help me i’m crying right now

Answer: The percent yield of the reaction is 77.0 %

Explanation:

[tex]2Pb+O_2\rightarrow 2PbO[/tex]

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

[tex]\text{Number of moles of lead}=\frac{451.4g}{207.2g/mol}=2.18moles[/tex]

[tex]\text{Number of moles of lead oxide}=\frac{374.7g}{223.2g/mol}=1.68moles[/tex]

According to stoichiometry:

2 moles of [tex]Pb[/tex] produces = 2 moles of [tex]PbO_2[/tex]

2.18 moles of [tex]Pb[/tex] is produced by=[tex]\frac{2}{2}\times 2.18=2.18moles[/tex] of [tex]PbO_2[/tex]

Mass of [tex]PbO_2[/tex] =[tex]moles\times {\text {Molar mass}}=2.18\times 223.2g/mol=486.6[/tex]

percent yield =[tex]\frac{374.7g}{486.6g}\times 100=77.0\%[/tex]

Answer:

Germs stick to the oil on your hands, and washing with just water doesn't work because oil and water don't mix, but soap dislodges the germs and oil from your hands

Explanation:

Answer:

You need soap to wash the oil off your hands because oil and water don't mix well and makes it difficult to remove  

Explanation:

Answer:

It must have sunlight and water and neutrants and be fertilized

Explanation:

If we add water to a concentrated acid, then the solution may boil very violently, splashing concentrated acid. If add acid to water, the solution that forms is very dilute and a small amount of heat is released.

When a strong acid is poured into water, it flows down the flask and mixes much better, so no boiling takes place. The addition of water to acid forms an extremely concentrated solution of acid initially. A large amount of heat is released and the solution may boil very violently, splashing concentrated acid out of the beaker and all this because the reaction is exothermic in nature.

The reason this takes place is due to a large amount of energy liberated in the hydration reaction of concentrated ions. Therefore, we add acid to water dropwise for the dilution with constant stirring and not water to acid directly.

If we add water to acid, then an exothermic reaction occurs and the solution may boil very violently. To form the dilute solution of any strong acid, you should add acid to water and the small amount of heat released is not sufficient to vaporize and spatter it.

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Answer:

Well the answer of 1 and 3 is WRONG based on the 1 star review and the answer of 3 is wrong too I just took a test with this question.

Explanation:

Sorry...

Answer:

it's 6

Explanation:

I just took the test and got it right

C. Antarctica and Greenland

Answer:

M KOH = 0.61 M

V H2SO4 = 14.5 ml

M H2SO4 = 0.47 M

Volume KOH = ?

( V . M . valensi) KOH = (V . M . valensi) H2SO4

V . 0.61 . 1 = 0.47 . 14.5 . 2

V KOH = (0.47 . 14.5 . 2) / 0.61

V KOH = 22.34 ml

see more the answer at the pic

Answer:

This question is incomplete

Explanation:

However, when the carboxylic acids and esters put together are obtained, the procedure below can be followed in drawing and naming them.

For carboxylic acid,

1) it should be noted that the functional group here is -COOH which is drawn as -C = OH

      |

     OH

2) The carbon of the functional group is included among the carbon to be counted when naming the structure. For example, the compound below is propanoic acid.

CH₃CH₂COOH - As you can see that there are 3 carbons linked chain there.

3) As can be seen in (2) above, the suffix "oic" is used to name carboxylic acids

4) The carbon chain here is saturated (meaning there is no double or triple bond within the carbon chain)

Example of a structure of carboxylic acid is

H₃C - CH₂ - CH₂ - C = OH

                              |

                             OH

The structure above is a butanoic acid

For ester

1)The functional group here is -COO- . which can be drawn as

- C = O

   |

  O -

(meaning one oxygen atom is double bonded to the carbon and the other oxygen atom is bonded to another carbon chain)

2) The alkyl group attached to the oxygen atom is first of all mentioned before the carbon chain attached from the left is mentioned. For example, CH₃CH₂CH₂COOCH₂CH₃ is ethyl butanoate

3) As seen from (2) above, the suffix "oate" is used to end the name of esters

4) As also seen from (2) above, the carbon of the functional group is also included while counting the carbon chain of the parent name (butanoate).

