What mass of carbon dioxide (CO2) will be produced if 2.90 moles of iron (Fe) is produced?

Hopefully this is close to what you looking for

One way :

-Dawn soap

-some water

-Salt crystals

-Put in freezer for a few hours

-StarGaze

(if this doesn't work comment)

I suggest using a little bit first, to see if it works for you.

Answer:

a. 74.55 g/mol.

b. 91.70 g.

c. 8.40%.

d. 1.23 mol/L.

Explanation:

a. Calculate the formula weight of KCl.

∵ Formula weight of KCl = atomic weight of K + atomic weight of Cl

atomic weight of K = 39.098 g/mol, atomic weight of Cl = 35.45 g/mol.

∴ Formula weight of KCl = atomic weight of K + atomic weight of Cl = 39.098 g/mol + 35.45 g/mol = 74.548 g/mol ≅ 74.55 g/mol.

b. Calculate the mass of KCl in grams.

no. of moles (n) = mass/molar mass.

∴ mass of KCl = n*molar mass = (1.23 mol)*(74.55 g/mol) = 91.69 g ≅ 91.70 g.

c. Calculate the percent by mass of KCl in this solution.

The mass % of KCl = (mass of KCl/mass of the solution) * 100.

mass of KCl = 91.70 g,

mass of the solution = 1000.0 g of water + 91.70 g of KCl = 1091.70 g.

∴ The mass % of KCl = (91.70 g/1091.70 g)*100 = 8.399% ≅ 8.40%.

d. Calculate the molarity of the solution.

Molarity is the no. of moles of solute per 1.0 L of the solution.

M = (no. of moles of KCl)/(Volume of the solution (L))

no. of moles of KCl = 1.23 mol,

Volume of the solution = mass of water / density of water = (1000.0 g)/(1.00 g/mL) = 1000.0 mL = 1.0 L.

M = (1.23 mol)/(1.0 L) = 1.23 mol/L.

a. The formula weight of KCl is 74.55 g/mol. b. The mass of KCl in grams is 91.39 g. c. The percent by mass of KCl in the solution is 9.14%. d. The molarity of the solution is 1.23 M.

a. The formula weight of KCl (potassium chloride) can be calculated by summing the atomic masses of potassium (K) and chlorine (Cl). The atomic mass of K is 39.10 g/mol and the atomic mass of Cl is 35.45 g/mol. Therefore, the formula weight of KCl is 39.10 g/mol + 35.45 g/mol = 74.55 g/mol.

b. To calculate the mass of KCl in the solution, we need to convert the given amount of KCl in moles to grams. Since 1 mole of KCl has a mass of 74.55 g (as calculated in part a), 1.23 mol of KCl will have a mass of 1.23 mol x 74.55 g/mol = 91.39 g.

c. The percent by mass of KCl in the solution can be calculated by dividing the mass of KCl (91.39 g, as calculated in part b) by the mass of the solution and multiplying by 100%. The mass of the solution is given as 1000.0 g. Therefore, the percent by mass of KCl in the solution is (91.39 g / 1000.0 g) x 100% = 9.14%.

d. The molarity of the solution can be calculated by dividing the number of moles of KCl by the volume of the solution in liters. The number of moles of KCl is given as 1.23 mol and the volume of the solution is 1000.0 g of water, which is equivalent to 1000.0 mL or 1.0000 L. Therefore, the molarity of the solution is 1.23 mol / 1.0000 L = 1.23 M.

Answer:

= 0.00325 moles of beryllium

Explanation:

Molarity or concentration is given by the formula;

Molarity = Number of moles/Volume in L

Therefore, to get the number of moles

Moles = Molarity × Volume

           = 0.025 M × 0.13 L

           = 0.00325 moles of beryllium

Answer:

1st answer:  A. Graphite

2nd answer:  B.  Mercury

Explanation:

Answer:

0.7692 M ≅ 0.77 M.

Explanation:

(MV) before dilution = (MV) after dilution.

M before dilution = 2.0 M, V before dilution = 0.25 L.

M after dilution = ??? M, V after dilution = 0.25 L + 0.40 L = 0.65 L.

∴ M after dilution = (MV) before dilution/(V) after dilution = (2.0 M)(0.25 L)/(0.65 L) = 0.7692 M ≅ 0.77 M.

