7. Which of the following is an element? a) Sugar b) Copper c) Salt d) Water

A battery is a device that converts chemical energy into electrical energy through a process known as an electrochemical reaction.

When a battery is connected to a circuit, the electrochemical reaction causes a flow of electrons from the anode to the cathode, generating an electric current that can power a device.

The metal chosen for the anode must be capable of losing electrons easily, while the metal chosen for the cathode must be capable of accepting electrons. The choice of metals can also affect the voltage and capacity of the battery, as well as its overall efficiency.

In general, the metals used in a battery should have a large difference in their electronegativity values, which determines how easily an atom can attract electrons. Common metals used in batteries include zinc, lithium, nickel, and cadmium.

Find out more on batteries at https://brainly.com/question/16553902

#SPJ1

By comparing the standard potentials for each reaction, we can estimate the standard potential of the unknown metal and determine the metal in question. To estimate the standard potential of the unknown metal, we need to use the Nernst equation:

[tex]E = Eo - (RT/nF) ln(Q)[/tex]

Where E is the standard potential, [tex]Eo[/tex] is the standard reduction potential, R is the gas constant, T is the temperature, n is the number of moles of electrons transferred, F is the Faraday constant, and Q is the reaction quotient.
First, we need to calculate the change in mass for each of the platinum plates. For the plate dipped in the copper (II) sulphate solution, the change in mass is:
Δ[tex]m = (3.600/100) * m = 0.036 * m[/tex]
For the plate dipped in the mercury (II) sulphate solution, the change in mass is:
Δ[tex]m = (6.675/100) * m = 0.06675 * m[/tex]
Next, we need to calculate the reaction quotient (Q) for each reaction. The reaction quotient is the ratio of the concentrations of the products to the concentrations of the reactants. For the copper (II) sulphate solution, the reaction quotient is:
[tex]Q = [Cu2+]/[Cu][/tex]
For the mercury (II) sulphate solution, the reaction quotient is:
[tex]Q = [Hg2+]/[Hg][/tex]
Now, we can plug these values into the Nernst equation to estimate the standard potential of the unknown metal. For the copper (II) sulphate solution:
[tex]E = Eo - (RT/nF) ln(Q)\\= Eo - (RT/nF) ln([Cu2+]/[Cu]) \\= Eo - (RT/nF) ln(0.036)[/tex]
For the mercury (II) sulphate solution:
[tex]E = Eo - (RT/nF) ln(Q) \\= Eo - (RT/nF) ln([Hg2+]/[Hg]) \\= Eo - (RT/nF) ln(0.06675)[/tex]

We can estimate the standard potential of the unknown metal and identify it by comparing the standard potentials for each reaction.

For more question on Nernst equation click on

https://brainly.com/question/30080689

#SPJ11

the molarity of the NaOH solution is 0.219 M (to three significant figures).

The balanced chemical equation for the reaction between NaOH and KHC8H4O4 is:

KHC8H4O4 + NaOH → KNaC8H4O4 + H2O

The stoichiometry of the reaction indicates that 1 mole of KHC8H4O4 reacts with 1 mole of NaOH.

The molecular weight of KHC8H4O4 is 204 g/mol, and the mass of KHC8H4O4 used in the titration is 1.45 g. Therefore, the number of moles of KHC8H4O4 used in the titration is:

n(KHC8H4O4) = mass/molar mass = 1.45 g / 204 g/mol = 0.007107 moles

The volume of NaOH used in the titration is 32.46 mL, or 0.03246 L.

Therefore, the molarity of NaOH can be calculated as:

Molarity = moles of NaOH / volume of NaOH

Since 1 mole of KHC8H4O4 reacts with 1 mole of NaOH, the number of moles of NaOH used in the titration is also 0.007107 moles.

Molarity = 0.007107 moles / 0.03246 L = 0.219 M

learn more about molarity here:

https://brainly.com/question/8732513

#SPJ4

Copper reacts with oxygen to form two oxides, x and y; 1. 535g of x yielded 1. 160g of copper in analysis.the chemical formula of x and y is Cu2O3.

the amount of oxygen in oxide is

1.535 g of oxide x contains 1.160 g of copper.

