II. Pure magnesium metal is often found as ribbons and can easily burn in the presence of oxygen. When 3.86 g of magnesium ribbon burns with 155ml of oxygen at 1.0 atm and 275 K , a bright, white light and a white, powdery product is formed, magnesium oxide. How many grams of excess reactant remain?

Answers

Answer 1

Answer:

[tex]Excess=3.53g[/tex]

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

[tex]2Mg(s)+O_2(g) \rightarrow 2MgO(s)[/tex]

Next, we identify the limiting reactant by computing the moles of magnesium oxide yielded by 3.86 g of magnesium and 155 mL of oxygen at the given conditions via their 2:1:2 mole ratios and the ideal gas equation:

[tex]n_{MnO}^{by \ Mg}=3.86gMg*\frac{1molMg}{24.3gMg}*\frac{2molMgO}{2molMg} =0.159molMgO\\\\n_{MnO}^{by \ O_2}=\frac{1atm*0.155L}{0.082\frac{atm*L}{molO_2*K}*275K} *\frac{2mol MgO}{1molO_2} =0.0137molMgO[/tex]

It means that the limiting reactant is the oxygen as it yields the smallest amount of magnesium oxide. Next, we compute the mass of magnesium consumed the oxygen only:

[tex]m_{Mg}^{consumed}=0.0137molMgO*\frac{2molMg}{2molMgO} *\frac{24.3gMg}{1molMg} =0.334gMg[/tex]

Thus, the mass in excess is:

[tex]Excess=3.86g-0.334g\\\\Excess=3.53g[/tex]

Regards!


Related Questions

Who would most likely be required to work with sodium hydroxide?

a plumber
a gardener
a bricklayer
a mechanic

Answers

Answer:

i think plumber

Sodium hydroxide is generally referred to as caustic soda used in soaps and cleaners. A plumber would most likely be required to work with sodium hydroxide. Hence, option A is correct.

What is the use of sodium hydroxide?

Soaps, paper, explosives, dyes, and petroleum are all made with sodium hydroxide. The presence of sodium hydroxide in a cleanser or a homemade aqueous solution converts these disconcerting fats into soaps, which are easily removed by water.

They have no odor and no color making them react with water and strong acids to produce salts. They are considered ionic compounds with sodium cation and chloride anion. They also are used in oxide coating and cleaning of metals.

Therefore, option A. plumber will most likely use sodium hydroxide.

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Calculate the density of an
object with a mass of 58g and a
volume of 20 mL.
Enter

Answers

Answer:

D = 2.9 g/mL

Explanation:

Density = Mass over Volume

D = m/V

Step 1: Define

m = 58 g

V = 20 mL

D = unknown

Step 2: Substitute and Evaluate for Density

D = 58 g/20 mL

D = 2.9 g/mL

What is the mass number of Carbon–12, which has 6 protons and 6 neutrons?

Answers

Answer:

It has the atomic mass of 12.

Electron spin around the nucleus in specific paths called?

Answers

Answer:

Electron cloud

Explanation:

the density of a wooden block that has a volume of 5 cm3 & a mass of 30.5 g

Formula: ____________
Mass = ____
Volume = ____
Density = ____

Answers

Answer:

The answer is 6.10 g/cm³

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question

mass = 30.5 g

volume = 5 cm³

We have

[tex]density = \frac{30.5}{5} \\ [/tex]

We have the final answer as

6.10 g/cm³

Hope this helps you

Which carboxylic acid can be combined with an alcohol to form the ester shown below?

Answers

Answer:

CH₃CH₂CH₂COOH.

Explanation:

To know which option is correct, let us hydrolysed the given ester. This is illustrated in the attached photo.

Hydrolysis of ester involves breaking the ester bond by a water molecule to produce the corresponding alcohol and carboxylic acid.

From the reaction given in the attached photo, we can see that the carboxylic acid needed to produce the desired ester is butanoic acid, CH₃CH₂CH₂COOH.

g If the pressure of each gas is increased at constant temperature until condensation occurs, which gas will condense at the lowest pressure

Answers

The question is incomplete; the complete question is;

If the pressure of each gas is increased at constant temperature until condensation occurs, which gas will condense at the lowest pressure?

A) Octane

B) Ethane

C) Butane

D) All the gases will condense at the same pressure

Answer:

Octane

Explanation:

If we study the table closely we will realize that octane has the greatest molecular mass among all the gases shown.

The greater the molecular mass, the lower the pressure required for the condensation of the gas. Hence, the lowest pressure is required for the condensation of octane at constant temperature.

Read the statement below and decide if it represents physical change or chamical change.
Iron is heated, causing it to melt.
O Physical Change
Chemical Change

Answers

It is a physical change because the appearance is the only thing that changes.

The lowest energy state of an atom is its

A. Highest-occupied energy level.
B. Principle quantum number.
C. Electron configuration.
D. Ground state.

Answers

Answer:

Principle quantum number.

