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3 years ago

Suppose you were required to make a solution by diluting 20.0 mL of an aqueous solution to a final volume of 750 mL.

1 answer:

7 0

The first thing you do before performing anything in the laboratory is to read the procedure and prepare the materials needed. Next, if you already have the solution where you are supposed to take your 20 mL sample, then have it near you. Then, prepare a volumetric flask (750 mL) and a 20-mL pipette. Wash the pipette 3 times with the sample solution. If your diluent is water, wash the flask 3 times with water. Now, get 20 mL of sample from your parent solution, then add it to the flask (previously washed with water). Finally, add water until the mark in the flask and make sure that the water added is up to the mark based on the lower meniscus reading to be accurate in the amount inside the flask.

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An ideal gas contained in 5.0 liter chamber at a temperature of 37°C. If

kodGreya [7K]

Answer:

i am doing this in science also i would like to know if u know

Explanation:

8 0

3 years ago

If 11.0 g of ccl3f is enclosed in a 1.1 −l container, will any liquid be present?if so, what mass of liquid?

Anastasy [175]

Considering that CCL3F gas behave like an ideal gas then we can use the Ideal Gas Law
PV = nRT, however is an approximation and not the only way to resolve this problem with the given data..So,at the end of the solution I am posting some sources for further understanding and a expanded point of view. 

Data: P= 856torr, T = 300K, V= 1.1L, R = 62.36 L Torr / KMol 

Solving and substituting in the Gas equation for n = PV / RT = (856)(1.1L) /( 62.36)(300) = 0.05 Mol. This RESULT is of any gas. To tie it up to our gas we need to look for its molecular weight:MW of CCL3F = 137.7 gm/mol. 

Then : 0.05x 137.5 = 6.88gm of vapor 

If we sustract the vapor weight from the TOTAL weight of liquid we have: 11.5gm - 6.88gm = 4.62 gm of liquid.d

8 0

3 years ago

The mass of an object Is 45 kilograms. It’s weight on earth is—— newtons, and it’s weight on the moon is ——newtons. Gravitationa

Lina20 [59]

Answer:

The weight of the object on earth =441N

Weight of the object on moon = 72N

Explanation:

Weight of a body is the product of its mass and acceleration due to gravity. Acceleration due to gravity varies between planetary bodies. The acceleration due to gravity on earth is 9.8 m/s² while on moon is 1.6m/s² and it goes different for others too.

Weight = Mass * acceleration due to gravity

Weight(e) = weight on earth

Weight (m) = weight on moon

Weight(e) = 45 * 9.8 = 441N

Weight (m) = 45 * 1.6 = 72N

Weight of a body is measured in a unit called Newton(N)

8 0

4 years ago

The solid-state transition of Sn(gray) to Sn(white) is in equilibrium at 18.0 ˚C and 1.00 atm, with an entropy change of 8.8 J K

Vika [28.1K]

Answer:

Transition temperature = 13 C

Explanation:

ΔS(transition) = 8.8 J/K.mol

ρ(gray) = 5.75 g/cm³ = 5750 kg/m³

ρ(white) = 7.28 g/cm³ = 7280 kg/m³

ΔP = 100 atm = 100 x 101325 = 10132500 Pa

M(Sn) = 118.71g/mol = 118.71 x 10⁻³ kg/mol

T(i) = 18 C, T(f) = ?

We know that

G = H - TS, where G is the gibbs free energy, H is the enthalpy, T is the temperature and S is the entropy

H = V(m) x P, hence the equation becomes

G = V(m) x P - TS

The change in Gibbs free energy going from G(gray) to G(white) = 0 as no change of state takes place hence it can be said that

ΔG(gray) - ΔG(white) = 0

replacing the G with it formula shown above we can arrange the equation such as

0 = V(m)(gray) - V(m)(white) x ΔP - (ΔS(gray) - ΔS(white)) x ΔT

solving for ΔT we get

ΔT = {V(m)(gray) - V(m)(white) x ΔP}/(ΔS(gray) - ΔS(white))

ΔT = {M(Sn)(1/ρ(gray) - 1/ρ(white) x ΔP}/(ΔS(gray) - ΔS(white))

ΔT = {118.71 x 10⁻³ x {(1/5750) - (1/7280)} x 10132500}/(8.8)) = 5.0 C

ΔT = T(initial) - T(transition)

T(transition) = T(initial) - ΔT = 18 - 5 = 13 C

5 0

3 years ago

What is the wavelength in picometers for an electron with 360 eV of kinetic energy?

Rom4ik [11]

Answer:

Wavelength = 64.635 pm

Explanation:

The expression for the deBroglie wavelength and kinetic energy is:

$\lambda=\frac {h}{\sqrt{2\times m\times K.E.}}$

Where,

$\lambda$ is the deBroglie wavelength

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

m is the mass of electron having value $9.11\times 10^{-31}\ kg$

K.E. is the kinetic energy of the electron.

Given, K.E. = 360 eV

Energy in eV can be converted to energy in J as:

1 eV = 1.6022 × 10⁻¹⁹ J

So, K.E. = $360\times 1.6022\times 10^{-19}\ J=5.76792\times 10^{-17}\ J$

Applying in the equation as:

$\lambda=\frac {h}{\sqrt{2\times m\times K.E.}}$

$\lambda=\frac{6.626\times 10^{-34}}{\sqrt {{2\times 9.11\times 10^{-31}\times 5.76792\times 10^{-17}}}}\ m$

$\lambda=\frac{10^{-34}\times \:6.626}{\sqrt{10^{-48}\times \:105.0915024}}\ m$

$\lambda=6.4635\times 10^{-11}\ m$

Also, 1 m = 10¹² pm

So, Wavelength = 64.635 pm

4 0

4 years ago