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Answer:

12.5

Explanation:

After three half-lives, one eighth (1/2 x 1/2 x 1/2) of the uranium-238 will remain. One-eighth equals 12.5%

Answer:

No, We cannot change a gravitational field directly. Gravity is due or caused by the energy in objects with mass. ... Either way, once a particle, it is an object thus a source of gravitational potential.

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there are no current practical outer space applications of artificial gravity for humans due to concerns about the size and cost of a spacecraft necessary to produce a useful centripetal force comparable to the gravitational field strength on Earth.

Answer:

neutralization reaction

Explanation:

This reaction involve an acid (HCl) reacting with a base (NaOH), producing a salt (NaCl) and water. Therefore it's a neutralization reaction

When different atoms join together, they are called a compound. Compounds are made of molecules (so molecules could be an alternate answer, but not all molecules are compounds)

Answer:

it is compound

Explanation:

Two or more elements combined into one substance through a chemical reaction, such as water, form a chemical compound. All compounds are substances, but not all substances are compounds.

Answer:

Freezing

Explanation:

When a liquid goes to a solid, this process is called freezing.

Answer:

The water molecules get condensed and form a solid matter called ice. This process is called Condensation.

Answer:I’ll ask my teacher

Explanation:

Answer:

The answer would be work with.

Explanation:

Because, if we know what the word interact means then we can look for a word similar to interact. hope this makes sense <3.

Answer:

Explanation:

The formula for determining the energy of state [tex]m_l[/tex] can be computed by using the formula:

[tex]Em_i = \dfrac{m_1^2h^2}{2I}[/tex]

Also, the momentum is:

[tex]l_2 = m_i h[/tex]

There are 22 electrons with two electrons in each of the lowest II energy levels so that the highest occupied states are [tex]m_1 = \pm 5[/tex]

The moment of inertia of an electron on a ring of radius 440 ppm is:

[tex]I = mR^2 \\ \\ = 9.109 \times 10^{31} \ kg (440 \times 10^{-12}) ^2 \\ \\ = 1.76 \times 10^{-49} \ kgm^2[/tex]

[tex]E_{\pm 5 } = \dfrac{25h^2}{2I} \\ \\ = \mathbf{7.89 \times 10^{-19} \ J}[/tex]

The angular  momentum is:

[tex]l_2 = \pm 5h \\ \\ = \pm 5 \tiems ( 1.05457 \times 10^{-34} \ Js)[/tex]

[tex]= \mathbf{5.275 \times 10^{-34} \ Js}[/tex]

B) Let's recall that:

The lowest occupied energy level is [tex]m_1 = \pm 6[/tex] which implies that the energy  [tex]E_{\pm 6}= 1.14 \times 10^{-18} \ J[/tex]

Thus;

[tex]\Delta E = E_{\pm 6} - E_{\pm 5} \\ \\ = 1.14 \times 10^{-18 \ J} - 0.79 \times 10^{-18} \ J \\ \\ = 0.35 \times 10^{-18} \ J \\ \\ 0.35 \times 10^{-18} \ J = hv \\ \\ 0.35 \times 10^{-18} \ J = h \dfrac{c}{\lambda}[/tex]

Hence, the radiation which would induce a transition that relates to the wavelength of about 570nm, a wavelength of visible light.

Answer:

0.1029(rounded to sig figs)

Explanation:

convert from grams to moles

Amount in grams/molar mass of substance

Molar mass of Mg=24.305

So, 2.500/24.305=0.1028594939

Rounded to 0.1029

Answer: looking for improvements

Explanation:

Answer:

B. Looking for improvements

Explanation:

took the quiz and got in right on a pex

Answer:

A

I honestly think it's A, but I could be wrong. It might be B, but I don't think so.

Answer:

See explanation

Explanation:

In the periodic table, hydrogen is placed in group 1 for convenience. Hydrogen is not a metal, however, its common oxidation state is +1. It easily forms a univalent positive ion just like group 1 elements.

So, when hydrogen is combined with strongly electropositive metals such as sodium, lithium, etc, hydrogen accepts one electron and exhibits an oxidation state of -1 in those compounds.

Such compounds in which hydrogen is combined with strongly electropositive metals to give a binary compound is called a hydride.

Answer:A cook prepare a solution for boiling by adding 12.5g of NaCl to a pot holding 0.750L of water. ... 12.5g of NaCl to a pot holding 0.750L of water. At what temperature should the solution in the not boil? *. 1 ... Which of the following is best suited to be counted by moles a. roses in a store b. books in a library c.

Explanation:

Answer:

32.7

Explanation:

I just did it and got it right

Answer:

12.76 g

Explanation:

Step 1: Write the balanced equation

4 Fes + 7 O₂ ⇒ 2 Fe₂O₃ + 4 SO₂

Step 2: Calculate the moles corresponding to 11.15 g of O₂

The molar mass of O₂ is 32.00 g/mol.

11.15 g × 1 mol/32.00 g = 0.3484 mol

Step 3: Calculate the moles of SO₂ produced from 0.3484 moles of O₂

The molar ratio of O₂ to SO₂ is 7:4.