Explanation:

why does adding salt to ice make it melt faster

Answers

Hi :)

The salt will dissolve the ice, hence making it melt faster which lowers its freezing point below the temperature of the ice

Ice in contact with salty water therefore melts

Hope this helps :)

What is the first step when using a microscope?


A. Place the microscope slide on the stage

B. Plug the microscope in and turn it on

C. Switch to the low power objective lens

D. Secure the slide to the stage clips

Answers

Answer:

I think the answer is B :)

Answer:

the first step is B

Explanation: I'm on this lesson

Ok here is the next one
I’m counting on you
Thanks.

Answers

food moves through the mouth by muscle movement

In two to three sentences, explain the trend for atomic size. Why does this trend occur?

Answers

Answer:

The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase. 2) As you move across a period, atomic radius decreases.

Explanation:

A cough syrup contains red dye #40, with a concentration of 4.68 x 10-3 M.a.If you dilute the cough syrup by adding 175 mL of water to a 250. mL sample of the cough syrup, what will be the final concentration?

How do I do this?

Answers

Answer:

[tex]M_2=2.75x10^{-3}M[/tex]

Explanation:

Hello.

In this case, since a dilution process is a process by which the concentration of a solution decreases due to the increase of volume by usually adding water, it is important to take into account that the moles remain unchanged:

[tex]n_1=n_2[/tex]

Whereas in terms of molarity (M=n/V) can be written as:

[tex]M_1V_1=M_2V_2[/tex]

In such a way, since the initial concentration is 4.68e-3 M and the volume of such solution is 250. mL, the final volume results from mixing 250 mL of this solution with 175 mL, that is, to a volume of 425 mL. Thus, the concentration turns out:

[tex]M_2=\frac{M_1V_1}{V_2} =\frac{4.68x10^{-3}M*250.mL}{425.mL} \\\\M_2=2.75x10^{-3}M[/tex]

Best regards.

If you dilute the cough syrup by adding 175 mL of water to a 250 mL sample of the cough syrup, the final concentration would be 0.00275 M

Using a simple dilution equation:

number of moles before dilution = number of moles after dilution

Recall that: number of moles = molarity x volume (MV)

Thus:

  M1V1 = M2V2

In this case, M1 = 4.68 x 10-3 M, M2 = ? V1 = 250 mL, and V2 = 425 mL

M2 = 4.68 x 10^-3 x 250/425

                  = 0.00275 M

                    = 0.00275 M

More on dilution principle can be found here: https://brainly.com/question/13844449

Living things help contribute to the water cycle.
A. true
B.false

Answers

A. hahwjwkwjwbwnkwwk
Answer: A

Living things are apart of the cycle

True or false: An oxidation number is not the same as an actual charge on an ion. True false question. True False

Answers

Answer:

True

Explanation:

They are actually the same

The answer is False.

The oxidation number is the number of electrons removed or added to an element or compound. This is also equal to the charge on the ion.

For example, if Sodium atom loses one electron, it becomes oxidized to the + 1 state.

Na → Na⁺ + e⁻.

So, the oxidation number of Sodium is the charge on the Sodium ion which is + 1.

So, the oxidation number is equal to the charge on the ion.

So, the answer is False.

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How many electrons does 2Na+1 have

Answers

Answer:

So... for the element of SODIUM, you already know that the atomic number tells you the number of electrons. That means there are 11 electrons in a sodium atom. Looking at the picture, you can see there are two electrons in shell one, eight in shell two, and only one in shell three.

Explanation:

brainliest pleaseeee <3

Answer:

so there would be 2 electrons because

Explanation:

sodium has 11 electrons but if you look at the shels it onl has one electron (from the image im looking at) and the other shell only have one so theres 2 electrons

Which of the following is the metric system based on?

Answers

Where is the “following” can you show us the answer choices
The metric system is a decimal-based system of measurement originally based on the meter and kilogram, which were introduced by France in 1799. "Decimal-based" means all the units are based on powers of 10.

The graph shows the average monthly rainfall for a
forested area.
In which month is a high alert for fire danger most
likely?

A. April
B. August
C. May
D. October

Answers

The answer is A. April

Answer:

The Answer would be A. April

Explanation:

Least amount of rainfall out of all the months we have to choose from.

Where is the north pole of the bar magnet, based on the magnetic field lines
shown?

Answers

Answer:On the Right End

Explanation: Trust me I just got it wrong on APEX to answer it for y’all On the right end is the correct answer

Answer:

Right end

Explanation:

Just did the quiz

Which changes MUST happen for elements to become a compound

Answers

Answer:

Chemical changes in compounds happen when chemical bonds are created or destroyed. Then the molecular structure changes; new molecules form and a new substance is created. Often heat is used to begin a chemical change, as when baking a cake. Another example of a chemical reaction is the rusting of a metal trash can.

Hope this helps you Do mark as brainliest ✌️

An element is constituted of only atoms and no other entities are present in it. Whereas a chemical compound is a substance made up of various identical molecules of the same or different atoms.