Therefore, the mass of oxygen in oxide x is:

1.535 g - 1.160 g = 0.375 g

moles of oxygen = 0.375 g / 16.00 g/mol = 0.0234 mol

moles of copper = 1.160 g / 63.55 g/mol = 0.0182 mol

Now, we can divide both moles by the smaller one to get the mole ratio:

0.0234 mol / 0.0182 mol = 1.28

0.0182 mol / 0.0182 mol = 1.00

total mass of copper and oxygen in both oxides = 1.535 g + unknown mass of oxide y

Mass of oxygen in oxide y = mass of copper and oxygen in both oxides - mass of copper in oxide x

mass of oxygen in oxide y = (1.535 g + unknown mass of oxide y) - 1.160 g

mass of oxygen in oxide y = 0.375 g + unknown mass of oxide y

mass of oxide y = 1.535 g - 0.375 g = 1.160 g

oxide y has a mass of 1.160 g. Since the total mass of copper and oxygen in oxide y is the same as in oxide x, the formula for oxide y is Cu2O3.

learn more about moles here:

https://brainly.com/question/28239680

#SPJ4

2.02 g mass of oxygen are produced during the decomposition of 4.04 g of potassium nitrate.

According to the law of conservation of mass, the total mass of the reactants in a chemical reaction is equal to the total mass of the products. Therefore, we can use this law to determine the mass of oxygen produced in the decomposition of potassium nitrate.

Let's assume that x grams of oxygen (O2) are produced during the decomposition of 4.04 g of potassium nitrate (KNO3). The balanced chemical equation for the decomposition of KNO3 is:

2 KNO3 --> 2 KNO2 + O2

From the equation, we can see that 2 moles of KNO3 produce 1 mole of O2. We can use this information to set up a proportion to solve for x:

2 mol KNO3 / 1 mol O2 = 4.04 g KNO3 / x g O2

Solving for x, we get:

x = (1 mol O2 / 2 mol KNO3) x (4.04 g KNO3) = 2.02 g O2

Therefore, 2.02 g of oxygen are produced during the decomposition of 4.04 g of potassium nitrate using law of conservation of mass.

Learn more on law of conservation of mass below.

https://brainly.com/question/1992248

#SPJ1

Answer:

154 g/mole

Explanation:

We are given the mass of the gas, but we also need the number of moles the 2.929g represents.  Since we are provided the conditions of the gas, we can the Ideal Gas law to find the number of moles of the mystery gas.  

Ideal Gas Law:  PV = nRT, where P, V, and T are the pressure, volume, and temperature (temperature must be in degrees Kelvin), n is the moles, and R is the gas constant.

Let's choose the gas constant that has the same units as we were given.  R = 0.0820575 [L⋅atm⋅/(K⋅mol)] comes the closest, but we'll still need to convert ml to liters(L) and °C to °K:

  426mL = 0.426L

  0°C = 273.25   [add 273.15 to the Centrigrade value]

Let's rearrnage the ideal gas law to solve for n, the number of moles:

                           n = (PV/RT)

Now enter the data:

                            n = (1atm)(0.426L)/[(0.0820575 L⋅atm⋅/(K⋅mol))*(273.15°K)]

n = (1atm)(0.426L)/[(0.0820575 L⋅atm⋅/(K⋅mol))*(273.15°K)]   [Units that cancle are highlighted]

n = (1)(0.426)/[(0.0820575 /(mol))*(273.15)]  [We are left only with moles (mol)

n = (0.426)/(0.0820575)/(273.15) [1/1/mol]  [Move the only unit out (1/1/mol)]

n = (0.426)/(0.0820575)/(273.15) [1/1/mol] = 0.0190 moles

Note that the unit moves to the top, i.e., : 1/1/mol = mole

We have the mass and the number of moles.  Divide the two to obtain molar mass:

      (2.929g)/(0.0190 moles) = 154 g/mole   This is also the molecular weight.

[I don't know what is a gas at 0°C and has that molecular weight]

The molecular mass of the substance is 181 g/mol if 22. 5 g dissolved in 250 g of water produces a solution whose freezing point is -0. 930°C.

To determine the molecular mass of the substance, we can use the freezing point depression formula:

ΔTf = Kf·m

Where ΔTf is the freezing point depression, Kf is the freezing point depression constant of water (1.86°C·kg/mol), and m is the molality of the solution, which is the number of moles of solute per kilogram of solvent.

