This is a net gain or loss of electrons

Answer:

Atomic mass = 27 amu

Explanation:

Given data:

Atomic mass of element X= ?

Abundance of X-28 = 75%

Abundance of X-24 = 100 - 75 = 25%

Atomic mass of X-28 = 28 amu

Atomic mass of X-24 = 24 amu

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

Average atomic mass = (75×28)+(25×24) /100

Average atomic mass =  2100 + 600 / 100

Average atomic mass = 2700 / 100

Average atomic mass = 27 amu.

Answer:

Boron

Explanation:

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

For example

In given atomic model we can see that there are five electrons out side the nucleus it means this atomic model is of that element which have atomic number 5 and it is boron.

It has 5 electron 5 proton and 6 neutrons.

It means its atomic number is five and mass number is 5+6 = 11

Answer:

1.27 moles (3 s.f.)

Explanation:

Mole ratio of water: C6H14

= 14:2

= 7:1

This means that to produce 7 moles of water, 1 mole of C6H14 is needed. Or 1/7 mole of C6H14 is needed to produce 1 mole of water. So if you need 8.86 moles of water, 8.86(1/7) moles of C6H14 is needed.

For 8.86mol of water, moles of C6H14 needed

= 8.86/7

= 1.27 moles (3 s.f.)

Answer: C. Suspension

Explanation: Suspensions are mixtures where its solute particles are not fully dissolved in a solvent. The size of its particles are much relatively the biggest among other mixtures such as solutions and colloids. Since its has bigger particle size it suspends and settle at the bottom of the container due to gravity. So when using suspensions it is advised to shake it well before using to mix the suspended particles.

A medicine that needs to be shaken well before use is considered a Suspension. This is a type of mixture where small solid particles are dispersed in a liquid and will settle if the mixture is not stirred.

A medicine that must be shaken well before use is typically a Suspension. A suspension is a type of mixture where small solid particles are dispersed throughout a liquid but are not dissolved in the liquid. A characteristic feature of suspensions is that the particles will eventually settle at the bottom of the mixture and are allowed to stand undisturbed, hence the instruction 'shake well before using'.

A solution, on the other hand, is a mixture where the solute is fully dissolved in the solvent, and it does not need to be stirred before use. An alloy is a solid mixture of two or more metals, and a colloid is a mixture where very small particles of one substance are dispersed evenly throughout another substance.

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Answer: 1000 g of water at 30°C

Explanation: Heat or thermal energy is directly proportional to the mass of an object, which implies that the more massive the object the greater thermal energy or heat it can absorb. Since the amount of matter present is much more enough to absorb heat energy.

Answer:

Explanation:

1 : False

A divergent plate boundary is when two plates pull apart.

2: A

I explained what a divergent boundary was in the previous question

3 : B

Think of the word converge/come together

4: D

When two continental plates collide, they form a mountain

When a continental, and oceanic plate collide, the oceanic plate sub-ducts, and melts. That causes a volcano. The volcano becomes a mountain to some extent.

5 : C

When the plates divert, magma spews from the mid ocean ridge.

6 : Divergent

7 : Transform plate boundaries move in opposite directions

8 : B

When the plates grind together, energy is stored, and then is suddenly released

9 : True

10 : True

11 : C

This is a set of questions and answers related to plate boundaries including divergent, convergent and transform boundaries. The Himalayan mountain range is a result of convergent plate boundaries, while new seafloors are created at divergent boundaries. Transform plate boundaries, which move in opposite or lateral directions, often yield earthquakes.

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Answer:

1 fempto = 10⁻¹⁵

Explanation:

Data Given:

9.2 fempto second = 9.2 ×10 ⁻¹⁵ seconds

exponential equivalent of fempto = ?

