The children in the class are more than 10 years old

Answer:

A. Solid aluminum oxide and solid iron

Explanation:

The reaction equation is given as:

    2Al  +   Fe₂O₃  →   Al₂O₃   + 2Fe

The species on the left hand side are the reactants

Those on the right hand side of the expression are the products.

The products are:

Al₂O₃   and Fe

 These are solid aluminum oxide and solid iron

Answer:

68.6 °C

Explanation:

From conservation of energy, the heat lost by acetone, Q = heat gained by aluminum, Q'

Q = Q'

Q = mL where Q = latent heat of vaporization of acetone, m = mass of acetone = 3.33 g and L = specific latent heat of vaporization of acetone = 518 J/g

Q' = m'c(θ₂ - θ₁) where m' = mass of aluminum = 44.0 g, c = specific heat capacity of aluminum = 0.9 J/g°C, θ₁ = initial temperature of aluminum = 25°C and θ₂ = final temperature of aluminum = unknown

So, mL = m'c(θ₂ - θ₁)

θ₂ - θ₁ = mL/m'c

θ₂ = mL/m'c + θ₁

substituting the values of the variables into the equation, we have

θ₂ = 3.33 g × 518 J/g/(44.0 g × 0.9 J/g°C) + 25 °C

θ₂ = 1724.94 J/(39.6 J/°C) + 25 °C

θ₂ = 43.56 °C + 25 °C

θ₂ = 68.56 °C

θ₂ ≅ 68.6 °C

So, the final temperature (in °C) of the metal block is 68.6 °C.

The final temperature of the metal block is 74.97°C

The specific heat of a substance is the required quantity of heat needed to raise the temperature of 1 gram of the substance by 1° C.

From the parameters given:

The number of moles of acetone is:

[tex]\mathbf{= 3.33 g \times \dfrac{mol}{58.08 \ mol}}[/tex]

= 0.0573 mol

At standard conditions, the heat of vaporization of acetone is:

[tex]\mathbf{\Delta H = 32.0 \ kJ/mol \times 0.0578 \ mol } \\ \\ \mathbf{\Delta H = 1.8496 \ kJ } \\ \\ \mathbf{ \Delta H = 1.85 \times 10^3 \ J}[/tex]

Given that:

The specific heat of the aluminum is = 0.903 J/g° C

The heat energy can be computed as:

q = msΔT

q = 41 g × 0.903 J/g° C × (x - 25°C)

Using the calorimetry principle, heat energy lost by metal = heat energy gained by acetone.

i.e.

[tex]\mathbf{q_{(acetone)} gain = q_{(metal)} lost }[/tex]

[tex]\mathbf{-1.85 \times 10^3 \ J = - 41 g \times 0.903 \ J/g^0 C \times ( x - 25^0 c) }[/tex]

[tex]\mathbf{1.85 \times 10^3 \ J = 41 g \times 0.903 \ J/g^0 C \times ( x - 25^0 c) }[/tex]

[tex]\mathbf{(x - 25 ^0 C) = \dfrac{1.85 \times 10^3 \ J }{ 41 g \times 0.903 \ J/g^0 C}}[/tex]

[tex]\mathbf{(x - 25 ^0 C) = 49.97^0 C}}[/tex]

[tex]\mathbf{x = 49.97^0 C+25 ^0 C}}[/tex]

x = 74.97 °C

Learn more about specific heat here:

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Answer:

Mass = 917.4 g

Explanation:

Given data:

Number of molecules = 3.00 ×10²⁴ molecules

Mass in gram = ?

Solution:

1 mole contain 6.022 × 10²³ molecules

3.00 ×10²⁴ molecules × 1 mol /  6.022 × 10²³ molecules

0.5×10¹ mol

5 mol

Mass in gram:

Mass = number of moles  × molar mass

Mass = 5 mol  × 183.48 g/mol

Mass = 917.4 g

Answer:

B: It is extremely reactive

Explanation:

Potassium metal is also soft and white with a silvery lustre, has a low melting point, and is a good conductor of heat and electricity.

Answer: Properties, occurrence, and uses. Potassium metal is soft and white with a silvery lustre, has a low melting point, and is a good conductor of heat and electricity. Potassium imparts a lavender colour to a flame, and its vapour is green.

Explanation: hope it helps

Answer:  [tex]6.047\times 10^{23}[/tex] atoms in 1.004 mol of arsenic

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.

To calculate the atoms, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given atoms}}{\text {avogadro's number}}[/tex]

[tex]1.004=\frac{x}{6.023\times 10^{23}}[/tex]

[tex]x=1.004\times 6.023\times 10^{23}=6.047\times 10^{23}[/tex]

Thus there are [tex]6.047\times 10^{23}[/tex] atoms in 1.004 mol of arsenic

Answer:

Each sample has the same number of molecules.

Explanation:

Just took the quiz on edge 2021

Taking into account the definition of Avogadro's number, each sample has the same number of molecules.

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole.

Avogadro's number applies to any substance.

Avogadro's number applies to any substance. This means that the number of molecules in 1 mol of oxygen is equal to the number of molecules in 1 mol of nitrogen.

