Please help asap chemistry worksheet doesn’t make sense

Answer:

1.false

2.true

3.true

4.true

5.false

6.false

7.false

8.true

9.false

10.true

Explanation:

I took the test

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Answer:

B

Explanation:

Option B is the correct answer. When you add 7 in front of the O2 in the left side, and then you add 4 and 6 in front of NO2 and H2O respectively, the number of oxygen atoms is the same in both sides.

Answer:

Forged parts are often tougher than cast parts. This can be determined by performing tensile tests on various areas on the parts. Additionally, the microstructures of forged and cast parts can be used to determine if a part was forged or cast. The microstructure of a cast part will have a more uniform grain structure.

Explanation:

Answer:

Neon 10,  mass: 20.18

Explanation:

Using Hess's law we found:

1) By adding reaction 10.2 with the reverse of reaction 10.1 we get reaction 10.3:

KOH(aq) + HCl(aq)  → H₂O(l) + KCl(aq)   ΔH  (10.3)

2) The ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy (ΔH).    

The reactions of dissolution (10.1) and neutralization (10.2) are:

KOH(s) → KOH(aq)   ΔHsoln    (10.1)

KOH(s) + HCl(aq) → H₂O(l) + KCl(aq)     ΔHneut     (10.2)

1) According to Hess's law, the total change in enthalpy of a reaction resulting from differents changes in various reactions can be calculated as the sum of all the enthalpies of all those reactions.      

Hence, to get reaction 10.3:

KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq)    (10.3)

We need to add reaction 10.2 to the reverse of reaction 10.1

KOH(s) + HCl(aq) + KOH(aq) → H₂O(l) + KCl(aq) + KOH(s)

Canceling the KOH(s) from both sides, we get reaction 10.3:

KOH(aq) + HCl(aq)  → H₂O(l) + KCl(aq)    (10.3)

2) The change in enthalpy for reaction 10.3 can be calculated as the sum of the enthalpies ΔHsoln and ΔHneut:

[tex] \Delta H = \Delta H_{soln} + \Delta H_{neut} [/tex]

The enthalpy of reaction 10.1 (ΔHsoln) changed its sign when we reversed reaction 10.1, so:

[tex] \Delta H = \Delta H_{neut} - \Delta H_{soln} [/tex]

Therefore, the ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy ΔH.

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I hope it helps you!

Answer:

Explanation:

The required pressure can be found by using the formula for Boyle's law which is

[tex]P_2 = \frac{P_1V_1}{V_2} \\[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

From the question we have

[tex]P_2 = \frac{1 \times 196}{26} = \frac{196}{26} \\ = 7.538461...[/tex]

We have the final answer as

Hope this helps you

This  problem provides the molar mass and radius of a metal that has an BCC unit cell and the density is required.

Firstly, we consider the formula that relates molar mass and also includes the Avogadro's number and the volume of the unit cell:

[tex]\rho =\frac{Z*M}{V*N_A}[/tex]

Whereas Z stands for the number of atoms in the unit cell, M the molar mass, V the volume and NA the Avogadro's number. Next, since BCC is able to hold 2 atoms and M and NA are given, we calculate the volume of the atom in the unit cell given the radius in meters:

[tex]V=a^3=(\frac{4R}{\sqrt{3} } )^3=(\frac{4*1.74x10^{-10}m}{\sqrt{3} } )^3=6.49x10^{-29}m^3[/tex]

And finally the required density in g/cm³:

[tex]\rho =\frac{2*341.1g/mol}{6.49x10^{-29}m^3\frac{m^3}{atom} *6.022x10^{23}\frac{atom}{mol} } =17455257.8g/m^3\\\\\rho=17.5g/cm^3[/tex]

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Answer:

KNO2, KBr

Explanation:

Chemical compounds are any substance composed of identical molecules consisting of atoms of two or more chemical elements. So NO2 and KBr are compounds, Br2 and Fe are not.

Answer:

Explanation:

The actual boiling point is probably between 34C and 40C.

Temperature measures the average kinetic energy of particles of the substances. Therefore, the correct option is option D that is the actual boiling point is probably between 34°C and 40°C.

Temperature is used to measure degree or intensity of heat of a particular substance. Temperature is measured by an instrument called thermometer.

Temperature can be measured in degree Celsius °c, Kelvin k or in Fahrenheit. Temperature is a physical quantity. Heat always flow from higher temperature source to lower temperature source.

