Help please I don’t know

Answer:

Explanation:

Both plastic and gasoline are products of pretroleum

Answer: i think it is A

Explanation:

hope this helps!

The phrase that most accurately describes a chemical change is; "A change on the molecular level."

The major difference between a physical change and a chemical change is that a chemical change involves a change in the composition of a substance.

This implies that the atoms in a substance are rearranged during a chemical change.

This rearrangement of atoms corresponds to change on a molecular level.

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Answer: Science is a particular way of knowing about the world. In science, explanations are restricted to those that can be inferred from confirmable data—the results obtained through observations and experiments that can be substantiated by other scientists. Anything that can be observed or measured is amenable to scientific investigation. Explanations that cannot be based on empirical evidence are not a part of science.

Explanation:

Answer:

Modeling can help scientists study things that they can’t directly observe. Plesiosaurs no longer exist. So, scientists can’t directly see how they moved their flippers. However, they can use existing evidence—the fossil structures of plesiosaurs—to bring these organisms to life in a computer model.

Explanation:

Sample but you can reword

Question: ¿What is molar mass of C7H6O2?

Answer: 122,12 g/mol

IamSugarBee

Answer:

Heat transfer in the atmosphere from the equatorial regions to higher latitudes occurs through the process of Convection

Explanation:

The equatorial regions of the earth's surface receive the most heat from the sun than any other region of the earth. This is because the are most directly in line with the direct heat from the sun.

Due to this heat from the sun, atmospheric air around the equatorial regions are hot and less dense than air in regions of higher latitudes, and thus, rises above the equator. The rising air at the equator is replaced by colder and denser air from higher latitudes north and south of the equator. As the rising air of the equatorial regions are being replaced by colder and denser air from higher latitudes, the hot and humid air moves away from the equator, toward regions of higher latitude, north and south thereby setting up a convection current of heat flow.

Answer:

Yes

Explanation:

It is heating up both

Answer:

Temperature decreases and density increases

Explanation:

Let us remember that density of a material increases as the temperature of the material decreases. So the cooler a material becomes, the denser it becomes also.

Between points B and C, the material rapidly cools down and the temperature decreases accordingly. This ultimately results in an increase in density since cooler materials are denser than hot materials.

* Lab question: How can you distinguish a physical change from a chemical change?

> Format: How can you distinguish A from B?

Answer! Comparison: physical changes vs. chemical changes

Answer:

It would be C because its continuing to the next. It doesn't stop nor does it absorb anything.

Explanation: I hope this helps :) I'm only in 8th grade but this seems easy so if I am wrong I am soo sorry.

Answer:

ork out which of the displacement (S), initial velocity (U), acceleration (A) and time (T) you have to solve for final velocity (V).

If you have U, A and T, use V = U + AT.

If you have S, U and T, use V = 2(S/T) - U.

If you have S, U and A, use V = SQRT(U2 + 2AS)

Answer:

.......................................................

Explanation:

the word dozen and the number 12 that makes a dozen

Answer:

Below are some patterns in the charge for elements in each group.

Group 1 elements : 1 valence electron and form ions with charge +1

Group 2 elements : 2 valence electrons and form ions with charge + 2

Group 3 elements : 3 valence electrons and form ions with charge + 3(there are some exceptions as well)

Elements in groups 4 and 5 are unpredictable also the D block elements consist of multiple oxidation states..

Group 6 elements : 6 valence electrons, form ions with charge -2

Group 7 elements: 7 valence electrons, form ions with charge -1  

The octet rule is being followed, the elements form either ionic bond or covalent bond to fulfill it.

eg: when a K atom forms a K+ ion, the ion has the same electron configuration as the noble gas Ar (argon).

When an O atom gains 2 electrons to form the O²⁻ ion, the ion has the same electron configuration as the noble gas Ne (neon).  

Note: Boron (B) is in Group 3 but doesn't form ions.

A noticeable pattern in the charge for elements in each group of the periodic table is that: Elements in the same group have the same charge.

Discussion:

The pattern in the charge for elements in each group is characterized by the adoption of the same charge for elements in the same group irrespective of the period they are situated in.

An example is evident in the alkali metal, halogen and alkali Earth metals group.

The alkali metals lose their only Valence electron, to assume the octet configuration of the preceeding noble gas.

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Answer:

Increasing your concentration of negative ions is a very important way to improve your health for a variety of reasons. They work to increase serotonin levels in your body, which improves mood and balances your mental health, helping combat depression and anxiety.

Explanation:

Answer:

See explanation and image attached

Explanation:

Let us examine the statements in the question carefully. First of all, we will discover that the products of the E2 elimination of the both compounds are isomeric. However Y does not undergo SN2 reaction as  X does.

The fact that SN2 reaction does not occur in Y confirms that the bromine atom is attached to a tertiary carbon atom and SN2 reaction does not occur due to steric hinderance. Since X undergoes SN2 reaction in aprotic solvent, the chlorine atom must be attached to a secondary carbon atom.

However, E2 reactions does occur with tertiary alkyl halides when strong bases such as OH^- or RO^- are used.

The question also stated that the catalytic hydrogenation of Z affords 3-ethylpentane.

Putting all these together, the structures of X and Y have been suggested in the image attached to this answer.

Answer:

The answer is slightly above 0°C.