Answer:

[tex]\boxed{\text{25 da}}[/tex]

Explanation:

Step 1. Convert pounds to milligrams

(a) Pounds to grams

[tex]\text{Mass} = \text{2 lb} \times \dfrac{\text{454 g}}{\text{1 lb}} = \text{910 g}[/tex]

(b) Grams to milligrams

[tex]\text{Mass} = \text{910 g} \times \dfrac{\text{1000 mg}}{\text{1 g}} = \text{910 000 mg}[/tex]

Step 2. Calculate the time

(a) Milligrams to minutes

[tex]t = \text{910 000 mg}} \times \dfrac{\text{20 min}}{\text{500 mg}} = \text{36 000 min}[/tex]

(b) Minutes to hours

[tex]t = \text{36 000 min} \times \dfrac{\text{1 h}}{\text{60 min}} = \text{610 h}[/tex]

(c) Hours to days

[tex]t = \text{ 610 h} \times \dfrac{\text{1 da}}{\text{24 h}} = \text{25 da}[/tex]

It will take [tex]\boxed{\textbf{25 da}}[/tex]to dissolve the iron oxide.

Answer : The time taken for the reaction is 36363.64 minutes.

Explanation :

First we have to convert the mass of iron oxide from milligram to pounds (lbs).

[tex]1\text{ lbs}=453592mg[/tex]

or,

[tex]1mg=\frac{1}{453592}\text{ lbs}[/tex]

As, [tex]1mg=\frac{1}{453592}\text{ lbs}[/tex]

So, [tex]500mg=\frac{500mg}{1mg}\times \frac{1}{453592}\text{ lbs}=0.0011\text{ lbs}[/tex]

Now we have to calculate the time taken for the reaction.

As, [tex]0.0011\text{ lbs}[/tex] of iron oxide take time = 20 minutes

As, [tex]2\text{ lbs}[/tex] of iron oxide take time = [tex]\frac{2\text{ lbs}}{0.0011\text{ lbs}}\times 20\text{ minutes}=36363.64\text{ minutes}[/tex]

Therefore, the time taken for the reaction is 36363.64 minutes.

Answer:

0.218 mol.

Explanation:

CH₄ + 2O₂ → CO₂ + 2H₂O,

It is clear that 1 mol of CH₄ reacts with 2 mol of O₂ to produce 1 mol of CO₂ and 2 mol of H₂O.

n = mass/molar mass = (7.84 g)/(18.0 g/mol) = 0.436 mol.

Using cross multiplication:

1 mol of CH₄ is needed to produce → 2 mol of H₂O, from stichiometry.

??? mol of CH₄ is needed to produce → 0.436 mol of H₂O.

∴ The no. of moles of CH₄ = (1 mol)(0.435 mol)/(2 mol) = 0.218 mol.

Answer:

0.16 rounded

Explanation:

I used a calculator to get this answer, one that compared grams and mol.

The mass of 0.000142 mole of vitamin C is approximately 0.025 grams. This is derived by multiplying the number of moles by the molar mass of vitamin C, which is 176.124 g/mol.

The mass in grams of 0.000142 mole of vitamin C can be calculated by using the formula:

Mass (grams) = number of moles x molar mass (g/mol)

Calculating the Mass of Vitamin C

We have 0.000142 mole of vitamin C, and the molar mass of vitamin C (ascorbic acid) is 176.124 g/mol. By multiplying these values, we get:

Mass = 0.000142 moles x  176.124 g/mol = 0.025010168 grams

Therefore, the mass of the recommended daily dietary allowance of vitamin C for children aged 4-8 years is approximately 0.025 grams.

Answer:

0.4444 g/cm³ ≅ 0.44 g/cm³ (2 significant figures).

Explanation:

d = m/V,

where, d is the density of the material (g/cm³).

m is the mass of the material (m = 28 g).

V is the volume of the material (V = 63.0 cm³).

∴ d = m/V = (28 g)/(63.0 cm³) = 0.4444 g/cm³ ≅ 0.44 g/cm³ (2 significant figures).

Answer:

37.25 grams/L.

Explanation:

M = (no. of moles of KCl)/(volume of the solution (L))

∵ no. of moles of KCl = (mass of KCl)/(molar mass of KCl)

∴ M = [(mass of KCl)/(molar mass of KCl)]/(volume of the solution (L))

∴ (mass of KCl)/(volume of the solution (L)) = (M)*(molar mass of KCl) = (0.5 M)*(74.5 g/mol) = 37.25 g/L.

