Which of the following types of models is generally used to predict long-term events? a. idea model b. physical model c. computer model d. none of the above Please select the best answer from the choices provided A B C D Mark this and return

Answer:

Step 1: Prepare for the project.

a) Read the entire Student Guide before you begin this project.

b) If anything is unclear, be sure to ask your teacher for assistance before you begin.

c) Gather the materials you will need to complete this project.

Step 2: Review the chemical reaction.

a) The chemical reaction that you will model is shown below. Calcium oxide (CaO) is a white

solid with a crystalline structure. It is made by heating limestone, coral, sea shells, or chalk,

which are composed mainly of calcium carbonate (CaCO3). During the heating process,

carbon dioxide (CO2) is released and calcium oxide (CaO) is produced. Commercially,

calcium oxide is called lime. One of the oldest uses of lime is to make mortar, a substance

used in construction to secure bricks, stones, and blocks together.

CaCO3  CaO + CO2

Step 3: Build a model of the reactant.

a) Use gumdrops and toothpicks to build a model of CaCO3.

b) Select one color of gumdrop for calcium, a second color for carbon, and a third color for

oxygen. Be sure to include a key of your chosen color scheme with your model.

c) Use the periodic table to help you determine the number of bonds each atom will form.

Step 4: Build models of the products.

a) Use gumdrops and toothpicks to build a model of CaO and a model of CO2.

b) Be sure to use the same colors of gumdrops for calcium, carbon, and oxygen as you did in

Step 3. Include a key of your chosen color scheme with your models.

c) Use the periodic table to help you determine the number of bonds each atom will form.

Step 5: Type one to two paragraphs that describe your models and explain the conservation of

mass in the chemical reaction.

a) Create a new blank document. Type your name at the top.

b) Type one to two paragraphs that describe your models and relate them to the law of

conservation of mass. Your document should:

i. identify the names of the reactants and products in the reaction.

ii. identify the number of molecules that make up the reactants and products.

iii. identify the type and number of atoms in each molecule of the reactants and products.

iv. explain what happens during the chemical reaction.

v. explain how mass is conserved during the chemical reaction.

Step 6: Evaluate your project using this checklist.

If you can check each criterion below, you are ready to submit your project.

 Did you create an accurate model of calcium carbonate (CaCO3)? Your model should include

the correct number of gumdrops for each element in calcium carbonate, consistent use of

colors for elements in calcium carbonate, and the correct number and placement of toothpicks

(bonds).

 Did you create an accurate model of calcium oxide (CaO)? Your model should include the

correct number of gumdrops for each element in calcium oxide, consistent use of colors for

elements in calcium oxide, and the correct number and placement of toothpicks (bonds).

 Did you create an accurate model of carbon dioxide (CO2)? Your model should include the

correct number of gumdrops for each element in carbon dioxide, consistent use of colors for

elements in carbon dioxide, and the correct number and placement of toothpicks (bonds).

Did you type one to two paragraphs that describe your models and relate them to the law of

conservation of mass? Your document should include the names of the reactants and

products in the reaction, the number of molecules that make up the reactants and products,

and the type and number of atoms in each molecule of the reactants and products. It should

also explain what happens during the chemical reaction and how mass is conserved during  the reaction

Step 7: Revise and submit your project.

a) If you were unable to check off all of the requirements on the checklist, go back and make  

b) When you have completed your project, submit your models to your teacher for grading.  

c) Submit your document through the virtual classroom. Be sure that your name is on it.

Step 8: Clean up your workspace.

a) Clean up your workspace. Return any extra materials to your teacher and throw away any  trash.

Explanation:

(a) The number of molecules contained by the balloon at the given condition is 6,438.97 moles.

(b) The mass of air in the balloon is 186.73 kg.

The given parameters;

The number of molecules contained by the balloon at the given condition is calculated as follows;

[tex]PV = nRT[/tex]

where;

[tex]n = \frac{PV}{RT} \\\\n = \frac{10,100 \times 1500}{8.314 \times 283} \\\\n = 6,438.97 \ moles[/tex]

The mass of air in the balloon is calculated as;

[tex]n = \frac{m}{M} \\\\m = nM\\\\m = 6,438.97\ moles \ \times \ 29 \ g/mol\\\\m = 186.73 \ kg[/tex]

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Answer:

Noble gases

Explanation:

Noble gases are nonreactive, nonmetallic elements in group 18 of the periodic table. As you can see in the periodic table in the figure below, noble gases include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).18 Jun 2021