Explanation:

The ice melts and absorbs 330 J/g × 100 g = 33000 joules.

Cooling 400 g of water from 25°C to 0°C requires

4 J/K-g × 400 g × 25°C = 40000 joules

The heat taken to melt is almost enough to cool the water all of the way to 0°C.

The answer is slightly above 0°C.

Answer: D is the right answer  pls  make me brainliest

Explanation:

Answer:

1.1 mol H₂O

General Formulas and Concepts:

Chemistry

Explanation:

Step 1: Define

6.8 × 10²³ molecules H₂O

Step 2: Convert

[tex]6.8 \cdot 10^{23} \ mc \ H_2O(\frac{1 \ mol \ H_2O}{6.022 \cdot 10^{23} \ mc \ H_2O} )[/tex] = 1.12919 mol H₂O

Step 3: Check

We are given 2 sig figs. Follow sig fig rules.

1.12919 mol H₂O ≈ 1.1 mol H₂O

Answer:

Our final conversion is 1.1 moles of water.

Explanation:

When we want to find the amount of moles in a substance, we can use dimensional analysis or conversion factors in order to convert it from molecules, grams, atoms, formula units, or virtually any other unit.

We are given that we want to convert 6.8 x 10²³ molecules of water to moles. We can set up a dimensional analysis table to solve this.

In dimensional analysis, we multiply across the top and then divide the results by the multiplied value on the bottom.

[tex]\begin{tabular}{c|c}6.8 \times 10^{23} \ \text{molec. of water} & \text{1 mol H}_2 \text{O} \\ \cline{1-2} 1 & 6.022 \times 10^{23} \ \text{molec. of water} & \end{tabular}[/tex]

Now, we will perform our calculations and find our final answer.

[tex](6.8 \times 10^{23}) \times (1) = 6.8 \times 10^{23}[/tex]

[tex](1) \times (6.022 \times 10^{23}) = 6.022 \times 10^{23}[/tex]

[tex]\huge\frac{6.8 \times 10^{23}}{6.022 \times 10^{23}} = 1.129192959[/tex]

[tex]\text{Round to significant figures} \rightarrow 1.129192959 \approx 1.1[/tex]

Therefore, using our table, we have determined that our final answer is 1.1 moles of water.

[tex]\begin{tabular}{c|c}6.8 \times 10^{23} \ \text{molec. of water} & \text{1 mol H}_2 \text{O} \\ \cline{1-2} 1 & 6.022 \times 10^{23} \ \text{molec. of water} & \end{tabular} = 1.1 \text{moles of water}[/tex]

The question is incomplete, the complete question is;

Chris the Chemist was working in the lab, and he wanted to see what would happen if he put copper chloride into a Bunsen burner flame. As soon as he put it in the flame, it began to emit a green color. Which of these BEST describes this outcome?

A) The heat split the nucleus and created a new element.

B) As the copper chloride was heated, electrons were turned into neutrons.

C) As the electrons moved to a higher energy level, a photon of light is emitted.

D) When excited electrons return back to the ground state, a photon of light is emitted.

Answer:

D) When excited electrons return back to the ground state, a photon of light is emitted.

Explanation:

According to Bohr's model of the atom, electrons may absorb energy and move up to higher energy levels.

These electrons quickly return to ground state from such higher energy excited states thereby emitting the excess energy absorbed during excitation.

If the higher energy level is E2 and the ground state is E1 then the energy of the photon emitted when the electron descends from energy level E2 to E1 is;

ΔE = E2 - E1

This photon emitted accounts for the green colour of the copper salt observed when it was heated.

Answer:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶

Explanation:

Iron is soft, bright white metal.

Its symbol is Fe, atomic number is 26 and atomic mass is 55.85 amu.

It is present in group 8 of periodic table.

It is used to make the steel.

It is malleable and ductile used to make the sheets.

It is good conductor of heat and electricity because of moveable electrons that can easily move from one to another atom.

Its density is 7.87 g/cm³.

Electronic configuration:

Fe₂₃ = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶

Abbreviated electronic configuration:

Fe₂₃ = [Ar] 3d⁶4s²

Answer: D. a mixture

Explanation: When you mix different types of nuts or snacks together including raisins, hazelnuts, almonds, and peanuts to make some kind of trail mix, then you are creating a mixture, specifically a heterogeneous mixture.

Answer:

Wave

Explanation:

Answer:

0.282 M

General Formulas and Concepts:

Chemistry - Solutions

Explanation:

Step 1: Define

5.85 g KI

0.125 L

Step 2: Identify Conversions

Molar Mass of K - 39.10 g/mol

Molar Mass of I - 126.90 g/mol

Molar Mass of KI - 39.10 + 126.90 = 166 g/mol

Step 3: Convert

[tex]5.85 \ g \ KI(\frac{1 \ mol \ KI}{166 \ g \ KI} )[/tex] = 0.035241 mol KI

Step 4: Find Molarity

M = 0.035241 mol KI / 0.125 L

M = 0.281928

Step 5: Check

We are given 3 sig figs. Follow sig fig rules and round.

0.281928 M ≈ 0.282 M

Frequency and wavelength are inversely proportional to each other. The wave with the greatest frequency has the shortest wavelength. Twice the frequency means one-half the wavelength. For this reason, the wavelength ratio is the inverse of the frequency ratio.