So, the grams/L of KCl = 37.25 grams/L.

In a 0.5 M KCl solution, there are 0.5 moles of KCl per liter. Given the molecular weight of KCl is 74.5 g/mol, this would translate to 37.25 grams of KCl per liter.

If you have a 0.5 M KCl solution, this means that the concentration of KCl in the solution is 0.5 moles per liter. To find the amount of solute in moles, you would simply use the concentration of the solution and the volume of the solution. In this case, if you have a 1-liter solution, you will have 0.5 moles of KCl, since the concentration is 0.5 M.

To convert this amount in moles to grams, you will need to use the molecular weight of KCl, which is given as 74.5 g/mol. By multiplying the number of moles by the molecular weight, you get the grams of the solute:

0.5 moles × 74.5 g/mol = 37.25 grams of KCl

Therefore, in a 1-liter solution of 0.5 M KCl, you would have 37.25 grams of KCl.

Answer:

The right choice is "burning gas → pan → water → eggs"

Explanation:

Heat will flow from the body of higher temperature to the cooler body.

So, heat will firstly flow from burning gas to pan by conduction then to the water in contact with pan then to the egg present inside the water.

So, the right choice is :

"burning gas → pan → water → eggs"

Answer: Option (c) is the correct answer.

Explanation:

When two objects of different temperature come in contact with each other then heat will flow from hot object to cold object. This process of transfer of heat is known as conduction.

For example, a pan of boiling  eggs on a gas burner will have transfer of heat from gas burner to the pan and then heat will flow from water to the eggs.

This process is also a conduction process.

Thus, we can conclude that the path of heat  flow will be as follows.

        [tex]\text{burning gas} \rightarrow \text{pan} \rightarrow \text{water} \rightarrow \text{eggs}[/tex]

Answer: Option (D) is the correct answer.

Explanation:

Bases are the substances that release hydroxide ions when dissolved in water.

A strong base will dissociate completely in water and give more number of hydroxide ions [tex](OH^{-})[/tex]. Whereas a weak base will slightly dissolve to give hydroxide ions [tex](OH^{-})[/tex] in water.

So, a strong base will have high electrical conductivity and a weak base will have low electrical conductivity.

Since, both are bases (strong base and weak base) therefore, both of them will have bitter taste, slippery texture and they will turn red litmus into blue.

Hence, we can conclude that electrical conductivity tests could be safely used to distinguish a strong base from a weak base.

Litmus paper tests could be safely used to distinguish a strong base from a weak base. The correct answer is C.

To distinguish a strong base from a weak base, one can use litmus paper as a safe and effective method. Litmus paper is a pH indicator that changes color in response to the acidity or basicity of a solution.

When a strong base, such as sodium hydroxide (NaOH), comes into contact with litmus paper, it will cause a dramatic color change, typically from red to blue in the case of blue litmus paper.

This is because strong bases have a high concentration of hydroxide ions (OH-) and can rapidly accept protons (H+), leading to a significant increase in pH.

On the other hand, a weak base, such as ammonia (NH3), will also cause a color change but to a lesser extent or more slowly, reflecting its lower ability to accept protons compared to a strong base.

The pH change will be less dramatic, and the color change on the litmus paper may be less pronounced or take longer to occur.

The other options are not suitable for distinguishing between strong and weak bases:

A. Taste -

Tasting chemicals is extremely dangerous and should never be done. It does not provide a safe method to distinguish between strong and weak bases.

B. Touch -

While some bases may feel slippery or soapy to the touch due to the formation of soap-like substances when they react with oils on the skin, this method is not safe and does not provide a clear distinction between strong and weak bases.

D. Electrical conductivity -

Both strong and weak bases can conduct electricity if they are ionic and dissociate into ions in solution. Therefore, electrical conductivity cannot be used to distinguish between the strength of bases.

In summary, litmus paper is the safest and most reliable method among the options provided to distinguish a strong base from a weak base based on the degree of color change and the speed of the reaction.

