Please help 25 points!!!​

Answer:

A. The total mass of materials present after a chemical reaction is the same as the total mass present before the reaction.

Explanation:

Law of conservation states that whatever mass you start with you will end with, mass cannot be gained or lost

Answer:

5.23 moles

Explanation:

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Answer:

alpha-linolenic acid and linoleic acid

Explanation:

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For this buffered solution with a pH of 7.5, B. The pH would become less than 7.0.

In Science, pH literally means the power of hydrogen ions and it can be defined as a measure of the molar concentration of hydrogen ions in a particular solution. Thus, it is typically used to specify the acidity, neutrality or basicity of any chemical solution.

On a pH scale, a solution with a pH of 7 is neutral while a solution with a pH below 7 is acidic and it's basic (alkaline) when its pH is above 7.

In this scenario, a buffered solution with a pH of 7.5 would become less than 7.0 when a small amount of acid is added to it.

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Answer:

Amount of Thermal Energy

Explanation:

Answer:

Nebula → Average Star → Red Giant → Planetary Nebula → White Dwarf

Nebula → Massive Star → Red Supergiant → Supernova → Neutron Star or Black Hole (for the second box)

-TheUnknownScientist 72

Answer:

top- nebula average star, reg giant, planetary nebula, white dwarf

bottom- nebula, massive star, red supergiant, supernova, neutron star-black dwarf

Answer:

that number formula units of mole that meansis You need to learn it on Yt

Example:

There are 6.022×1023 in 1 mole of anything, including formula units. You need to determine the number of moles in 0.335 g CaO . Once you know the number of moles of CaO , you can determine the number of formula units by multiplying the number of moles by 6.022×1023

The earth and other planets start drifting into space.

If the sun disappear from the universe, then Earth would be drawn to a new center of gravity. The gravity of Earth and the other planets of the solar system adversely affected due to no constant supply of energy from the sun which leads to drifting of earth into space.

In conclusion, the earth and other planets start drifting into space.

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Answer:

Are there any options or starting points for this question?

Explanation:

The equation that depicts a single replacement reaction would be: Zn(s) + 2HCl(aq)→ ZnCl2​​​(aq) ​​​​+ H2(g)

They are also known as single displacement reactions.

They are reactions in which one element takes the place of another in a compound. That is, one element replaces another in a compound.

Looking at all the reactions from A - D, one can see that the only reaction that exemplifies a single replacement reaction is D.

Here, Zn replaced H in HCl.

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Answer:

because of its electro affinity

Explanation:

it is electro positive

Answer:

14.28 [tex]cm^{2}[/tex]

Explanation:

Multiply length by width to get area: 3.4 x 4.2 = 14.28

The answer will be in units of cm x cm =  [tex]cm^{2}[/tex]

Answer:

it will decrease

Explanation:

Answer:

A. it will decrease

Explanation:

trust

The error of this scale measurement is equal to 0.02 kg.

Given the following data:

To calculate the error of the scale measurement:

Measurement can be defined as an act (process) through which the weight, size, magnitude or distance traveled by an object or body is taken, especially for the purpose of an experiment.

Mathematically, the error of a scale measurement is given by this formula:

[tex]Error = Actual \;measurement-Measured \;value[/tex]

Substituting the given parameters into the formula, we have;

[tex]Error = 5.00-4.98[/tex]

Error = 0.02 kg.

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Answer:

C12H6 : Molecular

C2H4O : Empirical

C8H8S4 : Molecular

Explanation:

Molecular formula : tells you the exact number of atoms of each element are in a compound. If the number of elements can be simplified it is molecular.

Empirical formula : tells you the most reduced ratio of elements in a compound. If the number of elements is already in it's simplest form it's likely empirical.

C12H6 - this is molecular because C12H6 can further be simplified to C2H

C2H4O - this is empirical because C2H4O cannot further be simplified

C8H8S4 - this is molecular because C8H8S4 can further be simplified to C2H2S

Answer:

C. Rock, dust, and ice.

Explanation:

Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices.

