\implies Volume\;of\;Oxygen\;in\;42\;Liter\;of\;Air = 8.8\;Liter}[/tex]

At STP : 22.4 Liter of Oxygen contains 6.023 × 10²³ Molecules of O₂

[tex]\mathsf{\implies Number\;of\;Oxygen\;Molecules\;in\;8.8\;Liter\;of\;Oxygen = (\frac{8.8 \times 6.023 \times 10^2^3}{22.4})}[/tex]

[tex]\mathsf{\implies Number\;of\;Oxygen\;Molecules\;in\;8.8\;Liter\;of\;Oxygen = 2.366 \times 10^2^3}}[/tex]

Final answer:

To calculate the number of oxygen molecules in a 50.0 g sample of air, determine the volume of air, calculate the moles of oxygen, and then convert moles to molecules using Avogadro's number.

Explanation:

To calculate the number of oxygen molecules in a 50.0 g sample of air, we first need to determine the volume of air. Given that the density of air is 1.19 g/L, we can calculate the volume using the formula:

Volume (V) = Mass (m) / Density (d)

Plugging in the values, we get:

V = 50.0 g / 1.19 g/L = 42.02 L

Next, we need to calculate the moles of oxygen in the sample. Oxygen makes up 20.95% of dry air by volume, so the volume of oxygen in the sample is:

Oxygen volume = 0.2095 x 42.02 L = 8.795 L

Now we can use Avogadro's law to calculate the number of oxygen molecules:

Number of oxygen molecules = Oxygen volume / Molar volume of oxygen

At standard temperature and pressure (STP), the molar volume of any gas is 22.4 L/mol. Therefore, the number of oxygen molecules in the 50.0 g sample of air is:

Number of oxygen molecules = 8.795 L / 22.4 L/mol = 0.393 mol

To convert moles to molecules, we use Avogadro's number (6.022 x 10²³ molecules/mol):

Number of oxygen molecules = 0.393 mol x 6.022 x 10²³ molecules/mol = 2.364 x 10²³ molecules

Answer:

116.3 kJ

Step-by-step explanation:

Three heat transfers are involved

q = Heat to warm ice + heat to melt ice + heat to warm water + heat to evaporate water + heat to warm steam

q =      q₁      +     q₂        +     q₃       +     q₄          +     q₅

q = mC₁ΔT₁ + mΔH_fus + mC₃ΔT₃ + mΔH_vap + mC₅ΔT₅

Step 1: Calculate q₁

m = 37.0 g

C₁ = 2.010 J·°C⁻¹g⁻¹

ΔT₁ = T_f – T_i  

ΔT₁ = 0.0 – (-10.0)

ΔT₁ = 10.0 °C  

q₁ = 37.0 × 2.010 × 10.0  

q₁= 743.7 J

q₁= 0.7437 kJ

===============

Step 2. Calculate q₂

ΔH_fus = 334 J/g

q₂ = 37.0 × 334

q₂ = 12 360 J

q₂ = 12.36 kJ

===============

Step 3: Calculate q₃

C₃ = 4.179 J·°C⁻¹g⁻¹

ΔT₃ = T_f – T_i  

ΔT₃ = 100 – 0  

ΔT₃ = 100 °C

q₃ = 37.0 × 4.179 × 100  

q₃ = 15 460 J

q₃ = 15.46 kJ

===============

Step 4. Calculate q₄

ΔH_vap = 2260 J/g

q₄ = 37.0 × 2260

q₄ = 83 620 J

q₄ = 83.62 kJ

===============

Step 5. Calculate q₅

C¬₅ = 2.010 J·°C⁻¹g⁻¹

ΔT₅ = T_f – T_i  

ΔT₅ = 155.0 – 1000  

ΔT₅ = 55.0 °C

q₅ = 37.0 × 2.010 × 55

q₅ = 4090 J

q₅ = 4.090 kJ

===============

Step 6. Calculate q

q = 0.7437 + 12.36 + 15.46 + 83.62 + 4.090

q = 116.3 kJ

The heat required is 116.3 kJ.

the first question is block A

because there isn't a lot of room for the particles to move around

Answer:

2.42 L  

Step-by-step explanation:

Since all other properties constant, we can use Boyle’s Law.

p₁V₁ = p₂V₂    Divide each side by p₁

  V₁ = V₂ × p₂/p₁

Data:

p₁ = 101.01 kPa; V₁ = ?

p₂ = 101.7   kPa; V₂ = 2.40 L

Calculations:

V₁ = 2.40 × 101.7/101.01

V₁ = 2.42 L

Each pH value with the correct description

1.Strong acid: 2 pH

2.Weak acid:6 pH

3.Strong base:13 pH

4.Weak base:8 pH

5.Neutral:7 pH

An acid is any hydrogen-containing substance capable of donating a proton or hydrogen ion to another substance while a base is a molecule capable of accepting a hydrogen ion from an acid.