Solution:

To find exponential equivalent of fempto

As we know

we look at the given data

That is fempto seconds = 9.2

when we write only seconds then we write 10⁻¹⁵ instead of fempto

that is

9.2 ×10 ⁻¹⁵ seconds

So the exponential equivalent of fempto = 10 ⁻¹⁵

That is -15 exponent to 10

So,

10 ⁻¹⁵ = 0.00000000000001

1 fempto = 10 ⁻¹⁵

Answer: No

Explanation:Combustion is the process where a hydrocarbon reacts with oxygen gas to produce carbon dioxide and water.

Combustion reaction:

CH + O2 => CO2 + H2O

Answer:

a. 0 J

b. - 9.5J

c. - 17.8 J

Explanation:

part a  (against a vacumm)

Data given:

initial volume V1 = 26.7 mL

Final volume V2 = 89.3 mL

work done w = ?

temperature = constant

Solution:

formula will be used

             w = - PΔV

where

ΔV = V2 -V1

so the above equation will be written as

          w = - P (V2 - V1) . . . . . . (1)

as we are calculating work against vacuum so the pressure will be 0 atm.

So,

P = 0 atm

Put values in above equation 1

              w = - [(0 atm)(89.3 mL - 26.7 mL)

              w = - [(0 atm)(62.6mL)

               w = - (0)J

               w = 0 J

so the work done will be 0

_________________

part b (against constant pressure of 1.5)

Data given:

initial volume V1 = 26.7 mL

Convert mL to L

1000 mL = 1 L

26.7 mL = 26.7/1000 = 0.0267 L

Final volume V2 = 89.3 mL

Convert mL to L

1000 mL = 1 L

89.3 mL = 89.3/1000 = 0.0893 L

work done w = ?

Pressure constant = 1.5 atm

Solution:

formula will be used

             w = - PΔV

where

ΔV = V2 -V1

so the above equation will be written as

          w = - P (V2 - V1) . . . . . . (1)

Put values in above equation 1

              w = - [(1.5 atm)(0.0893 L - 0.0267 L)

              w = - [(1.5 atm)(0.0626 L)

               w = - (0.0939 atm.L)

               w = - 0.0939 atm.L

convert atm.L to J

1 atm.L = 101.3 J

0.0939 atm.L = 0.0939 x 101.3 = 9.5 J

so the work done will be - 9.5 J

___________

Part c ( constant pressure of 2.8 atm)

Data given:

initial volume V1 = 26.7 mL

Convert mL to L

1000 mL = 1 L

26.7 mL = 26.7/1000 = 0.0267 L

Final volume V2 = 89.3 mL

Convert mL to L

1000 mL = 1 L

89.3 mL = 89.3/1000 = 0.0893 L

work done w = ?

Pressure constant = 2.8 atm

Solution:

formula will be used

             w = - PΔV

where

ΔV = V2 -V1

so the above equation will be written as

          w = - P (V2 - V1) . . . . . . (1)

Put values in above equation 1

              w = - [(2.8 atm)(0.0893 L - 0.0267 L)

              w = - [(2.8 atm)(0.0626 L)

               w = - (0.1753 atm.L)

               w = - 0.1753 atm.L

convert atm.L to J

1 atm.L = 101.3 J

0.1753 atm.L = 0.1753 x 101.3 = 17.8 J

so the work done will be - 17.8 J

Final answer:

Chemistry high school question about the work done by an expanding gas against different pressures. The work done against a vacuum is 0 J, against 1.5 atm is -9.49 J (approx.), and against 2.8 atm is -17.71 J (approx.). Calculations use the formula W=-P_ext×ΔV and the conversion 1 L·atm = 101.32 J.

Explanation:

The subject of this question is Chemistry, specifically the topic of thermodynamics as it relates to gases. In the scenario provided, a gas is expanding and the work done by the expansion needs to be calculated in different contexts:

(a) against a vacuum

(b) against a constant pressure of 1.5 atm

(c) against a constant pressure of 2.8 atm

To calculate the work (W) when a gas expands or contracts against an external pressure (Pext), the formula W=-Pext×ΔV is used, where ΔV is the change in volume. However, when a gas expands against a vacuum, the external pressure is zero, so the work done is zero as well.

