Please help? It’s for chem

Answer:

Nuclear fusion of hydrogen to form helium occurs naturally in the sun and other stars. It takes place only at extremely high temperatures. That's because a great deal of energy is needed to overcome the force of repulsion between the positively charged nuclei.

Explanation:

hope it helps

Answer:

67.824

Explanation:  You want to use the combined gas law equation (P1*V1)/(n1*T1)=(P2*V2)/(n2*T2). So first cross out what remains constant, so volume(V) and I assume moles (since it was not mentioned as a change). Then you can solve algebraically for the answer!

Hope this helped!

The new pressure will be 139.2 kpa .

According to combined gas law,

[tex]\rm\dfrac{PV}{nT} = R[/tex]

In the Combined Gas Law,if we change either one of the variables the others will also change.

When the moles of the gas is constant , the above equation can be written as ,

[tex]\rm \dfrac{P'V'}{T'}= \dfrac{PV}{T}[/tex]

Given is P = 84kpa , T= 350⁰ C and T' = 350+230=580⁰ C , V=V' , P'=?

So we will substitute the values in the above formula keeping volume constant.

[tex]\rm \dfrac{P'}{T'}= \dfrac{P}{T}[/tex]

[tex]\rm\dfrac{P'}{580}= \dfrac{84}{350}[/tex]

[tex]\rm P' = \dfrac{84\times 580}{350}[/tex]

[tex]\rm P'= 139.2 \;kpa[/tex]

Therefore the new pressure will be 139.2 kpa .

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Explanation:

after learning more about the position and would

Answer:

Calculating Atomic Mass

Change each percent abundance into decimal form by dividing by 100. Multiply this value by the atomic mass of that isotope. Add together for each isotope to get the average atomic mass.

Explanation:

have a nice day

Answer:

mark me brainlest

Explanation:

Electronegativity values generally increase from left to right across the periodic table. Electronegativities generally decrease from top to bottom of a group. The highest electronegativity value is for fluorine.

Answer:

       "Electronegativity increases as you move from left to right across a period because the number of charges on the nucleus increases." (sstudy30 on Quizlet)

Explanation:

    It explains itself haha!

Have a nice day!

    I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)

- Heather

Answer: Place a piece of white paper under the analyte flask throughout the titration

Explanation:

The end point of titration can be made easy by the use of indicators. But we have to be keenly observe for each drop from the burette because, the colour change will be sudden for a drop.

Titration is an analytical technique used to determine the unknown concentration using a standard reagent of known concentration. The standard reagent of known concentration is called titrant and the  one to be determined is called analyte.

Usually analyte is taken in a conical flask and titrant in a burette. The end point of titration is the point at which the reaction is completed in perfect stoichiometry.

In acid-base titrations, the indicators used having different colors in different pH. Hence, the indicator in the analyte will change in color when the acidity of the medium changes. We have to observe keenly for the color change because it happens for any drop.

The adding of titrant from the burette must be dropwise and thus we can get a time to notice the sudden colour change of indicator.

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Answer:

[Xe] 6s2

Explanation:

hope it helps Electron configuration

Answer:

you did not give the specific heat like formula like it takes 1kj to raise 28grams of water by 10 grams

[tex]2\text{Cr(NO}_3\text{)}_3} + 3\text{CuCl}_2 \longrightarrow 2\text{CrCl}_3 + 3\text{Cu(NO}_3\text{)}_2[/tex]

Answer:

Reaction time tests can be used to assess an individual's hand-eye coordination. One test involves catching a 1 metre ruler and measuring the distance, d in metres, that the ruler travelled before being caught. The reaction time t seconds is then calculated using the formula: = √2d/9.8

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Metals have tendency to loose electrons in order to get noble gas configuration, therefore they loose electrons to form Cations (positively charged ions)

for example ~ Sodium forms Na+

And

Non - metals have tendency to gain electrons in order to attain noble gas configuration , hence they gain electron from somewhere and bears a negative charge forming Anion.

for example ~ Chlorine forms Cl-

Answer:

elements with low first ionization energies and positive or slightly negative electron affinities generally form cations.

hope it is helpful:)

Answer:

One arrow is positioned in each box according to Hund's Rule which tells us to maximise the number of unpaired electrons in orbitals of the same subshell, and, to give those electrons the same "spin" (parallel spin).

Explanation:

An observer in one of those galaxies see the other galaxy moving away at 400000 km/s.

Relative velocity is the velocity of an object with respect to another object, that is the time rate of change of relative position of one object with respect to another object.

Since two galaxy are moving in opposite directions with a velocity of 200,000 km/s. Hence the relative velocity between the two galaxies is 400000 km/s (200000 + 200000)

Therefore an observer in one of those galaxies see the other galaxy moving away at 400000 km/s.

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Answer:

D 400,000km/s

Explanation:

Answer:

Similar: both processes of cell division; both processes take place in the nucleus of the cell

Different: mitosis divides into 2, meiosis divides into 4; one is the division of body cells and the other is of specifically sex cells

Explanation:

https://byjus.com/biology/mitosis-and-meiosis/

^ this has more info!

Answer:

Test for carbon dioxide gas.