Anything with a pH below 7 is acidic in nature while a pH above 7 is basic in nature, based on a pH scale point 0 to 14. This can be determined by testing using litmus paper.  When the paper turns red, it is an acid or while it turns blue, it is a base. 7 is neutral on the pH scale

When an acid reacts with a base, neutralization reaction results in the formation of salt and water, for example when HCL( Hydrochloric acid) which is a strong acid, NaOH (sodium hydroxide) which is strong base, it results in a salt (sodium chloride) and water.

Thus, each pH value with the correct description

1.Strong acid: 2 pH

2.Weak acid:6 pH

3.Strong base:13 pH

4.Weak base:8 pH

5.Neutral:7 pH

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Answer: Octet rule

Explanation: The elements which have filled s and p orbitals or noble gases are most stable and thus every element tends to get stable by completing their octet.

For example:  Sodium [Na] has atomic no of 11 and thus the electronic configuration is : [tex]Na:1s^22s^22p^63s^1[/tex] tends to get stable by losing one electron and gets converted to [tex]Na^+[/tex]

Electronic configuration for  [tex]Na^+:1s^22s^22p^6[/tex]

Thus acquiring stable configuration with filled s and p orbitals.

For example:  Fluorine [F] has atomic no of 9 and thus the electronic configuration is : [tex]NF:1s^22s^22p^5[/tex] tends to get stable by gaining one electron and gets converted to [tex]F^-[/tex]

Electronic configuration for [tex]F^-:1s^22s^22p^6[/tex]

Thus acquiring stable configuration with filled s and p orbitals.

Answer:

5.25 g NaF  

Step-by-step explanation:

We know we will need a balanced equation with masses and molar masses, so let’s gather all the information in one place.  

M_r:           41.99

               Na₂SiO₃ + 8HF ⟶ H₂SiF₆ + 2 NaF + 3H₂O

n/mol:                         8  

(1) Calculate the moles of NaF

The molar ratio is 2 mol NaF/8 mol HF.

Moles of F = 0.500 mol HF × (2 mol Na₂SiO₃/8 mol HF)

Moles of Na₂SiO₃ = 0.125 mol Na₂SiO₃

(2) Calculate the mass of NaF

Mass of NaF = 0.125 mol NaF × (41.99 g Na₂SiO₃/1 mol Na₂SiO₃)

Mass of NaF = 5.25 g NaF

the mass of ice taken = 10 g

the mass of water = 250 g

initial temperature of water = 20 C

the final temperature of water = 16. 8 C

specific heat of water = 4.18 J/g*K

the heat absorbed by ice to melt = heat loss by water

heat loss by water = mass X specific heat of water X change in temperature

heat loss by water = 250 X 4.18 X (20-16.8) = 3344 Joules

heat gained by ice = 3344 J

heat gained by ice = enthalpy of fusion X moles of ice

moles of ice = mass / molar mass = 10 / 18 = 0.56 moles

enthalpy of fusion = 3344 / 0.56 = 5971.43 J / mole

The statements 'An object can have only one type of energy at a time' and 'If an object has energy, it must be moving' are false. An object can possess more than one type of energy and doesn't necessarily need to be moving to contain energy. The statement 'All energy travels in waves' is not universally true as it does not apply to all types of energy.

The statements provided for evaluation are related to the concepts of energy and its properties. To answer these, we need to understand that energy manifests in different forms and an object can possess more than one type of energy at a time. Notably, the type of energy depends on the state of the object. For example, a ball held at a certain height has potential energy, yet when it falls and is in motion, it also has kinetic energy.

Firstly, the statement 'An object can have only one type of energy at a time' is false. As mentioned earlier, an object can possess both potential and kinetic energy, among other types.

Secondly, 'If an object has energy, it must be moving' is also false. An object does not have to be in motion to possess energy. For instance, a charged battery has electrical energy stored even though it is at rest.

Lastly, the statement 'All energy travels in waves' is not entirely true. While it's true for electromagnetic radiation like light and sound energy, it's not the case for potential or kinetic energy.

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2grams. Due to the las of consevation of mass.  These implies that mass quantity can not change,

Answer: The amount of reactant consumed is 2 grams

Explanation:

Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.  

This also means that total mass on the reactant side must be equal to the total mass on the product side.

We are given:

Mass of the product = 2 g

Applying law of conservation of mass, we get:

Mass of reactant = Mass of product = 2 g

Hence, the amount of reactant consumed is 2 grams

A earthquakes because the plates will suddenly shift quickly or gring quickly causing the ground to move because of the tectonic plates.

The correct answer is A.Earthquakes. Hope it helps!!

That would be electromagnetic waves .

They are of very  high energy.

Nitrogen trifluoride is the inorganic compound with the formula NF3. This nitrogen-fluorine compound is a colorless, odorless, nonflammable gas. It finds increasing use as an etchant in microelectronics.

(If you mean by a gas of some sort)

Answer:

Nathan Feuerstein

Explanation:

Explanation:

A mixture is a substance that contains two or more components which are mixed together but they are not chemically combined to each other.

For example, sand, salt and steel shavings in water is a mixture.

So, in order to separate its components we can do the following.

Step 1: Pass a magnet over the mixture to remove the steel. As this will remove steel from mixture.

After that, adding water will make a solution in which sand and salt are present.

Step 2: Add water to the sand/salt mixture and stir to dissolve the salt.

Step 3: Pour the mixture through a filter to separate the sand.

Step 4: Heat the mixture to evaporate the water.

Thus, we can conclude that correct order to separate the given mixture is 3, 4, 2, 1.

The best method for separating a mixture of sand, salt, and steel shavings is to add water and dissolve the salt, then filter out the sand particles, use a magnet to remove the steel shavings, and heat the mixture to evaporate the water.

The best method for separating a mixture of sand, salt, and steel shavings is as follows:

By adding water and stirring, the salt dissolves in the water. Then, pouring the mixture through a filter separates the sand particles from the liquid. Next, passing a magnet over the mixture allows the steel shavings to be attracted and separated. Finally, heating the mixture evaporates the water, leaving behind the separated components.

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B. Come on, Maryann. Try it. I’m totally sure that one puff won’t kill you

Hope this helped!

Answer:

B. Come on, Maryann. Try it. I’m totally sure that one puff won’t kill you

Explanation:

In letter B, Maryann is being prized by her friends to puff on something. Maryan's friends are using reasoning tactics to influence her to do what they want. This tactic is evident when they give Maryann a reason to puff this thing. The reason is that as dangerous as it sounds, just one puff won't kill her.

According to the electronic configuration, there are seven valence electrons present in the given atom.

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.

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One of the following that is NOT considered to be a pyroclastic material is;

D. Pahoehoe

Pyroclast material range in size from very small pieces of dust to ash to lapilli to bombs and block to cinders. A pahoehoe is just basaltic lava forming smooth undulating masses. Thus, it is not considered of pyroclastic material.

Pahoehoe lava flows are described by smooth, lightly undulating, or broadly hummocky surfaces. The liquid lava running beneath a thin, still-plastic crust drags and twists it into tapestry-like folds and rolls relating twisted rope. Pahoehoe lava flows are maintained substantially wholly internally by rivers of liquid lava flowing beneath a fixed or partly solidified surface.

Answer: A double replacement reaction occurs because potassium ions bond with sulfate ions to form a salt.

Explanation:

A double replacement reaction is defined as chemical reaction in which ions of two reactant interchange their position with each other to give out product.

[tex]AB+CD\rightarrow AD+CB[/tex]

Here, in question:

[tex]2KOH+H_2SO_4\rightarrow K_2SO_4+2H_2O[/tex]

In the above chemical reaction, when potassium hydroxide reacts with sulfuric acid, the interchanging of ions takes place in between the reactants that is [tex]OH^-[/tex] ion of KOH combines with [tex]H^+[/tex] ion of sulfuric acid to give water.

Also sulfate ion ([tex]SO_4^{2-}[/tex]) of sulfuric acid gets combine with two potassium ion ([tex]K^+[/tex])to give salt of  potassium sulfate, [tex]K_2SO_4[/tex].

Hence , it will be correct to say,A double replacement reaction occurs because potassium ions bond with sulfate ions to form a salt.

The statement that best describes the reaction is:

A double replacement reaction occurs because potassium ions bond with sulfate ions to form a salt (option B)

First, we shall define what is a single replacement and a double replacement reaction. Details below:

Single replacement reaction is a reaction in which a more reactive element replaces a less reactive element in solution. For example

Z replaces Y in the product

Double replacement reaction is a reaction in which there is an exchange of ions between the reacting species. For example

Now let us write the balanced equation for the reaction of potassium hydroxide (KOH) with sulfuric acid (H₂SO₄) to produce potassium sulfate (K₂SO₄) and water (H₂O). Details below:

2KOH + H₂SO₄ -> K₂SO₄ + 2H₂O

Ionically, we have:

2K⁺(aq) + 2OH⁻(aq) + 2H⁺(aq) + SO₄²⁻(aq) -> K₂SO₄ + H₂O

We can see that a double replacement reaction occurs as potassium ions, K⁺ bond with sulfate ion, SO₄²⁻ to form a salt, K₂SO₄ and hydrogen ions, H⁺ bond with hydroxide, OH⁻ to form a water, H₂O

Thus, the best statement that describes the reaction is:

A double replacement reaction occurs because potassium ions bond with sulfate ions to form a salt (option B)

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Answer:

The weights of all elements are always compared to the Carbon-12.

Explanation:

The weights of all elements are always compared to the Carbon-12 because the mass of carbon is 12 which is the exactly the sum of protons and neutrons.  

Oxygen was also considered the standard for some time but later this stander was rejected because in natural O¹⁷ and O¹⁸ were also present and this create the two different atomic mass tables.

AMU:

Atomic mass unit is define as the 1/12 the mass of an atom of carbon-12.

C12 has six neutron and six protons in the nucleus.

This unit is used to express the masses of atoms. We know that masses of atoms are very small and we do not have any such type of balance that can measure very small quantity. So that is way we use this scale to measure small quantity. For example, according to this scale

relative atomic mass of hydrogen is 1.008 amu

relative atomic mass of oxygen is 15.999 amu

relative atomic mass of uranium is 238.0289 amu

relative atomic mass of chlorine is 35.453 amu

Atomic weights are based on relative masses of atoms, with oxygen historically used as a standard. For instance, water's fixed composition reflects a constant ratio between hydrogen and oxygen, echoing the consistency and importance of atomic weights in chemistry.

The weights of all elements are defined relative to the atomic mass of other elements, and historically, oxygen was commonly used as the standard for comparison. Oxygen has an atomic weight of 16, which means if you compare it to hydrogen (the lightest element with an atomic weight close to 1), the ratio is 16:1. This is consistent with the Law of Multiple Proportions, where elements combine in simple whole number ratios.

For example, in water (H₂O), oxygen accounts for about 88.8% of the mass, and hydrogen about 11.2%, irrespective of the water's source or method of preparation. These percentages reflect the fixed mass ratio in which hydrogen and oxygen combine to form water, demonstrating the consistency in atomic weights and the fixed nature of chemical compounds.

Atomic weights are determined through experiments and calculations and provide a basis for the quantification in chemical reactions. Precise measurements and experimental uncertainties limit the precision of these values, typically to four significant figures. Atomic weight is crucial for understanding the composition of molecules and for converting between masses of substances and moles during chemical calculations.

a catalyst speed up the chemical reaction and will not appear as a part of product . plus it will decrease the amount of heat needed to do the reaction

Answer:

It speeds up the rate of a reaction.

Explanation:

A.P.E.X.

True, as an acid is soap which is slick and tastes bitter.

Yes, true.

Acids have a bitter taste because of the presence of alkali...

Rb+ is the largest. Hope it helps.

Fluorine has the largest electronegativity of all the elements. causing it to have the largest caution

Answer:

Mitosis

Explanation:

The ligand field diagram for octahedral complex is explained here.

In a free metal ion, all the five d-orbitals are degenerate (i.e, having equal energies). But according to crystal field theory, under the influence of ligand field, degenracy of d-orbital is destroyed and they split into two or more energy levels. The difference in energy between two sets of d-orbitals is called Crystal Field Splitting Energy (CFSE). The extent of splitting depends upon the strength of ligand. A strong ligand causes greater splitting whereas weak ligand causes smaller splitting.