Finally, the correct answer is the third option: each sample has the same number of molecules.

Learn more about Avogadro's Number:

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Answer:

by focal length of the eyepiece.

Explanation:

hope it helps!!plz mark as brainleist.

Answer:

Lithium sulphate (Li₂SO₄) and water (H₂O

Explanation:

H₂SO₄ + 2LiOH —> Li₂SO₄ + 2H₂O

The equation represented above indicates a neutralization reaction.

A neutralization reaction is a reaction involving acid and base which result in the production of salt and water.

In the equation above,

Reactant:

H₂SO₄ (acid)

LiOH (base)

Product:

Li₂SO₄ (salt)

H₂O (water)

Thus, lithium sulphate (Li₂SO₄) and water (H₂O) are the products of the reaction

Answer:

VALENCE ELECTRONS are involved in the bonding of atoms

Explanation:

Hope that helps

Answer:

it would become darker. there would be a higher level of water pressure. and there would be less animals, or different alimals.

Answer:

E) Plants take carbon from the atmosphere

Explanation:

Plants are a vital part in keeping the air clean. They take in CO2, H2O, and sunlight to start processing photosynthesis. The carbon taken in by the plant still remains with it after it dies, thus, fossil fuels.  

Answer:

e is correct

Explanation:

Answer:

fire

Explanation:

Answer:

ants if you splash a ant with sum water that shít is dead

Answer:

Between carbon and silicon, silicon element has the strongest attraction between its nucleus and its valence electrons.

because silicon's nucleus is bigger than carbon.silicon loses electrons easily than carbon.

Answer:

8.2

Explanation:

To solve this problem;

 The concentration of [H⁺]   = 6.8 x 10⁻⁹mol/L

So, we need to convert this to pH:

           pH  = -log [H⁺]

So;

          pH  = -log 6.8 x 10⁻⁹ = 8.2

Answer:

As Naphthalene undergoes sublimation, we use sublimation process. On condensing naphthalene can be separated.

Answer:

Buffalo and Watertown.

Explanation:

This is correct as the Interior lowlands are located ib the US. These are correct as the others are in the US but aren't located anywhere near the Interior Lowlands.

Answer:118

Explanation: it’s right

Answer:

118 elements

Hope that helps

Answer: [tex]Co+2Na_2S\rightarrow 4Na+CoS_2[/tex]

Explanation:

According to law of conservation of mass, mass can neither be created nor be destroyed. The atoms on the reactant side must be equal to the number of atoms on the product side so that the mass remains the same on reactant and product side. Thus the reactions are balanced.

Single displacement reaction is one where a more reactive element replaces the lesser reactive one.

The balanced chemical reaction will be:

[tex]Co+2Na_2S\rightarrow 4Na+CoS_2[/tex]

Answer:

1280L

Explanation:

Given parameters:

Initial pressure  = 0.727atm

Temperature  = 26.9°C

Initial volume  = 726mL  = 0.726L

New pressure  = 0.412atm

Unknown:

New volume of the gas sample  = ?

Solution:

To solve this problem, we apply boyles law;

            P1V1  = P2V2

P and V are pressure and temperature

1 and 2 are initial and new state

             0.727 x 0.726  = 0.412 x V2

                   V2  = 1.28mL  = 1280L

Answer:

1. Broadly, there are three different methods for how electricity is generated in the United States. They include; Fossil fuels, Nuclear energy, and Renewable energy sources.

2. Fossil fuels, are used the most, with Natural gas topping the list by 38%.

3. More should be invested into renewable gas. It is a clean source of energy and investing in it would bring about a cleaner and safer environment.

Explanation:

Fossil fuels arise from plants and animals that have been long dead and can can now be converted to sources of energy. Examples include; coal natural gas, crude oil. etc.  

Nuclear energy arises from the fission of uranium atoms, nuclear decay, and nuclear fusion. They are safe since green house gases are not emitted. Thermal energy can be generated as the byproduct of these reactions.

Renewable sources of energy are generated from natural sources which are always available. Examples are; sun, wind, biomass, water, and geothermal sources,

Answer:

detail is given below.

Explanation:

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

For example:

In given photosynthesis reaction:

6CO₂ + 6H₂O  → C₆H₁₂O₆ + 6O₂

The given equation is balanced chemical equation of photosynthesis. There are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.

If equation is not balanced,

CO₂ + H₂O  → C₆H₁₂O₆ + O₂

It can not follow the law of conservation of mass because mass is not equal on both side of equation.

Answer:

I think it would be Yellow

Answer:

Electrical and magnetic

You exert a gravitational force on the pupil and the pupil exerts an equal gravitational force on you. ... The size of the gravitational force depends on the mass of the objects involved. The greater the mass, the greater the gravitational force.

Explanation:

Answer:

0.55g/L

Explanation:

Given parameters;

Mass of salt  = 55g

Volume of water  = 100L

Unknown:

g/L concentration  = ?

Solution:

To solve this problem, we must understand that concentration is the amount of solute per solution

 g/L concentration  = [tex]\frac{55}{100}[/tex]   = 0.55g/L