PART OF WRITTEN EXAMINATION:
In the galvanic series, the more active metals:
A) are more cathodic metals than noble metals
B) will corrode if connected to a less active metal
C) will not corrode if connected to a less active metal
D) are generally resistant to corrosion

There are approximately 0.4495 moles of methane in a 7.21 gram sample. To calculate the number of moles of methane in a given sample, you need to divide the mass of the sample by the molar mass of methane.

The molar mass of methane (CH4) can be calculated by summing up the atomic masses of its constituent elements:

Molar mass of C (carbon) = 12.01 g/mol

Molar mass of H (hydrogen) = 1.008 g/mol

Molar mass of methane (CH4) = (1 × Molar mass of C) + (4 × Molar mass of H)

= (1 × 12.01 g/mol) + (4 × 1.008 g/mol)

= 16.04 g/mol

Now, we can calculate the number of moles of methane using the following formula:

Number of moles = Mass of sample / Molar mass

Plugging in the values:

Number of moles = 7.21 g / 16.04 g/mol

≈ 0.4495 mol (rounded to four decimal places)

Therefore, there are approximately 0.4495 moles of methane in a 7.21 gram sample.

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Answer:

They both combine with The help of valency, which is the combining capacity of elements

Explanation:

I find it easier to understand valency as part of the Bhor’s model of an atom.

In his model, it was stated that electrons are spread around the nucleus in such a way that there are rings around the model. Each ring has a n value. So, k has 1, l has 2, m has 3 and n has 4...

what you need to know to find the number of electrons in each ring is to solve the formula 2n squared

Then, the valency is the 8 minus the number of electrons in the outermost shell. Remember that 8 is max number I;outer most shell. If you try it out for oxygen, you will get the value of 2 remaining, which can be gained if combined with calcium.

Hope it helps

Answer:

you will need the molar mass of Fe. [1 mol Fe=55.85 g Fe]

Explanation:

Starting with 6.5 g of iron, we can produce 0.058 moles of iron (III) oxide.

Balanced chemical equations have same number and type of each atom on both sides of the equation.

Balanced chemical equation for reaction between iron (Fe) and oxygen (O2) is: 4Fe + 3O2 → 2Fe2O3

Equation tells us that 4 moles of iron react with 3 moles of oxygen to produce 2 moles of iron (III) oxide (Fe2O3).

6.5 g Fe / 55.85 g/mol Fe = x moles Fe

x = 6.5 g Fe / 55.85 g/mol Fe = 0.116 moles Fe

0.116 moles Fe x (2 moles Fe2O3 / 4 moles Fe) = 0.058 moles Fe2O3

Therefore, starting with 6.5 g of iron, we can produce 0.058 moles of iron (III) oxide.

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The fact that real yield is lower than theoretical yield is not due to the conservation of mass. According to the rule of conservation of mass, no new mass may be formed during a chemical process.

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the question is incomplete. the question you are looking for is

Which of the following is not a reason why actual yield is less than theoretical yield?

A. Impure reactants present

B. Loss of product during purification

C. Conservation of mass

D. Competing side reactions

The frequency of a red laser that has a wavelength of 676 nm would be 4.43 x \(10^{14\) hertz.

The frequency and wavelength of a wave are related by the following equation:

λf = c

Where λ is the wavelength of the wave in meters, f is the frequency in Hertz, and c is the speed of light in a vacuum.

in this case, λ = 676 nm = 6.76 x \(10^{-7\) m

c = 299,792,458 m/s

Making f the subject of the formula:

f = c/λ

  = 299,792,458/6.76 x \(10^{-7\)

  = 4.43 x \(10^{14\) hertz

In other words, the frequency of a red laser that has a wavelength of 676 nm would be 4.43 x \(10^{14\) hertz.

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The set of quantum numbers that represents the last electron added to an arsenic atom (As) is n=4, l=1, m=2.

An electron is a negatively charged particle that orbits the atomic nucleus in the atom's outermost shell. The electron contains practically no mass but has a charge of -1.

Quantum numbers help to explain and comprehend the structure of electrons. An electron is described by four quantum numbers, which give it a unique identification in a given atom's electronic configuration.

The sets of quantum numbers are: n, l, m, and s. Where n represents the principle quantum number, l is the angular momentum quantum number, m represents the magnetic quantum number, and s is the spin quantum number.