The atoms of the same or different species bond together to form a compound.

Chemical bonding is present among them that cannot be simply separated.

The compounds can have ionic, covalent and hydrogen bonds present in them.

When the new atoms combine the structure changes of the new molecule formed.

To learn more about compounds and atoms follow the link:

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A type of substance containing atoms of two or more different elements that are chemically bonded together is referred to as a

Answers

Answer:

Compound

Explanation:

A student heats 25 mL of water from 20°C to 96°C in a glass beaker. The
model represents the motion of the water molecules during heating.
Explain why some of the water molecules shown in the model have
longer arrows than other water molecules during heating.

Answers

Answer:

Because the have acquired energy from the heating process, that is why the start moving faster.

Explanation:

Hello.

In this case, since the  initial liquid water molecules have a certain energy content, which makes them move with the relatively medium velocity characteristic in liquid-phase substances, once energy starts being added, it is evidenced that the molecules acquire more energy which is able to make them move faster.

In such a way, since the initial water molecules velocity is marked by a medium range arrows, meaning that the molecules are moving not-so-fast, not-so-slow but the heated  water molecules are marked by longer arrows, meaning that they move faster, we infer that such velocity increase is due to the addition of heat due to the heating process from 20 °C to 96 °C (just before boiling).

Regards!

Molecular motion is the action of motion of the molecules or the particles in a specific direction. The molecules start moving faster due to the energy given by the heat.

What are the factors affecting molecular motion?

The movement of the molecules or the particles in the system is affected by the temperature and the heat given to the system by the external source.

The initial molecules have relative speed and motion in the system and after the addition of the factors the energy of the motion of the particles gets affected.

When the temperature of the water in the beaker is increased then the average kinetic energy of the molecules also increases and hence the motion of the molecules increases.

The medium ranged arrows depict the average speed of the molecule movement in the medium, while the longer arrows suggest the fast-moving molecules of the water.

Therefore, the heat increases energy and in turn the molecular motion.

Learn more about molecular motion here:

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Chemical properties can be observed without changing the substance

Answers

Answer:

chemical properties can only be measured only by changing a substance chemical identity

Explanation:

apex

A sample of an ideal gas has a volume of 2.38 L at 283 K and 1.03 atm. Calculate the pressure when the volume is 1.97 L and the temperature is 307 K.

Answers

Gas Has A Volume Of 2.21 L At 287 K And 1.11 Atm. Calculate The Pressure When The Volume Is 1.03 L And The Temperature

Explanation:

For the combustion of methane, CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l) △H = -213
kcal/mol

How many kilocalories of energy are released from 5.0 mol of methane?
How many moles of methane are needed to give 100. kcal heat?

Answers

Answer:

1.-213(kcal/mol)*5mol=1065kcal

2.100/213 mol

a. The energy released from 5.0 mol of methane is -1065 kcal/mol.

b. The number of moles of methane needed to give 100. kcal heat is 0.4694 moles.

What is combustion?

Combustion is a chemical process in which the element reacts with oxygen to produce heat and light. Burning of wood.

The equation of combustion of methane:

CH₄ (g) + 2O₂(g) ------> CO₂ (g) + 2H₂O (l)

a) Enthalpy of the reaction is H = -213 Kcal/mol

This means 213 Kcal heat is released in the burning of one mole of CH4

H reaction = [ H products ] - [ H reactants ]

Hr = [ H(CO₂)g + 2H(H₂O)l ] - [ H(CH₄)g ] = -213 kcal/mol

For 5 moles of methane:

5CH₄(g) + 10O₂(g) -----> 5CO₂(g) + 10H₂O(l)

therefore, new Hr = 5 x -213 = -1065 kcal/mol

H reaction = -1065 kcal/mol

b) 213 kcal is released per mole of Methane

then, to release 100 kcal we need, 100 / (213) = 0.4694 moles

Thus, the energy released is -1065 kcal/mol, and the number of moles is 0.4694 moles.

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Which of the following representations shows the correct placement of trophic levels?
Secondary Consumers
Primary Consumers
Producers

Answers

You have to start listing from the bottom :

3. Secondary Consumers

2. Primary Consumers

1. Producer

Pls help I am confused my sister got me sweating

Answers

Answer:

Im pretty sure its B. is released by salivary glands.

Explanation:

HELPPPPP plssssss!!!!!! Is the brain of the cell living or non-living?

Answers

Answer: living

Explanation: The brain of a cell is living. All parts of the cell must be alive in order for the human body to revive. The brain of a cell controls the cells, and cells are the basic block of human life.

Help pls:)?
If the low power objective has 10X printed on it, what would be the total magnification when looking through the microscope?

Answers

Answer:

The magnification of the microscope is equal to the magnification of the ocular lens times the magnification of the objective lens. Since the objective lens has 10x printed on them at "low power". The total magnification would be 10 times 10.

Explanation:

i hope this helps C:

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