Explanation:

At 25 °C Dissociation constant of water or Kw = 1× 10^-14 mol2dm-6

Ka × Kb = Kw for all diluted solutions

Ka×Kb = 1 × 10^-14 mol2dm-6

Therefore for question 1 -

COOH- is the conjugate base for HCOOH ( we find the conjugate base by removing an H atom and the Conjugate acid by adding an H atom)

COOH- (aq) + H2O ( l) <-----> HCOOH( aq) + OH-(aq)

So we can apply the above mentioned equation to find Kb value for COOH-

Kb = 5.56 × 10^-11 moldm-3

For question 2-

We can see that (CH3)2NH+2 is the conjugate acid of (CH3)2 NH. (A H atom has been removed so the one with a H atom less is the conjugate base.)

(CH3)2NH+2 (aq) + H2O (l) <-----> (CH3)2 NH (aq) + H3O+ (aq)

So applying the previously mentioned equation we get Ka = 1.85 × 10^-11 moldm-3

This problem is describe the mole-ratio composition of an allow composed by tin, lead and cadmium. Ratios are given as Sn:Pb 2.73:1.00 and Pb:Cd is 1.78:1.00, and we are asked to calculate the mass percent compositon of Pb in the allow.

In this case, according to the given information, it turns out possible realize that the following number of moles are present in the alloy, according to the aforementioned ratios:

[tex]2.73mol Sn\\\\1.00molPb\\\\\frac{1.00molPb*1.00molCd}{1.78molPb}= 0.562molCd[/tex]

Next, we calculate the masses by using each metal's atomic mass:

[tex]m_{Sn}=2.73mol*\frac{118.7g}{1mol}=324.05g\\\\ m_{Pb}=1.00mol*\frac{207.2g}{1mol}=207.2g\\\\m_{Cd}=0.562mol*\frac{112.4g}{1mol}=63.2g[/tex]

Thus, the mass percent composition of each metal is shown below:

[tex]\%Sn=\frac{324.05g}{324.05g+207.2g+63.2g} *100\%=54.5\%\\\\\%Pb=\frac{207.2g}{324.05g+207.2g+63.2g} *100\%=34.9\%\\\\\%Cd=\frac{63.2}{324.05g+207.2g+63.2g} *100\%=10.6\%[/tex]

So that of lead is 34.9 %.

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Answer:

engey

Explanation:

Answer:

All the carbon atoms in the human body were created in the stars. Elementary particles, such as protons, were formed during the "big bang"; that amazing moment about 14 billion years ago in which the universe got it's start.

As the solar nebula cooled METAL compounds are the first to condense from a gas to a solid. The solar nebula gave birth to the Solar system.

A solar nebula is a disc-shaped cloud of gases and grain dust, which gave birth to the Sun and planets of the Solar system, approximately 4.6 billion years ago.

The solar nebula is at the beginning a mixture of interstellar gases (hydrogen and helium) and dust grains.

As the solar nebula cools, heavy elements such as metals in the disk condensate into planetesimals.

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The explanation to the question is stated as follows:

Newton's first law of motion states that: a body will continue in its state of rest or uniform motion unless an external force acts on it. So then, the ball initially possesses potential energy because it was at rest. While the leg of the soccer player possesses kinetic energy because its in motion.

Thus, when the player hits the ball, a force known as push has been applied. This would ensure that the ball compels and moves in the direction of the applied force. Therefore after the interaction, the leg of the player now possesses potential energy, since it would come to rest after hitting the ball. While the ball would start moving, now possessing kinetic energy.

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Answer:

umm

Explanation:

matter makes up everything. everything is matter

the more matter an object has the more mass It has

Answer:

sound is given off

Explanation:

due to a number of scientific research sound that is given off of an object is not due to a chemical reaction.

The volume of sulphuric acid, H₂SO₄ needed for the complete reaction with 72.2 g of sodium hydroxide, NaOH is 5.31 L

We'll begin by calculating the number of mole in 72.2 g of NaOH. This can be obtained as follow:

Mass of NaOH = 72.2 g

Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol

Mole = mass / molar mass

Mole of NaOH = 72.2 / 40

2NaOH + H₂SO₄ —> Na₂SO₄ + 2H₂O

From the balanced equation above,

2 moles of NaOH reacted with 1 mole of H₂SO₄.

Therefore,

1.805 mole of NaOH will react with = 1.805 / 2 = 0.9025 mole of H₂SO₄.