In the case of the last electron added to an arsenic atom (As), the set of quantum numbers that represents it is n=4, l=1, m=2. This is because the last electron added will fill in the outermost shell of the atom.

Therefore, the principle quantum number (n) is equal to 4 because the valence shell is in the fourth shell. l, which is the angular momentum quantum number, is equal to 1 because it is the valence shell's subshell.

Finally, m, the magnetic quantum number, is equal to 2 because of the orientation of the orbital in which the electron is present. As a result, the answer is n=4, l=1, m=2.

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The total number of valence electrons that are present in a molecule of PCl3 is 26.

PCl3 stands for Phosphorus Trichloride. The molecular structure of PCl3 is trigonal pyramidal. It has three chlorine atoms and one phosphorus atom, which are bonded by three covalent bonds.

In order to determine the total number of valence electrons in PCl3, first we have to Count the valence electrons present in each atom. Phosphorus has 5 valence electrons. Chlorine has 7 valence electrons then Add the valence electrons from each atom.

P = 5 e- (phosphorus has 5 valence electrons)

Cl = 7 e- (chlorine has 7 valence electrons)

Total valence electrons in PCl3 = 5 + 7 × 3 = 5 + 21 = 26.

Therefore, there are 26 valence electrons in a molecule of PCl3.

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Answer:  50 nm

Explanation:  Two steps:

1.  Divide 3.25/6.5 = 0.5

2.  Divide 10^8/10^6 = 10^2

nm^2/nm = nm

Combine:  0.5x10^2 nm

or 50 nm

To multiply the numbers and round the answer to the correct number of significant figures, follow these steps: Multiply the numbers, and Determine the number of significant figures in the original numbers.       3.293 X 0.82 = 2.7 (rounded to 2 significant figures).

To multiply the numbers and round the answer to the correct number of significant figures, follow these steps:

Step 1: Multiply the numbers: 3.293 x 0.82 = 2.69726.

Step 2: Determine the number of significant figures in the original numbers. In this case, 3.293 has 4 significant figures, and 0.82 has 2 significant figures.

Step 3: Round the result to the least number of significant figures among the original numbers, which is 2 significant figures in this case.

Step 4: Round the result to 2 significant figures: 2.7.

Therefore, \(3.293 X 0.82 = 2.7\)  (rounded to 2 significant figures).

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The cleanser would need to contain approximately 1.52% KBrO3 by weight to produce an amount of iodine equivalent to that produced by an equal weight of cleanser containing 0.50% NaOCl by weight.

To solve this problem, we need to first calculate the amount of NaOCl in a 100-g sample of the cleanser, and then find the equivalent mass of KBrO3 that would produce the same amount of iodine.

Let's assume that the cleanser contains x% KBrO3 by weight. Then the mass of KBrO3 in a 100-g sample of the cleanser would be:

mass of KBrO3 = (x/100) * 100 g = x g

To find the amount of iodine produced by this amount of KBrO3, we need to convert the mass of KBrO3 to moles, and then use the stoichiometry of the reaction to calculate the moles of iodine produced:

mass of KBrO3 (g) → moles of KBrO3 → moles of I2 → mass of I2 (g)

x g KBrO3 → (x/MW(KBrO3)) mol KBrO3 → (3/1) * (x/MW(KBrO3)) mol I2 → (127/MW(I2)) * (3/1) * (x/MW(KBrO3)) g I2

where MW(KBrO3) and MW(I2) are the molecular weights of KBrO3 and I2, respectively.

Now we can set up the equation:

(127/MW(I2)) * (3/1) * (x/MW(KBrO3)) g I2 = (0.50/100) * 100 g NaOCl

Simplifying and solving for x, we get:

x = (0.50/100) * 100 * MW(KBrO3) * MW(I2) / (127 * 3)

x ≈ 1.52

Therefore, the cleanser would need to contain approximately 1.52% KBrO3 by weight to produce an amount of iodine equivalent to that produced by an equal weight of cleanser containing 0.50% NaOCl by weight.

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The mass fraction of the pro eutectoid phase is approximately 0, and of the pearlite phase is approximately 1.

In iron-carbon alloy with 0.60 wt% carbon, the pro eutectoid phase is cementite (Fe₃C). To calculate the mass fractions of the pro eutectoid phase and the pearlite phase,  consider the eutectoid reaction.