0.3484 mol O₂ × 4 mol SO₂/7 mol O₂ = 0.1991 mol SO₂

Step 4: Calculate the mass corresponding to 0.1991 moles of SO₂

The molar mass of SO₂ is 64.07 g/mol.

0.1991 mol × 64.07 g/mol = 12.76 g

Answer:

2) A catalyst is not consumed in the course of a reaction.

Explanation:

A catalyst is a substance which increases the rate of  chemical reaction and remains chemically unchanged at the end of the reaction.  The addition of a catalyst increases the rate of both reversible and irreversible reactions. including reversible reactions involving a final equilibrium state. In reversible reactions, catalysts speed up the time for equilibrium to be attained.

Considering the given statements about catalysts:

1) In an equilibrium process, a catalyst increases the rate of the forward reaction, but leaves the rate of the reverse reaction unchanged.

False: A catalyst increases both the forward and reverse reaction rates equally, thereby allowing the system to reach equilibrium faster.

2) A catalyst is not consumed in the course of a reaction.

True: Catalysts are substances that increase reaction rates without being consumed in the reaction.

3) A catalyst must be carefully chosen to shift the equilibrium toward products.

False: A catalyst does not affect the extent or position equilibrium of a reaction since a catalyst speeds up both the forward and back reactions by  equal amounts , rather it helps a reaction achieve equilibrium faster.

Explanation:

if they aren't in a solvent, then you magnetize first, to remove the iron fillings, secondly, you can sieve to separate the sand and pebbles

Separate the pebbles by either straining them out or pulling each one out separately with tweezers or your fingertips.

To separate their soil mixes using the tools you have supplied, ask the groups to develop a plan. They might consider using forceps to separate the soil, shaking it between two tumblers, placing it in a water-filled tumbler, or pouring it through air. Invite student groups to present their ideas.

Pbbles  - Separate the pebbles by either straining them out or pulling each one out separately with tweezers or your fingertips. As a strainer, a colander or a section of window screen works well. Iron fillings Using a magnet, it is simple to remove the tiny iron filings from the mixture.

Therefore, separate the pebbles by either straining them out or pulling each one out separately with tweezers or your fingertips.

To know more about separartion here:

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Answer:

they like smooth

Explanation:

Answer:

The lungs and respiratory system allow oxygen in the air to be taken into the body, while also letting the body get rid of carbon dioxide in the air breathed out. When you breathe in, the diaphragm moves downward toward the abdomen, and the rib muscles pull the ribs upward and outward.

Explanation:

The lungs and respiratory system allow oxygen in the air to be taken into the body, while also letting the body get rid of carbon dioxide in the air breathed out. When you breathe in, the diaphragm moves downward toward the abdomen, and the rib muscles pull the ribs upward and outward.

Answer:

D

Explanation:

balancing of chemical equations

Answer:

iron oxide. aka. oxygen

Explanation:

Rust is the result of a chemical reaction between iron and oxygen, otherwise known as iron oxide. Since steel wool -- and steel in general -- is largely made of iron, steel wool is prone to rust if it doesn't have a rustproof coating on it. The actual reaction that creates rust happens when two iron atoms mix with three oxygen atoms in water; the oxygen bonds to the metal, and a new compound is formed.

Answer:

3.55 x 10^23 molecules F2

Explanation:

molecules = moles x avogadro number

1 mole of gas occupies 22.4 L

moles of F2 = 13.2/22.4= 0.589 moles

moles F2 = 0.589 x 6.022 x 10^23 = 3.55 x 10^23 molecules F2

Answer:

Explanation:

Fossil fuels are hydrocarbons, namely, petroleum , coal and natural gas, formed from buried combustible geologic deposits of organic and natural materials. They are created from decayed animals and plants that convert into coal, crude oil or heavy oil due to constant exposure to pressure and heart in the earth’s crust.

The compounds that make up plankton and plants convert into fossil fuels. Plankton decomposes into natural gas and oil, while plants become coal. Nowadays, humans extract these resources through coal mining and the drilling of oil.

The term fossil fuel is defined as they are made from decomposing plants and animals. An example of a fossil fuel is coal, as well as oil and natural gas.

Because they were generated from the petrified, buried remains of plants and animals that once lived millions of years ago, coal, crude oil, and natural gas are all referred to as fossil fuels.

Thus, The remains of these animals underwent a transformation into what we now know as fossil fuels over millions of years at great pressure and high temperature.

To learn more about the fossil fuel, follow the link;

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Answer: The concentration of a benzene solution is 4.05 molal

Explanation:

Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.

[tex]Molality=\frac{n\times 1000}{W_s}[/tex]

where,

n = moles of solute

[tex]W_s[/tex] = weight of solvent in g

moles of [tex]C_6H_6[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{12.0g}{78g/mol}=0.154mol[/tex]

Now put all the given values in the formula of molality, we get

[tex]molality=\frac{0.154\times 1000}{38.0g}=4.05[/tex]  

Therefore, the concentration of a benzene solution is 4.05 molal