Mole of H₂SO₄ = 0.9025 mole

Molarity of H₂SO₄ = 0.170 M

Volume = mole / Molarity

Volume of H₂SO₄ = 0.9025 / 0.170

Thus, the volume of H₂SO₄ needed for the reaction is 5.31 L

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Answer:

Explanation:

The required pressure can be found by using the formula for Boyle's law which is

[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

From the question we have

[tex]P_2 = \frac{1 \times 196}{26} = \frac{196}{26} \\ = 7.538461...[/tex]

We have the final answer as

Hope this helps you

The number of moles of gas B present in the gas mixture is 2.72 moles.

The given parameters;

The total number of moles of the gases is calculated by applying ideal gas law;

PV = nRT

where;

R is ideal gas constant = 0.0821 L.atm./mol.K

n is the total mole of the gases

[tex]n =\frac{PV}{RT} \\\\n = \frac{8 \times 14}{0.0821 \times 323} \\\\n = 4.22 \ moles[/tex]

The number of moles of gas B is calculated as follows;

[tex]n_B = 4.22 - n_A\\\\n_B = 4.22 - 1.5\\\\n_B = 2.72 \ moles[/tex]

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Answer:

A-Solid

Explanation:

Waves travel faster in solids & slowest in gases

Answer:

LETTER

1. D. PURE SUBSTANCES CAN BE FURTHER BROKEN DOWN INTO SIMPLER SUBSTANCES.

2.A

PO PLEASE MARK A BRAINLIESTS ANG MARK A 5 STAR ANG HEART PO PLEASW

Answer:Charge on X  = (+ 2)

Explanation:

Charge on one Cl = -1

So Charge on two Cl = -2

The molecule = Neutral = 0 charge

So, to make total charge = 0 , the X should have +2 charge

XCl2 = +2 -2 = 0

X = +2

Alkaline earth metals(Be , Mg , Ca , Sr) form such type of compounds

Explanation:

This graph shows a straight line.

Answer:

The graph is a straight line that angles upward.

This problem is describing a system in which 100 kJ of energy is transferred from a cold reservior at 600 K to a hot one at 1050 K. This situation is opposed to the Clausius statement of the second law of thermodynamics, because it is widely known that heat is transferred from hot to cold systems.

However, we can calculate the total entropy change by using the following formula:

[tex]\Delta S =\Delta S _{Low}+\Delta S _{High}[/tex]

Which is broken down as follows:

[tex]\Delta S =\frac{-Q}{T_{Low}} + \frac{Q}{T_{High}}\\\\\\\Delta S =Q(\frac{-1}{T_{Low}} + \frac{1}{T_{High}})[/tex]

Since the heat is assumed to be equal for the both of them. Then, we plug in the given heat and temperatures to obtain:

[tex]\Delta S =100kJ(\frac{-1}{600K} + \frac{1}{1050K})\\\\\Delta S =-0.0714\frac{kJ}{K}[/tex]

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Answer:

D . GOD BLESS .

Explanation:

Cost-effective definition: producing good results without costing a lot of money. E.g: that machine is very cost effective, it made 200 shirts with only a dollar.

Time effective definition: how well time was used. E.g that machine is very time-effective, it made 200 pants in one hour!

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Answer:

you hear

Explanation:

beautiful hear can be wonderful day in your life so to be rotations is not a big deal

Answer:

The process by which food is broken down to release energy is called respiration

I hope it helps.

Answer:

Respiration

Explanation:

hope this helps.

Answer:

atom

Explanation:

The sodium atom has a single valence electron that it can easily lose. (If the sodium atom loses its valence electron, it achieves the stable electron configuration of neon.) The chlorine atom has seven valence electrons and can easily gain one electron.

Answer:

I wish i could

Explanation:

Answer:

In nature there are many different minerals we call "Salts". If you look very closely at the particles of table salt, you will find little cubic crystals. These salt crystals are made of sodium chloride (NaCl), and their cubic shape is due to a very specific arrangement of the atoms. As discussed earlier, all of the minerals classified as salts are held together through ionic bonds. The arrangement of atoms, the shapes of the crystals they form, and their mechanical, thermal, and electrical properties are all due to this special type of bonding

The two reasons why the model shows sodium chloride is that:

The other is that:

Note that a lot of Formula unit cannot exist as a single entity. Because of this, compound such as NaCl exist only as an aggregates of a more bigger number of ions that are oppositely charged .

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Answer:

Because oil have apolar molecules, while water have polar molecules