Answer:

Explanation:

The most common way to solve this kind of problem is to use the formula  

In your problem,

For NaOH

C₁ =??     v₁= 78.0 mL = 0.078 L

For H₂SO₄

C₁ =1.25 M     v₁= 50.0 mL = 0.05 L

but you must note that for the reaction of NaOH with H₂SO₄

2 mol of NaOH raect with 1 mol H₂SO₄

So, by applying in above formula

So, the answer is the concentration of an NaOH = 1.6 M

Answer:

B) There is more water in the air because the rate of evaporation increases

Explanation:

As the temperatures rise across the globe, the rate of evaporation also increases, resulting in more water in the air. The reason for the increased evaporation is that the ice sheets and glaciers are melting, thus there's more liquid water. The more liquid water there is, the more evaporation there will be. As the evaporation increases, there will be an increase in the formation of clouds, thus there will be more precipitation around the world, gradually leading to warmer and wetter climate.

The lithium atom provides the fluorine atom with one electron making both atoms stable. Fluorine has a better positive charge than lithium so fluorine will attract the electron. Now, the atoms fuse together to form an ionic bond and making lithium fluoride. Ionic bonds are caused by the attraction between two forces of atoms.

Answer:

The lithium atom has one electron in its outer shell, so it loses that one electron and becomes a [tex]Li^{1+}[/tex] ion. The fluorine atom has 7 electrons in its outer shell so it gains that one electron and becomes a [tex]F^{1-}[/tex] ion. The electrostatic force of attraction between the two ions, because of their charges, bonds them together in an ionic bond to make [tex]LiF[/tex], Lithium Fluoride.

Couldn't add a diagram, but hope it helps.

Answer:

nano3 is a solid so its not that one it has to be NH3

Explanation:

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Final answer:

The substance among the given options that is a gas is NH3 or ammonia, as indicated by (g) for gaseous state in the provided reference list.

Explanation:

Among the substances listed — NaNO3, KL, KCL, and NH3 — the one that is a gas is NH3, also known as ammonia. From the reference information provided, NH3 is indicated as NH3(g), where (g) denotes that it is in the gaseous state at standard temperature and pressure. The other substances NaNO3, KL (which seems to be a typo and should likely be KI), and KCL (KCl) are solids as indicated by the (s) in the reference list provided.

NH3 is a common gas known for its pungent odor and is used in various applications, including household cleaning products and fertilizers.

Answer:

I believe two correct statements are;

The vapor pressure is produced by water molecules that have evaporated.

The vapor pressure increases as the Sun heats the water in the pot.

Explanation:

When an uncovered pot of water lies out in the sun then the vapor pressure is produced by water molecules that have evaporated and increases as the Sun heats.

Vapor pressure is a property of the substance which may change into gaseous state.

When an uncovered pot of water lies out in the sun, then the vapor pressure is produced by the water molecules of the surface phase and they get evaporated. And due to heat transfer by the sun in the form of sunlight vapor pressure of water also increases, which results into more evaporation.

Hence, option (2) and (3) is correct it means vapor pressure increases as the sun heats the water in the pot and they get evaporated.

To know more about vapor pressure, visit the below link:

https://brainly.com/question/25863019

The

balanced reaction is:

2LiOH + CO2 = Li2CO3 + H2O

We

are given the amount of the reactants to be reacted. This will be the starting point of our

calculations. To determine the limiting reactant, we convert the amounts from grams to moles.

1.000 × 10^3 g LiOH  (1 mol / 25.95 g) = 38.54 mol LiOH

8.80 × 10^2 g CO2 ( 1mol / 44.01 g) = 20.00 mol CO2

From the balanced reaction, the molar ratio of the reactants is 2:1. This means that every two mole of lithium hydroxide, 1 mole of carbon dioxide is needed. It is clear that, from the given amounts, CO2 is the limiting reactant.

Answer: The limiting reagent is carbon dioxide and theoretical yield of the reaction is 360 g.

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 LiOH = [tex]1.00\times 10^3g[/tex]

Molar mass of LiOH = 23.95 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of LiOH}=\frac{1.00\times 10^3g}{23.95g/mol}=41.75mol[/tex]

Given mass of carbon dioxide = [tex]8.8\times 10^2g[/tex]

Molar mass of carbon dioxide = 44 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of carbon dioxide}=\frac{8.8\times 10^2g}{44g/mol}=20mol[/tex]

[tex]2LiOH(s)+CO_2(g)\rightarrow Li_2CO_3(s)+H_2O(l)[/tex]

By Stoichiometry of the reaction:

1 moles of carbon dioxide reacts with 2 moles of lithium hydroxide.