To calculate the work done against a constant pressure in joules, we first need to find the change in volume (ΔV) in liters and the pressure in atmospheres. Then we use the relationship 1 L·atm = 101.32 J to convert from L·atm to joules.

ΔV = 89.3 mL - 26.7 mL = 62.6 mL = 0.0626 L

Work done against a vacuum (Wvacuum) = 0 J

Work done against 1.5 atm (W1.5) = -1.5 atm × 0.0626 L × 101.32 J/L·atm = -9.4878 J

Work done against 2.8 atm (W2.8) = -2.8 atm × 0.0626 L × 101.32 J/L·atm = -17.7062 J

Note that the work is negative because work is done by the system (expansion of gas) against the surroundings.

Your answer would be Transpiration

Answer: The 3 indicates the 3rd shell

Explanation:

Answer: Double Displacement

Explanation: In a double displacement reaction it is shown through this generic description

AB+ CD => AD + CB

Where A and C are both metals and B and D are nonmetals.

A is Al

B is Br

C is K

D is SO4

In this reaction

Al displaces K to combine with SO4

K combines with Br forming KBr

I pretty sure its C. Work

If wrong lemme know

Assuming that the complete question is the following:

Calcium hydroxide reacts with Aluminum sulfate to form aluminum hydroxide and calcium sulfate. Write the balanced formula unit equation for the reaction.

Then the balanced formula unit equation would be:

3Ca(OH)₂ + Al₂(SO₄)₃ → 2Al(OH)₃ + 3CaSO₄

This is a double replacement reaction, where the cations and anions are interchanged.

Balancing this reaction is based on the Law of Conservation of Mass, which estates that matter is not created nor destroyed, meaning that the number of atoms at the right and the left of the chemical equation needs to be the same. We add coefficients in front of each species that intervenes in the reaction in order to achieve that equality.

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The question is about the chemical reaction between calcium hydroxide and aluminum sulfate, where aluminum hydroxide precipitates and calcium sulfate remains in solution. The aluminum hydroxide can be filtered out and then converted into aluminum oxide for electrolysis to produce metallic aluminum.

The student asks about the reaction between calcium hydroxide and aluminum sulfate. In a chemical reaction, calcium hydroxide, represented as Ca(OH)2, would react with aluminum sulfate, which is Al2(SO4)3 to form a precipitate of aluminum hydroxide (Al(OH)3) and a solution of calcium sulfate (CaSO4).

For such a reaction, the balanced chemical equation can be written as:

During this process, aluminum hydroxide precipitates from the solution, which can then be removed by filtration. Further treatment, such as heating, can convert the aluminum hydroxide to aluminum oxide (Al2O3), commonly used in the electrolysis process for aluminum production. This process involves dissolving aluminum oxide in a molten mixture of cryolite and calcium fluoride, followed by the application of an electric current to reduce aluminum ions to metallic aluminum at the cathode.

Answer:

its a

Explanation:

Answer:

0.000001

Explanation:

Answer: Physical change

Explanation: Condensation is the phase change of a gas to the liquid state. There is no formation of new products so it does not undergoes chemical change. Any phase change is considered a physical change.

Final answer:

Condensation of ethanol is a physical change because it only involves a change in the state of matter without altering the chemical composition of ethanol.

Explanation:

The condensation of ethanol is a physical change. This process involves a change in the state of matter from gas to liquid without altering the chemical composition of ethanol. Like the condensation of water vapor into liquid water, the process is exothermic, releasing energy. However, the ethanol remains chemically identical before and after condensation.

Answer:

A. Biodiversity can increase the rate of extinction

Explanation:

That statement is false because variety is better for a better ecosystem. With variety more can survive in certain situations that others cant.

Biodiversity can increase the rate of extinction is not a way that biodiversity is important to an ecosystem. Therefore, option A is correct.

The variety and variability of life on Earth is referred to as biodiversity or biological diversity. A measure of variation at the genetic, species, and ecosystem levels is called biodiversity.