Eutectoid reactions in iron-carbon alloys are usually found at a composition of approximately 0.76 wt% carbon. As the alloy in question contains 0.60 wt% carbon it is hypo-eutectoid (i.e., below the eutectoid composition).

The lever rule will be used to calculate this equation  as follows:

f₁ = \(\frac{C_{0} - C_{e} }{C_{1} - C_{e} }\)

where the values represent here :

f₁ = mass fraction of the pro eutectoid phase (cementite),

Cₒ =carbon content in the alloy (0.60 wt%),

Cₑ =eutectoid composition (0.76 wt%),

C₁ = carbon content in the cementite phase (6.70 wt% carbon).

After substituting the given values into the equation:

f₁ = \(\frac{0.60 - 0.76}{6.70 - 0.76} \\\)

f₁ = \(\frac{0.16}{5.94}\)

f₁ ≈ -0.027

Here the negative value of f₁ shows that there is no pro eutectoid phase present in the alloy. Rather, the entire alloy consists of the pearlite phase.

Hence ,  the mass fraction of the pro-eutectoid phase is approximately 0, and the mass fraction of the pearlite phase is approximately 1.

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Calcium carbonate (CaCO3) is a metal carbonate compound and reacts with hydrochloric acid (HCl) to produce carbon dioxide (CO2), calcium chloride (CaCl2) and water. You can see, carbon dioxide gas is released through the solution.

calcium carbonate and hydrochloric acid reaction

CaCO3 + HCl → CaCl2 + CO2 + H2O

Carlos likes to bowl. He timed how long it took his ball to travel the length of the bowling alley's 18-meter lane. The ball will travel 12 m far after it had travelled for 2 s.

Length can be defined as a term used for identifying the size of an object and distance travelled by the object from one point to another point.

The S.I. unit of length is meter.

It can also be defined as the amount of time that something can last.

Thus, Carlos likes to bowl. He timed how long it took for his ball to travel the length of an 18-m lane in the bowling alley. The ball will travel 12 m far after it had travelled for 2 s.

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Your question is incomplete but most probably your full question was

Carlos likes to bowl. He timed how long it took for his ball to travel the length of a an 18-m lane in the bowling alley. He plotted the final distance and time on a line graph. Carlos drew a line from this point to the origin of the graph.

How far down the lane was the ball after it had traveled for 2 s?

6 m

9 m

12 m

18 m

Answer:

It is true.

Explanation:

Its a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zero

Answer:

Explanation:

Decreasing the volume of a contained gas will increase its pressure, and increasing its volume will decrease its pressure. In fact, if the volume increases by a certain factor, the pressure decreases by the same factor, and vice versa. Volume-pressure data for an air sample at room temperature are graphed in Figure 5.

Because the volume has decreased, the particles will collide more frequently with the walls of the container. ... When the volume decreases, the pressure increases. This shows that the pressure of a gas is inversely proportional to its volume. This is shown by the following equation - which is often called Boyle's law.

The kinetic energy of the gas molecules increases, so collisions with the walls of the container are now more forceful than they were before. As a result, the pressure of the gas doubles. Decreasing the temperature would have the opposite effect, and the pressure of an enclosed gas would decrease.

For a fixed mass of gas at constant temperature, the volume is inversely proportional to the pressure. That means that, for example, if you double the pressure, you will halve the volume. If you increase the pressure 10 times, the volume will decrease 10 times.

Temperature, pressure, volume and the amount of a gas influence its pressure.

Gay Lussac's Law - states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature. If you heat a gas you give the molecules more energy so they move faster. This means more impacts on the walls of the container and an increase in the pressure.

i really hope some of this helped i would put more but its a lot too type

Answer:

valency of an element is a combining power of an element.

for example oxygen has six valance electron but its valency is 2.

hope it helps.

ethanol, c2h5oh, is used as a fuel for motor vehicles, particularly in brazil. the density of ethanol is 0.7893 g/ml, enthalpy of combustion of IL ethanol -2.11 X10 "KJ L.

heat absorbed per litre & calculated as h1=∆hrn/v= =-1234.8 kJ mol/0.058368 L molt= -21155.42 kJ L = =-211 X I0^4 KJL.enthalpy of combustion of IL ethanol -2.11 X10 "KJ L. The heat energy released whenever one mole of a material burns totally in oxygen is characterised as the enthalpy of combustion. A product's heat of combustion, also recognised as its calorific value as well as energy content, can be defined as the quantity of heat freed when a known quantity of the substance is burned. The enthalpy of combustion is the enthalpy of a specific compound's combustion reaction. The enthalpy of solution is the heat capacity of disbanding a chemical into solution, which can be expressed as a reaction.