So, 20 moles of carbon dioxide will react with = [tex]\frac{2}{1}\times 20=40mol[/tex] of lithium hydroxide.

As, given amount of lithium hydroxide is more than the required amount. So, it is considered as an excess reagent.

Thus, carbon dioxide is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of carbon dioxide produces 1 mole of water

So, 20 moles of carbon dioxide will produce = [tex]\frac{1}{1}\times 20=20moles[/tex] of water

Molar mass of water = 18 g/mol

Moles of water = 20 moles

Putting values in equation 1, we get:

[tex]20mol=\frac{\text{Mass of water}}{18g/mol}\\\\\text{Mass of water}=360g[/tex]

Hence, the limiting reagent is carbon dioxide and theoretical yield of the reaction is 360 g.

Answer:

An Arrhenius Base

Explanation:

The definition of this is a base that is a hydroxide ion donor.

A base is a substance that produces hydroxide ions in solutions.

A base that produces hydroxide ions in aqueous solution is also known as:  A. Arrhenius bases

An Arrhenius base is a compound that increases the OH− ion concentration in aqueous solution. The reaction between an Arrhenius acid and an Arrhenius base is called neutralization and results in the formation of water and a salt.

An Arrhenius base is a substrate that increases the concentration of hydroxide ions in the aqueous solution. The example for Arrhenius base is highly soluble sodium hydroxide compound in water, which dissociates to give sodium ion and hydroxide ion.

Other examples of Arrhenius acids include sulfuric acid (H2SO4), hydrobromic acid (HBr), and nitric acid (HNO3). Examples of Arrhenius bases include sodium hydroxide (NaOH) and potassium hydroxide (KOH).

To learn more about Arrhenius bases, refer

https://brainly.com/question/22759569

#SPJ2

Answer: -345.2 KJ

Explanation: As we know that ,dG=dH-TdS

T=25+273=298 K

dG= -356 x1000-298(-36)= -356000+10728

=-345272 j

= -345.2 KJ

Answer:

d) non-renewable resources

Explanation:

A natural resource such as coal, gas, or oil that, once consumed, cannot be replaced. Most energy resources currently in use are non-renewable while the renewable ones (such as wind and solar power) are not well developed. Also called depletable resource.

Answer: Non renewable resources.

Explanation: The non renewable resources can be defined as the resources that once used cannot be replenished. The resources like oil and copper takes very long time to form and this makes it non-renewable.

The natural resources like oil takes a long time to form inside the ocean and its extraction is also done after long time because its formation takes time.

Answer:

3718.628 kPa.

Explanation:

where, P is the pressure of the gas in atm (P = ??? atm).

V is the volume of the gas in L (V = 2.0 L).

n is the no. of moles of the gas in mol (n = 3.0 mol).

R is the general gas constant (R = 0.0821 L.atm/mol.K),

T is the temperature of the gas in K (T = 298.0 K).

∴ P = nRT/V = (3.0 mol)(0.0821 L.atm/mol.K)(298.0 K)/(2.0 L) = 36.7 atm.

∵ 1.0 atm = 101.325 kPa.

∴ P = (36.7 atm)(101.325 kPa/1.0 atm) = 3718.628 kPa.

Answer:

A large plateau forms in the interior of a continental plate when a large section of the plate rises evenly due to an even expansion of the underlying mantle. B.

Answer: Option (A) and (D)

Explanation: Epeirogenic process refers to the uplifting and sinking of the continental crust. It is the vertical movement of the crust due to certain mechanisms. Divergent movement of the plates leads to the thinning of the crust and in the convergent plate boundary between a continent and oceanic plate, creates an accretionary wedge that increases the vertical height of the crust. It is not related to the continental collision and plateaus are the stable part of the continent where there is not much change in the thickness of the crust.

Thus the correct answers are (A) and (D)

Hello There!

The Answer Is In Image Provided.

Your Unit Is Still Kilometers

Answer:

2,700 mmHg.

Explanation:

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

P₁V₁T₂ = P₂V₂T₁

P₁ = 760 mmHg, V₁ = 0.50 m³, T₁ = 33°C + 273 = 306.0 K.

P₂ = ??? mmHg, V₂ = 0.10 m³, T₂ = - 55°C + 273 = 218.0 K.