5) The carbon chains here are also saturated.

Example of this ester is

CH₃CH₂C = O

              |

             O - CH₂CH₃

The name of this compound is ethyl propanoate

Answer:

A & B

Explanation:

The answer for the first one is A because the proton is found in the nucleus with the neutron

The answer for the second was is B because the Neutrons, protons and electrons are all subatomic particles, as they are the main particles that make up an atom.

Proton = Positive Charge (+)

Neutron = Neutral charge (=)

Electron = Negative Charge (-)

Answer:

1- positive

2- A

3-A

Explanation:

Answer:

Carbohydrates

Explanation:

Living things use carbohydrates as their main source of energy. The breakdown of sugars, such as glucose, supplies immediate energy for cell activities. Plants, some animals, and other organisms also use carbohydrates for structural purposes.

Answer:

35

Explanation:

Answer:

C. 30

Explanation:

Use APE

Atomic number = Protons = Electrons

30=30

There are total three laws of newtons, first law of newtons, second law of newton and third law of newton. Therefore, when a golf club is subjected to an imbalanced force, its velocity changes, which is according to newton’s second law.

According to Newton's Second Law of Motion, acceleration (gaining speed) occurs when a force acts on a mass (object). Riding a bicycle is a great example of this rule of motion in action. The mass is represented by your bicycle. The force is generated by your leg muscles pulling on the pedals of your bicycle.

The ball remains balanced on the tee due to the balanced forces of gravity downhill and upward. Force equals mass multiplied by acceleration (f=ma). When a golf club is subjected to an imbalanced force, its velocity changes.

Therefore, when a golf club is subjected to an imbalanced force, its velocity changes, which is according to newton’s second law.

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Answer:

D.All three graph lines peak over the same few weeks of winter.

Explanation:

took the test

Answer:

Methyl propyl ether protonates at oxygen, and this makes the oxygen a good leaving group for  [tex]SN2[/tex] attack by iodide ion which is a good nucleophile.

We are aware that  [tex]SN2[/tex] prefers 1 degree carbocation and here both methyl , propyl group is 1 degree.  

So we have two possible carbon atoms to react with iodide which are methyl group and  propyl group. They will react with iodide at similar rates, and so there is no great preference of one over the other.

As [tex]HI[/tex]  is present in excess the hydrogen of [tex]HI[/tex]  protonates the oxygen which leads to cleavage  that can happen on both sides either methyl or propyl side leading to different products.

The reaction proceeds in the manner

[tex]CH3-O-CH2CH2CH3[/tex]  + [tex]HI[/tex]   → CH3I + CH3CH2CH2OH

OR

[tex]CH3-O-CH2CH2CH3[/tex] + [tex]HI[/tex]   → CH3OH + CH3CH2CH2I

Answer:

I hope you do well on the test good luck

Explanation:

Answer:

The flask has to be closed during the hydrochloric acid and sodium carbonate reaction as the resultant gas got trapped inside the closed flask.

Explanation:

The hydrochloric acid and sodium carbonate reaction was exothermic that caused the pressure to decrease. The flask has to be closed during the hydrochloric acid and sodium carbonate reaction as the resultant gas got trapped inside the closed flask.

In exothermic reactions, energy is produced in the form of heat or light.

Answer:

D. Electron pairs repelling each other push atoms apart

Explanation:

Hope this helps :) I just got it wrong on ap3x so I'm sure this is right

The VSEPR theory explain molecular shape by stating that the Electron pairs repelling each other push atoms apart. Hence, Option (D) is correct

Valence shell electron pair repulsion (VSEPR) theory, is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.