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Answer:

Physical

Explanation:

Physical weathering is defined as the geological process in which rocks are broken down but there is no change in their chemical composition.

Granite tor are the rock masses above the ground surface which are  associated with granites

Granite Tor is an example of physical weathering as they formed by freeze–thaw weathering. Granite tor are formed when magma present in the crust cools down and form batholith. Rocks above batholith gets erodes and left the batholith to expose.

Hence, the correct answer is "Physical weathering'.

Answer:

The equilibrium temperature of the system is 276.494 Kelvin.

Explanation:

Let consider the system formed by the sample of aluminium and water as a control mass, in which the sample is cooled and water is heated until thermal equilibrium is reached. The energy process is represented by First Law of Thermodynamics:

\(Q_{water} -Q_{sample} = 0\)

\(Q_{water} = Q_{sample}\)

Where:

\(Q_{water}\) - Heat received by water, measured in joules.

\(Q_{sample}\) - Heat released by the sample of aluminium, measured in joules.

Given that no mass is evaporated, the previous expression is expanded to:

\(m_{w}\cdot c_{p,w}\cdot (T-T_{w}) = m_{s}\cdot c_{p,s}\cdot (T_{s}-T)\)

Where:

\(m_{s}\), \(m_{w}\) - Mass of water and the sample of aluminium, measured in kilograms.

\(c_{p,s}\), \(c_{p,w}\) - Specific heats of the sample of aluminium and water, measured in joules per kilogram-Kelvin.

\(T_{s}\), \(T_{w}\) - Initial temperatures of the sample of aluminium and water, measured in Kelvin.

\(T\) - Temperature which system reaches thermal equilibrium, measured in Kelvin.

The final temperature is now cleared:

\((m_{w}\cdot c_{p,w}+m_{s}\cdot c_{p,s})\cdot T = m_{s}\cdot c_{p,s}\cdot T_{s}+m_{w}\cdot c_{p,w}\cdot T_{w}\)

\(T = \frac{m_{s}\cdot c_{p,s}\cdot T_{s}+m_{w}\cdot c_{p,w}\cdot T_{w}}{m_{w}\cdot c_{p,w}+m_{s}\cdot c_{p,s}}\)

Given that \(m_{s} = 0.380\,kg\), \(m_{w} = 2.40\,kg\), \(c_{p,s} = 910\,\frac{J}{kg\cdot K}\), \(c_{p,w} = 4186\,\frac{J}{kg\cdot K}\), \(T_{s} = 378\,K\) and \(T_{w} = 273\,K\), the final temperature of the system is:

\(T = \frac{(0.380\,kg)\cdot \left(910\,\frac{J}{kg\cdot K} \right)\cdot (378\,K)+(2.40\,kg)\cdot \left(4186\,\frac{J}{kg\cdot K} \right)\cdot (273\,K)}{(2.40\,kg)\cdot \left(4186\,\frac{J}{kg\cdot K} \right)+(0.380\,kg)\cdot \left(910\,\frac{J}{kg\cdot K} \right)}\)

\(T = 276.494\,K\)

The equilibrium temperature of the system is 276.494 Kelvin.

Answer:296

Explanation:

I got it right :) and mark me brainlest please

Answer:

A

Explanation:

They have the same number of positive protons & negative electrons, hope this helps

Answer: Aluminum is ideal for aircraft manufacture because it's lightweight and strong.

Explanation:

Answer:

The science of classifying organisms and

The thermometer will read -10°C after about 2.43 minutes.

(a) After four more minutes, the thermometer will read -1°C.

This is because the temperature difference between the room and outdoors is (24 - (-11)) = 35°C.

The thermometer then rises 7°C in one minute, so the thermometer is heated at 7°C/minute, i.e. 35°C in five minutes.

So the temperature of the thermometer after 4 more minutes is 7°C + 7°C + 7°C + 7°C = 28°C, 28°C - 35°C = -7°C, -7°C - 3°C = -10°C.

Thus the reading on the thermometer will be -1°C after four more minutes.