∴ P₂ = P₁V₁T₂/V₂T₁ = (760 mmHg)(0.50 m³)(218.0 K)/(0.10 m³)(306.0 K) = 2707.0 mmHg ≅  2,700 mmHg.

Answer:

2,700 mmHg.

Explanation:

Answer:  

--Acid is the substance when dissolved in water, increases the concentration of H+ ions.

--Such compound whose chemical formula begins with H, for example HCl (Hydrochloric acid), H3BO3 (Boric acid), CH2O3 (Carbonic

acid). Although CH3COOH (Acetic acid) is an exception.

--Its less than 7.

--Bases are the proton acceptor.

--Such compounds whose chemical formula ends with OH, for example KOH (Potassium hydroxide), NaOH (Sodium hydroxide).

--Its greater than 7.

Explanation:

One can distinguish between a strong acid and a strong base by using pH paper or a pH meter, observing the reaction in a neutralization process with known substances, and testing the conductivity of the solutions.

To distinguish between a strong acid and a strong base, one can use the following three safe methods:

It's important to handle all strong acids and bases with proper safety equipment and procedures due to their corrosive nature.

Answer:

[tex]\boxed{\text{2.0 atm}}[/tex]

Explanation:

If the temperature is constant, the only variables are pressure and volume, so we can use Boyle’s Law.

p₁V₁ = p₂V₂

Data:

p₁ = 4.4 atm; V₁ = 32.14 L

p₂ = ?;           V₂ = 72     L

Calculation:

4.4 × 32.14 = p₂ × 72

141 = 72p₂

[tex]p_{2} = \dfrac{141}{72} = \textbf{2.0 atm}[/tex]

The new pressure is [tex]\boxed{\textbf{2.0 atm}}[/tex]

Answer:

7366.328 kPa.

Explanation:

1.0 atm = 101.325 kPa.

The conversion factor = (101.325 kPa/1.0 atm)

∴ The critical pressure of carbon dioxide (in kPa) = (72.7 atm)(101.325 kPa/1.0 atm) = 7366.328 kPa.

Answer:

= 7366.328 kPa.

Explanation:

(72.7 atm)(101.325 kPa/1.0 atm)

= 7366.328 kPa.

Answer: 650 moles

Explanation: so converted in grams just to make it easy for me, its 5850 g of water right, which is 325 moles of water

so here's the balanced equation

MgCl2 + H20 ==> 2HCl + MgO

thus 1 mole of h20 gives us 2 moles of hcl, so 325 x 2 = 650 moles of hcl

Answer:

The second and third option are isotopes of Bromine

Z=  35 A = 79

A = 79  N= 44

Explanation:

Step 1: What are isotopes ?

⇒ Elements  with same atomic number (Z) ( this means the same number of electrons and protons) but a different number of neutrons (N)

The atomic number (visible on the periodic table) is the number of protons.

The atomic mass is  the sum of the protons (Z) and neutrons (N), and is showed as 'A'. So A = Z+N

If we look at the periodic table, we can see that the atomic number of bromine (Z) = 35. This means the amount of protons = 35. Since isotopes have the same amount of protons, all isotopes of bromine, have 35 protons.

1) Z = 79, A = 196

Z = protons = electrons .So this element has 79 protons, as well as 79 electrons.

196 = 79 + N ⇒ N = 196 - 79 = 117 neutrons

⇒Since it doesn't have 35 protons, it isn't an isotope of Bromine, but of Gold (Au): 196Au

2) Z = 35 , A = 79

Z = protons = electrons .So this element has 35 protons, as well as 35 electrons.

79 =35 + N ⇒ N = 79 - 35= 44 neutrons

⇒Since it does have 35 protons, it is an isotope of Bromine. This isotope has 44 neutrons

⇒ This is 79Br, which is a stable isotope of Bromine.

3) A=79, N = 44

Z = A - N ⇒ Z = 79 - 44 = 35

Z = protons = electrons .So this element has 35 protons, as well as 35 electrons. It also has 44 neutrons.

⇒Since it does have 35 protons, it is an isotope of Bromine, with 44 neutrons: 79Br

4) Z = 44, N = 44

Z = protons = electrons .So this element has 44 protons, as well as 44 electrons.

A = 44 + 44 ⇒ A = 88  

⇒Since it doesn't have 35 protons, it isn't an isotope of Bromine, but of Ruthenium (Ru) : 88Ru

⇔So the second and third option are isotopes of Bromine