It is also named the Gillespie-Nyholm theory after its two main developers, Ronald Gillespie and Ronald Nyholm.

Therefore, The VSEPR theory explain molecular shape by stating that the Electron pairs repelling each other push atoms apart. Hence, Option (D) is correct.

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Answer:

hope this helps you

Explanation:

Rejects New Methods: problem with peer review

Identifies sources of errors: reason for peer review

Directs funding: reason for peer review

Takes time: problem with peer review

Sometimes fails: problem with peer review

Answer:

Rejects new methods:  

✔ problem with peer review

Identifies sources of errors:  

✔ reason for peer review

Directs funding:  

✔ reason for peer review

Takes time:  

✔ problem with peer review

Sometimes fails:  

✔ problem with peer review

Explanation:

Answer:

Rock can bend and break

Explanation:

Btw I got it right

When stress builds faults, what happens is that: B. Rock can bend and break.

A rock can be defined as a solid naturally occurring landform that is made up of various minerals.

In Geology, stress can be defined as a force that acts on a rock per unit area.

There are four (4) main types of of stress associated with rocks and these are:

In conclusion, rocks can bend and break when stress builds up faults in them.

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Answer:

neutron

Explanation:

Neutron, neutral subatomic particle that is a constituent of every atomic nucleus except ordinary hydrogen. It has no electric charge

Answer:

neutrons

Explanation:

protons are positive and electrons are negative

Answer:

see the pic for more detail

The pH of the solution after the titration has been 1.318.

pH can be defined as the negative logarithmic values of the hydrogen ion concentration in the solution.

The remaining acid solution has been responsible for the pH of the solution.

The moles of acid can be given by:

Moles = Molarity × Volume

Moles of acetic acid = 0.1 M × 0.025 L

Moles of acetic acid = 0.0025 moles

Moles of NaOH = 0.1 M × 0.01 L

Moles of NaOH = 0.001 moles.

By the neutralization reaction, the moles of acid remaining has been:

Mole of acid remaining = Moles of acid - Moles of NaOH

Moles of acid remaining = 0.0025 - 0.001

Moles of acid remaining = 0.0015 moles.

The hydrogen ions liberated by the acetic acid have been equivalent to the moles of acetic acid.

Thus, the moles of hydrogen ions = 0.0015 mol.

The concentration of hydrogen ions has been:

Molarity = [tex]\rm \dfrac{moles}{volume\;(L)}[/tex]

Molarity of hydrogen ion = [tex]\rm \dfrac{0.0015}{0.025\;+\;0.01\lL}[/tex]

Molarity of the hydrogen ion has been = 0.0428 M.

The pH of the solution has been:

pH = -log [Hydrogen concentration]

pH = -log (0.0428)

pH = 1.318.

The pH of the solution after the titration has been 1.318.

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Answer: Spun yarn is made by twisting staple fibers together

To make a cohesive thread Or “single”. Twisting fibers, into yarn in the process called spinning can be dated back to the upper Paleolithic. Yarn spinning was one of the first processes to be industrialized.

Explanation:

Answer:

(3) sorry if I'm wrong

7.  (1-fertilization [sorry if wrong again]

8. (4-mitosis

Explanation:

I'm learning about this right now...Sorry if I'm wrong but I'm pretty sure they're right! Hope this helps tho! if I'm right maybe mark me brainliest?

Answer:

Alkali Metals

Explanation:

They're the most reactive elements in group one.

Answer: Sulfuric Acid

Explanation: correct on edg

Answer:

Sulfuric Acid

Explanation:

correct on edg

Hope this serves helpful to u!!

Hope this helps by the way as well

Good luck!!!

Answer:

Asteroids are made of rock, metals, and other elements. Some even contain water. Asteroids that are mostly stone sometimes are more likely to lose piles of rubble. Asteroids that are mostly iron are more rock-solid.

Explanation:

Answer:

asteriods are made of rocks.   asteroids that are mostly iron are more, well, rock-solid

Explanation: