At STP, how many moles are in 0.880L of He gas?

Consider the elements in Group 14. Which element has the highest electron affinity? A) Carbon B) Germanium C) Lead D) Silicon

svlad2 [7]

Electron affinity is a measure of the tendency of a neutral atom to gain electrons and form a negative ion. It can be represented by a general equation:

X + e- → X-

The value of electron affinity decreases on moving down a group. This is because on moving down a group the atomic size increases as a result the added electron feels less pull or attraction towards the nucleus.

In group 14, Carbon 'C' is the first member and therefore will have the highest electron affinity.

Ans : A) Carbon

3 0

2 years ago

Three 1.0-l flasks, maintained at 308 k, are connected to each other with stopcocks. initially the stopcocks are closed. one of

Licemer1 [7]

Answer:

0.6103 atm.

Explanation:

We need to calculate the vapor pressure of each component after the stopcocks are opened.

Volume after the stopcocks are opened = 3.0 L.

1) For N₂:

P₁V₁ = P₂V₂

P₁ = 1.5 atm & V₁ = 1.0 L & V₂ = 3.0 L.

P₂ of N₂ = P₁V₁ / V₂ = (1.5 atm) (1.0 L) / (3.0 L) = 0.5 atm.

2) For H₂O:

Pressure of water at 308 K is 42.0 mmHg.

we need to convert from mmHg to atm: (1.0 atm = 760.0 mmHg).

P of H₂O = (1.0 atm x 42.0 mmHg) / (760.0 mmHg) = 0.0553 atm.

We must check if more 2.2 g of water is evaporated,

n = PV/RT = (0.0553 atm) (3.0 L) / (0.082 L.atm/mol.K) (308 K) = 0.00656 mole.

m = n x cmolar mass = (0.00656 mole) (18.0 g/mole) = 0.118 g.

It is lower than the mass of water in the flask (2.2 g).

3) For C₂H₅OH:

Pressure of C₂H₅OH at 308 K is 102.0 mmHg.

we need to convert from mmHg to atm: (1.0 atm = 760.0 mmHg).

P of C₂H₅OH = (1.0 atm x 102.0 mmHg) / (760.0 mmHg) = 0.13421 atm.

We must check if more 0.3 g of C₂H₅OH is evaporated,

n = PV/RT = (0.13421 atm) (3.0 L) / (0.082 L.atm/mol.K) (308 K) = 0.01594 mole.

m = n x molar mass = (0.01594 mole) (46.07 g/mole) = 0.7344 g.

It is more than the amount in the flask (0.3 g), so the pressure should be less than 0.13421 atm.

We have n = mass / molar mass = (0.30 g) / (46.07 g/mole) = 0.00651 mole.

So, P of C₂H₅OH = nRT / V = (0.00651 mole) (0.082 L.atm/mole.K) (308.0 K) / (3.0 L) = 0.055 atm.

So, total pressure = P of N₂ + P of H₂O + P of C₂H₅OH = 0.5 atm + 0.0553 atm + 0.055 atm = 0.6103 atm.

3 0

1 year ago

What volume, in ml, of a 0.2089 m ki solution contains enough ki to react exactly with the cu(no3)2 in 43.88 ml of a 0.3842 m so

Triss [41]

The reaction is given as: $2Cu(NO_{3})_{2}+4KI\rightarrow 2CuI+I_{2}+4KNO_{3}$ Here, two moles of copper nitrate reacts with four moles of potassium iodide to give two moles of copper iodide, one mole of iodine and four moles of potassium nitrate. First, calculate the number of moles of copper nitrate. Number of moles is equal to the product of molarity and volume of solution in litre. Number of moles = $0.3842 M\times 0.04388 L$ (1 L =1000 mL)

= $0.016858696 mole$

Copper nitrate requires = $0.016858696 \times \frac{4}{2}$ mole of potassium iodide

= $0.033717392 mole$ of potassium iodide

Volume of solution in litre = $\frac{number of moles}{Molarity}$

Thus, volume of potassium iodide is = $\frac{0.033717392}{0.2089}$

= $0.1614 L$

1 L =1000 mL

Volume of potassium iodide in mL = $161.4 mL$

Hence, $161.4 mL$ 0.2089 M potassium iodide consist of sufficient potassium iodide to react with copper nitrate in 3.88 mL of a 0.3842 M solution of copper nitrate .

7 0

1 year ago

Three moles of helium gas (molar mass MM = 4.00 g/molg/mol) are in a rigid container that keeps the volume of the gas constant.

Anastaziya [24]

Answer:

The rms speed of the gas atoms after 3600 J of heat energy is added to the gas = 1150 m/s.

Explanation:

Mass of 3 moles of Helium = 3 moles × 4.00 g/mol = 12.00 g = 0.012 kg

The initial average kinetic energy of the helium atoms = (1/2)(m)(u²)

where u = initial rms speed of the gas = 850 m/s

Initial average kinetic energy of the gas = (1/2)(0.012)(850²) = 4335 J

Then, 3600 J is added to the gas,

New kinetic energy of the gas = 4335 + 3600 = 7935 J

New kinetic energy of Helium atoms = (1/2)(m)(v²)

where v = final rms speed of the gas = ?

7935 = (1/2)(0.012)(v²)

v² = (7935×2)/0.012

v² = 1,322,500

v = 1150 m/s

Hence, the rms speed of the gas atoms after 3600 J of heat energy is added to the gas = 1150 m/s.

Hope this Helps!!!

8 0

1 year ago

What are characteristics of absorption spectra? Check all that apply.

Amanda [17]

The absorption spectrum is the result of absorption of light radiation by a material (solid or liquid) as a function of wavelength or frequency. The figure is shown below:

7 0

2 years ago