Genetic, species, and ecosystem diversity are the typical three levels of biodiversity that are covered. The various genes that each unique plant, animal, fungus, and bacteria have constituted genetic variety. Both inside and between species, it happens.

Conservation of biodiversity safeguards the genetic, microbial, animal, and plant resources needed for agriculture, food production, and ecosystem services like soil nutrient cycling, pest and disease control, preventing erosive processes, and pollination plants and trees.

Thus, option A is correct.

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Redox reactions are the reactions that have been constituting reduction and oxidation. In the chemical equation, chlorine is reduced and bromine is oxidized. Thus, option B is correct.

A redox reaction is a combination of reduction and oxidation reactions. When a reactant loses an electron, then it is called oxidation, whereas the reactant that gains an electron is said to be where the reduction takes place.

The redox reaction is written as,

2 NaBr (aq) + Cl₂ (g) → 2 NaCl (aq) + Br₂ (aq)

Here, oxidation,

2 Br⁻¹ - 2 e⁻ → 2 Br⁰

Reduction,

2 Cl⁰ + 2 e⁻ → 2 Cl⁻¹

From the reaction, NaBr is a reducing agent as it has donated its electron, whereas chlorine gas is an oxidizing agent as it has an accepted electron.

Therefore, in the chemical reaction chlorine is reduced and bromine is oxidized.

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Answer: Temperature final = 103 °C

Explanation: To solve for final temperature we use the equation of heat:

Q= mc∆T

Next derive the equation to find final temperature

Q = mc(T final - T initial)

Q / mc = T final - T initial

Transpose T initial and change the sign so that T final will be left.

T final = Q / mc + T initial

Substitute the values:

T final = 305 J / 28.8 g x 0.128 J/(g°C)

= 305 J / 3.6864 J/°C

= 82.7 + 20.0°C

= 103 °C final temperature.

Answer:

Be (899 kj/mol) , Se (940.9 kj/mol), Ne(2081 kj/mol), He (2370 kj/mol),

Explanation:

For noble gases as they have complete octet so they require high amount of energy to remove the electron.

Trend along period:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.

Trend along group:

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.

As the size of atom increases the ionization energy from top to bottom also  decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus.

Answer:BaCl2 + Al2(SO4)3 -->BaSO4 + AlCl3.

Explanation:

Answer:

3.011×0²³  atoms of Ar

Explanation:

To find no.of atoms of Ar gas in 10.2 L at STP.

At STP 1 mole of a gas occupies 22.4  L  and contains 6.022×10²³ atoms/molecules or ions.

At STP

22.4 L contains 1 mole Ar t

10.2 L contains (10.2÷22.4)×1 Ar

[tex]\frac{1}{2}[/tex] mole Ar contains [tex]\frac{1}{2}[/tex]×6.022×10²³

=3.011×0²³  atoms of Ar

Final answer:

To calculate the number of atoms in 10.2 L of Ar gas at STP, we convert the volume of gas to moles and use Avogadro's number. The number of atoms in 10.2 L of Ar gas at STP is approximately 2.742 x [tex]10^{23}[/tex] atoms.

Explanation:

To determine the number of atoms in 10.2 L of Ar gas at STP, we need to convert the volume of gas to moles and then calculate the number of atoms using Avogadro's number.

First, we convert 10.2 L to moles using the molar volume of a gas at STP, which is 22.4 L/mol.

So, 10.2 L of Ar gas is equal to 10.2 L / 22.4 L/mol = 0.455 moles of Ar gas.

Next, we use Avogadro's number, which is 6.022 x 10^23 atoms/mol, to calculate the number of atoms in 0.455 moles of Ar gas.

So, the number of atoms in 10.2 L of Ar gas at STP is 0.455 moles x 6.022 x [tex]10^{23}[/tex] atoms/mol = 2.742 x [tex]10^{23}[/tex] atoms.

Answer: 18g/mol

Explanation:

H2O = (2 x 1) +16 = 2 + 16 = 18g/mol

Answer:

What are the statements please

Explanation:

Answer: Here are the statements

Explanation:

A.

