The catalytic decomposition of hydrogen peroxide yields oxygen gas and water. in an experiment, decomposition of hydrogen peroxide yielded 75.3 ml of gas collected over water at 25°c and 742 torr. what mass of oxygen gas was collected?

The mass of oxygen collected is 0.0928 grams

Explanation:

Step 1: Data given

Yield of oxygen gas = 75.3 mL

Temperature = 25°C

Pressure = 742 torr = 0.976 atm

vapor pressure of water at 25 °C = 23.7695 torr = 0.0313 atm

Molecular weight of O2 = 32 g/mol

universal gas constant = 0.08206 L* atm / K* mol

Step 2: Calculate the vapor pressure (= pO2)

Ptotal + pO2 + pH2O

pO2 = ptotal -pH2O

pO2 = 0.976 atm - 0.0313 atm =  0.9447 atm

Step 3: Calculate moles O2:

p*V = n*R*T

⇒ p = the pressure of O2 = 0.9447 atm

⇒ V = the volume = 0.0753 L

⇒ n = the number of moles = TO BE DETERMINED

⇒ R= the gas constant = 0.08206 L*atm/K*mol ( 24 torr)

⇒ T = the temperature = 25°C = 298.15 Kelvin

n = (p*V)/(R*T)

n = (0.9447 atm * 0.0753 L) /(0.08206 l*atm/K*mol * 298.15 K)

number of moles = 0.0029 moles O2

Step 4: Calculate mass of O2

Mass O2 = moles O2 * Molar mass O2

Mass O2 = 0.0029 * 32 g/mol

Mass O2 =0.0928 grams

The mass of oxygen collected is 0.0928 grams

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.