We can start by calculating the molality of the solution:

molality = moles of solute/mass of solvent (in kg)

Since we know that 22.5 g of the substance is dissolved in 250 g of water, we can calculate the mass of the solvent as:

mass of solvent = 250 g / 1000 = 0.250 kg

The mass of the solute can be calculated as:

mass of solute = 22.5 g / 1000 = 0.0225 kg

Now we can calculate the molality of the solution:

molality = 0.0225 kg / 0.250 kg = 0.09 mol/kg

Next, we can use the freezing point depression formula to calculate the molecular mass of the substance:

ΔTf = Kf·m

-0.930°C = 1.86°C·kg/mol x 0.09 mol/kg

Solving for the molecular mass (M):

M = (Kf x m) / ΔTf = (1.86°C·kg/mol x 0.09 mol/kg) / 0.930°C

M = 0.181 kg/mol = 181 g/mol

Therefore, the molecular mass of the substance is 181 g/mol.

Learn more about molecular mass:

https://brainly.com/question/18446366

#SPJ4

Recording temperature and barometric pressure is critical because they are two essential parameters that help determine weather conditions. One can affect the other, and understanding their relationship can provide valuable insights into weather patterns and changes.

Let's understand this in detail:

Barometric pressure affects temperature, and temperature affects barometric pressure. The two are closely linked and work together to influence weather patterns. Temperature affects barometric pressure through thermal expansion. As temperature increases, molecules within the air move around more vigorously, requiring more space.

The result is that the volume of air increases, which decreases the pressure. Conversely, when temperatures drop, molecules move less, requiring less space and increasing pressure.

Barometric pressure also affects temperature by affecting air density. When barometric pressure drops, the air expands, and density decreases. The air then rises and cools. Conversely, when barometric pressure increases, the air becomes denser and sinks, warming as it descends. Hence, temperature and barometric pressure affect each other.

#SPJ11

Learn more about barometric pressure: What is a barometric pressure? https://brainly.com/question/3083348

In order to make a bulb light up, certain conditions need to be met. Firstly, there must be a closed circuit, meaning that there is a continuous flow of current through the circuit. This can be achieved by connecting the bulb to a power source, such as a battery or a generator, and completing the circuit with wires.

Secondly, the bulb must be connected properly to the circuit. This involves connecting the positive and negative terminals of the bulb to the corresponding terminals of the power source or the wires.

Finally, the bulb must have the correct voltage and wattage rating. Using a bulb with a higher or lower rating than the power source can cause the bulb to either not light up or burn out quickly.

To learn more about battery refer to:

brainly.com/question/16953222

#SPJ4

Answer:

Microbiologists

Explanation:

Microbiologists are scientists who study the processes that make cells work.

Answer:

36 atoms

Explanation:

The reactants in the equation contain 6 carbon atoms, 12 hydrogen atoms, and 18 oxygen atoms. So the total number of atoms in the reactants is:

6 (carbon atoms) + 12 (hydrogen atoms) + 18 (oxygen atoms) = 36 atoms

The heat capacity of the metal when it is placed in 100 mL of water is 0.414 J/g°C.

The heat capacity of an unknown metal when it is placed in a 100 mL of water can be calculated using the formula given below; Q = mcΔT Where, Q = Heat supplied or absorbed mc = Mass of water x specific heat capacity of waterΔT = Temperature change Substituting the given values, we get; Q = 100 x 4.18 x (57 - 23)Q = 14104 Joules Heat supplied by the metal = Heat absorbed by the water Q = mcΔTm = Q / cΔT

Where, m = Mass of metal c = Specific heat capacity of metalΔT = Temperature change. Substituting the given values, we get;100 x c x (57 - 23) = 14104c = 14104 / 100 x 34c = 0.414 J/g°C. The heat capacity of the metal when it is placed in 100 mL of water is 0.414 J/g°C.

Know more about heat capacity

https://brainly.com/question/27991746

#SPJ11

When 100 mL of carbon disulfide is burned completely, we get 37.02 L of CO2 and 74.14 L of SO2 at STP.

What is STP?

STP stands for Standard Temperature and Pressure. It is defined as a temperature of 0 degrees Celsius (273.15 K) and a pressure of 1 atmosphere (or 101.325 kPa). STP is used as a reference point for many thermodynamic calculations and is often used to compare gas volumes under standardized conditions.

The balanced equation for the combustion of carbon disulfide (CS2) is:

CS2 + 3O2 → CO2 + 2SO2

From the equation, we can see that for every mole of CS2 burned, we get one mole of CO2 and two moles of SO2.