One that has 30.0 grams NaCl dissolved in 100 grams of water is more concentrated than one that has 15.0 grams NaCl dissolved in 100 grams of water.

B.

One that has 30.0 grams NaCl dissolved in 100 grams of water is more dilute than one that has 15.0 grams NaCl dissolved in 100 grams of water.

C.

One that has 30.0 grams NaCl dissolved in 100 grams of water would have the exact same molarity as one that has 15.0 grams NaCl dissolved in 100 grams of water.

D.

One that has 30.0 grams NaCl dissolved in 100 grams of water has less solute than one that has 15.0 grams NaCl dissolved in 100 grams of water.

Answer:

The statement that best describes the trend in first ionization enery of elements on the periodic table is:

It generally decreases down a group because valence electrons are farther from the nucleus.

The first ionization energy measures how difficult is to release an electron from the outermost shell. The higher the ionization energy the more difficult it is to release an electron, the lower the ionication energy the easier to release an electron.

As the atomic number of the atom increases (which is what happens  when you go down a group) the furthest the outermost shell of electrons will be (the size of the atoms increases) and so those electrons require less energy to be released, which means that the ionization energy decreases.

Hope it helps!

Answer:

1. Across a period , the ionization energy increases  because the formation of a cation becomes more difficult owing to the increase in nuclear charge.

2. Ionization energy decreases down the group because the outer electrons become progressively separated from the nucleus and so are less tightly held .

Explanation:

Explanation:

When two or more substances react and form some new substance it is called as chemical reaction .

A + B --> C + D

(reactants )   (products )

Types of chemical reaction

we come across different types of reactions that occur in nature .

Out of them , combination is also one type

Combination reaction

It is a reaction ,when two or more reactants react to form single product .

i.e A+B-----AB(IN THIS ONE SINGLE PRODUCT IS FORMED )

LIKE : H₂+Cl₂------HCL

         (E)    (E)         (PRODUCT )

           SO₂+O₂----SO₃

             ©   (E)        (PRODUCT )

           CO₂+H₂O----H₂CO₃

In the above asked equation :

C₂H₂ + 2 H₂ --> C₂H₆

Final answer:

The reaction C2H2 + 2H2 → C2H6 represents a hydrogenation reaction, converting acetylene to ethane by adding hydrogen. This process, central to organic chemistry, often requires a catalyst and is foundational in the synthesis of various compounds.

Explanation:

The given reaction C2H2 + 2H2 → C2H6 is an example of a hydrogenation reaction, where hydrogen (H2) is added to another compound. In this specific case, the hydrogenation of acetylene (C2H2) results in ethane (C2H6). The process involves the breaking of the triple bond in acetylene and the formation of a single bond to incorporate the additional hydrogen atoms, converting it into ethane. This is a common type of chemical reaction in organic chemistry which often requires a catalyst such as platinum or palladium to proceed under milder conditions.

The importance of understanding reactions like these lies in their application in the synthesis of various organic compounds, which are foundational in fields ranging from pharmaceuticals to materials science. Stoichiometry, a crucial concept in such reactions, involves the calculation of reactant and product quantities, often expressed in moles, to ensure that a reaction proceeds efficiently and yields the desired product.

Answer:

123 Celsius is equal to 396.15 Kelvin scale

Explanation:

Answer:

E. 1.5M

Explanation:

because there is total 175.32 g of NaCl dissolved in 2 liter of water, and 58.44 g = 1 mol

so total miles = 175.32/58.32 = 3 moles

now 3 moles are in 2 liter of water, hence one liter contains 3/2= 1.5

Therefore answer is E. 1.5M

Answer: A. 190 lbs.

Explanation: To find the mass in pounds we will use the following conversion factor: 1 lb = 0.45 kg

Solution:

87 kg x 1 lb / 0.45kg = 193 lbs.

Among the choices 190 lbs is the closest so it is the answer.

Answer: 107.87 g/mol

Explanation: I just took the test

Answer:

107.87 g/mol

Explanation: