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3 years ago

Help me please :3 :3 :3 ;3

Chemistry

2 answers:

jolli1 [7]3 years ago

7 0

I believe it would be A! -good vibes, and I hope you end up passing this test or homework assignment! (:

inna [77]3 years ago

6 0

A: because the light is lower than the hole, it will come in at in inclined angle. if the hole was say at the same level as the hole, it would shine straight to the other side of the box

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Two structures found in a plant cell but not in an animal cells are

morpeh [17]

Answer:

The plant cell has a cell wall, chloroplasts, plastids, and a central vacuole—structures not found in animal cells.

Explanation:

that is my answer

6 0

2 years ago

A sample of gas in a cylinder of volume 3.42 L at 298 K and 2.57 atm expands to 7.39 L by two different pathways. Path A is an i

lorasvet [3.4K]

Answer : The work done for path A and path B is -685.3 J and -478.1 J respectively.

Explanation :

To calculate the work done for path A :

First we have to calculate the moles of the gas.

$PV=nRT$

where,

$P_1$ = initial pressure of gas = 2.57 atm

$V_1$ = initial volume of gas = 3.42 L

n = moles of gas = ?

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

T = temperature of gas = 298 K

Now put all the given values in the above formula, we get:

$PV=nRT$

$(2.57atm)\times (3.42L)=n\times (0.0821atm.L/mol.K)\times (298K)$

$n=0.359mole$

According to the question, this is the case of isothermal reversible expansion of gas.

As per first law of thermodynamic,

$\Delta U=q+w$

where,

$\Delta U$ = internal energy

q = heat

w = work done

As we know that, the term internal energy is the depend on the temperature and the process is isothermal that means at constant temperature.

So, at constant temperature the internal energy is equal to zero.

$\Delta U=0$

$q=-w$

The expression used for work done will be,

$w=-nRT\ln (\frac{V_2}{V_1})$

where,

w = work done on the system = ?

n = number of moles of gas = 0.359 mole

R = gas constant = 8.314 J/mole K

T = temperature of gas = 298 K

$V_1$ = initial volume of gas = 3.42 L

$V_2$ = final volume of gas = 7.39 L

Now put all the given values in the above formula, we get :

$w=-0.359mole\times 8.314J/moleK\times 298K\times \ln (\frac{7.39L}{3.42L})$

$w=-685.3J$

Thus, the work done of path A is, -685.3 J

To calculate the work done for path B :

The formula used for isothermally irreversible expansion is :

$w=-p_{ext}dV\\\\w=-p_{ext}(V_2-V_1)$

where,

w = work done

$p_{ext}$ = external pressure = 1.19 atm

$V_1$ = initial volume of gas = 3.42 L

$V_2$ = final volume of gas = 7.39 L

Now put all the given values in the above formula, we get :

$w=-p_{ext}(V_2-V_1)$

$w=-(1.19atm)\times (7.39-3.42)L$

$w=-4.72L.atm=-4.72\times 101.3J=-478.1J$

Thus, the work done of path B is, -478.1 J

7 0

2 years ago

7. (1 point) Colligative properties are directly related to the ____. *

Hitman42 [59]

7. Colligative properties are directly related to the number of solute particles in a solution
8. chemical formula of sulfuric acid is H2SO4
9. the arhenius base in the choices is LiOH
10. A Lewis base is a substance that can donate a pair of electrons
14. basic
15. weak base

3 0

3 years ago

The__ contains all the elements l, arranged according to similarities in their properties

Inga [223]

It is the periodic table
* if helped you in anyway please be sure to leave a thanks :)

6 0

3 years ago

The molar mass of gallium (Ga) is 69.72 g/mol.

Thepotemich [5.8K]

Answer:

2.35 x 10²⁰ atoms Ga

Explanation:

After converting from mg to g, use the molar mass as the unit converter to convert to moles. Then using Avogadro's number, 6.022 x 10²³ convert from moles to atoms of Ga.

$27.2mgGa*\frac{1g}{1000mg} *\frac{1 mol Ga}{69.72gGa} *\frac{6.022*10^2^3 atoms Ga}{1 molGa} = 2.349 * 10^2^0 atoms Ga$

Then round to 3 significant figures = 2.35 x 10²⁰ atoms Ga.

6 0

3 years ago