(b) To find out when the thermometer will read -10°C, use the formula:

time = (temperature difference ÷ heating rate) + time to start

       = (-10°C - 7°C) ÷ 7°C/minute + 1 minute

       = -17°C ÷ 7°C/minute + 1 minute≈ -2.43 minutes

Thus, the thermometer will read -10°C after about 2.43 minutes.

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The density of aluminium crystallized in a face-centered cubic unit cell with an edge length of 405 pm is 2.7 g/cm3.

To calculate the density, divide the mass of the substance by the volume.

Mass can be calculated using the atomic mass of aluminium (26.98 amu) and the Avogadro constant (6.022x1023 atoms/mol) which can be used to convert moles of atoms to grams.

Volume can be calculated using the edge length of the unit cell (405 pm) and the Avogadro constant.

First, calculate the volume of the unit cell using the following formula:

Volume of a unit cell = (Edge Length)3

Plugging in the edge length of 405 pm, the volume of the unit cell is 8.096x10-23 cm3.

Next, calculate the mass of the substance by multiplying the atomic mass of aluminium (26.98 amu) by the Avogadro constant (6.022x1023 atoms/mol). This gives us a mass of 1.63x10-22 g.

Finally, calculate the density of aluminum by dividing the mass of the substance by the volume of the unit cell:

Density = Mass / Volume

Plugging in the mass and volume calculated above, the density of aluminum crystallized in a face-centered cubic unit cell with an edge length of 405 pm is 2.7 g/cm3.

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We are know that gas takes the shape of the container it is kept in. As a result, matter occupies the largest volume in the gaseous state.

Matter is anything that occupies space and has mass, in other sense, matter is the "something" from whichthe universe is formed. The fundamental building components of all stuff are called elements. They don't change into the other elements through normal chemical processes and have distinct chemical and physical properties.

The 3 states of matter include solid, liquid, & gas. It is possible to comprehend why they have various qualities by looking at the arrangement of their particles.

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1 moles Carbon to grams = 12.0107 grams

2 moles Carbon to grams = 24.0214 grams

3 moles Carbon to grams = 36.0321 grams

4 moles Carbon to grams = 48.0428 grams

5 moles Carbon to grams = 60.0535 grams

6 moles Carbon to grams = 72.0642 grams

7 moles Carbon to grams = 84.0749 grams

8 moles Carbon to grams = 96.0856 grams

9 moles Carbon to grams = 108.0963 grams

10 moles Carbon to grams = 120.107 grams

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 60g is the mass of  5.00 moles of carbon.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically, the formula for mole can be given as

mole of carbon =given mass of carbon  ÷ molar mass of carbon

number of mole of carbon=  5.00 moles

mass of carbon=?

molar mass of carbon= 12.0107 grams

Substituting the values in above formula we get

5.00 moles  = mass of carbon  ÷12.0107 grams

On calculations, we get

mass of carbon =60g

Therefore, 60g is the mass of  5.00 moles of carbon.

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The rad (an acronym for "radiation absorbed dose") is a unit of measurement used to quantify the amount of energy absorbed by a substance from ionizing radiation.

Specifically, the rad is defined as the absorption of 100 ergs of energy per gram of the substance. It is used to describe the amount of ionizing radiation that is absorbed by a person or object, and is commonly used in medical and industrial settings to measure exposure to radiation. One rad is equal to 0.01 gray (Gy), which is the International System of Units (SI) unit for measuring radiation dose.

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Making both reactants in excess and the concentration of Fe(SCN)* can be determined, Making FeSt in excess and SCN as the limiting reactant and the concentration of Fe(SCN)* will be equal to the concenation of SCN.

A reagent, sometimes known as an analytical reagent, in chemistry is a substance or compound supplied to a system to either initiate a chemical reaction or test whether one happens. Although the terms "reactant" and "reagent" are not frequently used interchangeably, "reactant" refers to a material that is consumed during a chemical reaction. The anion [SCN] is thiocyanate. Thiocyanic acid's conjugate base is it. The colorless compounds potassium thiocyanate and sodium thiocyanate are examples of common derivatives. In the past, pyrotechnics employed mercury(II) thiocyanate. Thiocyanic acid is a hydracid, which is cyanic acid in which the oxygen is substituted by a sulfur atom. SCN is a tiny, very acidic [1] pseudohalide thiolate.

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