Answer:

stick together like magnets

Explanation:

Answer:

If a positively charged body is brought near to a neutral or uncharged body, it induces a negative charge on the near side and a positive charge on the far side of the neutral object. This creates a force of attraction between the two bodies.

Answer:

Sulfur

Explanation:

S+2e−→S2−

Answer:

in text

Explanation:

But the main reason for using pure nitrogen is resistance to leakage. Nitrogen molecules find it harder to sneak out through the tire past the rubber molecules than oxygen molecules. This makes nitrogen a good bet for race car, aircraft and heavy-duty equipment where precise or constant pressure is critical.

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Answer:

First Energy Level: 2

Second Energy Level: 8

Third Energy Level: 18

Fourth Energy Level: 18

Element: Iodine

Group: 17

No. of electrons/shell: 2, 8, 18, 18, 7

Answer:

Chemical reactions that absorb (or use) energy overall are called endothermic. In endothermic reactions, more energy is absorbed when the bonds in the reactants are broken than is released when new bonds are formed in the products.

Answer:

72.7%

Explanation:

The first thing you need to do here is to figure out the mass of oxygen in

1 mole of carbon dioxide. To do that, you must use the compound's molar mass.

Now, carbon dioxide has a molar mass of 44.01 g mol−1. This means that 1 mole of carbon dioxide has a mass of 44.01 g. Oxygen has a molar mass of 16.0 g mol−1, so 1 mole of oxygen atoms has a mass of 16.0 g.

This means that if you take 44.01 g of carbon dioxide, you know for a fact that it will contain: 32g oxygen.

This means that 100 g of carbon dioxide will contain:

100gCO2 × 32gO2 / 44.01gCO2 = 72.7 g Oxygen

Therefore, carbon dioxide has a percent composition of 72.7% oxygen, i.e. for every 100 gof carbon dioxide you get 72.7 g of oxygen.

The substances that have Delta Hf = 0 kJ/mol are O2(g), Br2(l), He(g), Fe(s).

Delta Hf = 0 is the standard enthalpy of any element in its most stable form is equal to zero.

When enthalpy is negative, the delta Hf is minus zero, which means the system releases heat.

When the system gains heat, the delta Hf is positive.

Thus, the substances are O2(g),  Br2(l), He(g), Fe(s).

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Answer:

1,4,5,6

Explanation:

The volume of the container will be 0.45L.

This law states that the product of volume and its pressure is constant for any gas.

Given, the Volume 1 of container 6.0L

V2 =?

Pressure 1 is 150 kPa

Increased pressure 2 is 2 atm

Temperature is constant.

By Boyle's law:

P1V1 = P2V2

[tex]150 \times 6 = 2\times V2 = 450[/tex]

Thus, V2 = 0.45 L.

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The mass of bromine that would be formed is 639 g

From the question,

We are to determine how many grams of bromine would be formed

First, we will write the balanced chemical equation for the reaction,

The balanced chemical equation for the reaction is

F₂ + 2HBr → 2HF + Br₂

This means, 1 mole of fluorine reacts with 2 moles of HBr to produce 1 mole of bromine.

Then,

4.00 moles of fluorine will react with excess HBr to produce 4.00 moles of bromine.

Therefore,

The number of moles of bromine produced is 4.00 moles

Now, for the mass of bromine formed,

Using the formula,

Mass = Number of moles × Molar mass

Molar mass of bromine = 159.808 g/mol

Then,

Mass of bromine formed = 4.00 × 159.808

Mass of bromine formed = 639.232 g

Mass of bromine formed ≅ 639 g

Hence, the mass of bromine that would be formed is 639 g.

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Answer:

The forensic scientist must be able to tell the difference between the substances.

Explanation:

It is important for forensic scientists to be able to identify particular drugs so they have evidence for the case that a certain drug was present.

The goal of forensic drug chemistry is to determine whether the material submitted contains an illegal substance.

Answer:

O Generation of electricity

Explanation:

because the others dont make sense to me and tbh carbon is used everyway and everywhere

Answer:

A) 4.65mol

Explanation:

[tex]\frac{2.80x10^{24}atoms }{1} *\frac{1 mol}{6.02x10^{23}atoms } =4.65mol[/tex]