We can convert these units of temperature into one another. The relationship between degree Celsius and Fahrenheit can be expressed as:

°C={5(°F-32)}÷9

The actual boiling point is probably between 34°C and 40°C.

Therefore, the correct option is option D.

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Answer:

The Nucleus...

it perform many activities and stores DNA in a cell.

Answer:

The particles start moving faster and expand making the ball expand.

Explanation:

Answer:

i can't understand the question

Answer:

e

Explanation:

The energy taken in to break the bond is greater than the energy released after the bond is made therefore the reaction is endothermic.

A plot of energy against time is called a reaction profile. The hump in the plot is known as the activation energy of the reaction. It stands as the energy barrier between reactants and products.

Looking at the reaction profile as shown, we can see that more energy is taken in to break the bonds than energy that is given out after making the bonds hence the reaction is endothermic.

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Answer:

the answer is c

Explanation:

usa test prep says so!

Answer:

Tetrahedral molecules are normally spy hybridized.

Explanation:

Explanation:

frequency= velocity/ wavelength

= 340/1.36

=250

The number of moles of gas B present in the gas mixture is 2.72 moles.

The given parameters;

The total number of moles of the gases is calculated by applying ideal gas law;

PV = nRT

where;

R is ideal gas constant = 0.0821 L.atm./mol.K

n is the total mole of the gases

[tex]n =\frac{PV}{RT} \\\\n = \frac{8 \times 14}{0.0821 \times 323} \\\\n = 4.22 \ moles[/tex]

The number of moles of gas B is calculated as follows;

[tex]n_B = 4.22 - n_A\\\\n_B = 4.22 - 1.5\\\\n_B = 2.72 \ moles[/tex]

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Answer:

It is an unstable form of a chemical element that releases radiation as it breaks down and becomes more stable.

Answer:

go get the stuff.

Explanation:

Prior to writing the chemical formula of magnesium chloride, a question which any student will need to ask is: A.  What are the oxidation numbers of each atom?

A chemical formula can be defined as a scientific notation that is used to show (represent) the type and total number of atoms that constitute a particular chemical molecule or compound, by using the oxidation number, chemical symbols and subscripts.

Hence, a student would need to know the oxidation numbers of each atom when magnesium chloride is formed after a chemical reaction.

In Chemistry, an oxidation number represents the number of electrons gained or lost by an atom of a chemical element during a chemical reaction.

In conclusion, when magnesium chloride is formed, a question which the student will need to ask prior to writing the chemical formula is "what are the oxidation numbers of each atom?"

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Answer:

A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium.

Explanation:

While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position.

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hope this helped!

✼-answers by brookeangelx

The wave transmits energy from one point to another in the form of signals. Some waves require a medium for propagation while some others does not require a medium for the propagation.

The mechanical wave is defined as the wave which involves the oscillation of matter and it is responsible for the transfer of energy through a medium. These types of waves does not need a medium for propagation.

The mechanical waves cannot travel through vacuum. Some of the examples of mechanical waves are sound waves, water waves, seismic waves, etc. These waves are not capable of transmitting its energy through a vacuum.

The sound wave is a mechanical wave and the medium which it propagates can be solid, liquid or gas. It can travel fastest in solids and slower in gases.

Thus mechanical wave is an oscillation of matter.

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Answer: the answer is c.

Explanation:

i juss guessed and it was right?

Answer:

B

Explanation:

as temperature rises, the particles gain kinetic energy (they will move faster) so if temperatures stays constant, so will the movement or vibration of the particles

Answer:

im pretty sure its 2.7 gms

Explanation:

im not for sure tho

Answer:

During __asexual________ reproduction, an identical copy of the parent is produced.

Answer:

increase the number of gas particles

Explanation:

The reduction half equation of the galvanic cell is is;  3Cu2+(aq)  + 3e ------> 3Cu(s).

A galvanic cell is a cell that produces chemical energy by a spontaneous chemical reaction. The equation of the reaction is; 2Cr(s) + 3Cu2+(aq) → 2Cr3+ (aq) + 3Cu(s). We can see that chromium was oxidized and copper was reduced.

Since reduction occurs at the cathode, it follows that the reduction half equation is;  3Cu2+(aq)  + 3e ------> 3Cu(s).

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