To find the moles of CS2 in 100. mL, we need to convert the volume to mass using the density of CS2:

mL x (1.26 g/mL) = 126 g

The molar mass of CS2 is 76.14 g/mol, so the number of moles of CS2 is:

126 g / 76.14 g/mol = 1.655 mol

Therefore, we will get:

1.655 mol CO2 and 2 x 1.655 = 3.31 mol SO2

To convert these values to volume at standard temperature and pressure (STP), we can use the conversion factor:

1 mol of any gas at STP occupies 22.4 L

So:

1.655 mol CO2 x 22.4 L/mol = 37.02 L CO2

3.31 mol SO2 x 22.4 L/mol = 74.14 L SO2

Learn more about STP from given link

https://brainly.com/question/2783971

#SPJ1

a. Sodium hydroxide(aq) + ammonium sulfate(aq) will react to form solid ammonium hydroxide and sodium sulfate(aq). b. Niobium(V) sulfate(aq) + barium nitrate(aq) will react to form solid barium sulfate(s) and niobium(V) nitrate(aq).

Predicting whether a reaction will occur in aqueous solution is important in understanding chemical reactions and their potential outcomes. It allows chemists to determine what products will form and whether a reaction is feasible or not based on the solubility of the reactants and products.

To predict whether a reaction will occur in aqueous solution, one can use solubility rules to determine whether the products of the reaction will form an insoluble precipitate or remain in solution. If a precipitate forms, it indicates that a reaction has occurred, whereas if all the products remain in solution, the reaction will not occur. Additionally, one can use other chemical principles, such as redox reactions and acid-base reactions, to predict whether a reaction will occur.

Learn more about "Sodium hydroxide" here:

https://brainly.com/question/29327783

#SPJ1

Explanation:

Foremost among the threats is fishing bycatch—marine animals incidentally caught and killed in fishing operations.

This is a serious crisis, not only for these charismatic animals, but also for the health of our oceans, where cetaceans play an irreplaceable role as apex predators.

The valence electrons of oxygen are; 2s2 2p4

The valence electrons of nitrogen are 2s2 2p3

This is how we can be able to know the number of valence electrons.

Valence electrons are the electrons in the outermost shell of an atom. They are the electrons involved in chemical reactions and bonding with other atoms. In the case of nitrogen, its electron configuration is 1s^2 2s^2 2p^3, which means it has two electrons in the first shell, two electrons in the second shell, and three electrons in the outermost p orbital, giving it a total of 5 valence electrons.

Oxygen has an electron configuration of 1s^2 2s^2 2p^4, which means it has two electrons in the first shell, two electrons in the second shell, and four electrons in the outermost p orbital, giving it a total of 6 valence electrons.

Learn more about valence shell:https://brainly.com/question/2725863

#SPJ1

Answer:

Place the graduated cylinder on a flat surface and view the height of the liquid in the cylinder with your eyes directly level with the liquid.

hope it helps :)

Without knowing more about the individual balloon and its surroundings, it is impossible to estimate the precise amount of time it would take for a helium-filled balloon to deflate.

Nonetheless, based on helium's general characteristics and its slower rate of diffusion than hydrogen, we would anticipate that a helium-filled balloon will outlast a hydrogen-filled balloon under comparable circumstances.

Generally, the helium gas diffuses slowly as compared to the hydrogen gas and that's why many ballon these days are filled with helium gas. Helium gas has the larger atomic size and lower solubility in many materials.

To estimate the time it would take for a helium-filled balloon to go flat, we can use the same basic formula that governs the diffusion of gases through materials.

This formula, known as Fick's law of diffusion, describes the rate at which a gas diffuses through a material as proportional to the concentration gradient of the gas across the material, as well as to a constant known as the diffusion coefficient.

In summary it is very difficult to exactly state the time in which  helium balloon to go flat without knowing the environment and other important factors.

To know more about helium gas -

brainly.com/question/1780577

#SPJ4

The negative sign means that heat was transferred from the aluminium piece to the ethyl alcohol. Consequently, the heat exchange of the system is roughly -22,770 J, or -2.28 x 10^4 J (to 2 significant figures).

The mixture's temperature rises to 20 C. The mixture in the calorimeter is then dipped into by a metallic block of mass 1 kilogramme at 10°C. The temperature rises to 19 C once thermal equilibrium has been reached.

