What is the hydrogen concentration of a pH of 6.95, 7.25 and 8.1?

Answer:

D- 31.9988 g/mol

Explanation:

The molar mass of a substance is the mass in grams of one mole of the substance. For a compound, the molar mass is the gram - formula mass or gram - molecular weight. It is determined by the addition of its component atomic masses;

  To find molar mass of O₂;

      Atomic mass of O = 15.9994g/mol

 Molar mass of O₂ = 2(15.9994) = 31.9988g/mol

Answer:

1.133 kPa is the average pressure exerted by the molecules on the walls of the container.

Explanation:

Side of the cubic box = s = 20.0 cm

Volume of the box ,V=

Root mean square speed of the of helium molecule : 200m/s

The formula used for root mean square speed is:

where,

= root mean square speed

k = Boltzmann’s constant =

T = temperature = 370 K

M = mass helium =

= Avogadro’s number =

Moles of helium gas = n

Number of helium molecules = N =

N =

Ideal gas equation:

PV = nRT

Substitution of values of T and n from above :

(1 Pa = 0.001 kPa)

1.133 kPa is the average pressure exerted by the molecules on the walls of the container.

Final answer:

The question asks for the average pressure exerted by helium gas molecules on the walls of a cubic container. Using the equation PV = Nmv^2, we can calculate pressure by substituting the given values for volume, number of molecules, mass of one molecule, and root-mean-square speed.

Explanation:

The question is asking to calculate the average pressure exerted by helium gas molecules on the walls of a cubic container. The important formula relating pressure (P), volume (V), number of molecules (N), mass of a molecule (m), and the square of the rms speed (v2) of the molecules in a gas is:

PV = Nmv2,

First, we need to determine the volume of the container, which is the cube of one side, so V = (20 cm)3 = (0.2 m)3. Inserting the given values into the equation and solving for P gives us the desired answer. Recall that the rms speed is given, so no temperature calculations are needed.

Therefore, using all given data points:

Volume (V) = (0.2 m)3

Number of molecules (N) = 2.00 × 1023

Mass of one helium molecule (m) = 3.40 × 10-27 kg

Root-mean-square speed (vrms) = 200 m/s

By substituting these values, we can find the pressure exerted by the gas. This represents an application of kinetic theory of gases which assumes the behavior of an ideal gas.

Answer:

NONE OF THE ABOVE

Explanation:

None of the above are examples of an oxidation - reduction or a redox reaction . This is because there is no change in the oxidation state of any of the elements in the reaction when the reaction happens .

• For a redox reaction , transfer of electrons must take place.
• The oxidation states must increase or decrease in atleast 2 of the elements of a compound.
• For example :

⇒

Answer:

THE MOLARITY IS 2.22 MOL/DM3

Explanation:

The solution formed was as a result of dissolving 37.5 g of Na2S in 217 g of water

Relative molecular mass of Na2S = ( 23* 2 + 32) = 78 g/mol

Molarity in g/dm3 is the amount of the substance dissolved in 1000 g or 1 L of the solvent. So we have;

37.5 g of Na2S = 217 g of water

( 37.5 * 1000 / 217 ) g = 1000 g of water

So, 172.81 g/dm3 of the solution

So therefore, molarity in mol/dm3 = mol in g/dm3 / molar mass

Molarity = 172.81 g/dm3 / 78 g/mol

Molarity = 2.22 mol/dm3

The molarity of the solution is 2.22 mol/dm3

Answer:

The answer is 2.22mol

Explanation:

Among all three PCl₃, NO₃⁻ , I₃⁻, H₂Se only I₃⁻ will involve participation of d-orbitals in hybridization as bonding in I₃⁻ will include, s, p and d orbital as shown in the image attached. there will be sp³d hybridization, there will be presence of three lone pairs and 2 bonds as

I⁻ has 8 valence electrons and 2 neighbours atoms which will need one electron each to satisfy their valency.

so the number of electrons on central atom will be:

8-1-1=6

That 6 electrons will make 6/2 =3 lone pairs.