The reaction between baking soda and citric acid will form sodium ions, citric acid ions, carbon dioxide gas, and water. So all you have to do is add the gas produced (by gas displacement method or something) and test whether the gas is carbon dioxide, with lime water or other methods like hydrogencarbonate indicator. Hope this helped!

Explanation:

Answer:

depends on amount, but the reaction's endothermic (meaning its cold, absorbs heat from surroundings)

I hope it helps.

Answer:

I cannot tell yet

Explanation:

I don't take that class yet but ill get back to you

Answer:

The amount of force applied on an object that is moving in motion

Explanation:

In this exercise we want to calculate the amount of moles, so this is going to be:

[tex](4.6)(10^{-3}) \ mols \ CO_2[/tex]

Knowing that Henry's law is given by:

[tex]C = KHP[/tex]

Where constants are given by:

Before we can find the concentration of CO2 (and hence the moles of CO2), we first need to find its partial pressure.  We look up the vapor pressure of water at 25º and find it to be 0.03 atm.  Since the total pressure is equal to 0.1 atm, this mean the partial pressure of:

[tex]CO_2 = 0.1 \ atm - 0.03 \ atm = 0.07 \ atm[/tex]

Now using Henry's law, we find the concentration:

[tex]C = (0.033)*( 0.07) = (2.31)*(10^{-3})[/tex]

Converting to moles of CO2, we have:

[tex](2.31)*(10^{-3})*( 2) = (4.6)*(10^{-3})[/tex]

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Answer:

In chemistry: a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together.

Hope this helps :)

Answer:

5.57 x 10^24 atoms

Explanation:

first, you are seeking the number of ATOMS of Boron.

Boron has an Atomic mass of 10.8 g/mol (see #5 on the periodic table)

100 gm of Boron would have 100 g /10.8 g/mol =9.26 moles

each mole has Avogadros number of atoms 6.02 x 10^23

9.26 moles has 9.26 x 6.02 x 10^23 atoms =5.57 x 10^24 atoms

Answer:

c the answer is c that is the answer

The oxidation half equation is Zn ------> Zn^2+ + 2e while the reduction half equation is Cu^2+  + 2e------> Cu.

A redox reaction is a reaction in which there is a loss/gain of electrons. The specie that gives out electrons experiences an increase in oxidation number while the specie that gains the electrons experiences a decrease in oxidation number.

For the reaction; CuCl2 + Zn → ZnCl2 + Cu

The oxidation half equation is;

Zn ------> Zn^2+ + 2e

The reduction half equation is;

Cu^2+  + 2e------> Cu

The chloride ion is excluded because its oxidation number does not change from left to right in the reaction.

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This problem is referring to an anhydrous salt that is derive from a hydrated Epson salt (magnesium sulfate hydrate) and the atom economy is required. However, not enough information is provided, yet we can use the attached file as a reference to provide a methodology of calculation.

To begin with, we need to calculate the [tex]x[/tex] which refers to the degree of hydration of the salt, so that we use the mass before and after heating the sample to figure out the grams and subsequently moles of water that are in there:

[tex]m_w=3.648g-1.782g=1.866g\\\\n_w=0.103molH_2O[/tex]

Next, since 1.782g corresponds to the anhydrous salt, we calculate the moles in such a amount:

[tex]1.782gMgSO_4*\frac{1molMgSO_4}{120.4gMgSO_4}=0.0148mol[/tex]

Then, we divide the moles of water by those of the anhydrous salt to calculte [tex]x[/tex]:

[tex]x=\frac{0.103mol}{0.0148mol} =6.96=7[/tex]

This means the formula of the hydrate is:

[tex]MgSO_4\ 7H_2O[/tex]

Finally, for the atom economy we just divide the molar mass of the anhydrous salt by that of the hydrate:

[tex]A.E=\frac{120.4g/mol}{246.47g/mol} *100\%\\\\A.E=48.8\%[/tex]

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Answer:

Explanation:

Pencils are though formed of wood that acts as a bad conductor of electricity, quite strangely pencils can be electrically charged.

Here pencils have non-metal carbons present in its graphite tip and this makes the pencils charged.

When this pencil is held near the water of the tap, the hydrogen ions get attracted and thereby the water gets attracted to the pencil.

Water, however, is an excellent conductor of electricity and therefore water and electricity are a dangerous combination.

Answer:

Explanation:

They play a very important part. The geometry is not a straight line. It is an angle over 90 which means that the molecule has the same general shape as a boomerang. The two hydrogens and the 2 lone electron pairs try to get away as far as possible from each other. The actual shape results in a tetrahedron shape. But the two hydrogens and 1 oxygen actually look like the aforementioned boomerang.

The energy of the photon with a frequency of 9.50×10¹³ Hz is 6.29×10¯²⁰ J

From the question given above, the following data were obtained:

Frequency (f) = 9.50×10¹³ Hz

Planck's constant (h) = 6.626×10¯³⁴ Js

The energy of the photon can be obtained as follow:

E = hf

E = 6.626×10¯³⁴ × 9.50×10¹³

Therefore, the energy of the photon is 6.29×10¯²⁰ J

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