Q = m * c * T, where Q is the heat exchanged, m is the mass of the substance, c is the specific heat capacity, and T is the change in temperature, is the formula used to determine the heat exchanged.

We can use the following formula to determine the equilibrium temperature:

m_al * c_al * (T_eq - T_al) = m_et * c_et * (T_et - T_eq)

By entering the specified values, we obtain:

(0.100 kg) * (0.902 J/g°C) * (T_eq - 450.0°C) = (0.100 kg) * (2.44 J/g°C) * (80.0°C - T_eq)

Simplifying, we get:

90.2 J/C * (T_eq - 450.0) = 244 J/C * (80.0 - T_eq)

90.2 T_eq - 40590 = 19520 - 244 T_eq

334.2 T_eq = 60110

T_eq ≈ 179.7°C ≈ 180°C (to the nearest 10°C)

As a result, the mixture's equilibrium temperature is roughly 180 °C.

(B) We can apply the same formula as before to determine the system's heat exchange. We can suppose that the mixture has a specific heat capacity equal to that of ethyl alcohol.

Q = m_al * c_al * (T_eq - T_al) + m_et * c_et * (T_eq - T_et)

Plugging in the given values, we get:

Q = (0.100 kg) * (0.902 J/g°C) * (180.0°C - 450.0°C) + (0.100 kg) * (2.44 J/g°C) * (180.0°C - 80.0°C)

Q ≈ -22,770 J ≈ -2.28 x 10⁴ J (to 2 significant figures)

To know more about ethyl alcohol visit:-

https://brainly.com/question/29153788

#SPJ1

To draw the Lewis dot structure for each of the molecules, start by counting the total number of valence electrons. Each atom has its own specific number of valence electrons, which can be found on the periodic table. Once the total valence electrons are counted, arrange the atoms to create a skeletal structure. Then, add electrons to each atom, beginning with the central atom, until all of the valence electrons are used.

The electron group geometry can be determined by counting the number of electron groups around the central atom. These electron groups can be single bonds, double bonds, lone pairs, or other molecules. The molecular geometry is the shape of the molecule based on the positions of the atoms in the structure.

Once the Lewis dot structure is drawn and the electron groups and molecular geometry are identified.

Know more about electron groups here:

https://brainly.com/question/16661930

#SPJ11

The formula for the first Compound I is likely A2B, or O2N.

To show that the data are in accordance with the law of multiple proportions, we need to calculate the ratios of the masses of element B that combine with a fixed mass of element A in each compound. If these ratios are in simple whole-number ratios, then the law of multiple proportions is upheld.

For Compound I:

Mass of A (23.3 g) / Mass of B (3.00 g) = 7.77

For Compound II:

Mass of A (7.00 g) / Mass of B (4.50 g) = 1.56

These ratios are not equal, indicating that the two compounds have different ratios of A and B. However, we can simplify the ratio for Compound II by dividing both masses by the mass of B:

Mass of A (7.00 g / 4.50 g) = 1.56

This suggests that Compound II has a 2:3 ratio of A to B.

Using this information, we can determine the formula of Compound II. Let x be the atomic mass of A and y be the atomic mass of B:

(2x) + (3y) = 4.50 g

Solving for y gives us y = 1.00 g/mol. Since the formula of Compound II is AB2, we know that the atomic mass of A is 2 g/mol. Therefore, A is likely oxygen (atomic mass 16 g/mol).

For Compound I, we know that A is oxygen (atomic mass 16 g/mol). Using the same approach as above, we can determine that B has an atomic mass of 14 g/mol. Therefore, the formula for Compound I is likely A2B, or O2N.

For such more questions on Law of multiple proportions

https://brainly.com/question/13446182

#SPJ4

Answer:

1- Oxygen in water

2- Brass, bronze and sterling silver

3- Air

Answer:

the mass of Na2SO4 produced is 27.6 g.

Explanation:

determine the balanced chemical equation for the reaction between NaCl and H₂SO4, and then use stoichiometry to calculate the mass of Na2SO4 produced.

The balanced chemical equation for the reaction is:

2 NaCl + H₂SO4 → Na2SO4 + 2 HCl

This equation tells us that 2 moles of NaCl react with 1 mole of H₂SO4 to produce 1 mole of Na2SO4.

