Concentrated hydrogen peroxide solutions are explosively decomposed by traces of transition metal ions (such as mn or fe): 2h2o2(aq) > 2h2o(l) + o2(g)
what volume of pure o2(g), collected at 27c and 746 torr, would be generated by decomposition of 125 g of a 50.0% by mass hydrogen peroxide solution?

23.0733 L

Explanation:

The mass of hydrogen peroxide present in 125 g of 50% of hydrogen peroxide solution:

Mass = 62.5 g

Molar mass of = 34 g/mol

The formula for the calculation of moles is shown below:

Thus, moles are:

Consider the given reaction as:

2 moles of hydrogen peroxide decomposes to give 1 mole of oxygen gas.

Also,

1 mole of hydrogen peroxide decomposes to give 1/2 mole of oxygen gas.

So,

1.8382 moles of hydrogen peroxide decomposes to give

So,

Pressure = 746 / 760 atm = 0.9816 atm

Temperature = 27 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15  

So,  

T₁ = (27 + 273.15) K = 300.15 K

Using ideal gas equation as:

PV=nRT

where,  

P is the pressure

V is the volume

n is the number of moles

T is the temperature  

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

0.9816 atm × V = 0.9191 mol × 0.0821 L.atm/K.mol × 300.15 K

⇒V = 23.0733 L

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.