In octahedral complex, under the influence of ligand field, degenerate five d-orbitals  split into two sets of orbitals -one is [tex]t_{2g}[/tex] and another one is [tex]e_{g}[/tex]. [tex]t_{2g}[/tex] orbital consists of [tex]d_{xy} , d_{xz} , d_{yz}[/tex] and [tex]e_{g}[/tex] orbital consists of [tex]d_{x^{2}-y^{2}  }  and   d_{z^{2} }[/tex] orbitals.

The crystal field splitting diagram for octahedral complex is attached here.

In the diagram, Δo is crystal field splitting energy (CFSE).

Neon-22

Depending on the type of notation the question wants but that is generic term for it.

Answer:

The identity of the isotope is the neon atom because they have the same atomic number and different atomic mass.

Explanation:

An isotope is an atom that has the same atomic number but different atomic mass of the atom in the periodic table.

Atomic number is the amount of electrons (and also protons) that an atom has.

Atomic mass (or atom weight) is the sum of protons and neutrons of an atom.

Both atomic number and atomic mass are taken from the periodic table.

In this example the isotope contains:

protons= 11

electrons= 10

neutrons= 12

From this we can deduce that:

isotope atomic mass = protons + neutrons = 11 + 12 = 23

First it is necesary to find an atom with atomic number 11 or 10, because the atomic number doesn't change in the isotope. Those are sodium (Na) and neon (Ne).

sodium atomic number= 11

neon atomic number= 10

Also it is important to analyze the atomic mass:

sodium atomic mass= 23

neon atomic mass= 20

With these information we realize that sodium has:

protons: 11

electrons: 11

neutrons: atomic mass - atomic number= 23 - 11 = 12 neutrons

And neon has:

protons: 10

electrons: 10

neutrons: atomic mass - atomic number= 20 - 10 = 10 neutrons

According to the definition of atomic number, the particles that remains the same could be electrons or protons, so in this case both sodium and neon could be the isotope's identity.

Now it is necessary to determine which one is the correct element by analyzing the atomic mass, so according to the definition of isotope the identity of the isotope will be the one with a different atomic mass, that is the neon atom.

Answer is:  the number of bromine molecules is 1.35·10²⁴.

n(Br₂) = 2.25 mol; amount of bromine molecules.

Na = 6.022·10²³ mol⁻¹; Avogadro constant.

N(Br₂) = n(Br₂) · Na.

N(Br₂) = 2.25 mol · 6.022·10²³ mol⁻¹.

N(Br₂) = 13.54 ·10²³.

N(Br₂) = 1.35·10²⁴; number of bromine molecules.

Final answer:

The number of bromine (Br2) molecules present in 2.25 mol is calculated by multiplying the moles of substance by Avogadro's number, yielding 1.355 × 10^24 molecules of Br2.

Explanation:

To calculate the number of bromine (Br2) molecules present in 2.25 mol, we need to utilize Avogadro's number, which is approximately 6.022 × 1023 molecules/mol. The number of molecules can be found by multiplying the moles of substance by Avogadro's number.

Here’s the calculation:

Multiply the number of moles of bromine by Avogadro’s number: 2.25 mol × 6.022 × 1023 molecules/mol = 1.355 × 1024 molecules of Br2.

The correct answer is the bicarbonate buffer system.  

The bicarbonate buffer system refers to an acid-base homeostatic mechanism taking part in the balance of bicarbonate ion, carbonic acid, and carbon dioxide in order to sustain the pH in the duodenum and blood, among other tissues, to support the entire metabolic activities.  

The bicarbonate buffer system plays a vital role in the human body systems. In the duodenum and the stomach, the bicarbonate buffer system functions to both neutralize gastric acid and steady the intracellular pH of epithelial cells through the secretion of bicarbonate ion into the gastric mucosa.  

The answer is; C

Due to the intense heat and pressure on the rocks, they undergo physical and chemical changes and become new types of rocks called metamorphic rocks. An example of this change is that small crystals may be squeezed into large crystals and the crystals may be rearranged.

Answer:

C) recrystallize; metamorphic

The rocks are smashed together causing them to recrystallize due to the intense heat and pressure from the colliding plates and eventually forming metamorphic rock.