First, we need to determine the number of moles of NaCl and H₂SO4 we have:

moles of NaCl = mass / molar mass = 48.0 g / 58.44 g/mol = 0.821 mol

moles of H₂SO4 = mass / molar mass = 19.0 g / 98.08 g/mol = 0.194 mol

Since H₂SO4 is the limiting reactant (it is present in less amount than required for complete reaction), we need to use the number of moles of H₂SO4 to calculate the number of moles of Na2SO4 produced:

moles of Na2SO4 = moles of H₂SO4 / 1 x (1 mole Na2SO4 / 1 mole H₂SO4) = 0.194 mol x (1/1) = 0.194 mol

Finally, we can use the molar mass of Na2SO4 to calculate the mass of Na2SO4 produced:

mass of Na2SO4 = moles of Na2SO4 x molar mass = 0.194 mol x 142.04 g/mol = 27.6 g

Therefore, the mass of Na2SO4 produced is 27.6 g.

Pb + SO42- → PbSO4 + 2 e-, Reduction occurs at the cathode, so the answer is C. 2 MnO2 + 2 H+ → Mn2O3 + H2O, Oxidation occurs at the anode, so the answer is A. Cu → Cu2+ + 2 e-, Reduction occurs at the cathode, so the answer is C. 2 H+ + 2e- → H2, Reduction occurs at the cathode, so the answer is C.

Reduction is a chemical reaction in which an atom, ion, or molecule gains one or more electrons. During a reduction reaction, the oxidation state of the atom or molecule that accepts the electrons becomes more antagonistic or reduced.

An anode and a cathode are two electrodes used in various electrochemical devices, such as batteries, fuel cells, and electrolysis cells. The anode and cathode work together to allow electrons to flow between them, creating an electrical current.

To learn more about cathode, visit here:

https://brainly.com/question/4052514

#SPJ1

3.28 x 10³ mol of water has a mass of 59.1156 kg. This is the accurate answer to the given question.

We can use the molar mass of water, which is 18.02 g/mol, to calculate the mass of 3.28 x 10³ moles of H2O. The following equation can be used to translate the quantity of moles into grams:

mass is determined by multiplying the number of moles by the molar mass.

Inputting the values provided yields:

18.02 g/mol times 3.28 x 10 3 moles of mass equals 59,115.6 g.

Lastly, by dividing by 1000, we can change the mass from grams to kilograms:

mass is 59,115.6 grams per kilogram (59.1156 kg).

As a result, 3.28 x 10³ moles of H2O have a mass of 59.1156 kg.

To learn more about moles visit:

brainly.com/question/26416088

#SPJ1

The inner core of earth remains a solid ball of metal due to the immense pressure it experiences from the layers above it.

The inner core is made up of mostly iron and nickel and is the hottest part of the Earth, with temperatures reaching up to 5,400°C (9,800°F). However, despite the high temperatures, the inner core remains solid due to the immense pressure from the weight of the outer core, mantle, and crust above it.

This pressure is so great that it prevents the inner core from melting and keeps it in a solid state. Additionally, the inner core is also believed to be slowly growing as the outer core cools and solidifies onto it.

This growth is thought to contribute to the Earth's magnetic field, which is generated by the movement of molten metal in the outer core.

For more question on inner core of earth click on

https://brainly.com/question/7038352

#SPJ11

The birth rate is  28.2 births per year

The number of births per 1,000 persons in a particular population over a given time period is commonly used to determine the birth rate.

The following is the formula that can be used to calculate the birth rate:

(Number of births / Population) x 1,000 is the birth rate.

The birth rate can be obtained from;

Birth rate = (Number of births / Population) x 1,000

We know that the birth rate can be obtained from;

7.34 x 10^4 / 2.6 x 10^6  * 1000

= 28.2 births per year

Learn more about birth rate:brainly.com/question/14148819

#SPJ1

Answer:

4 grams of sulfur contains the same number of atoms as 7 g of iron

Explanation:

The statement "same number of atoms" is the same as stating "the same numer of moles."  Moles are a count of atoms/molecules/etc.

So let's convert the masses into moles.  Take the mass of an element and divide that by its molar mass (g/mole) to obtain moles of that element.

See the attached worksheet for these calculations.

The 7 grams of iron represents 0.125 moles of iron.  The worksheet tells us that 4 grams of sulfur is also 0.125 moles.  Nothing else has that number.  

7 g of iron contains the same number of atoms as 4 grams of sulfur.

 [1 mole = 6.02x10^23 particles].